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Sample records for pvdf-co-ctfe-g-pssa graft copolymer

  1. Polyether/Polyester Graft Copolymers

    Science.gov (United States)

    Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

    1986-01-01

    Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

  2. Polyether-polyester graft copolymer

    Science.gov (United States)

    Bell, Vernon L. (Inventor)

    1987-01-01

    Described is a polyether graft polymer having improved solvent resistance and crystalline thermally reversible crosslinks. The copolymer is prepared by a novel process of anionic copolymerization. These polymers exhibit good solvent resistance and are well suited for aircraft parts. Previous aromatic polyethers, also known as polyphenylene oxides, have certain deficiencies which detract from their usefulness. These commercial polymers are often soluble in common solvents including the halocarbon and aromatic hydrocarbon types of paint thinners and removers. This limitation prevents the use of these polyethers in structural articles requiring frequent painting. In addition, the most popular commercially available polyether is a very high melting plastic. This makes it considerably more difficult to fabricate finished parts from this material. These problems are solved by providing an aromatic polyether graft copolymer with improved solvent resistance and crystalline thermally reversible crosslinks. The graft copolymer is formed by converting the carboxyl groups of a carboxylated polyphenylene oxide polymer to ionic carbonyl groups in a suitable solvent, reacting pivalolactone with the dissolved polymer, and adding acid to the solution to produce the graft copolymer.

  3. New Polytetrahydrofuran Graft Copolymers.

    Science.gov (United States)

    1979-03-15

    chioroprene) , chiorobutyl - ~~~~~ rubber , bromobutyl rubber , chlorinated EPDM , chlorinated poly(buta— diene) and chlorinated butadiene styrene copolymer...for initial detailed studies (3 ,4 , 6 , 7 — 9 ) . Many soluble metal salts with cations capable of stabilizing an on].um ion polymerization (SO3CF 3

  4. Adsorption of graft copolymers onto silica and titania.

    NARCIS (Netherlands)

    Bijsterbosch, H.D.; Cohen Stuart, M.A.; Fleer, G.J.

    1998-01-01

    The adsorption of graft copolymers of poly(acrylamide) (PAAm, backbone) and poly(ethylene oxide) (PEO, side chains) from aqueous solution onto silica and titania was studied with reflectometry. Two high-molar-mass copolymers were used with different PEO graft densities (10 and 18% w/w PEO in copolym

  5. Block and Graft Copolymers of Polyhydroxyalkanoates

    Science.gov (United States)

    Marchessault, Robert H.; Ravenelle, François; Kawada, Jumpei

    2004-03-01

    Polyhydroxyalkanoates (PHAs) were modified for diblock copolymer and graft polymer by catalyzed transesterification in the melt and by chemical synthesis to extend the side chains of the PHAs, and the polymers were studied by transmission electron microscopy (TEM) X-ray diffraction, thermal analysis and nuclear magnetic resonance (NMR). Catalyzed transesterification in the melt is used to produce diblock copolymers of poly[3-hydroxybutyrate] (PHB) and monomethoxy poly[ethylene glycol] (mPEG) in a one-step process. The resulting diblock copolymers are amphiphilic and self-assemble into sterically stabilized colloidal suspensions of PHB crystalline lamellae. Graft polymer was synthesized in a two-step chemical synthesis from biosynthesized poly[3-hydroxyoctanoate-co-3-hydroxyundecenoate] (PHOU) containing ca. 25 mol chains. 11-mercaptoundecanoic acid reacts with the side chain alkenes of PHOU by the radical addition creating thioether linkage with terminal carboxyl functionalities. The latter groups were subsequently transformed into the amide or ester linkage by tridecylamine or octadecanol, respectively, producing new graft polymers. The polymers have different physical properties than poly[3-hydroxyoctanoate] (PHO) which is the main component of the PHOU, such as non-stickiness and higher thermal stability. The combination of biosynthesis and chemical synthesis produces a hybrid thermoplastic elastomer with partial biodegradability.

  6. Sulfomethylated graft copolymers of xanthan gum and polyacrylamide

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, I.W.; Empey, R.A.; Racciato, J.S.

    1978-08-08

    A water-soluble anionic graft copolymer of xanthan gum and polyacrylamide is described in which at least part of the amide function of the acrylamide portion of the copolymer is sulfomethylated and the xanthan gum portion of the copolymer is unreacted with formaldehyde. The copolymer is sulfomethylated by reaction with formaldehyde and sodium metabisulfite. The formaldehyde does not cause any appreciable cross-linking between hydroxyl groups of the xanthan moieties. The sulfomethylation of the acrylamido group takes place at temperatures from 35 to 70 C. The pH is 10 or higher, typically from 12 to 13. The degree of anionic character may be varied by adjusting the molar ratio of formaldehyde and sodium metabisulfite with respect to the copolymer. 10 claims.

  7. Synthesis and properties of polystyrene/polydimethylsiloxane graft copolymers

    Institute of Scientific and Technical Information of China (English)

    Wu Ningjing; Huang Likan; Zheng Anna

    2006-01-01

    Polystyrene-graft-polydimethylsiloxane (PS-g-PDMS) copolymers with different PDMS content were synthesized by the radical bulk copolymerization of PDMS macromonomer and styrene.The copolymers were characterized by Fourier transform infrared (FT-IR),1H-nuclear magnetic resonance (NMR),thermogravimetric analysis (TGA),dynamic mechanical analysis (DMA),transmission electron microscopy (TEM) and the mechanical properties of the copolymers were also carried out.It was indicated that the notched impact strength and elongation at break of the polymers increased with the increase of PDMS content.The thermal stability of PS-g-PDMS is better than that of PS.

  8. Biodegradable nanoparticles made from polylactide-grafted dextran copolymers.

    Science.gov (United States)

    Nouvel, C; Raynaud, J; Marie, E; Dellacherie, E; Six, J-L; Durand, A

    2009-02-15

    Polysaccharide-covered polyester nanoparticles were prepared using the emulsion/solvent evaporation process. The core of the nanoparticles was made either of PLA or of a blend of polylactide and polylactide-grafted dextran copolymer in various proportions. The surface of the nanoparticles was covered by dextran chains via the use of water-soluble polylactide-grafted dextrans as polymeric stabilizers during the emulsification step. The characteristics of the nanoparticles (size, surface coverage, thickness of superficial layer, colloidal stability) were correlated to the structural parameters (length and number of polylactide grafts) of the copolymers as well as to their surface active properties. The complete biodegradability of the nanoparticles was evaluated by considering the rate of hydrolysis of polylactide grafts in phosphate buffer and the rate of enzymatic degradation of dextran backbone by dextranase.

  9. CHARACTERIZATION OF RADIATION GRAFT COPOLYMER OF INORGANIC COMPOUND ONTO ALKENE

    Institute of Scientific and Technical Information of China (English)

    ZhangWanxi; CheJitai; 等

    1995-01-01

    In this paper,the radiation graft copolymer of MgO,SiO2 and Y-molecular sieve onto organic compounds,such as methacrylate,styrene and acrylomitrile obtained by per-radiation method were characterized by X-ray diffraction,pyrolysis gas chromatography,GPC and X-ray photoelectron spectroscopy.

  10. Surface energies and self-assembly of block copolymers on grafted surfaces.

    Science.gov (United States)

    Trombly, David M; Pryamitsyn, Victor; Ganesan, Venkat

    2011-09-30

    We present a theoretical analysis of the self-assembly of diblock copolymers on surfaces grafted with random copolymers. Our results demonstrate that the surface energies of homopolymeric components on grafted surfaces differ from the corresponding values for self-assembled morphologies. Moreover, grafted random copolymers are shown to adapt their conformations in response to the morphology of the overlaying block copolymer film to create chemical inhomogeneities which modulate the interfacial interactions. Consequently, the surface energy differences between the different components on the grafted substrate do not serve as a useful measure to predict the stability of self-assembly of the diblock copolymer film.

  11. Novel block, graft and random copolymers for biomedical applications

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Jankova Atanasova, Katja; Tanaka, Masaru;

    roles for this [2]. An artificial lung (oxygenator), already in use, is coated with high MW PMEA prepared by radical polymerization with AIBN [2]. To broaden the possibilities for designing biomedical devices [3] and inspired from these findings we first prepared homo polymers of MEA and their block...... copolymers with MMA [4] utilizing ATRP. Here we present other block, graft and random copolymers of MEA intended for biomedical applications. These macromolecular architectures have been constructed by employing controlled radical polymerization methods such as RAFT and ATRP....

  12. Crystallization studies of polyethylene -poly(ethylene glycol) graft copolymers

    Science.gov (United States)

    Mark, P. R.; Hovey, G. E.; Murthy, N. S.; Breitenkamp, K.; Kade, M.; Emerick, T.

    2006-03-01

    Structure and crystallization behavior of three copolymers obtained by grafting poly (ethylene glycol) (PEG) chains to polyethylene (PE) main chain was investigated by variable temperature x-ray diffraction and thermal analysis. The results show that PEG side chains and PE main chains crystallize into separate domains. This is especially true when grafted chains are long (50 and 100 repeat units), in which the PEG domains are same as in PEG homopolymer both in structure and in melting behavior. In the copolymer with shorter chains (25 repeat units), the PEG crystals are not distinct and melting is broad. The PEG domains can be dissolved in water or ethanol without altering the mechanical integrity of the film. PE crystallites in both samples are similar to that in PE homopolymer. For instance, the thermal expansion of the basal cell plane (a- and b-axes) of the PE domains agrees well with that of PE homopolymer over the entire temperature range from ambient to melt. However, the chain-axis dimension PE-lattice in the copolymer is shorter by ˜ 0.05 å and the basal dimensions are larger by ˜ 0.05 å. The changes in these dimensions due to the changes in the length of the grafted PEG chains were investigated.

  13. Mechanical properties of designed multicompartment gels formed by ABC graft copolymers.

    Science.gov (United States)

    Jiang, Tao; Wang, Liquan; Lin, Jiaping

    2013-10-01

    In the present work, we designed a multicompartment gel by taking advantage of the ABC graft copolymer with a solvophilic A backbone and solvophobic B and C grafts. The mechanical properties of such designed gels were investigated by a combination of dissipative particle dynamics simulation and a nonequilibrium deformation technique. The extensional moduli of multicompartment gels were found to be dependent on polymer concentration and architectural parameters of the graft copolymers (the sequence of graft arms and the position of the graft points). The graft copolymer solutions undergo a sol-gel transition as the polymer concentration increases. This leads to an abrupt increase in the extensional modulus. The studies also revealed that the multicompartment gels of graft copolymers exhibit higher extensional moduli than those of nonmulticompartment gels of graft copolymers and triblock copolymer gels. The position of graft points plays another important role in determining the extensional moduli of the multicompartment gels. The effects of graft positions on the gel modulus were found to be associated with the bridging fraction of graft copolymer chains. The results gained through the present work may provide useful guidance for designing high-performance gels.

  14. POTENTIAL USE OF GRAFT COPOLYMERS OF MERCERIZED FLAX AS FILLER IN POLYSTYRENE COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    Susheel Kalia

    2008-11-01

    Full Text Available Graft copolymerization of binary vinyl monomers onto mercerized flax fiber was carried out for the enhancement of mechanical properties of polystyrene composites. Binary vinyl monomer mixture of AA+AN has been found to show maximum grafting (33.55% onto mercerized flax. Graft copolymers thus synthesized were characterized with FT-IR spectroscopy, SEM, and TGA techniques. Mercerized flax (MF showed maximum thermal stability in comparison to graft copolymers. It has been found that polystyrene composites reinforced with graft copolymers showed improvement in mechanical properties such as wear resistance, compressive strength, and tensile strength.

  15. Morphologies of A_2B Simple Graft Copolymer Blends: Copolymer/Copolymer and Copolymer/Homopolymer Systems to Further Elucidate the Stability of Simple Graft Phase Behavior

    Science.gov (United States)

    Lee, Chin; Pochan, Darrin; Gido, Samuel P.; Pispas, Stergios; Mays, Jimmy; Tan, Nora Beck; Trevino, Samuel

    1997-03-01

    The morphological behavior of two series of binary blends of A_2B simple graft block copolymers (A is polyisoprene and B is polystyrene) was characterized via transmission electron microscopy (TEM) and small-angle neutron scattering (SANS). Binary blends of A_2B samples with other A_2B samples of similar relative volume fractions were composed to map out the volume fraction window of stability of the randomly oriented worm phase, or ROW. This novel equilibrium phase behavior was found to occur in a neat A_2B sample with a B volume fraction of 0.81. At this unique composition the single B graft chain first becomes large enough to force the two A chains to the concave side of the AB interface in the microphase separated state. Another set of binary blends of A_2B samples was composed with the respective homopolymers in order to more rigorously determine the phase boundaries relative to volume fraction of the respective microphase separated morphologies in the A_2B systems.

  16. Anti-fouling ultrafiltration membrane prepared from polysulfone-graft-methyl acrylate copolymers by UV-induced grafting method.

    Science.gov (United States)

    Hua, Helin; Li, Na; Wu, Linlin; Zhong, Hui; Wu, Guangxial; Yuan, Zonghuan; Lin, Xiangwei; Tang, Lianyi

    2008-01-01

    Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV (Ultraviolet-visible) irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR), scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact angle on the membrane surface decreases with the increase of methyl acrylate graft degree, which indicated that the hydrophilicity of graft copolymer membranes was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copolymer membranes.

  17. Anhydric maleic functionalization and polyethylene glycol grafting of lactide-co-trimethylene carbonate copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Díaz, A.; Valle, L.; Franco, L. del [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Sarasua, J.R. [Department of Mining-Metallurgy Engineering and Materials Science, University of the Basque Country (UPV/EHU), Bilbao (Spain); Estrany, F. [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Puiggalí, J., E-mail: Jordi.Puiggali@upc.es [Department of Mining-Metallurgy Engineering and Materials Science, University of the Basque Country (UPV/EHU), Bilbao (Spain)

    2014-09-01

    Lactide and trimethylene carbonate copolymers were successfully grafted with polyethylene glycol via previous functionalization with maleic anhydride and using N,N′-diisopropylcarbodiimide as condensing agent. Maleinization led to moderate polymer degradation. Specifically, the weight average molecular weight decreased from 36,200 to 30,200 g/mol for the copolymer having 20 mol% of trimethylene carbonate units. Copolymers were characterized by differential scanning calorimetry, thermogravimetry and X-ray diffraction. Morphology of spherulites and lamellar crystals was evaluated with optical and atomic force microscopies, respectively. The studied copolymers were able to crystallize despite the randomness caused by the trimethylene carbonate units and the lateral groups. Contact angle measurements indicated that PEG grafted copolymers were more hydrophilic than parent copolymers. This feature justified that enzymatic degradation in lipase medium and proliferation of both epithelial-like and fibroblast-like cells were enhanced. Grafted copolymers were appropriate to prepare regular drug loaded microspheres by the oil-in-water emulsion method. Triclosan release from loaded microspheres was evaluated in two media. - Highlights: • Pegylated copolymers of lactide and trimethylene carbonate have been synthesized. • Grafting with polyethylene glycol was able via maleic anhydride functionalization. • Drug-loaded microspheres could be prepared from new pegylated copolymers. • Hydrophilicity of lactide/trimethylene carbonate copolymers increased by pegylation. • New pegylated copolymers supported cell adhesion and proliferation.

  18. Preparation and Mechanical Properties of Solid-phase Grafting Nanocomposites of PVC/Graft Copolymers/MMT

    Institute of Scientific and Technical Information of China (English)

    ZHOU Dunbai; CAI Changgen; JIA Demin

    2006-01-01

    In order to improve the mechanical properties of PVC, by solid-phase grafting reaction, grafting on and nano-modifying the PVC process synchronously, acrylic monomers not only graft on PVC, but also are intercalated into the layers of MMT in the heating process. Blending PVC and the MMT-PVC grafting copolymers, we can get nanocomposites of PVC/ grafters/ MMT, and the mechanical performance of the material is improved.

  19. Effect of cationic grafted copolymer structure on the encapsulation of bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Nicholas [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Topal, Ç. Özge [School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Hikkaduwa Koralege, Rangika S. [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Hartson, Steve [Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078 (United States); Ranjan, Ashish; Liu, Jing; Pope, Carey [Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078 (United States); Ramsey, Joshua D., E-mail: josh.ramsey@okstate.edu [School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

    2016-05-01

    The aim of the present study was to evaluate a library of poly-L-lysine (PLL)-graft (g)-polyethylene glycol (PEG) copolymers for the ability to encapsulate effectively a model protein, bovine serum albumin (BSA), and to characterize the stability and protein function of the resulting nanoparticle. A library of nine grafted copolymers was produced by varying PLL molecular weight and PEG grafting ratio. Electrostatic self-assembly of the protein and the grafted copolymer drove encapsulation. The formation of protein/polymer nanoparticles with a core/shell structure was confirmed using PAGE, dynamic light scattering, and electron microscopy. Encapsulation of the BSA into nanoparticles was strongly dependent on the copolymer-to-protein mass ratio, PEG grafting ratio, and PLL molecular weight. A copolymer-to-protein mass ratio of 7:1 and higher was generally required for high levels of encapsulation, and under these conditions, no loss of protein activity was observed. Copolymer characteristics also influenced nanoparticle resistance to polyanions and protease degradation. The results indicate that a copolymer of 15–30 kDa PLL, with a PEG grafting ratio of 10:1, is most promising for protein delivery. - Highlights: • A 4–70 kDa range of PLL-g-PEG copolymers was able to encapsulate BSA into NPs. • Encapsulation of BSA by PLL-g-PEG not only retained but increased esterolytic activity. • NPs were stable against protease degradation and polyanion dissociation.

  20. Assembly of diblock copolymer grafted nanoparticles in a homopolymer blend matrix

    Science.gov (United States)

    Estridge, Cara; Jayaraman, Arthi

    2014-03-01

    Hybrid materials comprised of nanoscale fillers embedded in a polymer matrix, also terms polymer nanocomposites, are used in many applications, such as photovoltaics, photonics, automobile parts, where their macroscopic properties are governed by the nanocomposite morphology. The structure and composite morphology is controlled by the interactions of the nanoscale fillers and the polymer matrix. In this talk we show using molecular simulations that functionalization of the nanoparticle surface with AB diblock copolymer grafts is a way to tune the interactions between the grafted particle and the A and B homopolymer blend matrix. Specifically, our work demonstrates that by tailoring the copolymer composition and the copolymer grafting density one can tune the location of the copolymer grafted particles in the matrix, (e.g. within a domain versus interface of two domains). Additionally, in the case where the grafted particles locate themselves at the interface between the two domains, the interfacial tension is reduced below that possible with bare ungrafted particles at the interface.

  1. SYNTHESIS AND CHARACTERIZATION OF REACTIVE GRAFT COPOLYMER PDMS-g- (PEO-OH)

    Institute of Scientific and Technical Information of China (English)

    QIU Yongxing; YU Xiaojie; FENG Lingxian

    1995-01-01

    A new reactive graft copolymer, poly (dimethyl siloxane)-graft-ω-hydroxyl-poly (ethylene oxide) (PDMS-g-(PEO-OH)), was synthesized by the hydrosilylation reaction of α, ω-bifunctional PEO macromonomer (CH2=CH-CH2-PEO-OH) with poly (hydromethylsiloxane) (PHMS). The obtained copolymer, exhibited the expected comblike structure as indicated by the result of detailed characterization and the needed reactivity as demonstrated by the result of esterification between PDMS-g-(PEO-OH)and aminoacetic acid. This reactive graft copolymer is expected to be very useful in the preparation of new bioactive polymer materials.

  2. Anti-fouling ultrafiltration membrane prepared from polysulfone-graft-methyl acrylate copolymers by UV-induced grafting method

    Institute of Scientific and Technical Information of China (English)

    HUA Helin; LI Na; WU Linlin; ZHONG Hui; WU Guangxia; YUAN Zonghuan; LIN Xiangwei; TANG Lianyi

    2008-01-01

    Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV(Ultraviolet-visible)irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy(ATR/FT-IR), scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact allgle on the membrane surface decreases with the increase of methyl acrylate graftdegree. which indicated that the hydrophilicity of graft copolymer membranes Was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copoly mermembranes.

  3. STUDIES ON GRAFT COPOLYMERIZATION OF DL—LACTIDE ON CORN STARCH AND BIODEGRADABILITY OF THE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    YOUYingcai; ZHUChangying; 等

    2000-01-01

    The starch/D,L-lactide graft copolymers were synthesized by reacting D,L-lactide with corn starch in N,N-dimethylacetamide(DMAM)in the presence of triethylamine(NEt3)and anhydrous lithium chloride.The effect of reaction time and the molar ratio of D,L-lactide to glucose structural unit of starch on monomer conversion(C%),graft(G%)and graft efficiency(GE%)were studied,The C%,G%and GE% could approach 37.3% 179.7%and 68.0%,respectively when the molar ratio of D,L-lactide to glucose structuralunit of starch is 10:1 and the graft copolymerization was carried out at 80-85℃ for 4hr under nitrogen atmosphere.The Fourier transforms infra-red (FTIR) spectroscopy.differential scanning calorimetry(DSC)and X_ray diffraction (XRD) spectroscopy were used in order to characterize the graft copolymers.FTIR spectra show that absorption band at 1740cm-1 confirmed the formation of ester bond,indicating the starch /D,L-lactide graft copolymers were produced,the DSC characteristic results show the melting temperature of the graft copolymer were elevated slightly as the molar ratio of D,L-lactide to glucose structural units of starch increased and the X-ray diffraction spectra show the synthesized graft copolymers were amorphous.The degradability of graft copolymer was tested with the aid of acid,alkali and microbe such as bacillus subtilis and staphylococcus aureus.The results of water rsistance show the graft copolymer produced can be used as a component of impermeable coating for cardboard.

  4. Synthesis and Characterization of Graft Copolymer of Dextran and 2-Acrylamido-2-methylpropane Sulphonic Acid

    Directory of Open Access Journals (Sweden)

    Venkanna Azmeera

    2012-01-01

    Full Text Available A novel biodegradable graft copolymer of dextran (Dx and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS was synthesized by grafting poly-AMPS chains onto dextran backbone by free radical polymerization using ceric ammonium nitrate (CAN as an initiator. Different amounts of AMPS were used to synthesize four different grades of graft copolymers with different side chain lengths. These grafted polymers were characterized by elemental analysis, FTIR, 1HNMR, rheological technique, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and X-ray diffractometry (XRD. They exhibited efficient flocculation performance in kaolin suspension.

  5. Effect of the structure of ethylene-propylene-diene-graft-polystyrene graft copolymers on morphology and mechanical properties of SAN/EPDM blends

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available Ethylene-propylene-diene-graft-polystyrene (EPDM-g-PS copolymers were synthesized to obtain different structures of graft copolymers with different graft lengths and graft densities. The structure of synthesized EPDM-g-PS copolymers was characterized by gel permeation chromatography (GPC and by Fourier transforms infrared spectroscopy (FTIR. These presynthesized graft copolymers were added (5 phr to styrene-acrylonitrile (SAN and ethylene-propylene-diene (EPDM blends, prepared to maintain the following SAN/EPDM ratios a 95/5 and b 90/10. SAN/EPDM blends were characterized by the determination of mechanical properties (tensile strength, elongation at break while their morphology was inspected by scanning electronic microscopy, SEM. The obtained results show that various structures of EPDM-g-PS copolymers influence the miscibility in SAN/EPDM blends. Optimal concentration of side branches of graft copolymers provide the finest morphology and enhance mechanical properties.

  6. Flocculation of chromite ore fines suspension using polysaccharide based graft copolymers

    Indian Academy of Sciences (India)

    N C Karmakar; B S Sastry; R P Singh

    2002-11-01

    Graft copolymers are being experimented at the laboratory scale as flocculants. All the four graft copolymers, viz. starch--polyacrylamide, amylopectin--polyacrylamide, sodium alginate--polyacylamide and carboxymethyl cellulose--polyacrylamide performed well as flocculants on chromite ore fines suspension. Amylopectin--polyacrylamide, in particular, performed superior to the rest of the series from the point of view of settling velocity of flocs which is the most important aspect in solid–liquid separation.

  7. Formation of polymer vesicles by amphiphilic fluorosiloxane graft copolymers in solution

    Institute of Scientific and Technical Information of China (English)

    Rui Gang Hou; Ling Min Yi; He Ming Lin; Jia Wei Li; Chuan Xia Huang

    2011-01-01

    Amphiphilic fluorosiloxane graft copolymers with a poly(dimethylsiloxane) (PDMS) backbone, a hydrophobic fluorosiloxane side-chain and three hydrophilic polyether side-chains were synthesized by hydrosilation reaction in this work. The micellization of amphiphilic graft copolymers in the water/ethanol solvent system was investigated, and vesicles with different size were formed after the self-assembly system was aged for different time.

  8. Synthesis and characterization of a new type of levan-graft-polystyrene copolymer.

    Science.gov (United States)

    Kekez, Branka; Gojgić-Cvijović, Gordana; Jakovljević, Dragica; Pavlović, Vladimir; Beškoski, Vladimir; Popović, Aleksandar; Vrvić, Miroslav M; Nikolić, Vladimir

    2016-12-10

    Novel macromolecular graft copolymers were synthesized by reaction of the hydroxyl groups of the microbial polysaccharide levan, produced using Bacillus licheniformis, with polystyrene (Lev-g-PS). Synthesis was performed by the free radical reaction using potassium persulfate (PPS) as initiator. The prepared copolymer was characterized by FTIR, SEM, TG/DTA, XRD and (13)C NMR. The influence of the different conditions (reaction temperature, air or nitrogen atmosphere, reaction time, type of amines and ascorbic acid (AA) concentration) on the grafting reaction was investigated. Results showed that maximum percentage of grafting (58.1%) was achieved at a reaction temperature 70°C, in a nitrogen atmosphere and using dimethylethanolamine (DMEA) as the amine activator. On the basis of the obtained results, the likely reaction mechanism was proposed. Synthesized copolymers have better thermal stability in comparison with their initial components. Copolymers such as Lev-g-PS could potentially have many applications, such as compatibilizers and material for membranes.

  9. Preparation of starch-sodium lignosulfonate graft copolymers via laccase catalysis and characterization of antioxidant activity

    Science.gov (United States)

    Graft copolymers of waxy maize starch and sodium lignosulfonate (SLS) were prepared by Trametes Versicolor laccase catalysis in aqueous solution. Amount of SLS grafted based on phenol analysis was 0.5% and 1.0% in the absence and presence of 1-hydroxybenzotriazole (HBT), respectively. Starch-SLS gra...

  10. Effect of various initiators on molar mass determination of hydrolyzed potato starch-acrylamide graft copolymers

    Directory of Open Access Journals (Sweden)

    Đorđević Suzana

    2013-01-01

    Full Text Available This study is concerned with synthesis, characterization and properties of graft copolymer produced from hydrolyzed potato starch and acrylamide using various initiators (azobisisobutyronitrile, potassium persulfate and benzoyl peroxide. Starch hydrolysis was performed in order to reduce molecular mass. Acrylamide was grafted on shorter starch macromolecules creating side branches on the main chain resulting in a product that could be used in textile finishing more successfully. Various initiators were used, primarily, to produce graft monomer on the starch and also to obtain thinner or thicker packaging of side chains that can have a great influence on the behavior of textile yarns impregnated with these copolymers. Benzoyl peroxide, as initiator, proved to be very successful in grafting of acrylamide on hydrolyzed starch, in terms of yield, graft percentage and efficiency results. Grafting in the presence of azobisisobutyronitrile and potassium persulfate as initiators has slightly better monomer to polymer conversion values. FTIR spectra of hydrolyzed and grafted starch confirm by their characteristic bands that grafting was successful. Residual amounts of monomer in copolymer and molar mass distribution were determined by chromatography. Results show that the highest quantity of monomer is found in the sample of hydrolyzed starch grafted in the presence of potassium persulfate. Molar masses of hydrolysate and copolymer show differences ranging from 1∙102 to 2∙107 g/mol. Results of sizing using grafted starch show that sized yarns had higher strength (tenacity and lower elongation. Grafted hydrolyzed starch, as an agent for cotton yarn sizing, gives better results than non grafted starch, especially regarding sizing uniformity, yarn mechanical parameters and easier removal in following desizing process.

  11. Graft Copolymers of Maleic Anhydride and Its Isostructural Analogues: High Performance Engineering Materials

    CERN Document Server

    Rzayev, Zakir M O

    2011-01-01

    This review summarizes the main advances published over the last 15 years outlining the different methods of grafting, including reactive extruder systems, surface modification, grafting and graft copolymerization of synthetic and natural polymers with maleic anhydride and its isostructural analogues such as maleimides and maleates, and anhydrides, esters and imides of citraconic and itaconic acids, derivatives of fumaric acid, etc. Special attention is spared to the grafting of conventional and non-conventional synthetic and natural polymers, including biodegradable polymers, mechanism of grafting and graft copolymerization, in situ grafting reactions in melt by reactive extrusion systems, in solutions and solid state (photo- and plasma-induced graftings), and H-bonding effect in the reactive blend processing. The structural phenomena, unique properties and application areas of these copolymers and their various modifications and composites as high performance engineering materials have been also described.

  12. Photoinduced graft-copolymer synthesis and characterization of methacrylic acid onto natural biodegradable lignocellulose fiber.

    Science.gov (United States)

    Khan, Ferdous

    2004-01-01

    UV radiation induced graft copolymerization of methacrylic acid onto natural lignocellulose (jute) fiber was carried out both by "simultaneous irradiation and grafting" and by preirradiation methods using 1-hydroxycyclohexyl-phenyl ketone as a photoinitiator. In the "simultaneous irradiation and grafting" method, the variation of graft weight with UV-radiation time, monomer concentration, and the concentration of photoinitiator was investigated. In the case of the preirradiation method, the incorporation of 2-methyl-2-propene 1-sulfonic acid, sodium salt, into the grafting reaction solution played a most important role in suppressing the homopolymer/gel formation and facilitating graft copolymerization. The optimum value of the reaction parameters on the percentage of grafting was evaluated. In comparison, results showed that the method of graft-copolymer synthesis has significant influence on graft weight. The study on the mechanical and thermal properties of grafted samples was conducted. The results showed that the percentage of grafting has a significant effect on the mechanical and thermal properties in the case of grafted samples. Considering the water absorption property, the jute-poly(methacrylic acid)-grafted sample showed a maximum up to 42% increase in hydrophilicity with respect to that of the "as received" sample. Attenuated total reflection infrared studies indicate that the estimation of the degree of grafting could be achieved by correlating band intensities with the percent graft weight.

  13. Solid-state graft copolymer electrolytes for lithium battery applications.

    Science.gov (United States)

    Hu, Qichao; Caputo, Antonio; Sadoway, Donald R

    2013-08-12

    Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 °C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 °C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed.

  14. Preparation and characterization of polyethylene based graft copolymers. Applications in the immobilization of enzymes

    Science.gov (United States)

    Ferreira, L. M.; Rocha, J. M. S.; Andrade, M. E.; Gil, M. H.

    1998-06-01

    In the last few years new copolymeric supports for the immobilization of biological compounds have been developed. The graft copolymer polyethylene-g.co-hydroxyethyl methacrylate, partially hydrolyzed, has shown to be a very promising support for this purpose. The more recent work in the preparation and characterization of this copolymer, as well as the immobilization of a lipase, is reported in this paper. Branches of poly(hydroxyethyl methacrylate) were grafted onto low density polyethylene by using gamma radiation. The influence of the presence and absence of air, as well as the monomer concentration on the yield of grafting were evaluated. The obtained copolymers were characterized by DSC and FTIR. The influence of the support properties on the synthesis biocatalytic activity was detected.

  15. GRAFTED STYRENE-DIVINYLBENZENE COPOLYMERS CONTAINING BENZALDEHYDES AND THEIR WITTIG REACTIONS WITH VARIOUS PHOSPHONIUM SALTS

    Institute of Scientific and Technical Information of China (English)

    Adriana Popa; Gheorghe Ilia; Aurelia Pascariu; Smaranda Iliescu; Nicoleta Plesu

    2005-01-01

    A chloromethylated styrene-divinylbenzene copolymer support system functionalized with 4-benzaldehyde and 2-benzaldehyde was prepared. The degree of functionalization with aldehyde groups is well suited for the subsequent use of the products as Wittig reagents. The polymer bound aldehyde was reacted with Wittig reagents to give olefin groups grafted on styrene-divinylbenzene copolymers. The reactions were carried out in phase transfer catalysis conditions. A simple procedure for the calculation of the degree of functionalization and the statistical modeling of the structural repetitive unit of the copolymer are reported.

  16. Proton conducting graft copolymers with tunable length and density of phosphonated side chains for fuel cell membranes

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Takamuku, Shogo; Jankova Atanasova, Katja;

    2014-01-01

    matrix. increasing the ionic groups content in the graft copolymers led to extensive membrane swelling. To improve the dimensional stability the graft copolymers were blended with pyridine-modified polysulfone. The blend membranes were transparent with formation of nano-phase domains as revealed from TEM...... gravimetrical analyses. The proton conductivity of membrane prepared from the graft copolymer with the shortest phosphonated side chains was 134 mS cm(-1) at 100 degrees C under fully immersed conditions. The graft copolymer TEM image shows a nanophase separation of ion-rich segments within the polysulfone...... images. The acid-base blend membranes exhibited a slightly higher thermal stability but lower proton conductivity compared to the membranes formed from pure graft copolymers....

  17. PCP copolymers grafted with RGD enhance the rates of RGD-PCP micelles internalized into cells.

    Science.gov (United States)

    Chung, Tze-Wen; Tyan, Yu-Chang; Yang, Jean-Dean

    2010-01-01

    RGD-PCP copolymers were fabricated by grafting Arg-Gly-Asp (RGD) peptide to poly(epsilon-caprolactone)-b-chitooligosaccharide-b-poly(ethylene glycol) (PCP) copolymers and the rate of internalization of RGD-PCP micelles by PC 12 cells were examined. Increasing intensity of the absorbance of amine groups in FT-IR spectra of RGD-PCP copolymers compared with those of PCP copolymers indicated the presence of RGD in new copolymers. Moreover, the grafting efficiency and molar ratio of RGD peptides to PCP copolymers were 88.2% and 0.45, respectively, analysed with HPLC. The RGD-PCP copolymers self-assemble to micelles at the critical micelle concentration (CMC) of 0.018 wt% (178 mg L(-1)) and with a mean diameter of 90 nm using a dynamic light-scattering (DLS) analyser. Interestingly, the internalization of DPH-loaded RGD-PCP micelles into PC 12 cells is much faster (e.g. within 5 min) than that of PCP micelles. The new RGD-PCP micelles may potentially be used in cellular drug delivery.

  18. Structure, optical and thermal decomposition characters of LDPE graft copolymers synthesized by gamma irradiation

    Indian Academy of Sciences (India)

    M Madani

    2010-02-01

    Methyl methacrylate (MMA) monomer was grafted onto low density polyethylene by the direct method of radiation grafting. The effect of cohesive energy density of different organic solvents on the degree of grafting was investigated. It was found that the extent of grafting depends largely on the kind of solvent, in which the highest degree of grafting was achieved in the presence of dioxane, whereas the lowest degree of grafting occurred in the presence of methanol. This behaviour was attributed to the solubility parameters of the solvent, monomer and polymer. The change in structure of the LDPE graft copolymer films was characterized by scanning electron microscopy, X-ray diffraction, UV/vis absorption and thermogravimetric analysis. The X-ray diffraction results showed a decrease in the crystallinity of LDPE graft copolymer matrix at high degree of grafting. Studies were made on the UV-absorption edge, and indirect allowed transitions with their optical energy gaps are determined. At the same time the Urbach energy was evaluated. The activation energy of the thermal decomposition was calculated according to Horowitz and Metzger method.

  19. Convenient synthetic method of starch/lactic acid graft copolymer catalyzed with sodium hydroxide

    Indian Academy of Sciences (India)

    Qingling Wang; Yingmo Hu; Jianhua Zhu; Yang Liu; Xue Yang; Jing Bian

    2012-06-01

    Copolymer of starch grafted with lactic acid (LA) could be directly prepared by reaction of cornstarch with lactic acid and with sodium hydroxide (NaOH) as the catalyst. The structure of starch/LA copolymer was characterized by IR, XRD, SEM and 1H-NMR. The effects of NaOH concentration, ratios of starch and LA, reaction temperature and reaction time on the grafting degree were also investigated and the results showed that the highest grafting degree of starch could reach 33.60% when the graft copolymerization was carried out in 0.40 mol l-1 NaOH aqueous solution for 9 h at 90°C with 1: 6 ratio of starch and lactic acid.

  20. Synthesis and characterization of starch-poly(methyl acrylate) graft copolymers using horseradish peroxidase.

    Science.gov (United States)

    Wang, Su; Wang, Qiang; Fan, Xuerong; Xu, Jin; Zhang, Ying; Yuan, Jiugang; Jin, Heling; Cavaco-Paulo, Artur

    2016-01-20

    Horseradish peroxidase (HRP)-mediated graft polymerization in the presence of hydrogen peroxide (H2O2) and acetylacetone (Acac) has been successfully applied to the synthesis of starch-poly(methyl acrylate) (PMA). The graft copolymer was characterized by Fourier transform infrared (FT-IR), elemental analysis, nuclear magnetic resonance ((1)H NMR and (13)C NMR), and differential scanning calorimetry (DSC). FT-IR, elemental analysis and NMR confirmed that methyl acrylate (MA) was grafted onto starch successfully. DSC results showed the graft reaction had changed the crystalline regions of the gelatinized starch. The effects of pH, MA content, HRP dosage, incubation temperature and time on grafting percentage (GP) and grafting efficiency (GE) were also investigated. The GP and GE under optimal conditions reached 30.21% and 45.13%, respectively.

  1. Position transitions of polymer-grafted nanoparticles in diblock-copolymer nanocomposites

    Directory of Open Access Journals (Sweden)

    2011-04-01

    Full Text Available Self-assembly of block copolymer/nanoparticle blends has promising applications in the design and fabrication of novel functional nanomaterials. Precise control of the spatial positions of nanoparticles within block copolymer-based nanomaterials is crucial to achieve some special physical properties and functions. Here, we employ the self-consistent field method to theoretically investigate the self-assembly of polymer grafted-nanoparticles in a diblock copolymer. It is found that by varying the size and selectivity of nanoparticles, one can not only produce various self-assembled nanostructures but also modulate the spatial positions of the nanoparticles, either at the copolymer interfaces or in the center of one copolymer phase, within the nanostructures. A denser grafted polymer brush plays a role of shielding effect on nanoparticles and can position them into the center of one copolymer phase. The nanostructural transition we observed is dictated by the competition between entropy and enthalpy. On the basis of a number of simulations, two phase diagrams of self-assembled nanostructures are constructed. This study may be helpful for optimal design of advanced materials with desired nanostructures and enhanced performance.

  2. Nanoassemblies of Tissue-Reactive, Polyoxazoline Graft-Copolymers Restore the Lubrication Properties of Degraded Cartilage.

    Science.gov (United States)

    Morgese, Giulia; Cavalli, Emma; Müller, Mischa; Zenobi-Wong, Marcy; Benetti, Edmondo M

    2017-03-13

    Osteoarthritis leads to an alteration in the composition of the synovial fluid, which is associated with an increase in friction and the progressive and irreversible destruction of the articular cartilage. In order to tackle this degenerative disease, there has been a growing interest in the medical field to establish effective, long-term treatments to restore cartilage lubrication after damage. Here we develop a series of graft-copolymers capable of assembling selectively on the degraded cartilage, resurfacing it, and restoring the lubricating properties of the native tissue. These comprise a polyglutamic acid backbone (PGA) coupled to brush-forming, poly-2-methyl-2-oxazoline (PMOXA) side chains, which provide biopassivity and lubricity to the surface, and to aldehyde-bearing tissue-reactive groups, for the anchoring on the degenerated cartilage via Schiff bases. Optimization of the graft-copolymer architecture (i.e., density and length of side chains and amount of tissue-reactive functions) allowed a uniform passivation of the degraded cartilage surface. Graft-copolymer-treated cartilage showed very low coefficients of friction within synovial fluid, reestablishing and in some cases improving the lubricating properties of the natural cartilage. Due to these distinctive properties and their high biocompatibility and stability under physiological conditions, cartilage-reactive graft-copolymers emerge as promising injectable formulations to slow down the progression of cartilage degradation, which characterizes the early stages of osteoarthritis.

  3. Synthesis, Characterization, and Aqueous Lubricating Properties of Amphiphilic Graft Copolymers Comprising 2-Methoxyethyl Acrylate

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Røn, Troels; Jankova Atanasova, Katja

    2014-01-01

    of the corresponding monomers followed by deblocking reaction leads to well-defined amphiphiles with narrow molecular weight distributions (PDI ≤ 1.29) and varying content of methacrylic acid. The graft copolymers showed effective surface adsorption and lubrication for self-mated poly(dimethylsiloxane) (PDMS) contacts...

  4. Design of cationic graft copolymers as a potential inducer of B-Z transition.

    Science.gov (United States)

    Shimada, Naohiko; Kano, Arihiro; Maruyama, Atsushi

    2009-01-01

    Biological roles of transition from B form to Z form of DNA (B-Z transition) have recently received attention. The B-Z transition was also employed as driving machinery of a nano-mechanical DNA device. However, there are little reports of effective inducer of the B-Z transition. We previously reported that poly((L)-Lysine)-graft-dextran induces B-Z transition and grafted dextran plays an important role for the B-Z transition. In this report, we designed cationic graft copolymer as a potential inducer of B-Z transition. Series of the copolymers consisting of poly((L)-Lysine) backbone and abundant of dextran (Dex) or poly(ethylene glycol) (PEG) side chains were prepared. The B-Z transition of poly(dG-dC)/Poly(dG-dC) were observed in the presence of these copolymers. The copolymers having higher content of Dex or PEG effectively induced the B-Z transition compared to that having lower content. The result indicated that not only electrostatic interaction between DNA and the poly((L)-Lysine) backbone but also hydrophilic graft chains play a role for the B-Z transition. We speculated that Dex- or PEG-enriched environment is favorable for Z form.

  5. Preparation and characterization of poly(acrylic acid)-hydroxyethyl cellulose graft copolymer.

    Science.gov (United States)

    Abdel-Halim, E S

    2012-10-01

    Poly(acrylic acid) hydroxyethyl cellulose [poly(AA)-HEC] graft copolymer was prepared by polymerizing acrylic acid (AA) with hydroxyethyl cellulose (HEC) using potassium bromate/thiourea dioxide (KBrO(3)/TUD) as redox initiation system. The polymerization reaction was carried out under a variety of conditions including concentrations of AA, KBrO(3) and TUD, material to liquor ratio and polymerization temperature. The polymerization reaction was monitored by withdrawing samples from the reaction medium and measuring the total conversion. The rheological properties of the poly(AA)-HEC graft copolymer were investigated. The total conversion and rheological properties of the graft copolymer depended on the ratio of KBrO(3) to TUD and on acrylic acid concentration as well as temperature and material to liquor ratio. Optimum conditions of the graft copolymer preparation were 30 mmol KBrO(3) and 30 mmol TUD/100g HEC, 100% AA (based on weight of HEC), duration 2h at temperature 50 °C using a material to liquor ratio of 1:10.

  6. Anti-Biofouling Effect of PEG-Grafted Block Copolymer Synthesized by RAFT Polymerization.

    Science.gov (United States)

    Kim, Seon-Mi; Han, Sang Suk; Kim, A Young; Choi, Beom-Jin; Paik, Hyun-Jong; Lee, Inwon; Park, Hyun; Chun, Ho Hwan; Cho, Youngjin; Hwang, Do-Hoon

    2015-10-01

    Poly(glycidyl methadrylate-block-styrene) (PGMA-b-PS), a block copolymer consisting of glycidyl methacrylate and styrene, was synthesized via reversible addition-fragmentation chain transfer living polymerization. The synthesized PGMA-b-PS was then grafted with low-molecular-weight polyethylene glycol (PEG) via epoxy ring opening to give PGMA-g-PEG-b-PS, which was evaluated as an anti-biofouling coating material. As a preliminary test for the anti-biofouling effect, a protein adsorption experiment was performed on the synthesized block copolymer surface. The block copolymers were spin-coated onto silicon wafers, and protein adsorption experiments were carried out using fluorescein isothiocyanate conjugate-labeled bovine serum albumin. The fluorescence intensity of the protein adsorbed on the block copolymer surface was compared with that of a polystyrene film as a reference. The synthesized PGMA-g-PEG-b-PS film showed much lower fluorescence intensity than that of the PS film.

  7. SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE ) SIDE CHAIN STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    QIU Yongxing; YU Xiaojie; FENG Linxian; YANG Shilin

    1993-01-01

    Acryloyl terminated Poly (ethyleneoxide)macromonomers(PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called "selective dissolution", the well-defined structure of the purified copolymers was confirmed by IR, 1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed "comb-model" was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.

  8. Bioinert membranes prepared from amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rajkumar [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Patel, Madhumita [Department of Life Science, Dongguk University-Seoul, 3–26 Phil-dong, Chung-gu, Seoul 100-715 (Korea, Republic of); Ahn, Sung Hoon [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Sung, Yong Kiel [ReSEAT Program, Korea Institute of Science and Technology Information, 206-9 Cheongyangni-dong, Dongdaemun-gu, Seoul 130-742 (Korea, Republic of); Lee, Hyung-Keun [Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Dae-jeon 305-343 (Korea, Republic of); Kim, Jong Hak, E-mail: jonghak@yonsei.ac.kr [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Sung, Jung-Suk, E-mail: sungjs@dongguk.edu [Department of Life Science, Dongguk University-Seoul, 3–26 Phil-dong, Chung-gu, Seoul 100-715 (Korea, Republic of)

    2013-04-01

    Poly(vinyl chloride) (PVC) membrane was hydrophilically modified by grafting with poly(oxyethylene methacrylate) (POEM) using atom transfer radical polymerization (ATRP). The successful grafting of PVC main chain by POEM was characterized by Fourier transform infrared spectroscopy (FT-IR). The molecular weight and hydrophilicity of membranes increased with the amount of POEM grafting, as characterized by gel permeation chromatography (GPC) and contact angle measurement, respectively. Transmission electron microscope (TEM) and small angle X-ray scattering (SAXS) analysis revealed the microphase-separated structure of PVC-g-POEM and the domain spacing increased from 59.3 to 86.1 nm with increasing grafting degree. Scanning electron microscopy (SEM) was used for the direct visualization of the mouse embryonic fibroblast (MEF) cell and bacteria adhesion on the membrane surface. Protein adsorption and eukaryotic and prokaryotic cell adhesion tests showed that the bioinert properties of membranes were significantly increased with POEM content. Highlights: ► TEM and SAXS analysis revealed the microphase-separated structure of graft copolymer membranes. ► Protein adsorption and eukaryotic and prokaryotic cell adhesion tests were performed on graft copolymer membranes. ► Boinert properties of membranes were significantly increased with POEM content.

  9. Surface functionalization of cyclic olefin copolymer with aryldiazonium salts: A covalent grafting method

    Energy Technology Data Exchange (ETDEWEB)

    Brisset, Florian, E-mail: florian.brisset@etu.univ-rouen.fr [UMR CNRS 6014 COBRA, FR 3038, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France); Vieillard, Julien, E-mail: julien.vieillard@univ-rouen.fr [UMR CNRS 6014 COBRA, FR 3038, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France); Berton, Benjamin, E-mail: benjamin.berton@univ-rouen.fr [EA 3233 SMS, Université de Rouen, 1 rue du 7ème Chasseurs, BP281, 27002 Evreux Cedex (France); Morin-Grognet, Sandrine, E-mail: sandrine.morin@univ-rouen.fr [EA 3829 MERCI, Université de Rouen, 1 rue du 7ème Chasseurs, BP281, 27002 Evreux Cedex (France); Duclairoir-Poc, Cécile, E-mail: cecile.duclairoir@univ-rouen.fr [EA 4312 LMSM, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France); Le Derf, Franck, E-mail: franck.lederf@univ-rouen.fr [UMR CNRS 6014 COBRA, FR 3038, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France)

    2015-02-28

    Graphical abstract: - Highlights: • An effective method to modify cyclic olefin copolymer surface. • The surface of COC was modified by covalent grafting of aryl diazonium salts. • The wettability of COC surface was modulated by diazonium salts. • Photoinitiation and chemical reduction have to be combined to graft diazonium salt on COC surface. - Abstract: Covalent immobilization of biomolecules on the surface of cyclic olefin copolymer (COC) is still a tough challenge. We developed a robust method for COC surface grafting through reaction with aryldiazonium. Chemical diazonium reduction generated an aryl radical and the formation of a grafted film layer on the organic surface. We also demonstrated that the chemical reduction of diazonium salt was not sufficient to form a film on the COC surface. UV illumination had to be combined with chemical reduction to graft an aryl layer onto the COC surface. We optimized organic film deposition by using different chemical reducers, different reaction times and reagent proportions. We characterized surface modifications by fluorescence microscopy and contact angle measurements, infrared spectroscopy, X-ray photoemission spectroscopy and Raman spectroscopy, and assessed the topography of the aryl film by atomic force microscopy. This original strategy allowed us to evidence various organic functions to graft biomolecules onto COC surfaces with a fast and efficient technique.

  10. The Optimization of Synthesizing Graft Copolymer of Starch with Vinyl Monomers

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiyu; LIU Zuoxin

    2006-01-01

    The graft copolymerization of acrylamide (AM)/acrylic acid (AA) onto starch (St-g-pAA and St-g-p(AA-co-AM)) was carried out using an orthogonal test method. The combined effects of different reaction conditions on the water absorbency of the graft copolymers were optimized through mathematical statistical methods of range and square variance analysis. The maximum water absorbency was obtained when the ratio of dried starch to distilled water was 1∶8 (w/w), the ratio of starch to monomer 1∶6 (w/w), the initiator concentration 4.40×10-3 mol/L, the crosslinker concentration 10.86×10-2 mol/L, and the basicity to AA 0.70(mol/mol). Both the graft copolymers have an excellent water absorption capacity in distilled water and in 0.9wt% NaCl solution. It was also found that in distilled water the water absorbency of St-g-pAA was higher than that of St-g-p(AA-co-AM), while in 0.9wt% NaCl solution, the situation was just the reverse. The correlation between the water absorbency and the nature of the solution and the properties of the copolymers, which is related to the properties of the monomers, was discussed. The grafting of AA and AM onto starch was confirmed by the IR spectra of St-g-pAA and St-g-p(AA-co-AM).

  11. Polyaspartamide-Polylactide Graft Copolymers with Tunable Properties for the Realization of Fluorescent Nanoparticles for Imaging.

    Science.gov (United States)

    Craparo, Emanuela Fabiola; Porsio, Barbara; Mauro, Nicolò; Giammona, Gaetano; Cavallaro, Gennara

    2015-08-01

    Here, the synthesis and the characterization of novel amphiphilic graft copolymers with tunable properties, useful in obtaining polymeric fluorescent nanoparticles for application in imaging, are described. These copolymers are obtained by chemical conjugation of rhodamine B (RhB) moieties, polylactic acid (PLA), and O-(2-aminoethyl)-O'-methyl poly(ethylene glycol) (PEG) on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA). In particular, PHEA is first functionalized with RhB to obtain PHEA-RhB with a derivatization degree in RhB (DDRhB ) equal to 0.55 mol%. By varying the reaction conditions, different amounts of PLA are grafted on PHEA-RhB to obtain PHEA-RhB-PLA with DDPLA equal to 1.9, 4.0, and 6.2 mol%. Then, PEG chains are grafted on PHEA-RhB-PLA derivatives to obtain PHEA-RhB-PLA-PEG graft copolymers. The preparation of polymeric fluorescent nanoparticles with tunable properties and spherical shape is described by using PHEA-RhB-PLA-PEG with DD in PLA and PEG equal to 4.0 and 4.9 mol%, by following easily scaling up processes, such as emulsion-solvent evaporation and high pressure homogenization (HPH)-solvent evaporation techniques. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. NOVEL AMPHIPHILIC FLUORESCENT GRAFT COPOLYMER: SYNTHESIS,CHARACTERIZATION AND ENCAPSULATION OF A HYDROPHOBIC AGENT

    Institute of Scientific and Technical Information of China (English)

    Zhao-qiang Wu; Shu Yang; Wen-yan Liao; Ling-zhi Meng

    2006-01-01

    Novel amphiphilic fluorescent graft copolymer (PVP-PyAHy) was successfully synthesized by the free radical copolymerization of hydrophobic monomer N-(1-pyrenebutyryl)-N'-acryloyl hydrazide (PyAHy) with hydrophilic precursor polymers of vinyl-functionalized poly(N-vinylpyrrolidone) (PVP) in DMF. The copolymer is amphiphilic and has intrinsic fluorescence. FT-IR, 1H-NMR, TEM, gel permeation chromatography-multi-angle laser light scattering, UV-Vis spectroscopy and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation shows that the copolymer PVP-PyAHy forms micelles in aqueous solution. Results of fluorometric measurements illustrate that the critical micelle concentration (CMC) value of PVP-PyAHy in aqueous solution is about 0.90 mg/mL. To examine the encapsulation ability of the copolymer in aqueous media, methyl yellow was employed as a model hydrophobic agent. The loading level of the polymer to methyl yellow is 8.8 mg/g. The cytotoxicity assays for Madin Darby Canine Kidney (MDCK) cells shows good biocompatibility of PVP-PyAHy in vitro. These results suggest the potential of this copolymer PVP-PyAHy as drugs delivery carrier and fluorescent tracer.

  13. Polycation graft copolymers accelerating DNA strand exchange: involvement of ionic interaction.

    Science.gov (United States)

    Kim, W J; Ishihara, T; Akaike, T; Maruyama, A

    2001-01-01

    In the previous study (Chem. Eur. J., 7, 176 (2001)) we demonstrated that the comb-type polycationic copolymer (PLL-g-Dex) which is composed of poly (L-lysine) backbone and dextran graft chains expedited the DNA strand exchange reaction. In this study, fluorescence resonance energy transfer (FRET) was employed to explore the copolymer-mediated DNA strand exchange with higher time-resolution. To initiate strand exchange reaction the duplex prepared from 3'-fluorescein isothiocyanate (FITC)--and 5'-carboxytetramethylrhodamine(TAMRA)-labeled complementary DNAs was added to its non-labeled complementary single strand. DNA strand exchange was monitored by observing the recovery of the FITC quenching. More than 20,000 times increase in strand exchange rate at 37 degrees C by the copolymer was estimated. To investigate the accelerating mechanisms of the copolymer, the same reactions but at various ionic strenghts were studied. With increasing ionic strengths the strand exchange rate in the absence of the copolymer increased, suggesting that ionic repulsion among DNAs is unfavorable for the strand exchange to occur. Hence, alleviation of the electrostatic repulsion through interpolyelectrolyte complex formation is probably a role of the copolymer for accelerating the strand exchange reaction.

  14. STUDY OF GRAFT SITES IN EPOXY GRAFT COPOLYMERS BY QUANTUM CHEMISTRY CALCULATIONS

    Institute of Scientific and Technical Information of China (English)

    Song Chen; Xiao-yu Li

    2009-01-01

    Exploration and characterization of grafting productions by experimental methods are often cumbersome or sometimes impossible. Therefore, quantum chemistry calculations were performed to characterize the graft sites of epoxy resin. According to the Gibbs free energy criterion of the second law of thermodynamic, the reported graft sites were confirmed, and more important, some unreported graft sites were found. In addition, method of increasing the number of graft sites was studied in this article.

  15. Self-assembly of block copolymers grafted onto a flat substrate: Recent progress in theory and simulations

    Science.gov (United States)

    Zheng, Wang; Bao-Hui, Li

    2016-01-01

    Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanometers, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applications; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB diblock copolymers, junction point-grafted AB diblock copolymers (i.e., Y-shaped brushes), and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress. Project supported by the National Natural Science Foundation of China (Grant Nos. 20990234, 20925414, and 91227121), the Program for Changjiang Scholars and Innovative Research Team in University, China (Grant No. IRT1257), the Programme of Introducing Talents of Discipline to Universities, China, and by the Tianhe No. 1, China.

  16. Cellulose-based graft copolymers prepared by simplified electrochemically mediated ATRP

    Directory of Open Access Journals (Sweden)

    P. Chmielarz

    2017-02-01

    Full Text Available Brush-shaped block copolymer with a dual hydrophilic poly(acrylic acid-block-poly(oligo(ethylene glycol acrylate (PAA-b-POEGA arms was synthesized for the first time via a simplified electrochemically mediated ATRP (seATRP under both constant potential electrolysis and constant current electrolysis conditions, utilizing only 30 ppm of catalyst complex. The polymerization conditions were optimized to provide fast reactions while employing low catalyst concentrations and preparation of cellulose-based brush-like copolymers with narrow molecular weight distributions. The results from proton nuclear magnetic resonance (1H NMR spectral studies support the formation of cellulose-based graft (copolymers. It is expected that these new polymer brushes may find application as pH- and thermo-sensitive drug delivery systems.

  17. Chitosan-graft poly(p-dioxanone) copolymers: preparation, characterization, and properties.

    Science.gov (United States)

    Wang, Xiu-Li; Huang, Yan; Zhu, Jiang; Pan, Yan-Bo; He, Rui; Wang, Yu-Zhong

    2009-04-21

    A new biodegradable copolymer of chitosan and poly(p-dioxanone) (PPDO) was prepared through a protection-graft-deprotection procedure using N-phthaloyl-chitosan as an intermediate. PPDO terminated with the isocyanate group was allowed to react with hydroxyl groups of the N-phthaloyl-protected chitosan, and then the phthaloyl group was cleaved to give the free amino groups. The length of PPDO graft chains can be controlled easily by using the prepolymers of PPDO with different molecular weights. The resulting products were thoroughly characterized with FT-IR, (1)H NMR, TG, DSC, SEM, and WAXD. The copolymers were used as drug carriers for sinomenine (7,8-didehydro-4-hydroxy-3,7-dimethoxy-17-methyl-9alpha,13alpha,14alpha-morphinan-6-one) and these exhibited a significant controlled drug-releasing behavior whether in artificial gastric juice or in neutral phosphate buffer solution.

  18. Production of Natural Rubber Grafted Styrene Copolymer Latex as Water Base Coatings

    Directory of Open Access Journals (Sweden)

    M Utama

    2006-07-01

    Full Text Available Twelve kinds formulation of natural rubber grafted copolymer styrene (NR-g-S prepared by gamma radiation co-polymerization technique has been carried out. The characteristic of NR-g-S and its water base coating such as molecular structure, particle size, and the properties of latex and its film were evaluated. The results showed that the NR-g-S latex as a water base coating has low viscosity, height strength, good grease resistance, good flexibility, good aging and corrosion resistance on concrete cement and metal. The average particle size is between 270-300 nm, and the bonding between poly-isoprene of NRL and styrene molecules were grafted copolymer

  19. Graft (partially carboxymethylated guar gum-g-poly vinyl sulfonic acid) copolymer: from synthesis to applications.

    Science.gov (United States)

    Yadav, Mithilesh; Srivastav, Abhishek; Verma, Shiv Kumar; Behari, Kunj

    2013-09-12

    The aim of the paper is to study the physico-chemical phenomenon of synthesized graft copolymer (carboxymethylated guar gum-g-vinylsulfonic acid). The reaction optimum conditions for grafting has also been determined by studying the effect of vinylsulfonic acid, hydrogen ion, peroxymonosulphate, glycolic acid concentration and carboxymethylated guar gum along with time and temperature. Experimental results show that maximum grafting has been obtained at 1.8 g dm(-3) concentration of partially carboxymethylated guar gum and 5.3 × 10(-2) mol dm(-3) concentration of vinylsulfonic acid. It has been observed that grafting ratio, add on, conversion, efficiency increase up to 4.0 × 10(-3) mol dm(-3) of hydrogen ion, 4 × 10(-3) mol dm(-3) of glycolic acid, 14 × 10(-3) mol dm(-3) of peroxymonosulphate and 35 °C of temperature. Grafted copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis. Water swelling, flocculating, metal ion uptake and resistance to biodegradability properties of partially carboxymethylated guar gum-g-vinylsulfonic acid have been determined.

  20. Preparation,structure and properties of PP-g-AA grafting copolymer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Polypropylene grafting with AA was prepared by reactive extrusion with pre-irradiated PP (rPP) as the homogeneous initiator.The effects of the pre-irradiated dose,the fraction of rPP and the concentration of acrylic acid on the grafting reaction were studied and the grafted PP was characterized by Fourier transition infrared spectroscopy (FTIR),differential scanning calorimeter (DSC)and polarized light microscopy (PLM).The results show that the degradation of PP was suppressed efficiently with this novel method for preparing PP-g-AA copolymers,and the grafted copolymers with good mechanical properties were obtained.It was found that the product with higher graft degree (Gd)(0.19%) and relatively excellent mechanical properties can be produced if the mass ratio of PP/rPP/AA 4 kGy.Moreover,an adhesive strength of 4.88 kN/m was reached in the PP-g-AA/aluminum laminate.

  1. Biodegradation of polystyrene-graft-starch copolymers in three different types of soil.

    Science.gov (United States)

    Nikolic, Vladimir; Velickovic, Sava; Popovic, Aleksandar

    2014-01-01

    Materials based on polystyrene and starch copolymers are used in food packaging, water pollution treatment, and textile industry, and their biodegradability is a desired characteristic. In order to examine the degradation patterns of modified, biodegradable derivates of polystyrene, which may keep its excellent technical features but be more environmentally friendly at the same time, polystyrene-graft-starch biomaterials obtained by emulsion polymerization in the presence of new type of initiator/activator pair (potassium persulfate/different amines) were subjected to 6-month biodegradation by burial method in three different types of commercially available soils: soil rich in humus and soil for cactus and orchid growing. Biodegradation was monitored by mass decrease, and the highest degradation rate was achieved in soil for cactus growing (81.30%). Statistical analysis proved that microorganisms in different soil samples have different ability of biodegradation, and there is a significant negative correlation between the share of polystyrene in copolymer and degree of biodegradation. Grafting of polystyrene on starch on one hand prevents complete degradation of starch that is present (with maximal percentage of degraded starch ranging from 55 to 93%), while on the other hand there is an upper limit of share of polystyrene in the copolymer (ranging from 37 to 77%) that is preventing biodegradation of degradable part of copolymers.

  2. The polyvinylpyrrolidone graft copolymers and soft contact lenses on their basis

    Directory of Open Access Journals (Sweden)

    Oleg Suberlyak

    2014-12-01

    Full Text Available The graft polymerization of 2-hydroxyethyl methacrylate in presence of polyvinylpyrrolidone, which occurs through a stage of complex formation between the reactants, was investigated. The basic performance properties of hydrogel copolymers depending on their composition were investigated. A hydrogel polymeric material “Akrylan-LPI” for soft contact lenses was developed. Clinical testing confirmed the effectiveness of using of such lenses for vision correction as well as for eye injuries and burns treating.

  3. Polyethylene glycol-g-polyvinyl alcohol grafted copolymer: reproductive toxicity study in Wistar rats.

    Science.gov (United States)

    Heuschmid, Franziska F; Schneider, Steffen; Schuster, Paul; Lauer, Birthe; van Ravenzwaay, Bennard

    2013-07-01

    Polyethylene glycol-g-polyvinyl alcohol (PEG-PVA) grafted copolymer was administered by gavage to groups of 25 male and 25 female young Wistar rats at doses of 0 (vehicle control), 100, 300, or 1000 mg/kg bw/day for one generation (F0). The study followed the treated F0 generation through mating, gestation, lactation, and weaning of the F1 generation. F1 animals were mated and followed to gestation day (GD) 15-17 at which time F2 implants were evaluated. There were no indications from the various clinical and gross pathological examinations that the oral administration of PEG-PVA grafted copolymer to the F0-parental rats produced any signs of general, reproductive, or developmental toxicity in the F0 or F1 animals or F2 implants. Based on the lack of any dose-related or biologically relevant effects on fertility, reproduction, development, and overall health of rats gavaged with PEG-PVA grafted copolymer and their progeny, the no-observed-adverse effect level (NOAEL) was determined to be the highest dose tested of 1000 mg/kg bw/day.

  4. Subchronic toxicity of polyethylene glycol-g-polyvinyl alcohol grafted copolymer.

    Science.gov (United States)

    Heuschmid, Franziska F; Schuster, Paul; Lauer, Birthe; Buesen, Roland; Mellert, Werner; Groeters, Sibylle; van Ravenzwaay, Bennard

    2013-07-01

    The safety of polyethylene glycol-g-polyvinyl alcohol (PEG-PVA) grafted copolymer was evaluated in a 13-week oral toxicity study in rats and in a 9-month oral toxicity study in dogs. Wistar rats were administered 600, 3000, or 15,000 ppm PEG-PVA grafted copolymer in their drinking water whereas beagle dogs were fed 3000, 10,000, or 30,000 ppm PEG-PVA grafted copolymer in the diet. There were no mortalities, no adverse clinical signs, no toxicologically adverse effects on body weight or body weight gain, feed consumption, hematological, clinical chemistry or urinary parameters, or histopathology in either species. In rats, no treatment-related effects were observed in the functional observational battery (FOB) or related measurements of motor activity. Increased water consumption observed in rats at the highest dose was the only test substance-induced effect noted. The no-observed-adverse-effect level (NOAEL) was the highest concentration tested in both species: 15,000 ppm in rats (corresponding to a daily intake of 1611 mg/kg bw for males and 2191 mg/kg bw for females) and 30,000 ppm in dogs (corresponding to a mean daily intake of 783 mg/kg bw for males and 811 mg/kg bw for females).

  5. Developmental toxicity of polyethylene glycol-g-polyvinyl alcohol grafted copolymer in rats and rabbits.

    Science.gov (United States)

    Heuschmid, Franziska F; Schneider, Steffen; Schuster, Paul; Lauer, Birthe; van Ravenzwaay, Bennard

    2013-07-01

    Polyethylene glycol-g-polyvinyl alcohol (PEG-PVA) grafted copolymer was evaluated in developmental toxicity studies with Wistar rats and Himalayan rabbits. Pregnant Wistar rats were gavaged with 0 (vehicle control), 100, 300, or 1000 mg PEG-PVA grafted copolymer/kg bw/day from gestation day (GD) 6-15. Pregnant Himalayan rabbits received the same treatment from GD 6 to 19. On GD 20 and 29 for rats and rabbits, respectively, the animals were euthanized and were examined grossly. For each dam, corpora lutea were counted and number and distribution of implantation sites were determined. The fetuses were removed, sexed, weighed, and evaluated for any external, soft tissue, and skeletal findings. No significant findings were found that could be attributed to administration of PEG-PVA grafted copolymer. Under the conditions of these studies, the no-observed-adverse-effect level (NOAEL) for maternal and developmental toxicity in both species was the highest dose tested of 1000 mg/kg bw/day.

  6. Preparation, blood coagulation and cell compatibility evaluation of chitosan-graft-polylactide copolymers.

    Science.gov (United States)

    Wang, Qi; Liu, Pei; Liu, Peifeng; Gong, Tao; Li, Suming; Duan, Yourong; Zhang, Zhirong

    2014-02-01

    Biodegradable chitosan-graft-polylactide (PLA-CS) copolymers were prepared by the grafting of a poly(L-lactide) (PLLA) or poly(D-lactide) (PDLA) precursor to the backbone of chitosan using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC ⋅ HCl) and N-hydroxysuccinimide (NHS) as a coupling agent. The blood and cell compatibility of the graft copolymers were investigated in comparison to PLLA and PDLA homopolymers. The coagulation properties of PLA-CS were evaluated by hemolysis, plasma recalcification, dynamic blood clotting and protein absorption assays. PLA-CS copolymers present similar hemolysis ratio and plasma recalcification time as PLA, but slower dynamic blood clotting and lower protein absorption. The cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), agar diffusion and lactate dehydrogenase (LDH) experiments. All the samples presented no effect on the viability to cells. Inflammatory cytokine analysis using sandwich ELISAs revealed that PLA-CS would not stimulate inflammatory activity.

  7. RADICAL GRAFTING REACTIONS ONTO STARCH AND OTHER WATER-SOLUBLE COPOLYMERS IN ISOLATED GEL DROPLETS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liansheng; A.F.Johnson

    1993-01-01

    A novel radical grafting copolymerization process has been designed for water-soluble polymers which avoids the problems of conducting grafting reactions in highly viscous polymerization media.A variety of water-soluble graft copolymers having starch or dextran as the backbone chain with grafted side chains of polyacrylamide (-AM-),poly (acrylic acid) (-AA-),poly (acrylamide-co-acrylic acid) (-AM-NH4AA-) or poly (acrylamide-co-2-acrylamido-2-methyl-1-propanesulphinic acid)(-AM-AMPS-) have been synthesized in gel droplets using a ceric sulphate redox initiator,and their properties compared.The reaction conditions were optimized taking into account reaction kinetic data and the observed properties of the products produced under different reaction conditions.The effects of the ratios of [backbone]/[graft monomer],[AM]/[AA]/[AMPS],[Ce4+]/[S2O8=] and pH value on the reaction rate,conversion,grafting degree,grafted chain length and the product molecular weight have been investigated.

  8. Synthesis and Flocculation Property of Chitosan-Acrylamide Graft Copolymer

    Institute of Scientific and Technical Information of China (English)

    LI Liu-zhu; MAO Lu-yuan; WANG Xiu-li; YANG Yong; ZHUANG Yin-feng

    2004-01-01

    Chitosan, as a kind of natural polymer, has many advantages, such as abundant sources, biological degradation, no secondary contamination and facile modification. In this work, we prepared modified chitosan flocculants with double electrical behavior via polymerizing chitosan, acrylamide and sodium carboxymethyl cellulose together by using ammonium persulfate as the indicator in water. The product is a comb-type of chitosan copolymer and a polymeric ampholyte. And then we studied the product by FTIR, UV-Vis, TG, DSC spectrometeries and viscometry, etc. We also performed CACM′s water treat experiment. The effects of pH values, reaction time and dose of the new floccalant on treating various of waste water have been investigated, too.

  9. STUDY OF GRAFTING COPOLYMER OF STYRENE AND 2,2,6,6-TETRAMETHYL-4-PIPERIDINYL METHACRYATE ONTO POLYPROPYLENE DURING HEATING

    Institute of Scientific and Technical Information of China (English)

    PAN Jiangqing; ZHANG Can; MA Zhenmin

    1987-01-01

    The grafting of copolymer of styrene and 2, 2, 6, 6-tetramethyl-4-piperidinyl methacrylate onto polypropylene during heating was studied by IR and ESR. It is found that the graft reaction is going through the stable free radical >NO. mechanism.

  10. Water transport and clustering behavior in homopolymer and graft copolymer polylactide

    Energy Technology Data Exchange (ETDEWEB)

    Du, An; Koo, Donghun; Theryo, Grayce; Hillmyer, Marc A.; Cairncross, Richard A. (Drexel); (UMM)

    2015-02-19

    Polylactide is a bio-based and biodegradable polymer well-known for its renewable origins. Water sorption and clustering behavior in both a homopolymer polylactide and a graft copolymer of polylactide was studied using the quartz crystal microbalance/heat conduction calorimetry (QCM/HCC) technique. The graft copolymer, poly(1,5-cyclooctadiene-co-5-norbornene-2-methanol-graft-D,L-lactide), contained polylactide chains (95 wt.%) grafted onto a hydrophobic rubbery backbone (5 wt.%). Clustering is an important phenomenon in the study of water transport properties in polymers since the presence of water clusters can affect the water diffusivity. The HCC method using the thermal power signals and Van't Hoff's law were both employed to estimate the water sorption enthalpy. Sorption enthalpy of water in both polymers was determined to be approximately -40 kJ/mol for all water activity levels. Zimm-Lundberg analysis showed that water clusters start to form at a water activity of 0.4. The engaged species induced clustering (ENSIC) model was used to curve fit sorption isotherms and showed that the affinity among water molecules is higher than that between water molecules and polymer chains. All the methods used indicate that clustering of water molecules exists in both polymers.

  11. H-shaped double graft copolymers: Effect of molecular architecture on morphology

    Science.gov (United States)

    Lee, Chin; Gido, Samuel P.; Poulos, Yiannis; Hadjichristidis, Nikos; Tan, Nora Beck; Trevino, Samuel F.; Mays, Jimmy W.

    1997-10-01

    The morphologies formed by block copolymers with a double-graft, H or S2IS2 architecture were investigated using transmission electron microscopy (TEM) and small angle neutron scattering (SANS). Here S and I represent blocks of polystyrene and polyisoprene, respectively. These materials were synthesized using anionic polymerization and chlorosilane linking, and they were characterized using size exclusion chromatography, membrane osmometry, and low-angle laser light scattering. This characterization work confirmed the desired molecular architectures and narrow molecular weight distributions. The results of morphological characterization indicate that one can understand complex grafting architectures by decomposing them into fundamental building blocks, which are taken as the component single graft structures out of which the larger structure is constructed. We propose rules for dividing structures into these components, which we call constituting block copolymers. The morphological behavior of the more complex architecture is approximately equivalent to that of the constituting block copolymer structure. Through the use of the constituting block copolymers we map the experimentally determined morphological behavior of the H architecture onto the morphology diagram calculated by Milner for miktoarm stars [Macromolecules 27, 2333 (1994)]. Mapping the H architecture onto the morphology diagram in this way produces general agreement between experimental results and the model. However, it is found that in the case of the H architecture, as well as in previously published results for I2S and I3S miktoarm star materials, that the morphology diagram slightly overestimates the amount of shift in the order-order transition lines produced by asymmetry in molecular architecture. This overestimation in the theory is attribute to a junction point localization effect which was neglected in Milner's calculation.

  12. H‐shaped double graft copolymers: Effect of molecular architecture on morphology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chin; Gido, Samuel P. [Polymer Science and Engineering Department, W. M. Keck Electron Microscopy Laboratory, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Poulos, Yiannis; Hadjichristidis, Nikos [Department of Chemistry, University of Athens, Panepistimiopolis Zografou 15771, Athens, Greece, and Institute of Electronic Structure and Laser, 711 10 Heraklion, Crete (Greece); Tan, Nora Beck; Trevino, Samuel F. [Polymers Research Branch, U.S. Army Research Laboratory, APG, MD 211005‐5069, and Reactor Radiation Division, NIST, Gaithersburg, Maryland 20899 (United States); Mays, Jimmy W. [Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama 35294 (United States)

    1997-10-22

    The morphologies formed by block copolymers with a double‐graft, H or S{sub 2}IS{sub 2} architecture were investigated using transmission electron microscopy (TEM) and small angle neutron scattering (SANS). Here S and I represent blocks of polystyrene and polyisoprene, respectively. These materials were synthesized using anionic polymerization and chlorosilane linking, and they were characterized using size exclusion chromatography, membrane osmometry, and low‐angle laser light scattering. This characterization work confirmed the desired molecular architectures and narrow molecular weight distributions. The results of morphological characterization indicate that one can understand complex grafting architectures by decomposing them into fundamental building blocks, which are taken as the component single graft structures out of which the larger structure is constructed. We propose rules for dividing structures into these components, which we call constituting block copolymers. The morphological behavior of the more complex architecture is approximately equivalent to that of the constituting block copolymer structure. Through the use of the constituting block copolymers we map the experimentally determined morphological behavior of the H architecture onto the morphology diagram calculated by Milner for miktoarm stars [Macromolecules 27, 2333 (1994)]. Mapping the H architecture onto the morphology diagram in this way produces general agreement between experimental results and the model. However, it is found that in the case of the H architecture, as well as in previously published results for I{sub 2}S and I{sub 3}S miktoarm star materials, that the morphology diagram slightly overestimates the amount of shift in the order‐order transition lines produced by asymmetry in molecular architecture. This overestimation in the theory is attribute to a junction point localization effect which was neglected in Milner’s calculation.

  13. Synthesis, characterization and foaming of PHEA-PLLA, a new graft copolymer for biomedical engineering.

    Science.gov (United States)

    Carfì Pavia, Francesco; La Carrubba, Vincenzo; Brucato, Valerio; Palumbo, Fabio Salvatore; Giammona, Gaetano

    2014-08-01

    In this study a chemical grafting procedure was set up in order to link high molecular weight poly L-lactic acid (PLLA) chains to the hydrophilic α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) backbone. A graft copolymer named PHEA-g-PLLA (or simply PHEA-PLLA) was obtained bearing a degree of derivatization of 1.0 mol.% of PLLA as grafted chain. This new hybrid derivative offers both the opportune crystallinity necessary for the production of scaffolds trough a thermally induced phase separation (TIPS) technique and the proper chemical reactivity to perform further functionalizations with bio-effectors and drugs. PHEA-PLLA porous scaffolds for tissue engineering applications were successfully obtained via TIPS and characterized. Structures with an open porosity and a good level of interconnection were detected. As the applicability of the scaffold is mainly dependent on its pore size, preliminary studies about the mechanisms governing scaffold's pore diameter were carried out.

  14. Utilization of starch graft copolymers as selective depressants for lizardite in the flotation of pentlandite

    Science.gov (United States)

    Cao, Jian; Luo, Yong-Chun; Xu, Guo-Qiang; Qi, Li; Hu, Xiu-Qin; Xu, Peng-Fei; Zhang, Liu-Yi; Cheng, Shao-Yi

    2015-05-01

    This paper investigates the detrimental effect of lizardite surface characteristics on pentlandite flotation. To reduce the effect, two different starch graft copolymers, starch-graft-polyacrylamide (S-g-PAM) and starch-graft-polyacrylic acid (S-g-PAA) were synthesized as depressants for lizardite. The flotation results show that at pH value of 8, where the flotation of lizardite and pentlandite are routinely performed, S-g-PAM and S-g-PAA improve pentlandite recovery efficiently, compared with the traditional depressant carboxymethyl cellulose (CMC). Experimental results demonstrate that S-g-PAM and S-g-PAA disperse the hydrophilic lizardite particles from the pentlandite surface and also flocculate lizardite particles.

  15. Mechanism of radiation graft of methyl-. cap alpha. -fluoroacrylate and. cap alpha. ,. beta. ,. beta. -trifluorostyrene on perfluorinated copolymer. [Cobalt 60

    Energy Technology Data Exchange (ETDEWEB)

    Ivankin, A.N.; Tevlina, A.S.; Zagorets, P.A. (Moskovskij Khimiko-Tekhnologicheskij Inst. (USSR))

    1983-04-01

    The kinetics of radiation-induced graft copolymerization of methyl-..cap alpha..-fluoroacrylate and ..cap alpha.., ..beta.., ..beta..-trifluorostyrene to perfluorinated copolymer of hexafluoropropylene with tetrafluoroethylene has been studied. The orders of the grafting reaction towards the monomer and dose rate as well as the values of rate constants of radiation-induced grafting at various temperatures were determined, the effective activation energy of grafting (20.6 kJ/mol) was calculated. The kinetic scheme of elementary acts of radiation-induced graft copolymerization is discussed.

  16. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties.

    Science.gov (United States)

    Xu, Jingyuan; Krietemeyer, Elizabeth F; Finkenstadt, Victoria L; Solaiman, Daniel; Ashby, Richard D; Garcia, Rafael A

    2016-04-20

    Graft copolymers of waxy maize starch and poly-γ-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180°C and pH7.0 were the best reaction conditions resulting in a PGA graft of 0.45% based on nitrogen analysis. The average graft content and graft efficiency for the starch-PGA graft copolymer prepared at 180°C and pH7.0 were 4.20% and 2.73%, respectively. The starch-PGA graft copolymer produced at 180°C and pH7.0 could absorb more than 20 times its own weight amount of water and form a gel. The preliminary rheology study revealed that the starch-PGA graft copolymer gel exhibited viscoelastic solid behavior while the control sample of waxy starch showed viscoelastic liquid behavior. Published by Elsevier Ltd.

  17. Thermoresponsive copolymer-grafted SBA-15 porous silica particles for temperature-triggered topical delivery systems

    Directory of Open Access Journals (Sweden)

    S. A. Jadhav

    2017-02-01

    Full Text Available A series of poly(N-isopropylacrylamide-co-acrylamide thermoresponsive random copolymers with different molecular weights and composition were synthesized and characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR, differential scanning calorimetry (DSC, size exclusion chromatography (SEC and proton nuclear magnetic resonance (NMR spectroscopy. The lower critical solution temperatures (LCST of the copolymers were tuned by changing the mole ratios of monomers. Copolymer with highest molecular weight and LCST (41.2 °C was grafted on SBA-15 type mesoporous silica particles by a two-step polymer grafting procedure. Bare SBA-15 and the thermoresponsive copolymergrafted (hybrid SBA-15 particles were fully characterized by scanning electron microscope (SEM, ATR-FTIR, thermogravimetric analysis (TGA and Brunauer-Emmett-Teller (BET analyses. The hybrid particles were tested for their efficiency as temperature-sensitive systems for dermal delivery of the antioxidant rutin (quercetin-3-O-rutinoside. Improved control over rutin release by hybrid particles was obtained which makes them attractive hybrid materials for drug delivery.

  18. The Synthesis and Structural Characterization of Graft Copolymers Composed of γ-PGA Backbone and Oligoesters Pendant Chains

    Science.gov (United States)

    Kwiecień, Iwona; Radecka, Iza; Kowalczuk, Marek; Jelonek, Katarzyna; Orchel, Arkadiusz; Adamus, Grażyna

    2017-07-01

    The novel copolymers composed of poly-γ-glutamic acid (γ-PGA) and oligoesters have been developed. The structures of the obtained copolymers including variety of end groups were determined at the molecular level with the aid of electrospray ionization multistage mass spectrometry (ESI-MSn). The fragmentation experiment performed for the selected sodium adducts of the copolymers confirmed that the developed methods lead to the formation of graft copolymers composed of poly-γ-glutamic acid (γ-PGA) backbone and oligoesters pendant chains. Moreover, it was established that fragmentation of selected sodium adducts of graft copolymers proceeded via random breakage of amide bonds along the backbone and ester bonds of the oligoesters pendant chains. Considering potential applications of the synthesized copolymers in the area of biomaterials, the hydrolytic degradation under laboratory conditions and in vitro cytotoxicity tests were performed. The ESI-MSn technique applied in this study has been proven to be a useful tool in structural studies of novel graft copolymers as well as their degradation products.

  19. Fungal biodegradation of lignopolystyrene graft copolymers. [Pleurotus ostreatus; Phanerochaete chrysosporium; Trametes versicolor; Gloeophyllum trabeum

    Energy Technology Data Exchange (ETDEWEB)

    Milstein, O.; Gersonde, R.; Huttermann, A. (Forstbotanisches Inst. der Univ. Gottingen (Germany)); MengJiu Chen; Meister, J.J (Univ. of Detroit Mercy, MI (United States))

    1992-10-01

    White rot basidiomycetes were able to biodegrade styrene (1-phenylethene) graft copolymers of lignin containing different proportions of lignin and polystyrene (poly(1-phenylethylene)). The biodegradation tests were run on lignin-styrene copolymerization products which contained 10.3, 32.2, and 50.4{percent} (wt/wt) lignin. The polymer samples were incubated with the white rot fungi Pleurotus ostreatus, Phanerochaete chrysosporium, and Trametes versicolor and the brown rot fungus Gloeophyllum trabeum. White rot fungi degraded the plastic samples at a rate which increased with increasing lignin content in the copolymer sample. Both polystyrene and lignin components of the copolymer were readily degraded. Polystyrene pellets were not degradable in these tests. Degradation was verified for both incubated and control samples by weight loss, quantitative UV spectrophotometric analysis of both lignin and styrene residues, scanning electron microscopy of the plastic surface, and the presence of enzymes active in degradation during incubation. Brown rot fungus did not affect any of the plastics. White rot fungi produced and secreted oxidative enzymes associated with lignin degradation in liquid media during incubation with lignin-polystyrene copolymer.

  20. Drug release property of a pH-responsive double-hydrophilic hyperbranched graft copolymer

    Institute of Scientific and Technical Information of China (English)

    SUN XiaoYi; ZHOU YongFeng; YAN DeYue

    2009-01-01

    In this paper, we report the synthesis and self-assembly of double-hydrophilie hyperbranched graft copolymers of HPG-g-PDMAEMA, which consist of a hyperbranched polyglycerol (HPG) core and several grafted poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) arms. HPG was synthesized by cationic polymerization. Then HPG-Br macroinitiator was obtained by esterification of HPG with 2-bromoisobutyryl bromide, which was subsequently used in the preparation of HPG-g-PDMAEMA graft copolymers through atom transfer radical polymerization (ATRP) of DMAEMA monomers. The molecular structures were studied by 1H NMR arid GPC. The pyrene-based fluorescent probe method, 1H NMR and DLS were used to study the self-assembly behavior of HPG-g-PDMAEMA. The drug loading and pH-responsive release properties of HPG-g-PDMAEMA were also investigated by using coumarin 102 as a model drug. The results show that the HPG-g-PDMAEMA micelles can continuously release and re-encapsulate coumarin 102 as the pH continuously changes from 11.5 to 2.5; however, this process is not totally reversible.

  1. Drug release property of a pH-responsive double-hydrophilic hyperbranched graft copolymer

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, we report the synthesis and self-assembly of double-hydrophilic hyperbranched graft copolymers of HPG-g-PDMAEMA, which consist of a hyperbranched polyglycerol (HPG) core and several grafted poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) arms. HPG was synthesized by cationic polymerization. Then HPG-Br macroinitiator was obtained by esterification of HPG with 2-bromoisobutyryl bromide, which was subsequently used in the preparation of HPG-g-PDMAEMA graft copolymers through atom transfer radical polymerization (ATRP) of DMAEMA monomers. The molecular structures were studied by 1H NMR and GPC. The pyrene-based fluorescent probe method, 1H NMR and DLS were used to study the self-assembly behavior of HPG-g-PDMAEMA. The drug loading and pH-responsive release properties of HPG-g-PDMAEMA were also investigated by using coumarin 102 as a model drug. The results show that the HPG-g-PDMAEMA micelles can continuously release and re-encapsulate coumarin 102 as the pH continuously changes from 11.5 to 2.5; however, this process is not totally reversible.

  2. Poly(ester amide-Poly(ethylene oxide Graft Copolymers: Towards Micellar Drug Delivery Vehicles

    Directory of Open Access Journals (Sweden)

    Gregory J. Zilinskas

    2012-01-01

    Full Text Available Micelles formed from amphiphilic copolymers are promising materials for the delivery of drug molecules, potentially leading to enhanced biological properties and efficacy. In this work, new poly(ester amide-poly(ethylene oxide (PEA-PEO graft copolymers were synthesized and their assembly into micelles in aqueous solution was investigated. It was possible to tune the sizes of the micelles by varying the PEO content of the polymers and the method of micelle preparation. Under optimized conditions, it was possible to obtain micelles with diameters less than 100 nm as measured by dynamic light scattering and transmission electron microscopy. These micelles were demonstrated to encapsulate and release a model drug, Nile Red, and were nontoxic to HeLa cells as measured by an MTT assay. Overall, the properties of these micelles suggest that they are promising new materials for drug delivery systems.

  3. Synthesis of polyethylenimine grafted with copolymers of polyethylene glycol and polycaprolactone and its potential for siRNA delivery

    Institute of Scientific and Technical Information of China (English)

    Wei Huang; Ming Lv; Zhong Gao Gao

    2011-01-01

    Copolymers mPEG-PCL were prepared and grafted onto polyethylenimine (PEI) to synthesize copolymers mPEG-PCL-g-PEI with low cytotoxicity. The mPEG-PCL-g-PEI could condense siRNA to form nanoparticles with positive zeta potential. These nanoparticles could delivery siRNA into cells to effectively inhibit the expression of target gene, which suggested that mPEG-PCL-g-PEl could serve as a highly efficient vector for siRNA delivery.

  4. Properties of starch-polyglutamic acid (PGA) graft copolymer prepared by microwave irradiation - Fourier transform infrared spectroscopy (FTIR) and rheology studies

    Science.gov (United States)

    The rheological properties of waxy starch-'-polygutamic acid (PGA) graft copolymers were investigated. Grafting was confirmed by FTIR spectroscopy. The starch-PGA copolymers absorbed water and formed gels, which exhibited concentration-dependent viscoelastic solid properties. Higher starch-PGA conce...

  5. Graft-copolymer-based approach to clear, durable, and anti-smudge polyurethane coatings.

    Science.gov (United States)

    Rabnawaz, Muhammad; Liu, Guojun

    2015-05-26

    Clear anti-smudge coatings with a thickness of up to tens of micrometers have been prepared through a graft-copolymer-based approach from commercial precursors. The coatings repel water, diiodomethane, hexadecane, ink, and an artificial fingerprint liquid. In addition, they can be readily applied onto different substrates using different coating methods. These coatings could find applications in protecting hand-held electronic devices from fingerprints, windows from stains, and buildings from graffiti. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Space charge behaviour in maleic anhydride grafted polyethylene/ethylene - vinyl - acetate copolymer laminates

    Science.gov (United States)

    Lee, Seung Hyung; Park, Jung Ki; Han, Jae Hong; Suh, Kwang S.

    1997-01-01

    Charge distributions in maleic anhydride (MAH) grafted polyethylene (g-PE)/ethylene - vinyl - acetate (EVA) copolymer laminates have been measured with materials of different composition. All laminates showed interfacial charge, the polarity and the magnitude of which are explained by interfacial polarization. It was found that the interfacial charge increased with the increase of MAH content in the g-PE, whereas it decreased with the increase of vinyl - acetate content in the EVA. This feature was attributed to the differences in electrical conductivity of the materials. Details of the experimental results are described.

  7. Design of 3D scaffolds for tissue engineering testing a tough polylactide-based graft copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Dorati, R., E-mail: rossella.dorati@unipv.it [Department of Drug Sciences, University of Pavia, V.le Taramelli 12, 27100 Pavia (Italy); Center for Tissue Engineering (CIT), University of Pavia, Via Ferrata 1, 27100 Pavia (Italy); Colonna, C. [Department of Drug Sciences, University of Pavia, V.le Taramelli 12, 27100 Pavia (Italy); Center for Tissue Engineering (CIT), University of Pavia, Via Ferrata 1, 27100 Pavia (Italy); Tomasi, C. [C.S.G.I., Department of Chemistry, Division of Physical Chemistry, University of Pavia, V.le Taramelli 16 I, 27100 Pavia (Italy); Genta, I. [Department of Drug Sciences, University of Pavia, V.le Taramelli 12, 27100 Pavia (Italy); Center for Tissue Engineering (CIT), University of Pavia, Via Ferrata 1, 27100 Pavia (Italy); Bruni, G. [C.S.G.I., Department of Chemistry, Division of Physical Chemistry, University of Pavia, V.le Taramelli 16 I, 27100 Pavia (Italy); Conti, B. [Department of Drug Sciences, University of Pavia, V.le Taramelli 12, 27100 Pavia (Italy); Center for Tissue Engineering (CIT), University of Pavia, Via Ferrata 1, 27100 Pavia (Italy)

    2014-01-01

    The aim of this research was to investigate a tough polymer to develop 3D scaffolds and 2D films for tissue engineering applications, in particular to repair urethral strictures or defects. The polymer tested was a graft copolymer of polylactic acid (PLA) synthesized with the rationale to improve the toughness of the related PLA homopolymer. The LMP-3055 graft copolymer (in bulk) demonstrated to have negligible cytotoxicity (bioavailability > 85%, MTT test). Moreover, the LMP-3055 sterilized through gamma rays resulted to be cytocompatible and non-toxic, and it has a positive effect on cell biofunctionality, promoting the cell growth. 3D scaffolds and 2D film were prepared using different LMP-3055 polymer concentrations (7.5, 10, 12.5 and 15%, w/v), and the effect of polymer concentration on pore size, porosity and interconnectivity of the 3D scaffolds and 2D film was investigated. 3D scaffolds got better results for fulfilling structural and biofunctional requirements: porosity, pore size and interconnectivity, cell attachment and proliferation. 3D scaffolds obtained with 10 and 12.5% polymer solutions (3D-2 and 3D-3, respectively) were identified as the most suitable construct for the cell attachment and proliferation presenting pore size ranged between 100 and 400 μm, high porosity (77–78%) and well interconnected pores. In vitro cell studies demonstrated that all the selected scaffolds were able to support the cell proliferation, the cell attachment and growth resulting to their dependency on the polymer concentration and structural features. The degradation test revealed that the degradation of polymer matrix (ΔMw) and water uptake of 3D scaffolds exceed those of 2D film and raw polymer (used as control reference), while the mass loss of samples (3D scaffold and 2D film) resulted to be controlled, they showed good stability and capacity to maintain the physical integrity during the incubation time. - Highlights: • Tough PLA graft copolymer was proposed

  8. Synthesis of Antibacterial Silver–Poly(ɛ-caprolactone-Methacrylic Acid Graft Copolymer Nanofibers and Their Evaluation as Potential Wound Dressing

    Directory of Open Access Journals (Sweden)

    Mohammed A. Al-Omair

    2015-08-01

    Full Text Available Electrospun polycaprolacyone/polymethacrylic acid graft copolymer nanofibers (PCL/MAA containing silver nanoparticles (AgNPs were synthesized for effective wound disinfection. Surface morphology, AgNPs content, water uptake of electrospun PCL/MAA graft copolymer nanofibers without and with AgNPs, and levels of AgNPs leaching from the nanofibers in water as well as antimicrobial efficacy were studied. Scanning electron microscope images revealed that AgNPs dispersed well in PCL/MAA copolymer nanofibers with mean fiber diameters in the range of 200–579 nm and the fiber uniformity and diameter were not affected by the AgNPs. TEM images showed that AgNPs are present in/on the electrospun PCL/MAA graft copolymer nanofibers. The diameter of the electrospun nanofibers containing AgNPs was in the range of 200–579 nm, however, the diameter of AgNPs was within the range of 20–50 nm and AgNPs were observed to be spherical in shape. The PCL/MAA copolymer nanofibers showed a good hydrophilic property and the nanofibers containing AgNPs had excellent antimicrobial activity against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and against the Gram-positive bacteria Bacillus thuringiensis and Staphylococcus aureus, with a clear inhibition zone with a diameter between 22 and 53 mm. Moreover, electrospun PCL/MAA copolymer nanofibers sustained the release of AgNPs into water over 72 h.

  9. Delivery of antisense oligonucleotides using poly(alkylene oxide)-poly(propylacrylic acid) graft copolymers in conjunction with cationic liposomes.

    Science.gov (United States)

    Peddada, Lavanya Y; Garbuzenko, Olga B; Devore, David I; Minko, Tamara; Roth, Charles M

    2014-11-28

    The clinical application of gene silencing is hindered by poor stability and low delivery efficiency of naked oligonucleotides. Here, we present the in vitro and in vivo behaviors of a rationally designed, ternary, self-assembled nanoparticle complex, consisting of an anionic copolymer, cationic DOTAP liposome, and antisense oligonucleotide (AON). The multifunctional copolymers are based on backbone poly(propylacrylic acid) (PPAA), a pH-sensitive hydrophobic polymer, with grafted poly(alkylene oxides) (PAOs) varying in extent of grafting and PAO chemistry. The nanoparticle complexes with PPAA-g-PAO copolymers enhance antisense gene silencing effects in A2780 human ovarian cancer cells. A greater amount of AON is delivered to ovarian tumor xenografts using the ternary copolymer-stabilized delivery system, compared to a binary DOTAP/AON complex, following intraperitoneal injection in mice. Further, intratumoral injection of the nanoparticle complexes containing 1 mol% grafted PAO reduced tumoral bcl-2 expression by up to 60%. The data for complexes across the set of PAO polymers support a strong role for the hydrophilic-lipophilic balance of the graft copolymer in achieving serum stability and cellular uptake. Based upon these results, we anticipate that this novel nanoparticle delivery system can be extended to the delivery of plasmid DNA, siRNA, or aptamers for preclinical and clinical development. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. The Optimized Synthesis of Starch-g-Lactic Acid Copolymer with High Grafting Degree Catalyzed by Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    HU Zhiying

    2014-01-01

    The starch-g-lactic acid copolymer was synthesized with catalysis of sulfuric acid by one-step process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, 13C-NMR, HMBC, XRD, and SEM. The experimental results show that the maximum grafting degree of starch can reach 75%when the starch-g-lactic acid copolymer is activated at 80℃for 2 h and reacted with lactic acid at 90℃for 4 h in vacuum.

  11. Study of cross-linking process in grafted polyethylene and ethylene based copolymer using a phase resolved photoacoustic method

    Science.gov (United States)

    Dias, D. T.; Medina, A. N.; Baesso, M. L.; Bento, A. C.; Porto, M. F.; Muniz, E. C.; Rubira, A. F.

    2003-01-01

    In this work, the phase resolved photoacoustic method has been employed to monitor water saturated vapor cross linking in both copolymer and grafted polyethylene. The overtone bands and stretching frequencies combinations of the -Si-OH, =CH2, -CH3, and -CH2-CH3 were monitored and analyzed accordingly to a 32 factorial design with nine samples. The results showed that the cross-linking processes were more efficient when the samples were prepared at 80 °C with the catalyst in the concentration range between 3% and 5% for grafted PE, while 70 °C was the best temperature to obtain copolymer.

  12. Water soluble graft copolymer ({kappa}-carrageenan-g-N-vinyl formamide): preparation, characterization and application

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, M.M.; Yadav, M.; Sand, A.; Tripathy, J.; Behari, K. [University of Allahabad, Allahabad (India). Dept. of Chemistry

    2010-03-25

    {kappa}-Carrageenan-g-N-vinyl formamide was synthesized by free radical initiation using the potassium monopersulphate (PMS)/malonic acid redox pair in an inert atmosphere. The effects of variation of different reactant oil grafting parameters have been studied by varying the concentration. Grafting ratio, add on and conversion showed an increasing trend on increasing the concentration of N-vinyl formamide, malonic acid, kappa-carrageenart and the concentration of PMS from 6 x 10{sup -3} to 22 x 10{sup -3} mol dm{sup -3}. The optimum temperature and time for grafting of N-vinyl formamide onto {kappa}-carrageenan was found to be 40{sup o}C and 120 min, respectively. The metal ion sorption, swelling behaviour, flocculation and resistance to biodegradation properties have been studied. Flocculation capability of {kappa}-carrageenart and {kappa}-carrageenan-g-N-vinyl formamide for both coking and non-coking coals has been studied for the treatment of coal mine waste water. The graft copolymer was characterized by FT-IR spectroscopy and thermogravimetric analysis.

  13. Robust nanogenerators based on graft copolymers via control of dielectrics for remarkable output power enhancement

    Science.gov (United States)

    Lee, Jae Won; Cho, Hye Jin; Chun, Jinsung; Kim, Kyeong Nam; Kim, Seongsu; Ahn, Chang Won; Kim, Ill Won; Kim, Ju-Young; Kim, Sang-Woo; Yang, Changduk; Baik, Jeong Min

    2017-01-01

    A robust nanogenerator based on poly(tert-butyl acrylate) (PtBA)–grafted polyvinylidene difluoride (PVDF) copolymers via dielectric constant control through an atom-transfer radical polymerization technique, which can markedly increase the output power, is demonstrated. The copolymer is mainly composed of α phases with enhanced dipole moments due to the π-bonding and polar characteristics of the ester functional groups in the PtBA, resulting in the increase of dielectric constant values by approximately twice, supported by Kelvin probe force microscopy measurements. This increase in the dielectric constant significantly increased the density of the charges that can be accumulated on the copolymer during physical contact. The nanogenerator generates output signals of 105 V and 25 μA/cm2, a 20-fold enhancement in output power, compared to pristine PVDF–based nanogenerator after tuning the surface potential using a poling method. The markedly enhanced output performance is quite stable and reliable in harsh mechanical environments due to the high flexibility of the films. On the basis of these results, a much faster charging characteristic is demonstrated in this study. PMID:28560339

  14. CHARACTERIZATION OF AMPHIPHILIC AND MICROPHASE SEPARATED GRAFT COPOLYMERS Ⅱ SURFACE CHARACTERIZATION AND IN VITRO BLOOD-COMPATIBILITY ASSESSMENT OF POLYSTYRENE-GRAFT-ω-STEARYL-POLY (ETHYLENE OXIDE)

    Institute of Scientific and Technical Information of China (English)

    QIU Yongxing; YU Xiaojie; FENG Linxian; YANG Shilin

    1995-01-01

    This paper reported the research results concerning the surface characterization ofpolystyrene-graft- w -stearyl poly(ethylene oxide) (PS-g-SPEO) by means of XPS,contactangle measurement and TEM, and its in vitro blood compatibility assessment by measuringthe plasma recalcification time (RT) and partial thromboplastin time (PTT). The XPSresults demonstrated that the surface and bulk composition of the PS-g-SPEO graftcopolymers differ remarkably from each other,and that SPEO component was constantlyenriched at the copolymer/air interface. Contact angle studies indicated that the surfacewater wettability can be adjusted effectively by changing the composition of the copolymer.PS-g-SPEO graft copolymers can undergo microphase separation as clearly illustrated byTEM photographs. The relationship between the surface properties of PS-g-SPEO graftcopolymer and its blood compatibility was also discussed.

  15. Vinil polyacetate-cassava starch graft copolymer as coal dust suppressing agent

    Energy Technology Data Exchange (ETDEWEB)

    Luis Montero; Rafael Gonzalez; Edwin Primera; Juan Barcenas; R. Barranco [Universidad del Atlantico, Barranquilla (Colombia). Coal Research Centre and Polymer Research Centre, Engineering Faculty

    2007-07-01

    Graft copolymerisation of vinyl polyacetate (VPA) onto both native (NS) and oxidised (OS) cassava (manihot esculenta) starch was carried out. The OS-VPA graft copolymer gave the higher percentage of VPA at 74%, while that of NC-VPA showed the greater starch yield and higher rate of copolymerisation at 64%. The polymeric emulsions obtained with both starches were tested as coal dust suppressing agents. The tests were performed in a wind tunnel. Coal samples of a specific size distribution were sprayed with an aqueous polymeric emulsion ie. VPA + copolymer + residual starch, and sun dried, before being subjected to a 30 mph air stream. The performance of the polymeric dispersion when using a dosage between 2 and 4 g per 100 in{sup 2}, and solid concentrations of 2.5 and 5 %w/w, was satisfactory, giving coal dust losses of less than 0.5%. The addition of a surfactant remarkably enhanced the dust abatement properties of the polymeric emulsion, so as for a low dosage of 1.5 g per 100 in{sup 2}, the dust losses were virtually negligible. 7 refs., 1 figs., 1 tab.

  16. Weathering and Biodegradation Study on Graft Copolymer Compatibilized Hybrid Bionanocomposites of Poly(Lactic Acid)

    Science.gov (United States)

    Sajna, VP; Nayak, Sanjay K.; Mohanty, Smita

    2016-07-01

    This work reports on the influence of moisture absorption and accelerated weathering on the properties of graft copolymer compatibilized bionanocomposites of poly(lactic acid) (PLA). Moisture absorption tests were conducted for 30 days by immersing the samples in a distilled water bath at room temperature, and the amount of moisture absorbed in each time interval was measured. The rate of moisture uptake decreased by incorporation of C30B nanoclay and graft copolymer into fiber-reinforced PLA composites. Changes in the mechanical properties of composites in each time interval of moisture absorption were investigated using tensile and impact tests. Exposure to moisture caused significant drops in the mechanical properties. The morphological characterization of biocomposites during the aforementioned tests has been made using SEM, while bionanocomposites were analyzed by TEM. Further, this paper also reported the effect of accelerated weathering on the mechanical properties and the results are confirmed through SEM analysis. Biodegradation behaviors of PLA biocomposites and bionanocomposites have also been studied.

  17. Polyethylene glycol-polyvinyl alcohol grafted copolymer: study of the bioavailability after oral administration to rats.

    Science.gov (United States)

    Heuschmid, Franziska F; Schuster, Paul; Lauer, Birthe; Fabian, Eric; Leibold, Edgar; van Ravenzwaay, Bennard

    2013-07-01

    The absorption, urinary excretion, and the biliary excretion of a single oral dose of 10 or 1000 mg/kg bw of (14)C-polyethylene glycol-polyvinyl alcohol (PEG-PVA) grafted copolymer were studied in adult male and female rats. In a balance/excretion experiment, the total excretion of ingested radioactivity was determined over a period of 168 h and residual radioactivity was detected in selected tissues and the carcass. In a biliary excretion experiment, excretion of radioactivity via the bile duct was determined over a period of 48 h after administration of the substance to cannulated rats. Most, if not all, of the radioactivity (>100%) was excreted within 48 h via the feces regardless of sex or dose. Urinary excretion was very limited: 0.45-0.50% of dose at the low dose and 0.22-0.27% of dose at the high dose. At both dose levels, residual radioactivity in the carcass and all organs and tissues after 168 h was ≤ 0.02% of dose. Biliary excretion was 0.01-0.02% of dose. Based on these findings, the bioavailability of PEG-PVA grafted copolymer was determined to be <1% demonstrating that absorption was virtually negligible following a single oral administration to male and female rats.

  18. Soluplus graft copolymer: potential novel carrier polymer in electrospinning of nanofibrous drug delivery systems for wound therapy.

    Science.gov (United States)

    Paaver, Urve; Tamm, Ingrid; Laidmäe, Ivo; Lust, Andres; Kirsimäe, Kalle; Veski, Peep; Kogermann, Karin; Heinämäki, Jyrki

    2014-01-01

    Electrospinning is an effective method in preparing polymeric nanofibrous drug delivery systems (DDSs) for topical wound healing and skin burn therapy applications. The aim of the present study was to investigate a new synthetic graft copolymer (Soluplus) as a hydrophilic carrier polymer in electrospinning of nanofibrous DDSs. Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PCL-PVAc-PEG)) was applied in the nonwoven nanomats loaded with piroxicam (PRX) as a poorly water-soluble drug. Raman spectroscopy, X-ray powder diffraction, differential scanning calorimetry, and scanning electron microscopy (SEM) were used in the physical characterization of nanofibrous DDSs. According to the SEM results, the drug-loaded PCL-PVAc-PEG nanofibers were circular in cross-section with an average diameter ranging from 500 nm up to 2  µm. Electrospinning stabilized the amorphous state of PRX. In addition, consistent and sustained-release profile was achieved with the present nanofibrous DDSs at the physiologically relevant temperature and pH applicable in wound healing therapy. In conclusion, electrospinning can be used to prepare nanofibrous DDSs of PCL-PVAc-PEG graft copolymer (Soluplus) and to stabilize the amorphous state of a poorly water-soluble PRX. The use of this synthetic graft copolymer can open new options to formulate nanofibrous DDSs for wound healing.

  19. Properties of Starch-Poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) Graft Copolymers Prepared by Reactive Extrusion

    Science.gov (United States)

    Graft copolymers of starch with acrylamide and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were prepared by reactive extrusion in a twin-screw extruder. The weight ratio of total monomer to starch was fixed at 1:3, while the molar fraction of AMPS in the monomer feed ranged from 0 to 0.119. Mon...

  20. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties

    Science.gov (United States)

    Graft copolymers of waxy maize starch and poly-y-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180 deg C and pH 7.0 were the best reaction conditions resulti...

  1. Soluplus Graft Copolymer: Potential Novel Carrier Polymer in Electrospinning of Nanofibrous Drug Delivery Systems for Wound Therapy

    Directory of Open Access Journals (Sweden)

    Urve Paaver

    2014-01-01

    Full Text Available Electrospinning is an effective method in preparing polymeric nanofibrous drug delivery systems (DDSs for topical wound healing and skin burn therapy applications. The aim of the present study was to investigate a new synthetic graft copolymer (Soluplus as a hydrophilic carrier polymer in electrospinning of nanofibrous DDSs. Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PCL-PVAc-PEG was applied in the nonwoven nanomats loaded with piroxicam (PRX as a poorly water-soluble drug. Raman spectroscopy, X-ray powder diffraction, differential scanning calorimetry, and scanning electron microscopy (SEM were used in the physical characterization of nanofibrous DDSs. According to the SEM results, the drug-loaded PCL-PVAc-PEG nanofibers were circular in cross-section with an average diameter ranging from 500 nm up to 2 µm. Electrospinning stabilized the amorphous state of PRX. In addition, consistent and sustained-release profile was achieved with the present nanofibrous DDSs at the physiologically relevant temperature and pH applicable in wound healing therapy. In conclusion, electrospinning can be used to prepare nanofibrous DDSs of PCL-PVAc-PEG graft copolymer (Soluplus and to stabilize the amorphous state of a poorly water-soluble PRX. The use of this synthetic graft copolymer can open new options to formulate nanofibrous DDSs for wound healing.

  2. Graft copolymerization onto polybutadiene: Cross-linking and thermal degradation of vinyl polymers and copolymers

    Science.gov (United States)

    Jiang, Dayue (David)

    This work consists of three parts. In Part I, the graft copolymerization of methyl methacrylate, methyl acrylate, methacylic acid and acrylic acid onto polybutadiene and its copolymers by benzoyl peroxide, BPO, or 2, 2'azobis(2-methylpropionitrile), AIBN, initiation were explored. The results show that these monomers can be grafted onto butadiene region of butadiene-containing polymers. The extent of both graft copolymerization and homopolymerization are dependent on the time and temperature of the reaction and the concentration of all of the reactants. One must specify the monomer, initiator and solvent for the efficient graft copolymerization. The methyl methacrylate adds directly to the radical sites which are formed on the backbone by the interaction of the polymer and the primary radical form the initiator, while for the other three monomers, the graft copolymerization occurs by addition of macro-radical to the double bonds. In Part II, the cross-linking of polybutadiene, butadiene-styrene copolymers, and polystyrene by irradiation, thermal and chemical processes, and Friedel-Crafts chemistry and the effect of cross-linking on the thermal stability were investigated. The proof of cross-linking of the polymer comes from the insolubility of the product after the cross-linking reaction and is characterized by gel content and swelling ratio. The results show that the thermal stability of the polymer can be improved by cross-linking. In Part III, the thermal degradation of three vinyl polymers, poly(vinylsulfonic acid) and its sodium salt and poly(vinylphosphonic acid) were studied by combination technique: TGA/FTIR. The results show that TGA/FTIR combined with analysis of residues provides an excellent opportunity to understand the degradation pathway of the compounds. The observation of foaming indicates that the char which is formed contains carbon as well as the inorganic salts which have been observed. The carbon is in a partially graphitized form. The salts

  3. Study of the Effect of Grafted Antioxidant on the Acrylonitrile-Butadiene Copolymer Properties

    Directory of Open Access Journals (Sweden)

    Abdulaziz Ibrahim Al-Ghonamy

    2010-01-01

    Full Text Available The grafting of ADPEA onto natural rubber was executed with UV radiation. Benzoyl peroxide was used to initiate the free-radical grafting copolymerization. Natural rubber-graft-N-(4-aminodiphenylether acrylamide (NR-g-ADPEA was characterized with an IR technique. The paper aims interested to determine the crosslinking density by using the ultrasonic technique. The ultrasonic velocities of both longitudinal and shear waves were measured in thermoplastic discs of NBR vulcanizates as a function of aging time. Ultrasonic velocity measurements were taken at 2 MHz ultrasonic frequency using the pulse echo method. We studied the effect of aging on the mechanical properties, crosslinking density, and the swelling and extraction phenomena for acrylonitrile-butadiene copolymer (NBR vulcanizates, which contained the prepared NR-g-ADPEA and a commercial antioxidant, N-isopropyl-−-phenyl-p-phenylenediamine. The prepared antioxidant enhanced both the mechanical properties of the NBR vulcanizates and the permanence of the ingredients in these vulcanizates.

  4. The Mechanical Properties of Epoxy Composites Filled with Rubbery Copolymer Grafted SiO2

    Directory of Open Access Journals (Sweden)

    Linda S. Schadler

    2012-01-01

    Full Text Available This study demonstrated a method for toughening a highly crosslinked anhydride cured DGEBA epoxy using rubbery block copolymer grafted SiO2 nanoparticles. The particles were synthesized by a sequential reversible addition-fragmentation chain transfer (RAFT polymerization. The inner rubbery block poly(n-hexyl methacrylate (PHMA had a glass transition temperature below room temperature. The outer block poly(glycidyl methacrylate (PGMA was matrix compatible. A rubbery interlayer thickness of 100% and 200% of the particle core radius was achieved by grafting a 20 kg/mol and a 40 kg/mol PHMA at a graft density of 0.7 chains/nm2 from the SiO2 surface. The 20 kg/mol rubbery interlayer transferred load more efficiently to the SiO2 cores than the 40 kg/mol rubbery interlayer and maintained the epoxy modulus up to a loading of 10 vol% of the rubbery interlayer. Both systems enabled cavitation or plastic dilatation. Improvement of the strain-to-break and the tensile toughness was found in both systems. We hypothesize that plastic void growth in the matrix is the primary mechanism causing the improvement of the ductility.

  5. Amphiphilic Graft Copolymer Nanospheres: From Colloidal Self-Assembly to CO2 Capture Membranes.

    Science.gov (United States)

    Jeon, Harim; Kim, Dong Jun; Park, Min Su; Ryu, Du Yeol; Kim, Jong Hak

    2016-04-13

    Colloidal nanosphere self-assembly effectively generates ordered nanostructures, prompting tremendous interest in many applications such as photonic crystals and templates for inverse opal fabrication. Here we report the self-assembly of low-cost, graft copolymer nanospheres for CO2 capture membranes. Specifically, poly(dimethylsiloxane)-graft-poly(4-vinylpyridine) (PDMS-g-P4VP) is synthesized via one-pot, free radical dispersion polymerization to give discrete monodisperse nanospheres. These nanospheres comprise a surface-anchored highly permeable PDMS layer and internal CO2-philic P4VP spherical core. Their diameter is controllable below the submicrometer range by varying grafting ratios. The colloidal dispersion forms a long-range, close-packed hexagonal array on a substrate by inclined deposition and convective assembly. The array shows dispersion medium-dependent packing characteristics. A thermodynamic correlation is determined using different solvents to obtain stable PDMS-g-P4VP dispersions and interpreted in terms of Flory-Huggins interaction parameter. As a proof-of-concept, the implementation of these nanospheres into membranes simultaneously enhances the CO2 permeability and CO2/N2 selectivity of PDMS-based transport matrixes. Upon physical aging of the solution, the CO2/N2 selectivity is improved up to 26, one of the highest values for highly permeable PDMS-based polymeric membranes.

  6. RGD-grafted poly-L-lysine-graft-(polyethylene glycol) copolymers block non-specific protein adsorption while promoting cell adhesion.

    Science.gov (United States)

    VandeVondele, Stephanie; Vörös, Janos; Hubbell, Jeffrey A

    2003-06-30

    A novel class of surface-active copolymers is described, designed to protect surfaces from nonspecific protein adsorption while still inducing specific cell attachment and spreading. A graft copolymer was synthesized, containing poly-(L-lysine) (PLL) as the backbone and substrate binding and poly(ethylene glycol) (PEG) as protein adsorption-resistant pendant side chains. A fraction of the grafted PEG was pendantly functionalized by covalent conjugation to the peptide motif RGD to induce cell binding. The graft copolymer spontaneously adsorbs from dilute aqueous solution onto negatively charged surfaces. The performance of RGD-modified PLL-g-PEG copolymers was analyzed in protein adsorption and cell culture assays. These coatings efficiently blocked the adsorption of serum proteins to Nb(2)O(5) and tissue culture polystyrene while specifically supporting attachment and spreading of human dermal fibroblasts. This surface functionalization technology is expected to be valuable in both the biomaterial and biosensor fields, because different signals can easily be combined, and sterilization and application are straightforward and cost-effective.

  7. A new dextran-graft-polybutylmethacrylate copolymer coated on 316L metallic stents enhances endothelial cell coverage.

    Science.gov (United States)

    Derkaoui, S M; Labbé, A; Chevallier, P; Holvoet, S; Roques, C; Avramoglou, T; Mantovani, D; Letourneur, D

    2012-09-01

    Amphiphilic copolymers based on the copolymerization of hydrophilic and hydrophobic moieties offer versatility in various biomedical material applications. Here, a new biocompatible copolymer of dextran-graft-polybutylmethacrylate is synthesized for the coating of metallic endovascular stents. Coating of metallic surfaces is performed and analyzed by X-ray photoelectron spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, contact angle measurement, atomic force microscopy and scanning electron microscopy before and after deformation corresponding to stent deployment by a balloon catheter. In the conditions described here, the resulting coating is smooth and uniform with neither cracks nor detachment after stent expansion. Interestingly, surfaces coated with the copolymer greatly improve in vitro adhesion and growth of endothelial cells. This copolymer provides new opportunities for implanted biomaterials.

  8. ANTIBACTERIAL ACTIVITY OF SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS GRAFTED ON “GEL—TYPE” SYYRENE—DIVINYLBENZENE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    AdrianaPOPA; Corneliu-MircesaDAVIDESCU; 等

    2000-01-01

    A systematic study on the synthesis and antibacterial activity of the quaternary"onium" salts grafted on an insoluble"gel-type" stryene-7% divinylbenzene copolymer by polymer-analogous reactions is showed.Antibacterial activity of quaternary ammonium and/or phosphonium salts grafted on polymer-supports has been studied against staphylococcus aureus and Escherichia coli.A wide variety of "onium" salts bound to macromolecular supports with different quaternary groups and different quaternary chain length substituents were examined.The antibacterial activity of mixed "onium" salts increases as a consequence of the association of ammonium and phosphonium salts grafted on the same polymeric support.

  9. A novel route for the production of chitosan/poly(lactide-co-glycolide) graft copolymers for electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Xie Deming [Tissue Engineering Laboratory, Department of Biomedical Engineering, Jinan University, Guangzhou, 510630 (China); Huang Huamei [Morphological Experiments Center of Medical College, Jinan University, Guangzhou, 510630 (China); Blackwood, Keith; MacNeil, Sheila [Tissue Engineering Group, Department of Engineering Materials and Division of Biomedical Sciences and Medicine, Kroto Research Institute, University of Sheffield North Campus, Broad Lane, Sheffield S3 7HQ (United Kingdom)

    2010-12-15

    Both chitosan and polylactide/polyglycolide have good biocompatibility and can be used to produce tissue engineering scaffolds for cultured cells. However the synthetic scaffolds lack groups that would facilitate their modification, whereas chitosan has extensive active amide and hydroxyl groups which would allow it to be subsequently modified for the attachment of peptides, proteins and drugs. Also chitosan is very hydrophilic, whereas PLGA is relatively hydrophobic. Accordingly there are many situations where it would be ideal to have a copolymer of both, especially one that could be electrospun to provide a versatile range of scaffolds for tissue engineering. Our aim was to develop a novel route of chitosan-g-PLGA preparation and evaluate the copolymers in terms of their chemical characterization, their performance on electrospinning and their ability to support the culture of fibroblasts as an initial biological evaluation of these scaffolds. Chitosan was first modified with trimethylsilyl chloride, and catalyzed by dimethylamino pyridine. PLGA-grafted chitosan copolymers were prepared by reaction with end-carboxyl PLGA (PLGA-COOH). FT-IR and{sup 1}H-NMR characterized the copolymer molecular structure as being substantially different to that of the chitosan or PLGA on their own. Elemental analysis showed an average 18 pyranose unit intervals when PLGA-COOH was grafted into the chitosan molecular chain. Differential scanning calorimetry results showed that the copolymers had different thermal properties from PLGA and chitosan respectively. Contact angle measurements demonstrated that copolymers became more hydrophilic than PLGA. The chitosan-g-PLGA copolymers were electrospun to produce either nano- or microfibers as desired. A 3D fibrous scaffold of the copolymers gave good fibroblast adhesion and proliferation which did not differ significantly from the performance of the cells on the chitosan or PLGA electrospun scaffolds. In summary this work presents a

  10. Blood compatibility comparison for polysulfone membranes modified by grafting block and random zwitterionic copolymers via surface-initiated ATRP.

    Science.gov (United States)

    Xiang, Tao; Zhang, Li-Sha; Wang, Rui; Xia, Yi; Su, Bai-Hai; Zhao, Chang-Sheng

    2014-10-15

    For blood-contacting materials, good blood compatibility, especially good anticoagulant property is of great importance. Zwitterionic polymers have been proved to be resistant to nonspecific protein adsorption and platelet adhesion; however, their anticoagulant property is always inadequate. In this study, two kinds of zwitterionic copolymers (sulfobetaine methacrylate and sodium p-styrene sulfonate random copolymer and block copolymer) with sulfonic groups were covalently grafted from polysulfone (PSf) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) to improve blood compatibility. Field emission scanning electron microscopy (FE-SEM), attenuated total reflectance-Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and static water contact angle (WCA) were applied to characterize the morphologies, chemical compositions and hydrophilicity of the modified membranes. All the zwitterionic copolymer modified membranes showed improved blood compatibility, especially the anticoagulant property was obviously enhanced compared to the pristine PSf and simple zwitterionic polymer modified membranes. We also found that the random copolymer modified membranes showed better resistance to platelet adhesion than the block copolymer modified membranes. The zwitterionic copolymer modified membranes with integrated antifouling property and blood compatibility provided wide choice for specific applications such as hemodialysis, hemofiltration, and plasma separation.

  11. Grafting of copolymer styrene maleic anhydride on poly(ethylene terephthalate) film by chemical reaction and by plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Bigan, Muriel; Bigot, Julien [Laboratoire de Chimie Organique et Macromoleculaire (UMR 8009), Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Mutel, Brigitte [Laboratoire de Genie des Procedes d' Interactions Fluides reactifs-Materiaux (UPRES-EA 3751), Batiment C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France)], E-mail: Brigitte.mutel@univ-lille1.fr; Coqueret, Xavier [Laboratoire Reactions Selectives et Applications (UMR-CNRS 6519) Universite de Reims Champagne-Ardennes, B.P. 1039, 51687 Reims Cedex 2 (France)

    2008-02-15

    This work deals with the chemical grafting of a styrene maleic anhydride copolymer on the surface of a previously hydrolyzed polyethylene terephthalate (PET) film 12 {mu}m thick via covalent bond. Two different ways are studied. The first one involves an activation of the hydrolyzed PET by the triethylamine before the grafting step. In the second one, the copolymer reacts with the 4-dimethylaminopyridine in order to form maleinyl pyridinium salt which reacts with alcohol function of the hydrolyzed PET. Characterization and quantification of the grafting are performed by Fourier transform infrared spectroscopy. Factorial experiment designs are used to optimize the process and to estimate experimental parameters effects. The opportunity to associate the chemical process to a cold remote nitrogen plasma one is also examined.

  12. Preparation of lignosulfonate-acrylamide-chitosan ternary graft copolymer and its flocculation performance.

    Science.gov (United States)

    He, Kunpeng; Lou, Tao; Wang, Xuejun; Zhao, Wenhua

    2015-11-01

    As flocculant plays an important role in wastewater treatment, searching for high efficient and cost-effective flocculants has always become the challenge in chemical industry. In the current work, lignosulfonate-acrylamide-chitosan ternary copolymer was designed and prepared as a new kind of flocculant. The elemental analysis and structure characterization of FTIR and XRD showed that acrylamide successfully grafted onto the two natural polymers and amorphous macromolecules were formed. The natural polymers-based flocculant was water soluble and pH independent. As it had multiple functional groups from the raw materials, the amphoteric flocculant showed high color removal efficiency to anionic (acid blue 113, >95%), neutral (reactive black 5, >95%) and cationic dyes (methyl orange, >50%) in a wide range of flocculant dosage and pH windows. The ternary flocculant, based on lignosulfonate, chitosan, and acrylamide, might be a promising material in practical applications from the perspective of cost, source and performance.

  13. Synthesis of well-defined functional PE graft copolymers via ATRP process

    Institute of Scientific and Technical Information of China (English)

    CAO Chengang; DONG Jinyong; HU Youliang

    2005-01-01

    @@ Polyethylene (PE) is one of the most important polymeric materials. It has excellent physical mechanical properties and thus a widespread range of applications. However, due to the lack of polar functional groups on its polymer chain, PE usually suffers from poor adhesion to and incompatibility with other polymers or materials, which has significantly limited many of its end uses. To resolve this problem, one of the established approaches is to introduce a second functional polymeric component as side chains to synthesize PE graft copolymers that not only provide a large quantity of functional groups to impart polarity to PE but also preserve the original desired PE properties, such as crystallinity, melting point, and hydrophobicity[1].

  14. High-strain-induced deformation mechanisms in block-graft and multigraft copolymers

    KAUST Repository

    Schlegel, Ralf

    2011-12-13

    The molecular orientation behavior and structural changes of morphology at high strains for multigraft and block-graft copolymers based on polystyrene (PS) and polyisoprene (PI) were investigated during uniaxial monotonic loading via FT-IR and synchrotron SAXS. Results from FT-IR revealed specific orientations of PS and PI segments depending on molecular architecture and on the morphology, while structural investigations revealed a typical decrease in long-range order with increasing strain. This decrease was interpreted as strain-induced dissolution of the glassy blocks in the soft matrix, which is assumed to affect an additional enthalpic contribution (strain-induced mixing of polymer chains) and stronger retracting forces of the network chains during elongation. Our interpretation is supported by FT-IR measurements showing similar orientation of rubbery and glassy segments up to high strains. It also points to highly deformable PS domains. By synchrotron SAXS, we observed in the neo-Hookean region an approach of glassy domains, while at higher elongations the intensity of the primary reflection peak was significantly decreasing. The latter clearly verifies the assumption that the glassy chains are pulled out from the domains and are partly mixed in the PI matrix. Results obtained by applying models of rubber elasticity to stress-strain and hysteresis data revealed similar correlations between the softening behavior and molecular and morphological parameters. Further, an influence of the network modality was observed (random grafted branches). For sphere forming multigraft copolymers the domain functionality was found to be less important to achieve improved mechanical properties but rather size and distribution of the domains. © 2011 American Chemical Society.

  15. Uptake, transport and peroral absorption of fatty glyceride grafted chitosan copolymer-enoxaparin nanocomplexes: influence of glyceride chain length.

    Science.gov (United States)

    Wang, Linlin; Sun, Yujiao; Shi, Chenjun; Li, Liang; Guan, Jian; Zhang, Xin; Ni, Rui; Duan, Xiaopin; Li, Yaping; Mao, Shirui

    2014-08-01

    The objective of this paper is to elucidate the influence of fatty glyceride chain length in chitosan copolymers on the peroral absorption of enoxaparin. First of all, a series of chitosan copolymers with glyceryl monocaprylate (GM8), glyceryl monolaurate (GM12) and glyceryl monostearate (GM18) as the hydrophobic part were synthesized. The structure of the copolymers was characterized using proton nuclear magnetic resonance. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay demonstrated that all the copolymers were non-toxic. Enoxaparin nanocomplexes were prepared by self-assembly. Mucoadhesion of the nanocomplexes was characterized using the mucin particle method. Nanocomplex uptake and transport were quantified in Caco-2 cells and cellular localization was visualized by confocal laser scanning microscopy. Enoxaparin uptake was enhanced by nanocomplex formation, and was dependent on incubation time, concentration, temperature and glyceride chain length. The GM8 grafted chitosan-enoxaparin nanocomplex exhibited the strongest bioadhesion and the best uptake and transport in both cell culture and in vivo absorption in rats. The uptake mechanism was assumed to be adsorptive endocytosis via clathrin- and caveolae-mediated processes. In conclusion, oral absorption of enoxaparin can be further enhanced by using GM8 grafted chitosan copolymer as the carrier to form nanocomplexes.

  16. Effect of Grafting Density of Random Copolymer Brushes on Perpendicular Alignment in PS-b-PMMA Thin Films

    KAUST Repository

    Lee, Wooseop

    2017-07-18

    We modulated the grafting density (σ) of a random copolymer brush of poly(styrene-r-methyl methacrylate) on substrates to probe its effect on the formation of perpendicularly aligned lamellae of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA). Supported by coarse-grained simulation results, we hypothesized that an increase in σ will allow us to systematically tune the block copolymer interfacial interactions with the substrates from being preferential to one of the blocks to being neutral toward both blocks and will thereby facilitate enhanced regimes of perpendicularly aligned lamellae. We verified such a hypothesis by using a simple grafting-to approach to modify the substrates and characterized the thickness window for perpendicular lamellae as a function of brush thickness (or σ) on the grafted substrates using scanning force microscopy (SFM) images and grazing incidence small-angle X-ray scattering (GISAXS) measurements. The experimental results validated our hypothesis and suggested that the σ of random copolymer brushes can be used as an additional versatile parameter to modulate the interfacial interactions and the resulting alignment of block copolymer films.

  17. Graft [partially carboxymethylated guar gum-g-poly N-(hydroxymethyl) acrylamide] copolymer: from synthesis to applications.

    Science.gov (United States)

    Pandey, Vijay Shankar; Verma, Shiv Kumar; Behari, Kunj

    2014-09-22

    Graft copolymer of N-(hydroxymethyl) acrylamide with carboxymethylated guar gum was synthesized and the reaction conditions were optimized for better yield using potassium peroxymonosulfate and thiourea as a redox initiator. The optimum reaction conditions for grafting have also been determined by studying the effect of N-(hydroxymethyl) acrylamide, hydrogen ion, peroxymonosulphate, thiourea concentration and carboxymethylated guar gum along with time and temperature. Experimental results show that maximum grafting has been obtained at 1.4 g dm(-3) concentration of carboxymethylated guar gum and 16×10(-2) mol dm(-3) concentration of N-(hydroxymethyl) acrylamide. It has been observed that grafting ratio, add on, conversion, efficiency and rate of grafting increase up to 6.0×10(-3) mol dm(-3) of hydrogen ion, 2.4×10(-3) mol dm(-3) of thiourea, 14×10(-3) mol dm(-3) of peroxymonosulphate and 35°C of temperature. Grafted copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis. Water swelling, flocculating, and metal ion uptake properties of partially carboxymethylated guar gum-g-N-(hydroxymethyl) acrylamide have been determined.

  18. Atmospheric Solid Analysis Probe-Ion Mobility Mass Spectrometry: An Original Approach to Characterize Grafting on Cyclic Olefin Copolymer Surfaces.

    Science.gov (United States)

    Vieillard, Julien; Hubert-Roux, Marie; Brisset, Florian; Soulignac, Cecile; Fioresi, Flavia; Mofaddel, Nadine; Morin-Grognet, Sandrine; Afonso, Carlos; Le Derf, Franck

    2015-12-01

    A cyclic olefin copolymer (COC) was grafted with aryl layers from aryldiazonium salts, and then we combined infrared spectrometry, atomic force microscopy (AFM), and ion mobility mass spectrometry with atmospheric solid analysis probe ionization (ASAP-IM-MS) to characterize the aryl layers. ASAP is a recent atmospheric ionization method dedicated to the direct analysis of solid samples. We demonstrated that ASAP-IM-MS is complementary to other techniques for characterizing bromine and sulfur derivatives of COC on surfaces. ASAP-IM-MS was useful for optimizing experimental grafting conditions and to elucidate hypotheses around aryl layer formation during the grafting process. Thus, ASAP-IM-MS is a good candidate tool to characterize covalent grafting on COC surfaces.

  19. Poly(vinylidene fluoride-co-hexafluoropropylene)-graft-poly(dopamine methacrylamide) copolymers: A nonlinear dielectric material for high energy density storage

    Science.gov (United States)

    Rahimabady, Mojtaba; Qun Xu, Li; Arabnejad, Saeid; Yao, Kui; Lu, Li; Shim, Victor P. W.; Gee Neoh, Koon; Kang, En-Tang

    2013-12-01

    A nonlinear dielectric poly(vinylidene fluoride-co-hexafluoropropylene)-graft-poly(dopamine methacrylamide) [P(VDF-HFP)-g-PDMA] graft copolymer with ultra-high energy density of 33 J/cm3 was obtained by thermally initiated radical graft polymerization. It was observed that the dielectric constant of the graft copolymer films was 63% higher than that of P(VDF-HFP), with a large dielectric breakdown strength (>850 MV/m). Theoretical analyses and experimental measurements showed that the significant improvement in the electric polarization was attributed to the introduction of the highly polarizable hydroxyl groups in the PDMA side chains, and the large breakdown strength arose from the strong adhesion bonding of the catechol-containing graft copolymer to the metal electrode.

  20. Synthesis of Graft Copolymers Based on Poly(2‐Methoxyethyl Acrylate) and Investigation of the Associated Water Structure

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Tanaka, Masaru; Ogura, Keiko;

    2012-01-01

    Graft copolymers composed of poly(2‐methoxyethyl acrylate) are prepared employing controlled radical polymerization techniques. Linear backbones bearing atom transfer radical polymerization (ATRP) initiating sites are obtained by reversible addition–fragmentation chain transfer copolymerization...... of 2‐methoxyethyl acrylate (MEA) and 2‐(bromoisobutyryloxy)ethyl methacrylate (BriBuEMA) as well as 2‐hydroxyethyl methacrylate and BriBuEMA in a controlled manner . MEA is then grafted from the linear macroinitiators by Cu (I)‐mediated ATRP. Fairly high molecular weights (>120 000 Da) and low...

  1. Synthesis of new EVA graft copolymer and its pour point depressant performance evaluation for Daqing crude oil

    Institute of Scientific and Technical Information of China (English)

    伍丽娟; 张帆; 关中原; 郭淑凤

    2008-01-01

    EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA’s property.EVA has long side chains and nitrogen polar groups to enforce its adaptability and effect of waxy oil.The pure amine,maleicanhydride and their reaction product were tested using infrared spectra and the NMR spectral.The results show that when the modified EVA is added into oil,the wax deposits not only on the main chain but also on the side chains.And the polar groups have the function to avoid and resist the wax crystals connection each other to form the net.Using the reaction product of maleicanhydride and high carbonic amine(C12,C16,C18 amine) as the graft component,the toluene as the solvent and BPO as the initiator,the series of new EVA graft copolymer with special side chains are prepared under controlled condition.A series of cylmaleimide exist indeed in modified EVA and the highest grafted percentage is 18.8%.EVA-16,the new graft copolymer,is better than EVA about 3 ℃ more in depressant the pour-point of Daqing waxy crude oil.

  2. Multifunctional organized mesoporous tin oxide films templated by graft copolymers for dye-sensitized solar cells.

    Science.gov (United States)

    Park, Jung Tae; Ahn, Sung Hoon; Roh, Dong Kyu; Lee, Chang Soo; Kim, Jong Hak

    2014-07-01

    The synthesis of organized mesoporous SnO2 films with high porosity, larger pores, and good interconnectivity, obtained by sol-gel templating with an amphiphilic graft copolymer, poly(vinyl chloride)-graft-poly(oxyethylene methacrylate), is reported. An improved performance of dye-sensitized solar cells (DSSCs) is demonstrated by the introduction of a 400 nm thick organized mesoporous SnO2 interfacial (om-SnO2 IF) layer between nanocrystalline TiO2 (nc-TiO2 ) and a fluorine-doped tin oxide substrate. To elucidate the improved efficiency, the structural, optical, and electrochemical properties of the devices were characterized by SEM, UV/Vis spectroscopy, noncontact 3D surface profilometry, intensity-modulated photocurrent/voltage spectroscopy, incident photon-to-electron conversion efficiency, and electrochemical impedance spectroscopy measurements. The energy-conversion efficiency of the solid polymerized ionic liquid based DSSC fabricated with the om-SnO2 IF/nc-TiO2 photoanode reached 5.9% at 100 mW cm(-2) ; this is higher than those of neat nc-TiO2 (3.5%) and organized mesoporous TiO2 interfacial/nc-TiO2 layer (5.4%) photoanodes. The improved efficiency is attributed to the antireflective property, cascadal energy band gap, good interconnectivity, and high electrical conductivity of the om-SnO2 IF layer, which results in enhanced light harvesting, increased electron transport, reduced charge recombination, and decreased interfacial/internal resistance.

  3. Periodically Grafted Amphiphilic Copolymers: Effects of Steric Crowding and Reversal of Amphiphilicity.

    Science.gov (United States)

    Mandal, Joydeb; Ramakrishnan, S

    2015-06-01

    Two series of periodically clickable polyesters were prepared; one of them carries alkylene segments along its backbone, whereas the other carries poly(ethylene glycol) (PEG) segments. These polyesters were clicked with either MPEG-350 azide or docosyl (C22) azide to yield periodically grafted amphiphilic copolymers (PGACs) carrying either flexible hydrophilic or crystallizable hydrophobic backbone segments. The immiscibility between hydrocarbon and PEG segments causes both of these systems to fold in either a zigzag or hairpin-like conformation; the hairpin-like conformation appears to be preferred when flexible PEG segments are present in the backbone. The folded chains further reorganize in the solid state to develop a lamellar morphology that permits the collocation of the PEG and hydrocarbon (HC) segments within alternate domains; evidence for the self-segregation was gained from DSC, SAXS, and AFM studies. SAXS studies revealed the formation of an extended lamellar structure, whereas AFM images showed uniform layered morphology with layer heights that matched reasonably well with the interlamellar spacing obtained from the SAXS study. Labeling one representative PGAC, carrying crystallizable long alkylene segments in the backbone and pendant PEG-350 side chains, with a small mole fraction of pyrene fluorophore permitted the examination of the conformational transition that occurs upon going from a good to a poor solvent; this single-chain folded conformation, we postulate, is the intermediate that organizes into the lamellar morphology.

  4. Bioresponse to polymeric substrates: Effect of surface energy, modulus, topography, and surface graft copolymers

    Science.gov (United States)

    Wilson, Leslie Hoipkemeier

    Biofouling is the accumulation of biological matter on a substrate. It is essential to elucidate and model the major factors that affect both biological settlement and adhesion to substrates in order to develop coatings that minimize initial fouling or ease the removal of this fouling. To date, models that have estimated adhesion strength to coatings primarily included bulk elastic modulus and surface energy. Topography, however, has been found to dominate both these terms in the reduction of settlement and has been found to affect the adhesion strength as well. Silicone foul release coatings have demonstrated moderate success in the prevention of marine biofouling because of their low modulus and low surface energy. Problems exist with durability and eventual fouling of the coating due to the overgrowth of foulants that prefer hydrophobic substrates. This research details the characterization and the surface and bulk modification of a commercially available silicone elastomer. The modifications include bulk additives, surface topography, and surface graft copolymers. The effect of these modifications on biological response was then assayed using the alga Ulva as a model for marine biofouling. The unmodified silicone elastomer has a bulk modulus of approximately 1 MPa. The addition of vinyl functional polydimethylsiloxane oils allowed for a greater than 200% increase or a 90% decrease in the bulk modulus of the material. The addition of non-reactive polydimethylsiloxane oils allowed for a change in the surface lubricity of the elastomer without a significant change in the mechanical properties. Topographical modifications of the surface show a profound effect on the bioresponse. Appropriately scaled engineered microtopographies replicated in the silicone elastomer can produce a 250% increase in algal zoospore fouling or an 85% reduction in settlement relative to a smooth silicone elastomer. Finally, the modification of the surface energy of this material was

  5. Regiocontroll synthesis cellulose-graft-polycaprolactone copolymer (2,3-di-O-PCL-cellulose by a new route

    Directory of Open Access Journals (Sweden)

    K. L. Wang

    2017-12-01

    Full Text Available A new and convenient route to the regiocontrolled synthesis of a cellulose-based derivate copolymer (2,3-di-O-polycaprolactone-cellulose grafting ε-caprolactone (ε-CL from α-cellulose, cellulose-graft-polycaprolactone (cellulose-g-PCL, by a classical ring-opening polymerization (ROP reaction, using stannous octoate (Sn(Oct2 as catalyst, in 68% concentration of zinc chloride aqueous solution at 120 °C was presented. By controlling the hydroxyl of cellulose/ε-CL, catalyst/monomer ratio and the reaction time, the molecular architecture of the copolymers can be altered. The solubility of cellulose in zinc chloride aqueous was indicated by UV/VIS spectrometer and rheological measurements. The structures and thermal properties of cellulose-g-polycaprolactone copolymers were characterized using Fourier Transform Infrared (FT-IR, Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR, X-ray Diffraction (XRD, Thermogravimetric Analysis (TGA, Differential Scanning Calorimetry (DSC and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES. The interesting results confirm that zinc chloride solution can break the intra-molecular hydrogen bonds of cellulose selectively (not only O3H···O5, but also O2H···O6, and has no effect on the inter-molecular hydrogen bonds (O6H···O3. And the grafting reactivity of hydroxyl on cellulose is C2–OH > C3–OH >> C6–OH in zinc chloride solution, and this is clearly different from other researches. Most importantly, this work confirms that the method to regiocontrolled synthesis cellulose-based derivative polymers by regiobreaking hydrogen bonds is feasible. It is strongly believed that the new discovery may give a novel, environmental, simple and inexpensive method to modify cellulose chemically with various side chains grafted on a given hydroxyl, through liberating hydroxyl as reactive group from hydrogen bonds broken selectively by different solvents.

  6. Equilibrium and kinetics study on hexavalent chromium adsorption onto diethylene triamine grafted glycidyl methacrylate based copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Maksin, Danijela D., E-mail: dmaksin@vinca.rs [University of Belgrade, Vinca Institute of Nuclear Sciences, P.O. Box 522, Belgrade (Serbia); Nastasovic, Aleksandra B., E-mail: anastaso@chem.bg.ac.rs [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Njegoseva 12, Belgrade (Serbia); Milutinovic-Nikolic, Aleksandra D., E-mail: snikolic@nanosys.ihtm.bg.ac.rs [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Njegoseva 12, Belgrade (Serbia); Surucic, Ljiljana T., E-mail: ljilja_m@yahoo.com [University of Belgrade, Faculty of Forestry, Kneza Viseslava 1, Belgrade (Serbia); Sandic, Zvjezdana P., E-mail: zvjezdana.sandic@gmail.com [Faculty of Science, Mladena Stojanovica 2, Banja Luka, Bosnia and Herzegovina (Bosnia and Herzegowina); Hercigonja, Radmila V., E-mail: radah@ffh.bg.ac.rs [University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12-16, 11001 Belgrade (Serbia); Onjia, Antonije E., E-mail: onjia@vinca.rs [University of Belgrade, Vinca Institute of Nuclear Sciences, P.O. Box 522, Belgrade (Serbia)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Methacrylate based copolymers grafted with diethylene triamine as Cr(VI) sorbents. Black-Right-Pointing-Pointer Chemisorption and pore diffusion are characteristics of this sorption system. Black-Right-Pointing-Pointer Langmuir isotherm provided best fit and maximum adsorption capacity was 143 mg g{sup -1}. Black-Right-Pointing-Pointer Cr(VI) sorption onto amino-functionalized copolymer was endothermic and spontaneous. Black-Right-Pointing-Pointer A simple, efficient and cost-effective hexavalent chromium removal method. - Abstract: Two porous and one non-porous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) [abbreviated PGME] were prepared by suspension copolymerization and functionalized with diethylene triamine [abbreviated PGME-deta]. Samples were characterized by elemental analysis, mercury porosimetry, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and transmission electron microscopy. Kinetics of Cr(VI) sorption by PGME-deta were investigated in batch static experiments, in the temperature range 25-70 Degree-Sign C. Sorption was rapid, with the uptake capacity higher than 80% after 30 min. Sorption behavior and rate-controlling mechanisms were analyzed using five kinetic models (pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion and Bangham model). Kinetic studies showed that Cr(VI) adsorption adhered to the pseudo-second-order model, with definite influence of pore diffusion. Equilibrium data was tested with Langmuir, Freundlich and Tempkin adsorption isotherm models. Langmuir model was the most suitable indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption. The maximum adsorption capacity from the Langmuir model, Q{sub max}, at pH 1.8 and 25 Degree-Sign C was 143 mg g{sup -1} for PGME2-deta (sample with the highest amino group concentration) while at 70 Degree-Sign C Q{sub max} reached the high value of 198

  7. Temperature-triggered gelation of aqueous laponite dispersions containing a cationic poly(N-isopropyl acrylamide) graft copolymer.

    Science.gov (United States)

    Liu, R; Tirelli, N; Cellesi, F; Saunders, B R

    2009-01-06

    In this work, temperature-triggered gelation of aqueous laponite dispersions containing a cationic poly(N-isopropylacrylamide) (PNIPAm) graft copolymer was investigated. The copolymer used was PDMA(+)(30)-g-(PNIPAm(210))(14) [Liu et al. Langmuir 2008, 24, 7099]. DMA(+) is quarternarized N,N-dimethylaminoethyl methacrylate. The presence of small concentrations of laponite enabled temperature-triggered gel formation to occur at low copolymer concentrations (e.g., 1 wt %). Dynamic rheological measurements of the gels showed that they had storage modulus values of up to 400 Pa when the total solid volume fraction (polymer and laponite) was only about 0.02. The storage modulus was dependent on both the temperature and the composition of the dispersion used for preparation. The key component that provided the temperature-triggered gels with their elasticity was found to be self-assembled nanocomposite (NC) sheets. These NC sheets spontaneously formed at room temperature upon addition of laponite to the copolymer solution. The NC sheets had lateral dimensions on the order of hundreds of micrometers and a thickness of a few micrometers. The NC sheets were present within the temperature-triggered gels and formed elastically effective chains. The NC sheets exhibited temperature-triggered contraction with a contraction onset temperature of 27 degrees C. A conceptual model is proposed to qualitatively explain the relationship between gel elasticity and dispersion composition.

  8. Selective adsorption of Pb (II) ions by amylopectin-g-poly (acrylamide-co-acrylic acid): A bio-degradable graft copolymer.

    Science.gov (United States)

    Sasmal, Dinabandhu; Maity, Jayanta; Kolya, Haradhan; Tripathy, Tridib

    2017-04-01

    Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution. The Pb (II) ion removal capacity of the graft copolymer was also compared with another laboratory developed graft copolymer Amylopectin-g-poly (acrylamide) (AP-g-PAM). Both the graft copolymers were also used for the competitive metal ions removal with Pb (II)/Cd (II), Pb (II)/Zn (II), Pb (II)/Ni (II), Pb (II)/Cu (II) pairs separately under similar conditions. AP-g-poly (AM-co-AA) showed better Pb (II) ion adsorbing power over AP-g-PAM and also much selective towards Pb (II) ions. The adsorption follows a second order rate equation and Langmuir isotherm model.

  9. An amphiphilic graft copolymer-based nanoparticle platform for reduction-responsive anticancer and antimalarial drug delivery

    Science.gov (United States)

    Najer, Adrian; Wu, Dalin; Nussbaumer, Martin G.; Schwertz, Geoffrey; Schwab, Anatol; Witschel, Matthias C.; Schäfer, Anja; Diederich, François; Rottmann, Matthias; Palivan, Cornelia G.; Beck, Hans-Peter; Meier, Wolfgang

    2016-08-01

    Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL-1. Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (+/-)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block.Medical applications of anticancer and antimalarial drugs often suffer from low aqueous

  10. Neutron scattering characterization of homopolymers and graft-copolymer micelles in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chillura-Martino, D; Triolo, R. [Palermo Univ. (Italy). Ist. di Chimica Fisica; McClain, J.B. [North Carolina Univ., Chapel Hill, NC (United States)] [and others

    1995-12-31

    Supercritical fluids are becoming an attractive alternative to the liquid solvents traditionally used as polymerization media. As the synthesis proceeds, a wide range of colloidal aggregates form, but there has hitherto been no way to measure such structures directly. We have applied small-angle neutron scattering (SANS) to characterize such systems, and although SCF polymerizations are carried out at high pressures, the penetrating power of the neutron beam means that typical cell windows are virtually transparent. Systems studied include molecules soluble in CO{sub 2} (e.g. polyfluoro-octyl acrylate or PFOA) and this polymer has previously been shown to exhibit a positive second virial coefficient (A{sub 2}). Other CO{sub 2}-soluble polymers include hexafluoro-polypropylene oxide (HFPPO), which appears to have a second virial coefficient which is close to zero (10{sup 4}A{sub 2} {approx_equal} 0 +{+-} 0.2 cm{sup 3} g{sup -2} mol). Polydimethylsiloxane (PDMS), is soluble on the molecular level only in the limit of dilute solution and seems to form aggregates as the concentration increases (c > 0.01 g cm{sup -3}). Other polymers (e.g. polystyrene) are insoluble in CO{sub 2}, though polymerizations may be accomplished via the use of PS-PFOA blockcopolymer stabilizers, which are also amenable to SANS characterization, and have been shown to form micelles in CO{sub 2}. Other amphiphilic surfactant molecules that form micelles include PFOA-polyethylene oxide (PFOA-PEO) graft copolymers, which swell as the CO{sub 2} medium is saturated with water. These systems have been characterized by SANS, by taking advantage of the different contrast options afforded by substituting D{sub 2}O for H{sub 2}O. This paper illustrates the utility of SANS to measure molecular dimensions, thermodynamic variables, molecular weights, micelle structures etc. in supercritical CO{sub 2}.

  11. Protected graft copolymer-formulated fibroblast growth factors mitigate the lethality of partial body irradiation injury

    Science.gov (United States)

    Castillo, Gerardo M.; Nishimoto-Ashfield, Akiko; Jones, Cynthia C.; Kabirov, Kasim K.; Zakharov, Alexander; Lyubimov, Alexander V.

    2017-01-01

    We evaluated the mitigating effects of fibroblast growth factor 4 and 7 (FGF4 and FGF7, respectively) in comparison with long acting protected graft copolymer (PGC)-formulated FGF4 and 7 (PF4 and PF7, respectively) administered to C57BL/6J mice a day after exposure to LD50/30 (15.7 Gy) partial body irradiation (PBI) which targeted the gastrointestinal (GI) system. The PGC that we developed increased the bioavailability of FGF4 and FGF7 by 5- and 250-fold compared to without PGC, respectively, and also sustained a 24 hr presence in the blood after a single subcutaneous administration. The dose levels tested for mitigating effects on radiation injury were 3 mg/kg for the PF4 and PF7 and 1.5 mg each for their combination (PF4/7). Amifostine administered prior to PBI was used as a positive control. The PF4, PF7, or PF4/7 mitigated the radiation lethality in mice. The mitigating effect of PF4 and PF7 was similar to the positive control and PF7 was better than other mitigators tested. The plasma citrulline levels and hematology parameters were early markers of recovery and survival. GI permeability function appeared to be a late or full recovery indicator. The villus length and crypt number correlated with plasma citrulline level, indicating that it can act as a surrogate marker for these histology evaluations. The IL-18 concentrations in jejunum as early as day 4 and TPO levels in colon on day 10 following PBI showed statistically significant changes in irradiated versus non-irradiated mice which makes them potential biomarkers of radiation exposure. Other colon and jejunum cytokine levels are potentially useful but require larger numbers of samples than in the present study before their full utility can be realized. PMID:28207794

  12. 接枝聚合物PVA-g-PNIPA的合成%Synthesis of Graft Copolymer PVA-g-PNIPA

    Institute of Scientific and Technical Information of China (English)

    王俊卿; 陈岚; 苏致兴

    2001-01-01

    采用自由基溶液聚合制备了具有温敏性的N-异丙基丙烯酸胺的线性均聚物(PNIPA).利用活性酰胺与聚乙烯醇(PVA)中羟基的交换反应将PNIPA接枝在PVA链上得到接枝聚合物PVA-g-PNIPA.用化学交联法在W/O体系中将PVA-g-PNIPA制成微球.结果表明,接枝聚合物仍具有温敏性.接枝聚合物中PNIPA的含量随PNIPA/PVA(投料比)的增加而增加,并且影响微球的成球率.%Linear homopolymer of N-isopropylacrylamide has been made with AIBN as initiator and DMF as solvent, and it was thermosensitive.Graft copolymer PVA-g-PNIPA could be prepared through the reaction of the terminal active amide of PNIPA and the hydroxy group of PVA.Microspheres could be made of graft copolymer PVA-g-PNIPA with glutaraldehyde as cross-link agent in water/oil system.It was found that graft copolymer PVA-g-PNIPA still had thermosensitivity,and the content of PNIPA in PVA-g-PNIPA could be controlled by the feed proportion of PNIPA and PVA, and microsphere was made readily but it could be affected by the content of PNIPA.

  13. Graft copolymers of polyurethane with various vinyl monomers via radiation-induced miniemulsion polymerization: Influential factors to grafting efficiency and particle morphology

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hua [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: pstwmz@ustc.edu.cn; Ge Xuewu [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: xwge@ustc.edu.cn

    2009-02-15

    Graft copolymers of polyurethane (PU) with various vinyl monomers were synthesized through a one-pot but two-step miniemulsion polymerization process. Firstly, the polycondensation of isophorone diisocyanate (IPDI) with hydroxyl-terminated polybutadiene (HTPB) had been performed in aqueous miniemulsion at 40 deg. C in order to obtain PU dispersions. Consecutively, an in-situ graft copolymerization of the vinyl monomers with the synthesized PU was initiated by {gamma}-ray radiation at room temperature. The grafting efficiency of PU with vinyl monomer (G{sub PU/monomer}) was calculated from {sup 1}H NMR spectra and the particle morphology of the final hybrid latex was observed by transmission electron microscopy (TEM). As there was no monomer transferring in miniemulsion system, homogenous hybrid particles would be synthesized provided that the monomer was miscible with PU, such as styrene. With the increase of the polarity of the monomer, the compatibility of PU with monomer decreased. G{sub PU/monomer} varied as G{sub PU/styrene}(37%)>G{sub PU/butyl} {sub acrylate} {sub (BA)}(21%)>G{sub PU/methyl} {sub methacrylate} {sub (MMA)}(12%). The proportion of homogeneous nucleation would increase as the hydrophilicity of the monomer increased. High temperature would destabilize the miniemulsion so as to result in a less grafting efficiency. Compared to the phase separation during the seeded emulsion polymerization, the miniemulsion polymerization method facilitated the preparation of homogeneous materials owing to its monomer droplet nucleation mechanism.

  14. Preparation of dual-sensitive graft copolymer hydrogel based on N-maleoyl-chitosan and poly(N-isopropylacrylamide) by electron beam radiation

    Indian Academy of Sciences (India)

    Jinchen Fan; Jie Chen; Liming Yang; Han Lin; Fangqi Cao

    2009-10-01

    Organic solvent-soluble N-maleoyl-chitosan (NMCS) was synthesized by reaction of chitosan with maleic anhydride (MAH) in N,N-dimethylformamide (DMF). N-maleoyl-chitosan-graft-poly(N-isopropylacrylamide) (NMCS-g-PNIPAAm) copolymer hydrogel was prepared via free radical polymerization by electron beam (EB) irradiation. The copolymer obtained was analysed by FT–IR, XRD and thermal gravimetric analysis (TGA). It was found that the grafting yield and grafting efficiency increased with increasing radiation absorbed dose and monomer amount, and then decreased. The swelling ratio of the copolymer hydrogel was low at pH 4–5, and LCST of the hydrogel was around 32°C.

  15. Mesoporous TiO2 Bragg Stack Templated by Graft Copolymer for Dye-sensitized Solar Cells

    OpenAIRE

    Jung Tae Park; Won Seok Chi; Sang Jin Kim; Daeyeon Lee; Jong Hak Kim

    2014-01-01

    Organized mesoporous TiO2 Bragg stacks (om-TiO2 BS) consisting of alternating high and low refractive index organized mesoporous TiO2 (om-TiO2) films were prepared to enhance dye loading, light harvesting, electron transport, and electrolyte pore-infiltration in dye-sensitized solar cells (DSSCs). The om-TiO2 films were synthesized via a sol-gel reaction using amphiphilic graft copolymers consisting of poly(vinyl chloride) backbones and poly(oxyethylene methacrylate) side chains, i.e., PVC-g-...

  16. A pH-and temperature-sensitive macrocyclic graft copolymer composed of PEO ring and multi-poly(2-(dimethylamino) ethyl methacrylate) lateral chains

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel method for the synthesis of macrocyclic graft copolymers was developed through combination of anionic ring-opening polymerization (AROP) and atom transfer radical polymerization (ATRP).A linear α,ω-dihydroxyl poly(ethylene oxide) with pendant acetal protected hydroxyl groups (l-poly(EO-co-EEGE)) was prepared first by the anionic copolymerization of ethylene oxide (EO) and ethoxyethyl glycidyl ether (EEGE).Then l-poly(EO-co-EEGE) was cyclized.The crude cyclized product containing the linear byproduct was hydrolyzed and purified by being treated with α-CD.The pure cyclic copolymer [c-poly(EO-co-Gly)] was esterified by reaction with 2-bromoisobutyryl bromide,and then used as ATRP macroinitiators to initiate polymerization of 2-(dimethylamino) ethyl methacrylate (DMAEMA),and a series of pH-and temperature-sensitive macrocyclic graft copolymers composed of a hydrophilic PEO as the ring and PDMAEMA as side chains (c-PEO-g-PDMAEMA) were obtained.The behavior of pH-and temperature-sensitive macrocyclic copolymers was studied in aqueous solution by fluorescence and dynamic light scattering (DLS).The critical micellization pH values of macrocyclic graft copolymers and their corresponding linear graft copolymers (l-PEO-g-PDMAEMA) were measured.Under the same conditions,the cyclic graft copolymer with the shorter side chains gave the higher critical micellization pH value.The c-PEO-g-PDMAEMA showed the lower critical micellization pH value than the corresponding l-PEO-g-PDMAEMA.The average hydrodynamic diameters (Dh) of the micelles were measured by DLS with the variation of the aqueous solution pH value and temperature.

  17. Preparation and Characterization of Lignin Graft Copolymer as a Filtrate Loss Control Agent for the Hydrocarbon Drilling Industry

    Directory of Open Access Journals (Sweden)

    Mohamad Nasir Mohamad Ibrahim

    2014-01-01

    Full Text Available Lignin graft copolymer (LGC was prepared using an addition polymerization technique that involved grafting a 2-acrylamido-2-methylpropane sulfonic acid (AMPS monomer onto soda lignin (SL. The optimal polymerization conditions were found to be as follows: soda lignin, 2.0 g; initiator, 3% (w/w potassium persulphate of SL; mass ratio of AMPS to SL, 1:2; reaction time, 7 h; and reaction temperature, 60 °C. The LGC was characterized using a Fourier transform infrared (FTIR spectroscopy, a thermogravimetric analyzer (TGA, and gel permeation chromatography (GPC. The filtrate loss controlling ability of the LGC was evaluated using the American Petroleum Institute Recommended Practice 13-B 1 standard procedures. The results showed that the LGC has remarkable rheological and filtration controlling properties at both room temperature and high aging temperatures (190 °C.

  18. Amphiphilic graft copolymer based on poly(styrene-co-maleic anhydride with low molecular weight polyethylenimine for efficient gene delivery

    Directory of Open Access Journals (Sweden)

    Duan XP

    2012-09-01

    Full Text Available Xiaopin Duan,1,2 Jisheng Xiao,2 Qi Yin,2 Zhiwen Zhang,2 Shirui Mao,1 Yaping Li21School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 2Center of Pharmaceutics, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, ChinaBackground and methods: A new amphiphilic comb-shaped copolymer (SP was synthesized by conjugating poly(styrene-co-maleic anhydride with low molecular weight polyethyleneimine for gene delivery. Fourier transform infrared spectrum, 1H nuclear magnetic resonance, and gel permeation chromatography were used to characterize the graft copolymer.Results: The buffering capability of SP was similar to that of polyethyleneimine within the endosomal pH range. The copolymer could condense DNA effectively to form complexes with a positive charge (13–30 mV and a small particle size (130–200 nm at N/P ratios between 5 and 20, and protect DNA from degradation by DNase I. In addition, SP showed much lower cytotoxicity than polyethyleneimine 25,000. Importantly, the gene transfection activity and cellular uptake of SP-DNA complexes were all markedly higher than that of complexes of polyethyleneimine 25,000 and DNA in MCF-7 and MCF-7/ADR cell lines.Conclusion: This work highlights the promise of SP as a safe and efficient synthetic vector for DNA delivery.Keywords: poly(styrene-co-maleic anhydride, polyethylenimine, DNA, gene delivery

  19. Controlled grafting of comb copolymer brushes on poly(tetrafluoroethylene) films by surface-initiated living radical polymerizations.

    Science.gov (United States)

    Yu, W H; Kang, E T; Neoh, K G

    2005-01-04

    Surface modification of poly(tetrafluoroethylene) (PTFE) films by well-defined comb copolymer brushes was carried out. Peroxide initiators were generated directly on the PTFE film surface via radio frequency Ar plasma pretreatment, followed by air exposure. Poly(glycidyl methacrylate) (PGMA) brushes were first prepared by surface-initiated reversible addition-fragmentation chain transfer polymerization from the peroxide initiators on the PTFE surface in the presence of a chain transfer agent. Kinetics study revealed a linear increase in the graft concentration of PGMA with the reaction time, indicating that the chain growth from the surface was consistent with a "controlled" or "living" process. alpha-Bromoester moieties were attached to the grafted PGMA by reaction of the epoxide groups with 2-bromo-2-methylpropionic acid. The comb copolymer brushes were subsequently prepared via surface-initiated atom transfer radical polymerization of two hydrophilic vinyl monomers, including poly(ethylene glycol) methyl ether methacrylate and sodium salt of 4-styrenesulfonic acid. The chemical composition of the modified PTFE surfaces was characterized by X-ray photoelectron spectroscopy.

  20. Graft Copolymers of Maleic Anhydride and Its Isostructural Analogues: High Performance Engineering Materials

    OpenAIRE

    Rzayev, Zakir M. O.

    2011-01-01

    This review summarizes the main advances published over the last 15 years outlining the different methods of grafting, including reactive extruder systems, surface modification, grafting and graft copolymerization of synthetic and natural polymers with maleic anhydride and its isostructural analogues such as maleimides and maleates, and anhydrides, esters and imides of citraconic and itaconic acids, derivatives of fumaric acid, etc. Special attention is spared to the grafting of conventional ...

  1. Block and Hetero Ethyl Cellulose Graft Copolymers Synthe- sized via Sequent and One-pot ATRP and "Click" Reactions%Block and Hetero Ethyl Cellulose Graft Copolymers Synthe- sized via Sequent and One-pot ATRP and "Click" Reactions

    Institute of Scientific and Technical Information of China (English)

    李琴梅; 康宏亮; 刘瑞刚; 黄勇

    2012-01-01

    Ethyl cellulose graft copolymers with block and hetero side chains, ethyl cellulose graft [polystyrene-b-poly- (ethylene glycol)] [EC-g-(PS-b-PEG)] and ethyl cellulose graft polystyrene and polyethylene glycol [EC-g-(PS-PEG )] were synthesized by atomic transfer radical polymerization (ATRP) and alkyne-azide "click" reactions and "one-pot" ATRP and "click" reactions, respectively. For the synthesis of EC-g-(PS-b-PEG), the macroinitiator for ATRP was first synthesized via the esterification of hydroxyl groups of EC with 2-bromoisobutyryl bromide to re- sult ethyl cellulose 2-bromoisobutyryl ester (EC-Br). The degree of substitution of bromide groups, which deter- mined the graft density, can be tailored by varying the feeding ratios of the hydroxyl groups to 2-bromoisobutyryl bromide. Then ATRP was carried out for preparing EC-g-PS-Br with well-defined length of PS chains. The EC-g-PS-Br copolymers were then converted to EC-g-PS-N3 and then reacted with end alkyne-functionalized PEG via click to result in EC-g-(PS-b-PEG). The EC-g-(PS-PEG) copolymers were synthesized by converting bromide groups of EC-Br to azide groups (EC-Br-N3) and then by one-pot ATRP and "click" reactions. The resultant graft copolymers were characterized by FTIR and IH NMR. The results indicate the success of the synthetic procedure of the cellulose grail copolymers with block and hetero side chains.

  2. Versatile antifouling polyethersulfone filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive.

    Science.gov (United States)

    Zhao, Yi-Fan; Zhang, Pei-Bin; Sun, Jian; Liu, Cui-Jing; Yi, Zhuan; Zhu, Li-Ping; Xu, You-Yi

    2015-06-15

    Here we describe the development of versatile antifouling polyethersulfone (PES) filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive. Amphiphilic polyethersulfone-block-poly(2-hydroxyethyl methacrylate) (PES-b-PHEMA) was beforehand designed and used as the blending additive of PES membranes prepared by phase inversion technique. The surface enriched PHEMA blocks on membrane surface acted as an anchor to immobilize the initiating site. Poly(sulfobetaine methacrylate) (PSBMA) were subsequently grafted onto the PES blend membranes by surface-initiated atom transfer radical polymerization (SI-ATRP). The analysis of surface chemistry confirmed the successful grafting of zwitterionic PSBMA brushes on PES membrane surface. The resulted PES-g-PSBMA membranes were capable of separating proteins from protein solution and oil from oil/water emulsion efficiently. Furthermore, the modified membranes showed high hydrophilicity and strongly antifouling properties due to the incorporation of well-defined PSBMA layer. In addition, the PES-g-PSBMA membranes exhibited excellent blood compatibility and durability during the washing process. The developed antifouling PES membranes are versatile and can find their applications in protein filtration, blood purification and oil/water separation, etc.

  3. Novel phosphate-grafted ePTFE copolymers for optimum in vitro mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Wentrup-Byrne, Edeline; Suzuki, Shuko; Groendahl, Lisbeth [Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, QLD 4059 (Australia); Suwanasilp, Juthakarn Jessica, E-mail: l.grondahl@uq.edu.a [School of Chemistry and Molecular Biosciences, University of Queensland, Cooper Rd, St Lucia, QLD 4072 (Australia)

    2010-08-01

    Surface modification via graft copolymerization is an attractive method for optimizing polymers used in biomedical applications. We developed a novel method using a mixed solvent system (either water and dichloromethane (DCM) or water, methanol and DCM) consisting of two solvent phases for grafting 2-(methacryloyloxy)ethyl phosphate onto expanded polytetrafluoroethylene (ePTFE). This new method resulted in the fabrication of grafted membranes with greater grafting extents (GEs) (as evaluated from x-ray photoelectron spectroscopy (XPS)) in the organic phase than those obtained when grafting was carried out in a single phase. It also made it possible to graft in the aqueous phase, a process that is otherwise inhibited by the concomitant formation of large amounts of highly crystalline homopolymer. Thorough characterization of the grafted membranes using gravimetric, XPS and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) not only permitted evaluation of the grafting outcomes but also made it possible to analyze their dependence on monomer concentration and solvent composition. A selection of membranes was tested for their in vitro mineralization capacity using simulated body fluid. It was found that an 'ideal' mineralization outcome, i.e. a uniform coating of carbonated hydroxyapatite (cHAP) formed on the sample grafted in the aqueous phase of the water/DCM two-phase solvent system. A detailed discussion bringing together these results, as well as results from a series of earlier studies, allows conclusions regarding polymer chemistry and the topology necessary for cHAP mineralization.

  4. Synthesis by ATRP of triblock copolymers with densely grafted styrenic end blocks from a polyisobutylene macroinitiator

    DEFF Research Database (Denmark)

    Truelsen, Jens Høg; Kops, Jørgen; Pedersen, Walther Batsberg

    2000-01-01

    A macroinitiator was prepared from a triblock copolymer of polyisobutylene (PIB) with end blocks of poly(p-methylstyrene) (P(p-MeS)) by bromination to obtain initiating bromomethyl groups for atom transfer radical polymerization (ATRP). Controlled polymerization of styrene and p-acetoxystyrene yi......A macroinitiator was prepared from a triblock copolymer of polyisobutylene (PIB) with end blocks of poly(p-methylstyrene) (P(p-MeS)) by bromination to obtain initiating bromomethyl groups for atom transfer radical polymerization (ATRP). Controlled polymerization of styrene and p...

  5. Preparation of thermo-responsive graft copolymer by using a novel macro-RAFT agent and its application for drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Song, Cunfeng; Yu, Shirong [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Liu, Cheng; Deng, Yuanming; Xu, Yiting [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Fujian Provincial Key Laboratory of Fire Retardant Materials, Xiamen University, Xiamen 361005 (China); Chen, Xiaoling, E-mail: tinachen0628@163.com [Department of Endodontics, Xiamen Stomatology Hospital, Teaching Hospital of Fujian Medical University, Xiamen 361003 (China); Dai, Lizong, E-mail: lzdai@xmu.edu.cn [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Fujian Provincial Key Laboratory of Fire Retardant Materials, Xiamen University, Xiamen 361005 (China)

    2016-05-01

    A methodology to prepare thermo-responsive graft copolymer by using a novel macro-RAFT agent was proposed. The macro-RAFT agent with pendant dithioester (ZC(S)SR) was facilely prepared via the combination of RAFT polymerization and esterification reaction. By means of ZC(S)SR-initiated RAFT polymerization, the thermo-responsive graft copolymer consisting of poly(methyl methacrylate-co-hydroxylethyl methacrylate) (P(MMA-co-HEMA)) backbone and hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) side chains was constructed through the “grafting from” approach. The chemical compositions and molecular weight distributions of the synthesized polymers were respectively characterized by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) and gel permeation chromatography (GPC). Self-assembly behavior of the amphiphilic graft copolymers (P(MMA-co-HEMA)-g-PNIPAAm) was studied by transmission electron microscopy (TEM), dynamic light scattering (DLS) and spectrofluorimeter. The critical micelle concentration (CMC) value was 0.052 mg mL{sup −1}. These micelles have thermo-responsibility and a low critical solution temperature (LCST) of 33.5 °C. Further investigation indicated that the guest molecule release property of these micelles, which can be well described by a first-order kinetic model, was significantly affected by temperature. Besides, the micelles exhibited excellent biocompatibility and cellular uptake property. Hence, these micelles are considered to have potential application in controlled drug delivery. - Highlights: • A novel macro-RAFT agent with ZC(S)SR was used for preparing graft copolymer. • P(MMA-co-HEMA)-g-PNIPAAm was successful prepared via the “grafting from” approach. • Thermo-responsibility of the P(MMA-co-HEMA)-g-PNIPAAm micelles was investigated. • The drug release behavior of the P(MMA-co-HEMA)-g-PNIPAAm micelles was studied. • These micelles exhibited excellent biocompatibility and cellular uptake property.

  6. Star-shaped copolymer grafted PEI and REDV as a gene carrier to improve migration of endothelial cells.

    Science.gov (United States)

    Lv, Juan; Hao, Xuefang; Li, Qian; Akpanyung, Mary; Nejjari, Abdelilah; Neve, Agnaldo Luis; Ren, Xiangkui; Feng, Yakai; Shi, Changcan; Zhang, Wencheng

    2017-01-17

    In this work, a biodegradable star-shaped copolymer poly(lactide-co-3(S)-methyl-morpholine-2,5-dione)6 (Star-(PLMD)6) was synthesized via ring-opening polymerization (ROP), and subsequently a gene carrier Star-PLMD-g-PEI-g-PEG-CREDVW was prepared by grafting polyethyleneimine (PEI), polyethylene glycol (PEG) and targeting peptide REDV onto Star-(PLMD)6. This gene carrier could form stable micelles to condense pEGFP-ZNF580 through electrostatic interaction. The resulting complexes were biocompatible and showed high efficiency in gene delivery. In addition, these complexes exhibited high selectivity for endothelial cells (ECs), high transfection efficiency and enhanced migration of ECs. The protein level of ZNF580 expression was significantly high (up to 85%), while the control group was only 51%. This combination of degradability, targeting ligand and star-structure strategy exhibits a significant advantage in transfection efficiency and migration of ECs.

  7. Synthesis of graft copolymer (k-carrageenan-g-N,N-dimethylacrylamide) and studies of metal ion uptake, swelling capacity and flocculation properties

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, D.K.; Tripathy, J.; Behari, K. [University of Allahabad, Allahabad (India). Dept. of Chemistry

    2008-03-15

    Graft copolymer of k-carrageenan and N,N-dimethylacrylamide has been synthesized by free radical polymerization using peroxymonosulphate/glycolic acid redox pair in an inert atmosphere. The grafting parameters i.e. grafting ratio, add on and efficiency decrease with increase in concentration of k-carrageenan from 0.6 to 1.4 g dm{sup -3} and hydrogen ion from 3 x 10{sup -3} to 7 x 10{sup -3} mol dm{sup -3}, but these grafting parameters increase with increase in concentration of N,N-dimethylacrylamide from 16 x 10{sup -2} to 32 x 10{sup -2} mol dm{sup -3}, and peroxymonosulphate from 0.8 x 10{sup -2} to 2A x 10{sup -2} Mol dm{sup -3}. The metal ion sorption, swelling behaviour and flocculation properties have been studied. The intrinsic viscosity of pure and grafted samples has been measured by using Ubbelohde capillary viscometer. Flocculation capability of k-carrageenan and k-carrageenan-g-N,N-dimethylacrylamide for both coking and non-coking coals has been studied for the treatment of coal mine waste water. The graft copolymer has been characterized by Infrared (IR) spectroscopy and thermogravimetric analysis.

  8. Synthesis and characterization of multi-active site grafting starch copolymer initiated by KMnO4 and HIO4/H2SO4 systems.

    Science.gov (United States)

    Guo, Qiaoxia; Wang, Yanqing; Fan, Ya; Liu, Xiwen; Ren, Shenyong; Wen, Yuanzhen; Shen, Baojian

    2015-03-06

    A novel initiator system containing KMO4, HIO4, and H2SO4 for synthesizing grafting starch copolymers is reported. In this system, KMnO4 was used to oxidize the primary hydroxyl group to aldehyde group of glucose in the starch, and the formed aldehyde group reacted with Mn(4+), Mn(3+) to afford starch free radical. At the same time HIO4 perform as the oxidant to open the C2C3 bond of glucose ring in starch to form two more aldehyde groups, and then two more free radicals are generated. As a result one glucose unit could provide ultimately three active sites for starch grafting reaction. Graft copolymers with a higher grafting ratio and grafting efficiency could be obtained by using the composite initiation system than the KMnO4/H2SO4 initiation system. The grafting of polyacrylamide onto the corn starch backbone was confirmed by viscometry, elemental analysis, infrared spectroscopy, nuclear magnetic resonance, X-ray diffraction and scanning electron microscopy.

  9. Preparation of thermo-responsive graft copolymer by using a novel macro-RAFT agent and its application for drug delivery.

    Science.gov (United States)

    Song, Cunfeng; Yu, Shirong; Liu, Cheng; Deng, Yuanming; Xu, Yiting; Chen, Xiaoling; Dai, Lizong

    2016-05-01

    A methodology to prepare thermo-responsive graft copolymer by using a novel macro-RAFT agent was proposed. The macro-RAFT agent with pendant dithioester (ZC(S)SR) was facilely prepared via the combination of RAFT polymerization and esterification reaction. By means of ZC(S)SR-initiated RAFT polymerization, the thermo-responsive graft copolymer consisting of poly(methyl methacrylate-co-hydroxylethyl methacrylate) (P(MMA-co-HEMA)) backbone and hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) side chains was constructed through the "grafting from" approach. The chemical compositions and molecular weight distributions of the synthesized polymers were respectively characterized by (1)H nuclear magnetic resonance ((1)H NMR) and gel permeation chromatography (GPC). Self-assembly behavior of the amphiphilic graft copolymers (P(MMA-co-HEMA)-g-PNIPAAm) was studied by transmission electron microscopy (TEM), dynamic light scattering (DLS) and spectrofluorimeter. The critical micelle concentration (CMC) value was 0.052 mg mL(-1). These micelles have thermo-responsibility and a low critical solution temperature (LCST) of 33.5°C. Further investigation indicated that the guest molecule release property of these micelles, which can be well described by a first-order kinetic model, was significantly affected by temperature. Besides, the micelles exhibited excellent biocompatibility and cellular uptake property. Hence, these micelles are considered to have potential application in controlled drug delivery.

  10. Experimental and theoretical studies of xanthan gum and its graft co-polymer as corrosion inhibitor for mild steel in 15% HCl

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Amrita; Pal, Sagar; Udayabhanu, G., E-mail: g_udayabhanu@hotmail.com

    2015-10-30

    Highlights: • Xanthan gum and its graft co-polymer used as corrosion inhibitors for mild steel in 15% HCl. • Electrochemical and weight loss studies give comparable corrosion rates. • Both the inhibitors are mixed type in nature. • Modified graft co-polymer is a more effective corrosion inhibitor. • Theoretical calculations taking monomer units of the polymer support the experimental results. - Abstract: Xanthan gum (XG) and its graft co-polymer have been investigated as corrosion inhibitors for mild steel in 15% HCl. Gravimetric analysis, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were employed for investigating the effectiveness of these inhibitors. Results indicate that both the inhibitors are of mixed type and follow Langmuir adsorption isotherm. Scanning electron microscopy (SEM) study also confirmed the protection of the metal surface by XG and xanthan gum-graft-poly(acrylamide) (XG-g-PAM). Theoretical calculations using Density Functional Theory (DFT) were used to establish the correlation between the structure and corrosion protection efficiencies.

  11. Reengineered graft copolymers as a potential alternative for the bone tissue engineering application by inducing osteogenic markers expression and biocompatibility.

    Science.gov (United States)

    Thangavelu, Muthukumar; R Narasimha, Raghavan; Adithan, Aravinthan; A, Chandrasekaran; Jong-Hoon, Kim; Thotapalli Parvathaleswara, Sastry

    2016-07-01

    Composite scaffolds of nano-hydroxyapatite with demineralized bone matrix were prepared and they were graft copolymerized for better bone regeneration and drug delivery applications. The graft copolymers were characterized for their physiochemical properties using conventional methods like FTIR, TGA, XRD and SEM. The scaffolds were seeded with 3T3 and MG63 cells for studying their biocompatibility and their temporal expression of ALP activity, the rate of calcium deposition and their gene expression of collagen type I (Coll-1), osteopontin (OP), osteonectin (ON), and osteocalcin (OC) were studied. In vivo studies were conducted using sub-cutaneous implantation models in male Wister rats for 6 months. Periodic radiography and post-autopsy histopathology was analysed at 15days, 1, 2, 3, 4, 5, and 6 months. The obtained in vitro results clearly confirm that the bone scaffolds prepared in this study are biocompatible, superior osteoinductivity, capable of supporting growth, maturation of MG 63 osteoblast like cells; the gene expression profile revealed that the material is capable of supporting the in vitro growth and maturation of osteoblast-like cells and maturation. The in vivo results stand a testimony to the in vitro results in proving the biocompatibility and osteoinductivity of the materials.

  12. Immortal Ring-Opening Polymerization of rac-Lactide Using Polymeric Alcohol as Initiator to Prepare Graft Copolymer

    Directory of Open Access Journals (Sweden)

    Na Liu

    2016-01-01

    Full Text Available In the presence of a small molecular protic initiator, immortal ring-opening polymerization (ROP of lactide (LA is a highly efficient strategy to synthesize polylactide in a controllable manner, while using polymeric alcohol as an initiator has been less investigated. A series of polymeric alcohols (PS–OH composed of styrene and 4.3%–18% hydroxyl functional styrene (diethyl(hydroxy(4-vinylphenylmethylphosphonate, St–OH were synthesized through reversible addition-fragmentation transfer (RAFT polymerization. Using PS–OH as an initiator, the immortal ROP of rac-LA was catalyzed by dibutylmagnesium (MgnBu2 under various ratios of monomer to hydroxyl group within PS–OH to generate polystyrene-g-polylactide (PS–g–PLA copolymers with different graft lengths. After thermal annealing at 115 °C, the PLA domain aggregated to nanospheres among the PS continuum. The size of the nanospheres, varying from 130.1 to 224.2 nm, was related to the graft density and length of PS–g–PLA. Nanoporous films were afforded through chemical etching of the PLA component.

  13. Synthesis of Starch Grafted Acrylamide Copolymers and its Mechanism%淀粉接枝丙烯酰胺絮凝剂合成及机制

    Institute of Scientific and Technical Information of China (English)

    曹文仲; 王磊; 田伟威; 钟宏

    2012-01-01

    应用水溶液聚合法合成淀粉接枝丙烯酰胺聚合物,研究了聚合反应机制.以过硫酸铵为引发剂,淀粉与丙烯酰胺在水溶液中进行接枝共聚反应,研究了反应温度、淀粉种类、糊化、pH值对接枝反应的单体转化率、接枝率、接枝效率以及产品支链聚合物相对分子质量的影响.结果表明:在反应温度50℃、丙烯酰胺与淀粉的质量比2∶1的条件下,产品接枝率71%,单体转化率97%,支链聚合物的相对分子质量700万.用偏光显微镜、扫描电镜分析等手段表征了淀粉及其接枝共聚物的形态结构.结果显示:合成的淀粉接枝共聚物保持团粒结构,表面接枝丙烯酰胺均聚物低;糊化的淀粉接枝后,形成了均匀的淀粉接枝共聚物.%Starch grafted acrylamide copolymer was synthesized using starch and acrylamide as raw materials and ammonium persulfate as initiator, respectively. The polymerization mechanism was also discussed. The influences of temperature, types of starch and gelatinization on monomer conversion rate, grafting ratio, graft efficiency and the molecular weight of polyacrylamide grafted, were investigated during the synthesized processes. The results showed that the grafting ratio, the monomer conversion rate, and the molecular weight of polyacrylamide grafted on starch is 71% ,97% ,and 7 million, respectively, when the reaction temperature was 50℃ and the mass ratio of acrylamide to starch was 2:1. The morphology of starch graft copolymers were characterized by polarizing microscope and SEM. After the graft reaction of ungelatinized starch,the morphology of the copolymers kept the aggregate structure , and acrylamide copolymer is grafted on the surface of starch; The gelatinized starch forms homogeneous polymer, which is totally different from ungelatinized products.

  14. SYNTHESIS AND CHARACTERISTICS OF GRAFT COPOLYMERS OF POLY (BUTYL ACRYLATE AND CELLULOSE WITH ULTRASONIC PROCESSING AS A MATERIAL FOR OIL ABSORPTION

    Directory of Open Access Journals (Sweden)

    Ping Qu

    2011-11-01

    Full Text Available A series of materials used for oil absorption based on cellulose fiber grafted with butyl acrylate (BuAc have been prepared by radical polymerization under ultrasonic waves processing. Effects of ultrasonic dose for the maximum graft yield were considered. The dependency of optimum conditions for oil absorption rate on parameters such as ultrasonic processing time and ultrasonic power were also determined. Fourier infrared (FT-IR analysis was used to confirm the chemical reaction taking place between cellulose and butyl acrylate. The thermogravimetric behavior of the graft copolymer was characterized by thermogravimetric analysis (TGA. Scanning electron microscope (SEM analysis was used to determine the surface structure of the grafted material. With the increase of the ultrasonic treatment dose, the surface of the ultrasonic processed material became more regular, and the material was transformed into a homogeneous network polymer having a good structure and good adsorbing ability.

  15. Drug-loading capacity and nuclear targeting of multiwalled carbon nanotubes grafted with anionic amphiphilic copolymers

    Directory of Open Access Journals (Sweden)

    Tsai HC

    2013-11-01

    Full Text Available Hsieh-Chih Tsai,1,* Jeng-Yee Lin,2,* Faiza Maryani,1 Chun-Chiang Huang,1 Toyoko Imae1,31Graduate Institute of Applied Science and Technology, 2Division of Plastic Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei Medical University, 3Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan *These authors contributed equally to this work Abstract: In this study, three types of hybrid nanotubes (NTs, ie, oxidized multiwalled carbon NTs (COOH MWCNTs, heparin (Hep-conjugated MWCNTs (Hep MWCNTs, and diblock copolymer polyglycolic acid (PGA-co-heparin conjugated to MWCNTs (PGA MWCNTs, were synthesized with improved biocompatibility and drug-loading capacity. Hydrophilic Hep substituents on MWCNTs improved biocompatibility and acted as nucleus-sensitive segments on the CNT carrier, whereas the addition of PGA enhanced drug-loading capacity. In the PGA MWCNT system, the amphiphilic copolymer (PGA-Hep formed micelles on the side walls of CNTs, as confirmed by electron microscopy. The PGA system encapsulated the hydrophobic drug with high efficiency compared to the COOH MWCNT and Hep MWCNT systems. This is because the drug was loaded onto the PGA MWCNTs through hydrophobic forces and onto the CNTs by ∏–∏ stacking interactions. Additionally, most of the current drug-carrier designs that target cancer cells release the drug in the lysosome or cytoplasm. However, nuclear-targeted drug release is expected to kill cancer cells more directly and efficiently. In our study, PGA MWCNT carriers effectively delivered the active anticancer drug doxorubicin into targeted nuclei. This study may provide an effective strategy for the development of carbon-based drug carriers for nuclear-targeted drug delivery. Keywords: carbon nanotube, amphiphilic copolymer, drug loading, nucleus targeting, cancer therapy

  16. Graft copolymer based on (sodium alginate-g-acrylamide): Characterization and study of Water swelling capacity, metal ion sorption, flocculation and resistance to biodegradability.

    Science.gov (United States)

    Sand, Arpit; Vyas, Aparna; Gupta, A K

    2016-09-01

    Graft copolymer of alginate and acrylamide was synthesized by grafting acrylamide chains on to alginate by free radical polymerization using potassium bromate/thiourea redox system in an inert atmosphere. The reaction conditions for maximum grafting have been optimized by varying the reaction variables, including the concentration of acrylamide (3.0×10(2)-9.3×10(2)moldm(-3)), potassium bromate (8×10(-3)-16×10(-3)moldm(-3)), thiourea (1.6×10(-3)-4.8×10(-3)moldm(-3)), sulphuric acid (3.0×10(-3)-7×10(-3)moldm(-3)), alginate (0.6-1.6gdm(-3)) along with time duration (60-180min) and temperature (30-50°C). Water swelling capacity, metal ion sorption, flocculation and resistance to biodegradability studies of synthesized graft copolymer have been performed with respect to the parent polymer. The grafted polymers were characterized by FTIR spectroscopy and thermo gravimetric analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Bioinert membranes prepared from amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymers.

    Science.gov (United States)

    Patel, Rajkumar; Patel, Madhumita; Ahn, Sung Hoon; Sung, Yong Kiel; Lee, Hyung-Keun; Kim, Jong Hak; Sung, Jung-Suk

    2013-04-01

    Poly(vinyl chloride) (PVC) membrane was hydrophilically modified by grafting with poly(oxyethylene methacrylate) (POEM) using atom transfer radical polymerization (ATRP). The successful grafting of PVC main chain by POEM was characterized by Fourier transform infrared spectroscopy (FT-IR). The molecular weight and hydrophilicity of membranes increased with the amount of POEM grafting, as characterized by gel permeation chromatography (GPC) and contact angle measurement, respectively. Transmission electron microscope (TEM) and small angle X-ray scattering (SAXS) analysis revealed the microphase-separated structure of PVC-g-POEM and the domain spacing increased from 59.3 to 86.1 nm with increasing grafting degree. Scanning electron microscopy (SEM) was used for the direct visualization of the mouse embryonic fibroblast (MEF) cell and bacteria adhesion on the membrane surface. Protein adsorption and eukaryotic and prokaryotic cell adhesion tests showed that the bioinert properties of membranes were significantly increased with POEM content. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. DMFC Performance of Polymer Electrolyte Membranes Prepared from a Graft-Copolymer Consisting of a Polysulfone Main Chain and Styrene Sulfonic Acid Side Chains

    Directory of Open Access Journals (Sweden)

    Nobutaka Endo

    2016-08-01

    Full Text Available Polymer electrolyte membranes (PEMs for direct methanol fuel cell (DMFC applications were prepared from a graft-copolymer (PSF-g-PSSA consisting of a polysulfone (PSF main chain and poly(styrene sulfonic acid (PSSA side chains with various average distances between side chains (Lav and side chain lengths (Lsc. The polymers were synthesized by grafting ethyl p-styrenesulfonate (EtSS on macro-initiators of chloromethylated polysulfone with different contents of chloromethyl (CM groups, and by changing EtSS content in the copolymers by using atom transfer radical polymerization (ATRP. The DMFC performance tests using membrane electrode assemblis (MEAs with the three types of the PEMs revealed that: a PSF-g-PSSA PEM (SF-6 prepared from a graft copolymer with short average distances between side chains (Lav and medium Lsc had higher DMFC performance than PEMs with long Lav and long Lsc or with short Lav and short Lsc. SF-6 had about two times higher PDmax (68.4 mW/cm2 than Nafion® 112 at 30 wt % of methanol concentration. Furthermore, it had 58.2 mW/cm2 of PDmax at 50 wt % of methanol concentration because of it has the highest proton selectivity during DMFC operation of all the PSF-g-PSSA PEMs and Nafion® 112.

  19. Preparation of Al Fe{sub 2}O{sub 3} Core-Shell Composites Using Amphiphilic Graft Copolymer Template

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rajkumar; Kim, Sang Jin; Kim, Jin Kyu; Kim, Jong Hak [Yonsei University, Seoul (Korea, Republic of); Park, Jung Su [Agency for Defense and Development (ADD), Daejeon (Korea, Republic of)

    2014-04-15

    A graft copolymer of poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) was synthesized via atom transfer radical polymerization (ATRP) and used as a structure-directing agent to prepare Al Fe{sub 2}O{sub 3} core-shell nanocomposites through a sol-gel process. The amphiphilic property of PVC-g-POEM allows for good dispersion of Al particles and leads to specific interaction with iron ethoxide, a precursor of Fe{sub 2}O{sub 3}. Secondary bonding interaction in the sol-gel composites was characterized by Fourier transform-infrared (FT-IR) spectroscopy. The well-organized morphology of Al Fe{sub 2}O{sub 3} core-shell nanocomposites was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were used to analyze the elemental composition and crystallization structure of the composites.

  20. Characterization of bonding between poly(dimethylsiloxane) and cyclic olefin copolymer using corona discharge induced grafting polymerization.

    Science.gov (United States)

    Liu, Ke; Gu, Pan; Hamaker, Kiri; Fan, Z Hugh

    2012-01-01

    Thermoplastics have been increasingly used for fabricating microfluidic devices because of their low cost, mechanical/biocompatible attributes, and well-established manufacturing processes. However, there is sometimes a need to integrate such a device with components made from other materials such as polydimethylsiloxane (PDMS). Bonding thermoplastics with PDMS to produce hybrid devices is not straightforward. We have reported our method to modify the surface property of a cyclic olefin copolymer (COC) substrate by using corona discharge and grafting polymerization of 3-(trimethoxysilyl)propyl methacrylate; the modified surface enabled strong bonding of COC with PDMS. In this paper, we report our studies on the surface modification mechanism using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measurement. Using this bonding method, we fabricated a three-layer (COC/PDMS/COC) hybrid device consisting of elastomer-based valve arrays. The microvalve operation was confirmed through the displacement of a dye solution in a fluidic channel when the elastomer membrane was pneumatically actuated. Valve-enabled microfluidic handling was demonstrated.

  1. Lysozyme immobilization via adsorption process using sulphonic acid functionalized silane grafted copolymer.

    Science.gov (United States)

    Anirudhan, T S; Rauf, Tharun A

    2013-07-01

    A unique silane based adsorbent material, [stearyl alcohol (SA)-grafted-epichlorohydrin (E)]-grafted-aminoproypyl silanetriol (APST) was synthesized and functionalized with sulphonyl groups via sulphonation process [(SA-g-E)-g-APST/SO3H]. The adsorbent material characterization was done by FTIR, XRD, and TGA analysis. Immobilization of protein Lysozyme (LYZ) using batch adsorption process was carried out for studying the protein-particle interaction. The most suitable pH for maximum adsorption was found to be 7.0. Pseudo-second-order kinetic model was found to be the best fit and the adsorption equilibrium was attained within 3h. Studies on diffusion parameters explained that the adsorption mechanism was controlled by film diffusion mode. The adsorption process was then evaluated using the various isotherm models and the Sips isotherm model proved to be the best fit with a maximum adsorption capacity of 37.68 mg/g. The isotherm favorability of the adsorption process was calculated by calculating the separation factor (R(L)) and the values confirmed the favorability of the adsorption process. Studies on adsorption percentage with respect to temperature and thermodynamic studies revealed that adsorption process is exothermic, spontaneous with maximum entropy. Batch adsorption/desorption studies in acidic medium, for over six cycles showed the repeatability and regeneration capability of the adsorbent material (SA-g-E)-g-APST/SO3H.

  2. Glycidyl methacrylate macroporous copolymer grafted with diethylene triamine as sorbent for Reactive Black 5

    Directory of Open Access Journals (Sweden)

    Sandić Zvjezdana P.

    2014-01-01

    Full Text Available In this paper, macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine [PGME-deta], was evaluated as Reactive Black 5 (RB5 sorbent. Batch RB5 removal from aqueous solution by PGME-deta was investigated by varying pH, contact time, sorbent dosage, initial dye concentration and temperature. The sorption is pH sensitive having maximum at pH 2 (dye removal of 85%, decreasing with the increase of pH (dye removal of 24% at pH=11 after 60 min. Sorption kinetics was fitted to chemical-reaction and particle-diffusion models (pseudo-first-order, pseudo-second-order, intraparticle diffusion and Mckay models. The pseudo-second-order kinetic model accurately predicted the RB5 amount sorbed under all investigated operating conditions, while the intraparticle diffusion was the dominant rate-limiting mechanism. The diffusion mechanism was more prevalent with the decrease in temperature and the increase in concentration. The isotherm data was best fitted with the Langmuir model, indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption, with the maximum sorption capacity of 353 mg g-1. The calculated sorption rates improved with increasing temperature and an activation energy close to 40 kJ mol-1 was determined, suggesting that chemisorption was also rate-controlling. [Projekat Ministarstva nauke Republike Srbije, br. III 43009, br. TR 37021 i br. III 45001

  3. Soft Tissue Response to the Presence of Polypropylene-G-Poly(ethylene glycol Comb-Type Graft Copolymers Containing Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Derya Burcu Hazer

    2011-01-01

    Full Text Available The aim of this study is to evaluate the soft tissue response of the pure and Au-embedded PPg-PEG. PP-g-PEG2000, PP-g-PEG4000, Au-PP-g-PEG2000, and AuPP-g-PEG4000 were obtained via chlorination of polypropylene and polyethylene glycol in the presence of a base with a “grafting onto” technique. Solvent cast films of these four copolymers with PP as a control group were embedded into five different rats. After 30 days of implantation, microscopic evaluation of inflammation and SEM analysis were done. PP had the most intense inflammatory reaction among the other polymers. PP-PEG block copolymers with high molecular weight and gold-nanoparticles-embedded ones revealed mild inflammatory reaction independently. SEM assessment revealed punched hole-like defects on the surface of all polymer samples except for PP. Graft copolymers with PEG, especially Au-attached ones, have favorable soft tissue response, and inflammatory reaction becomes milder as the number of PEG side chains increases.

  4. Soft tissue response to the presence of polypropylene-G-poly(ethylene glycol) comb-type graft copolymers containing gold nanoparticles.

    Science.gov (United States)

    Hazer, Derya Burcu; Hazer, Baki; Dinçer, Nazmiye

    2011-01-01

    The aim of this study is to evaluate the soft tissue response of the pure and Au-embedded PPg-PEG. PP-g-PEG2000, PP-g-PEG4000, Au-PP-g-PEG2000, and AuPP-g-PEG4000 were obtained via chlorination of polypropylene and polyethylene glycol in the presence of a base with a "grafting onto" technique. Solvent cast films of these four copolymers with PP as a control group were embedded into five different rats. After 30 days of implantation, microscopic evaluation of inflammation and SEM analysis were done. PP had the most intense inflammatory reaction among the other polymers. PP-PEG block copolymers with high molecular weight and gold-nanoparticles-embedded ones revealed mild inflammatory reaction independently. SEM assessment revealed punched hole-like defects on the surface of all polymer samples except for PP. Graft copolymers with PEG, especially Au-attached ones, have favorable soft tissue response, and inflammatory reaction becomes milder as the number of PEG side chains increases.

  5. Positron annihilation study on free volume of amino acid modified, starch-grafted acrylamide copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, K.R. [Physics and Chemistry Department, Faculty of Education, Tanta University, Kafr El-Shaikh (Egypt)]. E-mail: kamalreyad@hotmail.com; Al-Sigeny, S. [Physics and Chemistry Department, Faculty of Education, Tanta University, Kafr El-Shaikh (Egypt); Sharshar, T. [Physics and Chemistry Department, Faculty of Education, Tanta University, Kafr El-Shaikh (Egypt); El-Hamshary, H. [Department of Chemistry, Faculty of Science, King Faisal University, Al-Ahsa 31982 (Saudi Arabia)

    2006-05-15

    Free volume measurements using positron annihilation lifetime spectroscopy was performed for uncrosslinked and crosslinked starch-grafted polyacrylamide, and their modified amino acid samples including some of their iron(III) complexes. The measurements were performed at room temperature. The analysis of lifetime spectra yielded mostly three lifetime components. It was observed that the values of the short lifetime component {tau} {sub 1} are slightly higher than the lifetime associated with the self-decay of para-positronium atoms in polymers. The free volume was probed using ortho-positronium pick-off annihilation lifetime parameters. The mean free volume has also been calculated from the lifetime data. The avrage value of this parameter of the crosslinked polymer were found to be higher than those of the uncrosslinked polymer.

  6. Positron annihilation study on free volume of amino acid modified, starch-grafted acrylamide copolymer

    Science.gov (United States)

    Mahmoud, K. R.; Al-Sigeny, S.; Sharshar, T.; El-Hamshary, H.

    2006-05-01

    Free volume measurements using positron annihilation lifetime spectroscopy was performed for uncrosslinked and crosslinked starch-grafted polyacrylamide, and their modified amino acid samples including some of their iron(III) complexes. The measurements were performed at room temperature. The analysis of lifetime spectra yielded mostly three lifetime components. It was observed that the values of the short lifetime component τ1 are slightly higher than the lifetime associated with the self-decay of para-positronium atoms in polymers. The free volume was probed using ortho-positronium pick-off annihilation lifetime parameters. The mean free volume has also been calculated from the lifetime data. The avrage value of this parameter of the crosslinked polymer were found to be higher than those of the uncrosslinked polymer.

  7. Synthesis and characterization of processable multi-walled carbon nanotubes-sulfonated polydiphenylamine graft copolymers.

    Science.gov (United States)

    Lee, Kwang-Pill; Gopalan, Anantha Iyengar; Kim, Kyu Soo; Santhosh, Padmanabhan

    2007-10-01

    Water soluble and processable nanocomposites composed of multi-walled carbon nanotubes (MWNTs) and poly(diphenylamine sulfonic acid) (PDPASA) are synthesized and characterized. Two types of methodologies are adopted. MWNTs are covalently functionalized with 2,5-diaminobenzene sulfonic acid (DABSA) and further in situ polymerized with diphenylamine-4-sulfonic acid (DPASA). This results in the formation of nanocomposites, MWNT(DABSA)-g-PDPASA, in which PDPASA is presented as the graft chains onto MWNTs. In another approach, DPASA is in situ polymerized in presence of unfunctionalized MWNTs, results in a nanocomposite in which MWNTs are present as entrapped mass in PDPASA matrix. Both nanocomposites are found to be water soluble and can form free standing films. The conductivity of MWNT(DABSA)-g-PDPASA and MWNT/PDPASA is found to be 1.25 mS x cm(-1) and 0.65 mS x cm(-1), respectively, which is higher than that of pristine PDPASA (0.25 x 10(-5) S x cm(-1)). The nanocomposites are characterized for their structure, morphology, optical and thermal properties.

  8. Synthesis of hemicellulose-acrylic acid graft copolymer super water absorbent resin by ultrasonic irradiation technology

    Directory of Open Access Journals (Sweden)

    Fangfang LIU

    2015-12-01

    Full Text Available The hemicellulose super water absorbent resin is prepared by using ultrasonic irradiation technology, with the waste liquid produced during the preparation of viscose fiber which contains a large amount of hemicellulose as raw material, acrylic acid as graft monomer, N,N’-methylene bis acrylamide (NMBA as cross linking agent, and (NH42S2O8-NaHSO3 as the redox initiation system. The synthesis conditions, structure and water absorption ability of resin are discussed. The results indicate that water absorbency of the resin is 311 g/g, the tap water absorbency is 102 g/g, the normal saline absorbency is 55 g/g, and the artificial urine absorbency is 31 g/g under the optimal synthesis conditions, so the resin has great water absorption rate and water retaining capacity. The FT-IR and SEM analysis shows that the resin with honeycomb network structure is prepared. The successfully synthesized of the resin means that the hemicellulose waste liquid can be highly effectively recycled, and it provides a kind of new raw material for the synthesis of super water absorbent resin.

  9. Amphiphilic block-graft copolymer templates for organized mesoporous TiO2 films in dye-sensitized solar cells

    Science.gov (United States)

    Lim, Jung Yup; Lee, Chang Soo; Lee, Jung Min; Ahn, Joonmo; Cho, Hyung Hee; Kim, Jong Hak

    2016-01-01

    Amphiphilic block-graft copolymers composed of poly(styrene-b-butadiene-b-styrene) (SBS) backbone and poly(oxyethylene methacrylate) (POEM) side chains are synthesized and combined with hydrophilically preformed TiO2 (Pre-TiO2), which works as a structural binder as well as titania source. This results in the formation of crack free, 6-μm-thick, organized mesoporous TiO2 (OM-TiO2) films via one-step doctor-blading based on self-assembly of SBS-g-POEM as well as preferential interaction of POEM chains with Pre-TiO2. SBS-g-POEM with different numbers of ethylene oxide repeating units, SBS-g-POEM(500) and SBS-g-POEM(950), are used to form OM-TiO2(500) and OM-TiO2(950), respectively. The efficiencies of dye-sensitized solar cells (DSSCs) with a quasi-solid-state polymer electrolyte reach 5.7% and 5.8% at 100 mW/cm2 for OM-TiO2(500) and OM-TiO2(950), respectively. The surface area of OM-TiO2(950) was greater than that of OM-TiO2(500) but the light reflectance was lower in the former, which is responsible for similar efficiency. Both DSSCs exhibit much higher efficiency than one (4.8%) with randomly-organized particulate TiO2 (Ran-TiO2), which is attributed to the higher dye loading, reduced charge recombination and improved pore infiltration of OM-TiO2. When utilizing poly((1-(4-ethenylphenyl)methyl)-3-butyl-imidazolium iodide) (PEBII) and mesoporous TiO2 spheres as the solid electrolyte and the scattering layer, the efficiency increases up to 7.5%, one of the highest values for N719-based solid-state DSSCs.

  10. Soft Tissue Response to the Presence of Polypropylene-G-Poly(ethylene glycol) Comb-Type Graft Copolymers Containing Gold Nanoparticles

    OpenAIRE

    Derya Burcu Hazer; Baki Hazer; Nazmiye Dinçer

    2011-01-01

    The aim of this study is to evaluate the soft tissue response of the pure and Au-embedded PPg-PEG. PP-g-PEG2000, PP-g-PEG4000, Au-PP-g-PEG2000, and AuPP-g-PEG4000 were obtained via chlorination of polypropylene and polyethylene glycol in the presence of a base with a “grafting onto” technique. Solvent cast films of these four copolymers with PP as a control group were embedded into five different rats. After 30 days of implantation, microscopic evaluation of inflammation and SEM analysis were...

  11. Cassava starch graft copolymers an eco-friendly corrosion inhibitor for steel in H{sub 2}SO{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xianghong; Deng, Shuduan [Southwest Forestry University, Kunming (China)

    2015-11-15

    Cassava starch graft copolymer (CSGC) was prepared by grafting acryl amide (AA) onto cassava starch (CS). The inhibition effect of CSGC on the corrosion of cold rolled steel (CRS) in 1.0M H{sub 2}SO{sub 4} solution was first studied by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) methods. The results show that CSGC is a good inhibitor, and inhibition efficiency of CSGC is higher than that of CS or AA. The adsorption of CSGC on steel surface obeys Langmuir adsorption isotherm. CSGC is a mixed-type inhibitor at 20 .deg. C, while mainly a cathodic inhibitor at 50 .deg. C.

  12. Synthesis of Graft Copolymer of Starch and Phenolic by Horseradish Peroxidase Catalysis%HRP催化淀粉与酚类接枝聚合物的合成

    Institute of Scientific and Technical Information of China (English)

    弓瑞; 吕生华; 闫小亮; 侯明明

    2012-01-01

    The free radical graft copolymerization of degraded starch and 3,5-dihydroxy benzoic acidwas carried out with horseradish peroxidase/H2O2 as catalyst in order to prepare a graft copolyrner ofstarch and phenolic. The effect of temperature and pH on the enzymatic activity was discussed. And theeffect of graft conditions on the graft copolymerization was also investigated. The structure andproperties of the copolymer were characterized by means of fourier transform infrared spectroscopy( FTIR ) , nuclear magnetic resonance ( ' HNMR ) and gel permeation chromatography ( GPC ). Thecopolymer was used as tanning agent, and the application results show that it has excellent tanningproperties.%以辣根过氧化物酶( HRP)/H2O2为催化体系,催化降解淀粉和3,5-二羟基苯甲酸(3,5-DBA)进行自由基接枝共聚反应,合成了淀粉和酚类接枝共聚物.探讨了温度和pH对酶活力的影响以及接枝条件对接枝共聚反应的影响.通过FTIR、1HNMR和GPC对接枝改性淀粉的化学结构进行了表征.产物用作皮革鞣剂时,显示了良好的应用性能.

  13. Impact of molecular weight and degree of conjugation on the thermodynamics of DNA complexation and stability of polyethylenimine-graft-poly(ethylene glycol) copolymers.

    Science.gov (United States)

    Smith, Ryan J; Beck, Rachel W; Prevette, Lisa E

    2015-01-01

    Poly(ethylene glycol) (PEG) is often conjugated to polyethylenimine (PEI) to provide colloidal stability to PEI-DNA polyplexes and shield charge leading to toxicity. Here, a library of nine cationic copolymers was synthesized by grafting three molecular weights (750, 2000, 5000Da) of PEG to linear PEI at three conjugation ratios. Using isothermal titration calorimetry, we have quantified the thermodynamics of the associations between the copolymers and DNA and determined the extent to which binding is hindered as a function of PEG molecular weight and conjugation ratio. Low conjugation ratios of 750Da PEG to PEI resulted in little decrease in DNA affinity, but a significant decrease-up to two orders of magnitude-was found for the other copolymers. We identified limitations in determination of affinity using indirect assays (electrophoretic mobility shift and ethidium bromide exclusion) commonly used in the field. Dynamic light scattering of the DNA complexes at physiological ionic strength showed that PEI modifications that did not reduce DNA affinity also did not confer significant colloidal stability, a finding that was supported by calorimetric data on the aggregation process. These results quantify the DNA interaction thermodynamics of PEGylated polycations for the first time and indicate that there is an optimum PEG chain length and degree of substitution in the design of agents that have desirable properties for effective in vivo gene delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Improvement in the water solubility of drugs with a solid dispersion system by spray drying and hot-melt extrusion with using the amphiphilic polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer and d-mannitol.

    Science.gov (United States)

    Ogawa, Noriko; Hiramatsu, Tomoki; Suzuki, Ryohei; Okamoto, Ryohei; Shibagaki, Kohei; Fujita, Kosuke; Takahashi, Chisato; Kawashima, Yoshiaki; Yamamoto, Hiromitsu

    2017-09-08

    The aim of this study was to prepare and characterize solid dispersion particles with a novel amphiphilic polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer, as a water-soluble carrier. Solid dispersion particles were prepared by hot-melt extrusion and spray drying. Indomethacin (IMC) was used as a model comprising drugs with low solubility in water and d-mannitol (MAN) was used as an excipient. The physicochemical properties of prepared particles were characterized by scanning electron microscopy, thermal analysis, powder X-ray diffraction (PXRD) analysis, FTIR spectra analysis, and drug release studies. Stability studies were also conducted under stress conditions at 40°C, 75% relative humidity. We found that dissolution behavior of the original drug crystal could be improved by solid dispersion with the polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer. The PXRD pattern and thermal analysis indicated that the solid dispersion prepared with the polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer and IMC was in an amorphous state. FTIR spectra analysis indicated that the interaction manner between the polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer and IMC may differ with the preparation method and formulation of solid dispersions. Stability studies proved that the amorphous state of IMC in solid dispersion particles was preserved under stress conditions for more than two weeks. Copyright © 2017. Published by Elsevier B.V.

  15. Chitosan-graft-poly(n-butyl acrylate) copolymer: Synthesis and characterization of a natural/synthetic hybrid material.

    Science.gov (United States)

    Anbinder, Pablo; Macchi, Carlos; Amalvy, Javier; Somoza, Alberto

    2016-07-10

    Two chitosan polymers with different deacetylation degree and molecular weight were subjected to grafting reactions with the aim to enhance the properties of these bio-based materials. Specifically, n-butyl acrylate in different proportions was grafted onto two different deacetylation degree (DD%) chitosan using radical initiation in a surfactant free emulsion system. Infrared spectroscopy was used to confirm grafting and products grafting percentage and efficiency were evaluated against acrylate/chitosan ratio and DD%. Thermal and structural properties and the behavior against water of the raw and grafted biopolymers were studied using several experimental techniques: differential scanning calorimetry, transmission electron microscopy, dynamic light scattering, water swelling, contact angle and positron annihilation lifetime spectroscopy. The influence of the grafting process on the morphological and physicochemical properties of the prepared natural/synthetic hybrid materials is discussed.

  16. Self-aggregated nanoparticles based on amphiphilic poly(lactic acid-grafted-chitosan copolymer for ocular delivery of amphotericin B

    Directory of Open Access Journals (Sweden)

    Zhou WJ

    2013-09-01

    Full Text Available Wenjun Zhou,1 Yuanyuan Wang,2 Jiuying Jian,2 Shengfang Song1 1Department of Ophthalmology, Yongchuan Hospital, Chongqing Medical University, Chongqing, People’s Republic of China; 2College of Life Science, Chongqing Medical University, Chongqing, People’s Republic of China Background: The purpose of this study was to develop a self-aggregated nanoparticulate vehicle using an amphiphilic poly(lactic acid-grafted-chitosan (PLA-g-CS copolymer and to evaluate its potential for ocular delivery of amphotericin B. Methods: A PLA-g-CS copolymer was synthesized via a “protection-graft-deprotection” procedure and its structure was confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra. Amphotericin B-loaded nanoparticles based on PLA-g-CS (AmB/PLA-g-CS were prepared by the dialysis method and characterized for particle size, zeta potential, and encapsulation efficiency. Studies of these AmB/PLA-g-CS nanoparticles, including their mucoadhesive strength, drug release properties, antifungal activity, ocular irritation, ocular pharmacokinetics, and corneal penetration were performed in vitro and in vivo. Results: Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra showed that the PLA chains were successfully grafted onto chitosan molecules and that crystallization of chitosan was suppressed. The self-aggregated PLA-g-CS nanoparticles had a core-shell structure with an average particle size of approximately 200 nm and zeta potentials higher than 30 mV. Amphotericin B was incorporated into the hydrophobic core of the nanoparticles with high encapsulation efficiency. Sustained drug release from the nanoparticles was observed in vitro. The ocular irritation study showed no sign of irritation after instillation of the PLA-g-CS nanoparticles into rabbit eyes. The minimal inhibitory concentration of the AmB/PLA-g-CS nanoparticles showed antifungal

  17. Lignin poly(lactic acid) copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.

    2017-02-14

    Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.

  18. Solution Property of Amphiphilic Graft Copolymer PSt-g-PEO%PSt-g-PEO两亲接枝共聚物溶液的性质

    Institute of Scientific and Technical Information of China (English)

    陈永春; 易昌风; 徐祖顺; 程时远

    2001-01-01

    The solution property of amphiphilic graft copolymer has been examined by means of NMR,TEM and viscometry. It is found that water and toluene are selective solvent for PSt-g-PEO. When it is dissolved in water, micelle can be formed with hydrophobic PSt backbone as the core and hydrophilic PEO side chains as the shell. On the other hand, in selective solvent toluene, the reversed-micelle can be formed with PEO as core and PSt as the shell. In toluene, with an increase in concentration, the conformation of PSt-g-PEO can be transformed from stretched single molecule to spherical reversed-micelle. The critical micelle concentration(CMC) is determined at different temperature and with the increase of temperature and the content of PEO the reversed-micelle can be formed in lower concentrations.

  19. Morphology and Phase Transitions in Styrene-Butadiene-Styrene Triblock Copolymer Grafted with Isobutyl Substituted Polyhedral Oligomeric Silsesquioxanes (Postprint)

    Science.gov (United States)

    2007-01-01

    thickness. The copolymer samples were dissolved in a toluene, a neutral solvent, in a 3.0 wt % concentration. Approximately 0.1 wt % Irganox 1010 ...self- assembled microstructure on the nanometer scale, which has led to applications in membranes, templates for nanoparticle synthesis , photonic

  20. Improvement of Uveal and Capsular Biocompatibility of Hydrophobic Acrylic Intraocular Lens by Surface Grafting with 2-Methacryloyloxyethyl Phosphorylcholine-Methacrylic Acid Copolymer

    Science.gov (United States)

    Tan, Xuhua; Zhan, Jiezhao; Zhu, Yi; Cao, Ji; Wang, Lin; Liu, Sa; Wang, Yingjun; Liu, Zhenzhen; Qin, Yingyan; Wu, Mingxing; Liu, Yizhi; Ren, Li

    2017-01-01

    Biocompatibility of intraocular lens (IOL) is critical to vision reconstruction after cataract surgery. Foldable hydrophobic acrylic IOL is vulnerable to the adhesion of extracellular matrix proteins and cells, leading to increased incidence of postoperative inflammation and capsule opacification. To increase IOL biocompatibility, we synthesized a hydrophilic copolymer P(MPC-MAA) and grafted the copolymer onto the surface of IOL through air plasma treatment. X-ray photoelectron spectroscopy, atomic force microscopy and static water contact angle were used to characterize chemical changes, topography and hydrophilicity of the IOL surface, respectively. Quartz crystal microbalance with dissipation (QCM-D) showed that P(MPC-MAA) modified IOLs were resistant to protein adsorption. Moreover, P(MPC-MAA) modification inhibited adhesion and proliferation of lens epithelial cells (LECs) in vitro. To analyze uveal and capsular biocompatibility in vivo, we implanted the P(MPC-MAA) modified IOLs into rabbits after phacoemulsification. P(MPC-MAA) modification significantly reduced postoperative inflammation and anterior capsule opacification (ACO), and did not affect posterior capsule opacification (PCO). Collectively, our study suggests that surface modification by P(MPC-MAA) can significantly improve uveal and capsular biocompatibility of hydrophobic acrylic IOL, which could potentially benefit patients with blood-aqueous barrier damage. PMID:28084469

  1. Structural color-tunable mesoporous bragg stack layers based on graft copolymer self-assembly for high-efficiency solid-state dye-sensitized solar cells

    Science.gov (United States)

    Lee, Chang Soo; Park, Jung Tae; Kim, Jong Hak

    2016-08-01

    We present a facile fabrication route for structural color-tunable mesoporous Bragg stack (BS) layers based on the self-assembly of a cost-effective graft copolymer. The mesoporous BS layers are prepared through the alternating deposition of organized mesoporous-TiO2 (OM-TiO2) and -SiO2 (OM-SiO2) films on the non-conducting side of the counter electrode in dye-sensitized solar cells (DSSCs). The OM layers with controlled porosity, pore size, and refractive index are templated with amphiphilic graft copolymers consisting of poly(vinyl chloride) backbones and poly(oxyethylene methacrylate) side chains, i.e., PVC-g-POEM. The morphology and properties of the structural color-tunable mesoporous BS-functionalized electrodes are characterized using energy filtered transmission electron microscopy (EF-TEM), field emission-scanning electron microscopy (FE-SEM), spectroscopic ellipsometry, and reflectance spectroscopy. The solid-state DSSCs (ssDSSCs) based on a structural color-tunable mesoporous BS counter electrode with a single-component solid electrolyte show an energy conversion efficiency (η) of 7.1%, which is much greater than that of conventional nanocrystalline TiO2-based cells and one of the highest values for N719 dye-based ssDSSCs. The enhancement of η is due to the enhancement of current density (Jsc), attributed to the improved light harvesting properties without considerable decrease in fill factor (FF) or open-circuit voltage (Voc), as confirmed by incident photon-to-electron conversion efficiency (IPCE) and electrochemical impedance spectroscopy (EIS).

  2. A comparative study of natural, formaldehyde-treated and copolymer-grafted orange peel for Pb(II) adsorption under batch and continuous mode.

    Science.gov (United States)

    Lugo-Lugo, Violeta; Hernández-López, Susana; Barrera-Díaz, Carlos; Ureña-Núñez, Fernando; Bilyeu, Bryan

    2009-01-30

    Natural, formaldehyde-treated and copolymer-grafted orange peels were evaluated as adsorbents to remove lead ions from aqueous solutions. The optimum pH for lead adsorption was found to be pH 5. The adsorption process was fast, reaching 99% of sorbent capacity in 10 min for the natural and treated biomasses and 20 min for the grafted material. The treated biomass showed the highest sorption rate and capacity in the batch experiments, with the results fitting well to a pseudo-first order rate equation. In the continuous test with the treated biomass, the capacity at complete exhaustion was 46.61 mg g(-1) for an initial concentration of 150 mg L(-1). Scanning electronic microscopy and energy dispersive X-ray spectroscopy indicated that the materials had a rough surface, and that the adsorption of the metal took place on the surface. Fourier transform infrared spectroscopy revealed that the functional groups responsible for metallic biosorption were the -OH, -COOH and -NH(2) groups on the surface. Finally, the thermogravimetric analysis indicates that a mass reduction of 80% can be achieved at 600 degrees C.

  3. A comparative study of natural, formaldehyde-treated and copolymer-grafted orange peel for Pb(II) adsorption under batch and continuous mode

    Energy Technology Data Exchange (ETDEWEB)

    Lugo-Lugo, Violeta; Hernandez-Lopez, Susana [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon interseccion Paseo Tollocan S/N, C.P. 50120, Toluca, Estado de Mexico (Mexico); Barrera-Diaz, Carlos [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon interseccion Paseo Tollocan S/N, C.P. 50120, Toluca, Estado de Mexico (Mexico)], E-mail: cbarrera@uaemex.mx; Urena-Nunez, Fernando [Instituto Nacional de Investigaciones Nucleares, A.P.18-1027, Col. Escandon, Delegacion Miguel Hidalgo, C.P. 11801, Mexico, D.F. (Mexico); Bilyeu, Bryan [Xavier University of Louisiana, Department of Chemistry, 1 Drexel Drive, New Orleans, LA 70125 (United States)

    2009-01-30

    Natural, formaldehyde-treated and copolymer-grafted orange peels were evaluated as adsorbents to remove lead ions from aqueous solutions. The optimum pH for lead adsorption was found to be pH 5. The adsorption process was fast, reaching 99% of sorbent capacity in 10 min for the natural and treated biomasses and 20 min for the grafted material. The treated biomass showed the highest sorption rate and capacity in the batch experiments, with the results fitting well to a pseudo-first order rate equation. In the continuous test with the treated biomass, the capacity at complete exhaustion was 46.61 mg g{sup -1} for an initial concentration of 150 mg L{sup -1}. Scanning electronic microscopy and energy dispersive X-ray spectroscopy indicated that the materials had a rough surface, and that the adsorption of the metal took place on the surface. Fourier transform infrared spectroscopy revealed that the functional groups responsible for metallic biosorption were the -OH, -COOH and -NH{sub 2} groups on the surface. Finally, the thermogravimetric analysis indicates that a mass reduction of 80% can be achieved at 600 deg. C.

  4. 温度及pH双敏感性的新型接枝共聚物%Synthesis and Characterization of Novel Temperature and pH Responsive Hydroxylpropyl Cellulose-based Graft Copolymers

    Institute of Scientific and Technical Information of China (English)

    李小军; 尹明辉; 张国亮; 张风宝

    2009-01-01

    In this study, double-hydrophilic hydroxylpropyl cellulose (HPC) based copolymers with poly(Nisopropylaerylamide) (PNIPAM) and poly(acrylic acid) (PAA) as graft chains were synthesized and characterized. The release behavior of drug-loaded micelles was studied. The results show that the hydrophilicity of copolymers improves as the pH increases, whereas the hydrophobicity of copolymers enhances as the temperature increases, and all the phase behaviors are reversible. The diameter of micelles decreases and then increases with pH increase. It shows different micellizing behavior under acidic and basic conditions according to the temperature increase. In vitro release experiments, which used theophylline as a model drug, show that the micelles enhance pH sensitivity in the release process.

  5. Calorimetric study on pH-responsive block copolymer grafted lipid bilayers: rational design and development of liposomes.

    Science.gov (United States)

    Pippa, Natassa; Chountoulesi, Maria; Kyrili, Aimilia; Meristoudi, Anastasia; Pispas, Stergios; Demetzos, Costas

    2016-09-01

    This study is focused on chimeric advanced drug delivery nanosystems and specifically on pH-sensitive liposomes, combining lipids and pH-responsive amphiphilic block copolymers. Chimeric liposomes composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and two different forms of block copolymers, i.e. poly(n-butylacrylate)-b-poly(acrylic acid) (PnBA-b-PAA) at 70 and 85% content of PAA at six different molar ratios, each form respectively. PAA block exhibits pH-responsiveness, because of the regulative group of -COOH. -COOH is protonated under acidic pH (pKa ca. 4.2), while remains ionized under basic or neutral pH, leading to liposomes repulse and eventually stability. Lipid bilayers were prepared composed of DPPC and PnBA-b-PAA. Experiments were carried out using differential scanning calorimetry (DSC) in order to investigate their thermotropic properties. DSC indicated disappearance of pre-transition at all chimeric lipid bilayers and slight thermotropic changes of the main transition temperature. Chimeric liposomes have been prepared and their physicochemical characteristics have been explored by measuring the size, size distribution and ζ-potential, owned to the presence of pH-responsive polymer. At percentages containing medium to high amounts of the polymer, chimeric liposomes were found to retain their size during the stability studies. These results were well correlated with those indicated in the DSC measurements of lipid bilayers incorporating polymers in order to explain their physicochemical behavior. The incorporation of the appropriate amount of these novel pH-responsive block copolymers affects thus the cooperativity, the liposomal stabilization and imparts pH-responsiveness.

  6. Short-chain grafting of tetrahydrofuran and 1,4-dioxane cycles on vinylchloride-maleic anhydride copolymer

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Mass increase of vinylchloride-maleic anhydride (VC-MA copolymer samples aged in tetrahydrofuran (THF or in 1,4-dioxane results from chemical interaction of VC-MA macromolecules with 1,4-dioxane or THF. Microstructure of the products of such modification was proved by infrared spectroscopy (IR- and nuclear magnetic resonance spectroscopy (13C NMR and 1H NMR. Mechanism of modification has been proposed. The results of microstructure research of VC-MA samples aged in THF and in 1,4-dioxane coincide with already known data on the reactions of opening of these and other oxygen-containing cycles under mild conditions.

  7. Synthesis of a gamma irradiation grafted polytetrafluoroethylene (PTFE) based olefinic copolymer; Estudo da sintese de copolimero olefinico a base de politetrafluoroetileno (PTFE) por meio da enxertia induzida por radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Ferreto, Helio Fernando Rodrigues

    2006-07-01

    The extrusion of linear low density polyethylene (LLDPE) is limited by a process related defect known as 'melt fracture' or 'sharkskin', which is a surface defect of the extruded polymer. This defect results in a product with a rough surface that lacks luster and in alterations of specific surface properties. The aim of this study was to obtain a recycled polytetrafluoroethylene polymer with an olefin that could improve the extrudability of the LLDPE. The copolymer was obtained by irradiating recycled PTFE in an inert atmosphere followed by the addition of an olefinic monomer to graft the latter in the polymeric matrix (PTFE). After a certain time of contact, the copolymer was heat treated to permit recombination and elimination of the radicals, both in a reactive and/or inert atmosphere. Three olefinic monomers were used, namely; acetylene, ethylene and 1,3-butadiene. The 1,3-butadiene monomer was found to be more effective with respect to grafting. The specimens were studied using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). 0.2-2.0 wt% of the copolymer that was obtained was mixed with LLDPE. The rheological properties of the mixture were determined with a torque rheometer. The results indicated that the process used rendered a copolymer which when added to LLDPE, improved the extrusion process and eliminated the defect 'melt fracture'. (author)

  8. Design and Comparative Evaluation of In-vitro Drug Release, Pharmacokinetics and Gamma Scintigraphic Analysis of Controlled Release Tablets Using Novel pH Sensitive Starch and Modified Starch- acrylate Graft Copolymer Matrices

    OpenAIRE

    Kumar, Pankaj; Ganure, Ashok Laxmanrao; Subudhi, Bharat Bhushan; Shukla, Shubhanjali

    2015-01-01

    The present investigation deals with the development of controlled release tablets of salbutamol sulphate using graft copolymers (St-g-PMMA and Ast-g-PMMA) of starch and acetylated starch. Drug excipient compatibility was spectroscopically analyzed via FT-IR, which confirmed no interaction between drug and other excipients. Formulations were evaluated for physical characteristics like hardness, friability, weight variations, drug release and drug content analysis which satisfies all the pharm...

  9. Design and Comparative Evaluation of In-vitro Drug Release, Pharmacokinetics and Gamma Scintigraphic Analysis of Controlled Release Tablets Using Novel pH Sensitive Starch and Modified Starch- acrylate Graft Copolymer Matrices

    Science.gov (United States)

    Kumar, Pankaj; Ganure, Ashok Laxmanrao; Subudhi, Bharat Bhushan; Shukla, Shubhanjali

    2015-01-01

    The present investigation deals with the development of controlled release tablets of salbutamol sulphate using graft copolymers (St-g-PMMA and Ast-g-PMMA) of starch and acetylated starch. Drug excipient compatibility was spectroscopically analyzed via FT-IR, which confirmed no interaction between drug and other excipients. Formulations were evaluated for physical characteristics like hardness, friability, weight variations, drug release and drug content analysis which satisfies all the pharmacopoeial requirement of tablet dosage form. Release rate of a model drug from formulated matrix tablets were studied at two different pH namely 1.2 and 6.8, spectrophotometrically. Drug release from the tablets of graft copolymer matrices is profoundly pH-dependent and showed a reduced release rate under acidic conditions as compared to the alkaline conditions. Study of release mechanism by Korsmeyer’s model with n values between 0.61-0.67, proved that release was governed by both diffusion and erosion. In comparison to starch and acetylated starch matrix formulations, pharmacokinetic parameters of graft copolymers matrix formulations showed a significant decrease in Cmax with an increase in tmax, indicating the effect of dosage form would last for longer duration. The gastro intestinal transit behavior of the formulation was determined by gamma scintigraphy, using 99mTc as a marker in healthy rabbits. The amount of radioactive tracer released from the labelled tablets was minimal when the tablets were in the stomach, whereas it increased as tablets reached to intestine. Thus, in-vitro and in-vivo drug release studies of starch-acrylate graft copolymers proved their controlled release behavior with preferential delivery into alkaline pH environment. PMID:26330856

  10. Triblock Copolymers with Grafted Fluorine-Free Amphiphilic Non-Ionic Side Chains for Antifouling and Fouling-Release Applications

    Energy Technology Data Exchange (ETDEWEB)

    Y Cho; H Sundaram; C Weinman; M Paik; M Dimitriou; J Finlay; M Callow; J Callow; E Kramer; C Ober

    2011-12-31

    Fluorine-free, amphiphilic, nonionic surface active block copolymers (SABCs) were synthesized through chemical modification of a polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene triblock copolymer precursor with selected amphiphilic nonionic Brij and other surfactants. Amphiphilicity was imparted by a hydrophobic aliphatic group combined with a hydrophilic poly(ethylene glycol) (PEG) group-containing moiety. The surfaces were characterized by dynamic water contact angle, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) analysis. In biofouling assays, settlement (attachment) of both spores of the green alga Ulva and cells of the diatom Navicula on SABCs modified with Brij nonionic side chains was significantly reduced relative to a PDMS standard, with a nonionic surfactant combining a PEG group and an aliphatic moiety demonstrating the best performance. Additionally, a fouling-release assay using sporelings (young plants) of Ulva and Navicula suggested that the SABC derived from nonionic Brij side chains also out-performed PDMS as a fouling-release material. Good antifouling and fouling-release properties were not demonstrated for the other two amphiphilic surfaces derived from silicone and aromatic group containing nonionic surfactants included in this study. The results suggest that small differences in chemical surface functionality impart more significant changes with respect to the antifouling settlement and fouling-release performance of materials than overall wettability behavior.

  11. 自由基聚合法合成天然橡胶接枝共聚物的研究综述%Review on Synthesis of Graft Copolymer of Natural Rubber by Free-radical Polymerization

    Institute of Scientific and Technical Information of China (English)

    廖禄生; 廖建和; 李一民; 陈永平; 黄桂春; 陈桂雄

    2011-01-01

    Natural rubber (NR) modification by polymer grafting is an important way to improve the properties of NR and to expand its application. Currently, graft copolymers of natural rubber are mainly synthesized by free-radical polymerization (FRP). The reaction mechanism and processing conditions are summarized. An outlook to the synthesis method of NR graft copolymer is made from the perspective of structural controllability of the copolymer and controlled/"living" radical polymerization.%通过聚合物接枝改性天然橡胶(NR)是改善NR性能和扩展其应用范围的重要方法之一.目前,人们主要通过自由基聚合(freeradical po1ymerization,FRP)法合成NR接枝共聚物,本文就其反应机理和反应工艺进行了综述,并从接枝共聚物的结构可控性和可控/"活性"自由基聚合的角度对NR接枝共聚物的合成方法进行了展望.

  12. 淀粉接枝DAC的合成及其絮凝性能研究%Synthesis and Flocculating Properties of Starch Graft DAC Copolymers

    Institute of Scientific and Technical Information of China (English)

    孙伟民; 张广成; 李和霖; 柴莉娜; 李东东

    2011-01-01

    以过硫酸钾(KPS)为引发剂,在水溶液中进行了玉米淀粉(St)接枝丙烯酰氧乙基三甲基氯化铵(DAC)的合成.采用正交试验优化了St-g-DAC的合成条件,得到的最佳反应条件为:引发剂的质量为0.15g,St与单体的质量比为1:3,反应温度为55℃.以此制备出St-g-DAC,测得其平均阳离子度为48.34%,接枝率为82.18%.通过傅里叶变换红外光谱(NFIR)对淀粉接枝丙烯酰氧乙基三甲基氯化铵(St-g-DAC)的表征表明,DAC已经成功地接枝到淀粉上.比较了St-g-DAC、淀粉接枝丙烯酰胺(St-g-AM)、商品聚丙烯酰胺(PAM)对粘土配水和生活污水的絮凝效果,研究表明,St-g-DAC对粘土配水和生活污水的絮凝性能较其余两种絮凝剂更强.%The graft copolymer of starch St-g-DAC were synthesized through corn starch(St. ) and aacryloxyethyltrimethyl ammonium chloride (DAC) with potassium peroxydisulfate(KPS) as initiator in water solution. The process was optimized through orthogonal tests, the best reaction condition was that the weigh of initiator was 0. l5g, the ratio of St and monomer was 1: 3, the reaction temperature was 55℃ ,the St-g-DAC was synthesized based on this conditions, its cationic ratio was 48. 34 %, graft ratio was 82. 18%, the DAC had been grafted to starch successfully through its structure which was characterized by Fourier transform infrared spectroscopy(FTIR), and the flocculating properties of starch graft acrylamide (St-g-AM), polyacrylamide(PAM) and St-g-DAC were contrasted through jar test for clay water suspension and sewage. The result shows that St-g-DAC is a better flocculant, it has better flocculating performance than PAM and St-g-PAM for clay water and sewage treatment.

  13. Study on preparing gelatin graft copolymer emulsion as sizing agent%明胶接枝共聚物乳液施胶剂的研制

    Institute of Scientific and Technical Information of China (English)

    张光华; 刘丽娟; 王帆

    2011-01-01

    With acrylic acid(AA) as functional monomer,styrene(St) as hard monomer.butyl acrylate(BA)as soft monomer and polyvinyl alcohol ( PVA ) as protective agent and dispering agent, a gelatin graft copolymer(gelatin-g-copolymer) emulsion with core/shell structre as sizing agent was prepared by soap-free seeded emulsion polymerization,according to cation characteristic of gelatin in acidic solution. The optimal process conditions of preparing sizing agent were preferred by single factor experiment method ,and the physicochemical properties and application properties of the sizing agent were investigated. The results showed that the application properties of sizing paper.which was treated by the gelatin-g-copolymer emulsion,were nearer or more than those by the import congeneric product,the water resistance of sizing paper was better than that of raw paper because the water contact angles of the former and the latter were 104° and 73° respectively when mass ratio of m(gelatin):m(AA):m(St):m(BA):m(PVA) was 3:0.5:6:4:0.25.and mass fraction of initiator was 5% and reaction temperature was 85 ℃.%以丙烯酸(AA)为功能单体、苯乙烯(St)为硬单体、丙烯酸丁酯(BA)为软单体、聚乙烯醇(PVA)为保护剂和分散剂,根据明胶在酸性溶液中呈阳离子的特点,采用无皂种子乳液聚合法制备核/壳型明胶接枝共聚物乳液施胶剂.采用单因素试验法优选制备施胶剂的最佳工艺条件,并对施胶剂的理化性能和应用性能进行了研究.结果表明:当m(明胶):m(AA):m(St):m(BA):m(PVA)=3:0.5:6:4:0.25、w(引发剂)=5%和反应温度为85℃时,明胶接枝共聚物乳液施胶纸的应用性能接近甚至超过进口同类产品,其耐水性明显优于原纸(两者水接触角分别为104°、73°).

  14. Characterization of the paclitaxel loaded chitosan graft Pluronic F127 copolymer micelles conjugate with a DNA aptamer targeting HER-2 overexpressing breast cancer cells

    Science.gov (United States)

    Thach Nguyen, Kim; Nguyen, Thu Ha; Do, Dinh Ho; Huan Le, Quang

    2017-03-01

    In this work we report the isolation of DNA aptamer that is specifically bound to a HER-2 overexpressing SK-BR-3 human breast cancer cell line, using SELEX strategy. Paclitaxel (PTX) loaded chitosan graft Pluronic F127 copolymer micelles conjugate with a DNA aptamer was synthesized and its structure was confirmed by TEM image. This binary mixed system consisting of DNA aptamer modified Pluronic F127 and chitosan could enhance PTX loading capacity and increase micelle stability. Morphology images confirmed the existence of PTX micelles, with an average size of approximately 86.22 ± 1.45 nm diameters. Drug release profile showed that the PTX conjugate maintained a sustained PTX release. From in vitro cell experiment it was shown that 89%–93%, 50%–58%, 55%–62%, 24%–28% and 2%–7% of the SK-BR-3, NS-VN-67, LH-VN-48, HT-VN-26 and NV-VN-31, respectively, were dead after 6–48 h. These results demonstrated a novel DNA aptamer-micelle assembly for efficient detection and a system for the delivery of PTX targeting specific HER-2 overexpressing. We have also successfully cultivated cancer tissues of explants from Vietnamese patients on a type I collagen substrate. The NS-VN-67, LH-VN-48, HT-VN-26 and NV-VN-31cell lines were used as cellular model sources for the study of chemotherapy drug in cancer.

  15. Hydrophobic-core PEGylated graft copolymer-stabilized nanoparticles composed of insoluble non-nucleoside reverse transcriptase inhibitors exhibit strong anti-HIV activity.

    Science.gov (United States)

    Leporati, Anita; Novikov, Mikhail S; Valuev-Elliston, Vladimir T; Korolev, Sergey P; Khandazhinskaya, Anastasia L; Kochetkov, Sergey N; Gupta, Suresh; Goding, Julian; Bolotin, Elijah; Gottikh, Marina B; Bogdanov, Alexei A

    2016-11-01

    Benzophenone-uracil (BPU) scaffold-derived candidate compounds are efficient non-nucleoside reverse transcriptase inhibitors (NNRTI) with extremely low solubility in water. We proposed to use hydrophobic core (methoxypolyethylene glycol-polylysine) graft copolymer (HC-PGC) technology for stabilizing nanoparticle-based formulations of BPU NNRTI in water. Co-lyophilization of NNRTI/HC-PGC mixtures resulted in dry powders that could be easily reconstituted with the formation of 150-250 nm stable nanoparticles (NP). The NP and HC-PGC were non-toxic in experiments with TZM-bl reporter cells. Nanoparticles containing selected efficient candidate Z107 NNRTI preserved the ability to inhibit HIV-1 reverse transcriptase polymerase activities with no appreciable change of EC50. The formulation with HC-PGC bearing residues of oleic acid resulted in nanoparticles that were nearly identical in anti-HIV-1 potency when compared to Z107 solutions in DMSO (EC50=7.5±3.8 vs. 8.2±5.1 nM). Therefore, hydrophobic core macromolecular stabilizers form nanoparticles with insoluble NNRTI while preserving the antiviral activity of the drug cargo.

  16. An investigation into the adsorption of thorium(IV) from aqueous solutions by a carboxylate-functionalised graft copolymer derived from titanium dioxide-densified cellulose.

    Science.gov (United States)

    Anirudhan, T S; Sreekumari, S S; Jalajamony, S

    2013-02-01

    The use of a carboxylate-functionalized graft copolymer (PGTDC-COOH) based on titanium dioxide-densified cellulose (TDC) for the removal and recovery of thorium(IV) [Th(IV)] from industrial wastewater is reported in this paper. Infrared spectroscopy and X-ray diffractometer were used to characterize the adsorbent material. Batch equilibrium experiments showed that the adsorbent exhibited 98.6 ± 3.1% adsorption from an initial concentration of 10 mg/L Th(IV) solution at pH 5.0. The sorption kinetics have been analysed by pseudo-first-order and pseudo-second-order kinetic models and the adsorption kinetics was described by pseudo-second-order model. The experimental data obeyed Langmuir isotherm and the maximum monolayer adsorption capacity for Th(IV) was also found to be 92.23 ± 2.4 mg/g at 30 °C. The desorption capacity of HCl concentrations of different strengths ranging from 0.001 to 0.1 M was also studied. Maximum desorption of 98.2 ± 2.8% for Th(IV) occurred with 0.1 M HCl. The adsorption efficiency towards Th(IV) ion removal was tested using artificial sea water. Almost complete removal was possible with 3.5 g of the adsorbent from 1 L of the sea water.

  17. Protected Graft Copolymer (PGC in Imaging and Therapy: A Platform for the Delivery of Covalently and Non-Covalently Bound Drugs

    Directory of Open Access Journals (Sweden)

    Alexei A. Bogdanov Jr, Mary Mazzanti, Gerardo Castillo, Elijah Bolotin

    2012-01-01

    Full Text Available Initially developed in 1992 as an MR imaging agent, the family of protected graft copolymers (PGC is based on a conjugate of polylysine backbone to which methoxypoly(ethylene glycol (MPEG chains are covalently linked in a random fasion via N-ε-amino groups. While PGC is relatively simple in terms of its chemcial composition and structure, it has proved to be a versatile platform for in vivo drug delivery. The advantages of poly amino acid backbone grafting include multiple available linking sites for drug and adaptor molecules. The grafting of PEG chains to PGC does not compromise biodegradability and does not result in measurable toxicity or immunogenicity. In fact, the biocompatablility of PGC has resulted in its being one of the few 100% synthetic non-proteinaceous macromolecules that has suceeded in passing the initial safety phase of clinical trials. PGC is capable of long circulation times after injection into the blood stream and as such found use early on as a carrier system for delivery of paramagnetic imaging compounds for angiography. Other PGC types were later developed for use in nuclear medicine and optical imaging applications in vivo. Recent developments in PGC-based drug carrier formulations include the use of zinc as a bridge between the PGC carrier and zinc-binding proteins and re-engineering of the PGC carrier as a covalent amphiphile that is capabe of binding to hydrophobic residues of small proteins and peptides. At present, PGC-based formulations have been developed and tested in various disease models for: 1 MR imaging local blood circulation in stroke, cancer and diabetes; 2 MR and nuclear imaging of blood volume and vascular permeability in inflammation; 3 optical imaging of proteolytic activity in cancer and inflammation; 4 delivery of platinum(II compounds for treating cancer; 5 delivery of small proteins and peptides for treating diabetes, obesity and myocardial infarction. This review summarizes the experience

  18. Poly(ethylene-co-acrylic acid)-g-poly(ethylene glycol) graft copolymer templated synthesis of mesoporous TiO{sub 2} thin films for quasi-solid-state dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rajkumar; Jung, Ye Eun; Kim, Dong Jun; Kim, Sang Jin; Kim, Jong Hak, E-mail: jonghak@yonsei.ac.kr

    2014-02-03

    An amphiphilic graft copolymer, poly(ethylene-co-acrylic acid)-graft-poly(ethylene glycol) (PEAA-g-PEG), consisting of a PEAA backbone and PEG side chains was synthesized via an esterification reaction. {sup 1}H nuclear magnetic resonance and Fourier-transformed infrared analysis demonstrated esterification between carboxylic acid of PEAA and hydroxyl group of PEG. Small angle X-ray scattering results revealed that the crystalline domain spacing of PEAA increased from 11.3 to 12.8 nm upon using a more polar solvent with a higher affinity for poly(acrylic acid), while the crystalline domain spacing of PEAA disappeared with PEG grafting, indicating structural change to an amorphous state. Mesoporous TiO{sub 2} thin films were synthesized via a sol–gel reaction using PEAA-g-PEG graft copolymer as a structure-directing agent. The hydrophilically-preformed TiO{sub 2} nanoparticles were selectively confined in the hydrophilic PEG domains of the graft copolymer, and mesoporous TiO{sub 2} thin films were formed, as confirmed by scanning electron microscopy. The morphology of TiO{sub 2} films was tunable by varying the concentrations of polymer solutions and the amount of preformed TiO{sub 2}. A quasi-solid-state dye-sensitized solar cell fabricated with PEAA-g-PEG templated TiO{sub 2} film exhibited an energy conversion efficiency of 3.8% at 100 mW/cm{sup 2}, which was greater than that of commercially-available paste (2.6%) at a similar film thickness (3 μm). The improved performance was due to the larger surface area for high dye loading and organized structure with good interconnectivity. - Highlights: • Poly(ethylene-co-acrylic acid)-g-poly(ethylene glycol) (PEAA-g-PEG) graft copolymer is synthesized. • Amphiphilic PEAA-g-PEG acts as a structure directing agent. • Mesoporous TiO{sub 2} thin films are prepared by sol–gel reaction using PEAA-g-PEG template. • Efficiency of DSSC with templated TiO{sub 2} is greater than with commercial TiO{sub 2} paste.

  19. Multilayer self-assembly of TiO₂ nanoparticles and polyaniline-grafted-chitosan copolymer (CPANI) for photocatalysis.

    Science.gov (United States)

    Mahanta, Debajyoti; Manna, Uttam; Madras, Giridhar; Patil, Satish

    2011-01-01

    A photocatalytic thin film of TiO₂ nanoparticles and polyaniline-grafted-chitosan (CPANI) was fabricated by layer-by-layer (LbL) approach. The growth of the self-assembly of polymer nanocomposite was monitored by UV-vis spectroscopy and the thin film morphology was analyzed from scanning electron microscopy (SEM). Poly(styrene sulfonate) (PSS) was used as a bridging layer between TiO₂ nanoparticles and CPANI. Incorporation of CPANI within the LbL self-assembly of polymer nanocomposites enhanced the dye degradation ability of the thin film. These results indicate that the presence of CPANI improves the adsorption of dye in the self-assembly. The effect of surface area and the amount of catalyst was also examined. The reusability of the thin films for dye degradation study ensures the stability of the self-assembly.

  20. Poly(vinyl chloride)-g-poly(2-(dimethylamino)ethyl methacrylate) graft copolymers templated synthesis of mesoporous TiO{sub 2} thin films for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rajkumar; Ahn, Sung Hoon; Seo, Jin Ah; Kim, Sang Jin; Kim, Jong Hak, E-mail: jonghak@yonsei.ac.kr [Yonsei University, Department of Chemical and Biomolecular Engineering (Korea, Republic of)

    2012-07-15

    A poly(vinyl chloride) (PVC) main chain was grafted with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) containing a quaternary amine group using atom transfer radical polymerization. The successful synthesis of a PVC-g-PDMAEMA graft copolymer was confirmed by Fourier transform infrared, nuclear magnetic resonance, thermogravimetric analysis, and transmission electron microscopy. The PVC-g-PDMAEMA graft copolymer was used as a structure-directing agent (SDA) for the fabrication of a mesoporous thin film containing a titanium dioxide (TiO{sub 2}) layer. To control the porosity of the resultant inorganic layer, the ratio of SDA to TTIP as well as the concentration of the sol-gel was varied. The structure and porosity of the mesoporous film were characterized by XRD and SEM analysis. The mesoporous TiO{sub 2} film fabricated on the FTO surface was used as a photoanode for the dye-sensitized solar cell (DSSC). DSSC performance was the greatest when using TiO{sub 2} film with a higher porosity and lower interfacial resistance. The highest energy conversion efficiency reached 3.2 % at 100 mW/cm{sup 2}, which was one of the highest reported values for a quasi-solid-state DSSC with 600-nm-thick TiO{sub 2} film.

  1. Bimodal porous TiO2 structures templated by graft copolymer/homopolymer blend for dye-sensitized solar cells with polymer electrolyte

    Science.gov (United States)

    Kim, Jin Kyu; Lee, Chang Soo; Lee, Sang-Yup; Cho, Hyung Hee; Kim, Jong Hak

    2016-12-01

    Bimodal porous TiO2 (BP-TiO2) with large surface area, high porosity, good interconnectivity, and excellent light-scattering ability are synthesized via a facile one-step method using a self-assembled blend template consisting of an amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer and a hydrophobic poly(vinyl chloride) (PVC) homopolymer. The hydrophilically surface-modified TiO2 nanoparticles selectively interact with the hydrophilic POEM chains, while the addition of the PVC homopolymer increases the hydrophobic domain size, resulting in the formation of dual pores (i.e., macropores and mesopores). The sizes and numbers of macropores can easily be controlled by changing the molecular weight and amount of the PVC homopolymer. The polymer electrolyte dye-sensitized solar cells (DSSCs) fabricated with BP-TiO2 photoanodes exhibited energy conversion efficiencies of up to 7.6% at 100 mW cm-2, which is much higher than those of mesoporous TiO2 (5.8%) with PVC-g-POEM only and conventional nanocrystalline TiO2 (4.9%) with commercial Dyesol paste. The enhanced energy conversion efficiencies mostly resulted from the light-scattering effects of the macropores, which increased the light-harvesting efficiencies. The improved light-harvesting and photovoltaic performances of the DSSCs were characterized by UV-vis spectroscopy, incident photon-to-current conversion efficiency analysis, electrochemical impedance spectroscopy, intensity-modulated photocurrent spectroscopy, and intensity-modulated photovoltage spectroscopy.

  2. Effect of polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer on bioadhesion and release rate property of eplerenone pellets.

    Science.gov (United States)

    Kendre, Prakash Namdeo; Chaudhari, Pravin Digambar

    2017-05-01

    The present study involved the design and development of oral bioadhesive pellets of eplerenone. A solid dispersion of eplerenone was developed with a hydrophilic carrier, polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus(®)). Bioadhesive pellets were prepared from this solid dispersion using a combination of HPMC K4M and Carbopol 934P. Both the solid dispersion and the pellets were evaluated for various physicochemical properties such as solubility, entrapment efficiency, drug content, surface morphology, mucoadhesion and swelling behavior. Analysis carried out using FT-IR, DSC and XRD found no interaction between the eplerenone and excipients. The solid dispersion had irregular-shaped smooth-surfaced particles of diameter 265 ± 105.5 μm. In TEM analysis, eplerenone particles of size 79-120 nm were found. The solubility and dissolution of eplerenone in the Soluplus(®)-based solid dispersion were 5.26 and 2.50 times greater, respectively. Investigation of the swelling behavior of the pellets showed that the thickness of the gel layer increased continuously over the duration of the study. Moreover, a correlation was observed between the thickness and strength of the gel layer and the percentage release. The mechanism of drug release was found to be non-Fickian (anomalous), with the release kinetics approaching first-order kinetics. The bioavailability of the eplerenone bioadhesive pellet formulation was studied using Wistar rats and was found to be improved. An in vivo mucoadhesion study showed that the pellets are retained for 24 h in rabbits. It was concluded that Soluplus(®) had a positive effect on the solubility and dissolution of pellets without affecting the bioadhesion.

  3. Preparation, property of the complex of carboxymethyl chitosan grafted copolymer with iodine and application of it in cervical antibacterial biomembrane

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yang, Yumin; Liao, Qingping [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Yang, Wei [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Ma, Wanfeng [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Zhao, Jian [Department of Gynaecology and Obstetrics, The First Hospital of Peking University, Beijing 100034 (China); Zheng, Xionggao [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yang, Yang [Zhejiang Sanchuang Biological Technology Co., Ltd., Jiaxing, Zhejiang Province 314031 (China); Chen, Rui [Department of Gynaecology and Obstetrics, The First Hospital of Peking University, Beijing 100034 (China)

    2016-10-01

    Cervical erosion is one of the common diseases of women. The loop electrosurgical excisional procedure (LEEP) has been used widely in the treatment of the cervical diseases. However, there are no effective wound dressings for the postoperative care to protect the wound area from further infection, leading to increased secretion and longer healing time. Iodine is a widely used inorganic antibacterial agent with many advantages. However, the carrier for stable iodine complex antibacterial agents is lack. In the present study, a novel iodine carrier, Carboxymethyl chitosan-g-(poly(sodium acrylate)-co-polyvinylpyrrolidone) (CMCTS-g-(PAANa-co-PVP), was prepared by graft copolymerization of sodium acrylate (AANa) and N-vinylpyrrolidone (NVP) to a carboxymethyl chitosan (CMCTS) skeleton. The obtained structure could combine prominent property of poly(sodium acrylate) (PAANa) anionic polyelectrolyte segment and good complex property of polyvinylpyrrolidone (PVP) segment to iodine. The bioactivity of CMCTS could also be kept. The properties of the complex, CMCTS-g-(PAANa-co-PVP)-I{sub 2}, were studied. The in vitro experiment shows that it has broad-spectrum bactericidal effects to virus, fungus, gram-positive bacteria and gram-negative bacteria. A CMCTS-g-(PAANa-co-PVP)-I{sub 2} complex contained cervical antibacterial biomembrane (CABM) was prepared. The iodine release from the CABM is pH-dependent. The clinic trial results indicate that CABM has better treatment effectiveness than the conventional treatment in the postoperative care of the LEEP operation. - Highlights: • The multifunctional iodine complexing carrier CMCTS-g-(PAANa-co-PVP) was prepared. • CMCTS-g-(PAANa-co-PVP)-I{sub 2} with high antibacterial property and bio-safety was studied. • By compositing it with CMCTS and gelatin further, CABM with multifunction was deduced. • The releasing properties of the activated iodine from CABM showed pH sensitivity. • CABM showed good treating effect for

  4. Removal of Pb(2+) and Fe(3+) from water using N-TiO2 blended copolymer grafted asymmetric membranes.

    Science.gov (United States)

    Mungondori, Henry H; Tichagwa, Lilian; Katwire, David M

    2016-01-01

    The aim of this study was to evaluate the photo-catalytic properties of nitrogen-doped titanium dioxide nano-particles supported on polymer membranes in the photo-reduction of Fe(3+) and Pb(2+) from synthetic wastewater. The morphology of the prepared N-TiO2 nanoparticles was evaluated using transmission electron microscopy. Successful grafting of methacrylic acid side chains onto poly(vinylidene difluoride) (PVDF) backbone was confirmed by Fourier-transform infrared spectroscopy. The photo-catalytic asymmetric membranes were prepared through the dry-wet phase inversion technique. The asymmetric morphology was evaluated using scanning electron microscopy. The highest Fe(3+) photo-reduction efficiency (76.2%) was achieved in 6 hours using 1% N-TiO2-PMAA-g-PVDF/PAN (PMAA: poly(methacrylic acid); PAN: poly(acrylonitrile)) asymmetric membrane under solar irradiation. Increasing the photo-catalyst loading to 3% was found to negatively impact the photo-reduction of Fe(3+). Very high photo-reduction efficiencies were observed in the photo-reduction of Pb(2+) using 1% N-TiO2-PAN, 1% N-TiO2-PMAA-g-PVDF/PAN and 1% N-TiO2-PVDF membranes (90.5%, 88.9% and 86.9%, respectively) under similar conditions. Increasing the photo-catalyst loading to 3% N-TiO2 was observed to slightly increase the photo-reduction efficiency in the removal of Pb(2+) unlike in the case of Fe(3+). The best support material for the N-TiO2 photo-catalyst was PMAA-g-PVDF/PAN.

  5. Poly(l-lysine)-graft-folic acid-coupled poly(2-methyl-2-oxazoline) (PLL-g-PMOXA-c-FA): a bioactive copolymer for specific targeting to folate receptor-positive cancer cells.

    Science.gov (United States)

    Chen, Yin; Cao, Wenbin; Zhou, Junli; Pidhatika, Bidhari; Xiong, Bin; Huang, Lu; Tian, Qian; Shu, Yiwei; Wen, Weijia; Hsing, I-Ming; Wu, Hongkai

    2015-02-04

    In this study, we present the preparation, characterization and application of a novel bioactive copolymer poly(l-lysine)-graft-folic acid-coupled poly(2-methyl-2-oxazoline) (PLL-g-PMOXA-c-FA), which has a specific interaction with folate receptor (FR)-positive cancer cells. Glass surface immobilized with PLL-g-PMOXA-c-FA was demonstrated to be adhesive to FR-positive cancer cells (HeLa, JEG-3) while nonadhesive to FR-negative ones (MCF-7, HepG2) in 3 h. The specific interaction between conjugated FA on the substrate and FRs on the cells could hardly be inhibited unless a high concentration (5 mM) of free FA was used due to the multivalent nature of it. The FA functionality ratio of the copolymer on the substrate had a significant influence on the adhesion of HeLa cells, and our experiments revealed that the affinity of the substrate to the cells declined dramatically with the decrease of functionality ratio. This was believed to be caused by the polydispersity of PMOXA tethers, as supported by GPC and ToF-SIMS data. As a proof of concept in the application of our material, we demonstrated successful recovery of HeLa cells from mixture with MCF-7 (1:100) on the copolymer-coated glass, and our results showed that both high sensitivity (95.6 ± 13.3%) and specificity (24.3 ± 8.6%) were achieved.

  6. Synthesis of Graft Copolymer of Acryl Amide onto Guar Gum by Inverse Emulsion%瓜尔胶/丙烯酰胺的反相乳液接枝共聚

    Institute of Scientific and Technical Information of China (English)

    林兆云; 张贤贤; 李友明; 万小芳; 刘军

    2012-01-01

    A graft copolymer of guar gum with acryl amide was made by using ammonium eerie nitrate/ nitric acid as initiator. The effects of m ( AM): m ( GG), initiator concentration, reaction temperature and reaction time on polymerization were investigated. The results indicate that the grafting ratio and comonomer conversion of grafting copolymerization were 147. 05% and 87.7% when m{ AM} :m( GG) = 3:2,initiator concentration was 4 mmol/L,reaction time was 4 h and reaction temperature was 45 ℃. The largest molecule of the graft copolymer could reach a dimension of 1. 73 × 106. The analysis of IR spectrum shows that AM was substantially grafted onto the molecular chain of guar gum. TGA indicates that the grafted AM has no effect on the thermal stability of guar gum.%以硝酸铈铵/硝酸为引发剂,在反相乳液中引发瓜尔胶/丙烯酰胺的接枝共聚反应.考察了m(丙烯酰胺AM)∶m(瓜尔胶GG)、引发剂浓度、反应温度和反应时间对接枝聚合的影响.结果表明,当m(AM)∶m(GG)=3∶2,引发剂浓度为4mmol/L,反应时间为4h,反应温度为45℃时,接枝共聚反应的接枝率和单体转化率分别为147.05%和87.7%.接枝共聚物的最大相对分子质量(简称分子量,下同)可达到1.73×106.红外光谱(IR)分析证明了AM确实接枝到GG分子链上,热重分析(TGA)显示接枝的AM单体并未影响GG的热稳定性.

  7. 壳聚糖接枝聚乳酸共聚物性能及其体外释药行为研究%PROPERTIES AND DRUG RELEASE IN VITRO BEHAVIOR OF POLY ( LACTIC ACID ) GRAFTING CHITOSAN COPOLYMER

    Institute of Scientific and Technical Information of China (English)

    吴景梅; 邰燕芳; 王传虎

    2011-01-01

    采用原位聚合法合成了含聚乳酸链段的壳聚糖接枝共聚物.通过X射线衍射(XRD)和热重(TG)分析研究共聚物的结晶性能和热失重行为.结果表明,共聚物的结晶度和热分解温度降低,壳聚糖的高结晶性能得到改善.接触角测试表明,相对于聚乳酸,共聚物材料具有较好的亲水性.通过溶剂挥发法制备了5-氟尿嘧啶/共聚物载药微球,并用紫外分光光度法研究了载药微球的体外释药行为.实验表明,壳聚糖接枝聚乳酸共聚物具有较壳聚糖与聚乳酸更为优良的综合性能,拓展了该类型材料作为生物医学材料的应用领域.%Poly (lactic acid ) (PLA) grafting chitosan(CS) copolymers were synthesized by in-situ polymerization. The crystallization property and thermal stabilities were studied by X-ray diffraction ( XRD ) and thermogravimetry analysis ( TG ). The results showed that the copolymers exhibited low crystallinity and thermal degradation temperature due to the introduction of PLA and the high crystallization property of chitosan was improved. The contact angle test results demonstrated that the copolymers were more hydrophilic than PLA. The 5-Fluorouracil / copolymer microspheres enveloped were prepared by emulsion-solvent evaporation method and the drug release in vitro behaviors were detected by UV spectrophotometry. According to the experiment the comprehensive properties of the copolymer were excellent than that of CS and PLA respectively. The copolymer could expand the application of the materials in the biomedical field.

  8. 木粉-丙烯酰胺接枝共聚物的制备及其絮凝性能%Preparation and flocculation properties of graft copolymer from fir powder and acrylamide

    Institute of Scientific and Technical Information of China (English)

    郭立颖; 史铁钧

    2011-01-01

    首先用微波加热法(400 W,90℃)将杉木粉溶解在离子液体氯代1-(2-羟乙基)-3-乙基咪唑([HeEIM]Cl)中,再将溶解体系和丙烯酰胺(AM)原位共混,在过硫酸钾热引发条件下使溶解后的木粉和丙烯酰胺在离子液体介质中接枝共聚,制备了改性絮凝剂AM-g-wood,并用FTIR和XRD对其化学结构和结晶结构进行表征,比较研究离子液体和水分别作为反应介质对接枝共聚的影响,考察絮凝剂AM-g-wood对煤泥污水和陶土污水的絮凝效果.FTIR和XRD结果表明杉木粉与丙烯酰胺发生了接枝反应,其中以离子液体为介质制备的共聚物性能远远优于水介质,该絮凝剂对较细颗粒的陶土污水处理效果要优于煤泥污水,特别是在无机絮凝剂氯铝盐的协同作用下,絮凝效果更好.%Fir powder was dissolved in ionic liquid of 1-(2-hydroxylethyl)-3-ethyl imidazolium chloride ([HeEIM]Cl) by microwave heating (400 W, 90℃), then acrylamide (AM) was grafted onto the dissolved wood with initiator of K2S2O8 in the dissolution system to prepare the graft copolymer AM-g-wood, which was a novel modified flocculant. The chemical structure and crystalline structure of the flocculant were determined by FTIR and XRD respectively. The effects of ionic liquid and aqueous medium on graft copolymerization were studied. The flocculation properties of AM-g-wood on coal slurry water and argil wastewater were investigated. The results of FTIR and XRD showed that graft copolymerization occurred between AM and fir powder. The performance of AM-g-wood prepared in ionic liquid medium was far superior to that prepared in aqueous medium, and the graft copolymer was more suitable for treating argil wastewater with tiny particles. The effect of flocculation was better when inorganic flocculant of poly aluminum chloride (PAC) was used as synergistic agent.

  9. Development of poly(N-isopropylacrylamide)/alginate copolymer hydrogel-grafted fabrics embedding of berberine nanosuspension for the infected wound treatment.

    Science.gov (United States)

    Xu, He; Yuan, Xu-Dong; Shen, Bao-De; Han, Jin; Lv, Qing-Yuan; Dai, Ling; Lin, Ming-Gui; Yu, Chao; Bai, Jin-Xia; Yuan, Hai-Long

    2014-05-01

    In the present study, a novel hydrogel-grafted fabrics embedding of berberine nanosuspension was developed for the treatment of infected wound. Hydrogel-grafted fabric was prepared by graft copolymerization of N-isopropylacrylamide and alginate using ceric ammonium nitrate as initiator. Berberine nanosuspension was prepared and embedded in the hydrogel-grafted fabrics to achieve sustained drug release. The prepared hydrogel-grafted fabrics embedding of berberine nanosuspension was characterized by FT-IR spectroscopy, scanning electron microscopy, and swelling degree studies. Fourier transform infrared spectroscopy revealed that berberine was embedded into the matrix of hydrogel-grafted fabrics, rather than on the surface. Scanning electron microscopy showed that a thin hydrogel layer was formed on the surface of nonwoven fibers. The swelling study showed that hydrogel-grafted fabric had water absorbing characteristic with reversible temperature sensitivity. The drug release study demonstrated that hydrogel-grafted fabrics can be used as a sustained drug delivery system of hydrophobic compounds. The berberine nanosuspension embedded hydrogel-grafted fabric was further investigated in an animal infected wound model and was found to be a very promising wound healing dressing for the treatment and healing of infected wounds.

  10. Formation and Compatibilizing Effect of the Grafted Copolymer in the Reactive Blending of 2-Diethylsuccinate Containing Polyolefins With Poly-ε-caprolactam (Nylon-6)

    NARCIS (Netherlands)

    Passaglia, Elisa; Aglietto, Mauro; Ruggeri, Giacomo; Picchioni, Francesco

    1998-01-01

    The intermolecular reaction and its role in determining the partial compatibility between diethylsuccinate containing linear low-density polyethylene or ethylene propylene copolymer and poly-ε-caprolactam (PA6) has been investigated in the melt using a Brabender mixer. The reaction product has been

  11. Grafting of diethyl maleate and maleic anhydride onto styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS)

    NARCIS (Netherlands)

    Picchioni, F.; Ghetti, S.; Passaglia, E.; Ruggeri, G.

    2000-01-01

    In this paper a study of the bulk functionalization of styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS) with diethyl maleate (DEM) or maleic anhydride (MAH) and dicumyl peroxide (DCP) as initiator in a Brabender mixer is described. The determination of the functionalization degre

  12. New synthesis of amphiphilic copolymers PE-g-PEO via esterfication

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new series of high molecular weight amphiphilic graft copolymers PE-g-PEO has been prepared. The esterifications between PE-p-MS-g-MA and PEO with OH group at the chain end are carried out under different conditions. The compositions of these graft copolymers are studied by NMR and FTIR. It is found to be a convenient and efficient way to prepare high molecular weight PE-g-PEO graft copolymers.

  13. Preparation of Canna edulis Ker Starch-Acrylic Acid Graft Copolymer by Inverse Microemulsion Method%反相微乳液法制备芭蕉芋淀粉接枝丙烯酸盐共聚物

    Institute of Scientific and Technical Information of China (English)

    顾千辉; 黄赣辉; 顾振宇

    2011-01-01

    Canna edulis Ker starch-acrylic acid graft copolymer was prepared by an inverse microemulsion method using ammonium persulfate as the initiator and N,N'-meyhylene-bisacrylamide as cross-linking agent under nitrogen protection.An inverse emulsion system containing Canna edulis Ker starch was formed under an oil-to-water ratio of 1.2:1,complex emulsifier amount of 30%,and emulsifier HLB(hydrophilic-lipophilic balance) of 7.36.The optimal copolymerization conditions of Canna edulis Ker starch and acrylic acid were acrylic acid amount of 16 mL,initiator amount of 3.5%,cross-linking agent amount of 0.8%,and neutralization degree of acrylic acid of 70%.The water-absorbing capacity of graft copolymers prepared under the optimal conditions was 1340 g/g.Meanwhile,infrared spectral analysis revealed that acrylic acid was successfully grafted onto Canna edulis Ker starch.%在氮气保护的环境下,以过硫酸铵为引发剂、N,N'-亚甲基双丙烯酰胺为交联剂,采用反相微乳液法制备芭蕉芋淀粉接枝丙烯酸盐共聚物;确定含芭蕉芋淀粉的稳定反相微乳液体系的制备工艺:油水比为1.2:1、复合乳化剂用量为30%、乳化剂的亲水亲油平衡值(hydrophile lipophylic balance,HLB)为7.36;利用正交试验法优化利用反相微乳液法制备淀粉接枝丙烯酸盐共聚物的工艺条件,在最佳工艺(单体丙烯酸的用量16mL、引发剂用量3.5%、交联剂用量0.8%、单体丙烯酸中和度70%)条件下,制备出芭蕉芋淀粉接枝丙烯酸盐共聚物的吸水倍率可达1340g/g。红外光谱分析结果表明,聚合过程中芭蕉芋淀粉与丙烯酸发生了接枝共聚反应。

  14. Synthesis of Graft Copolymer of Natural Rubber by ATRP Ⅲ.Preparation of NR-g-PMMA%采用ATRP合成天然橡胶接枝共聚物——Ⅲ.NR-g-PMMA的制备

    Institute of Scientific and Technical Information of China (English)

    赵伟; 廖建和; 廖禄生; 杨耀华; 黄仙红; 陈永平

    2012-01-01

    An atom transfer radical polymerization(ATRP) macroinitiator, bromo-(natural rubber) [NR-Br(l) ], was synthesized by the reaction of natural rubber (NR) with N-bromosuccinimide. A novel graft copolymer, (natural rubber)-g-poly( methyl methacrylate) [NR-g-PMMA(2) ] , was prepared from methyl methacrylate (MMA) using 1 as a macroinitiator and CuBr/PMDTA as the catalyst by ATRP. The structures were characterized by !H NMR and IR. The results of preliminary study of graft copolymerization dynamics showed that the reaction of NR with NBS at high temperature easily occurred addition and cyclization, 1 prepared at room temperature exhibited higher initiating activity, and the graft copolymerization accorded with first-order kinetic reaction because the molecular weight of 2 increaseed as MMA monomer conversion increases.%N-溴代丁二酰亚胺与天然橡胶(NR)反应合成了大分子引发剂——溴代天然橡胶[NR-Br(1)].通过原子转移自由基聚合(ATRP),以CuBr/PMDTA为催化体系,1引发甲基丙烯酸甲酯(MMA)接枝共聚制得新型天然橡胶-g-聚甲基丙烯酸甲酯[NR-g-PMMA(2)],其结构经1H NMR和IR表征.初步聚合反应动力学研究结果表明,NBS与NR在高温下反应容易伴随双键加成和环化反应,于室温反应所得1具有较高的引发活性;接枝聚合符合一级动力学反应,即2的分子量随MMA单体转化率的提高而增加.

  15. MOLECULAR DESIGN SYNTHESIS AND PROPERTIES OF SIX KINDS OF MULTIPHASE (STYRENE-ETHYLENE OXIDE) COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    XIE Hongquan; ZHOU Peiguang; SUN Wenbo; XIA Jun; LIU Jin; XIE Dong

    1991-01-01

    @@ Multiphase copolymers of styrene (S) and ethylene oxide (EO) are amphiphilic,because of the hydrophobic and amorphous polystyrene (PS) segments and the hydrophilic and crystalline polyoxyethylene (PEO). They have many uses including polymeric surfactants, electrostatic charge reducers, compatibilizer in polymer blending, phase transfer catalysts or solid polymer electrolytes. These copolymers include different types of block copolymers, graft copolymers and star-shaped block copolymers.

  16. Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation

    Directory of Open Access Journals (Sweden)

    S. Iskandar

    2011-04-01

    Full Text Available To obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by -ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months

  17. Studies on the rheological,phase morphologic,thermal and mechanical properties of poly(trimethylene terephthalate)/ethylene propylene diene monomer copolymer grafted with maleic anhydride/metallocene polyethylene blends

    Institute of Scientific and Technical Information of China (English)

    RUN Mingtao; SONG Hongzan; WANG Yingjin; YAO Chenguang; GAO Jungang

    2007-01-01

    s The rheological,phase morphologic,thermal and mechanical properties of poly(trimethylene terephthalate)/metallocene polyethylene(PTT/mPE)blends in the presence of ethylene propylene diene monomer copolymer grafted with maleic anhydride(EPDM-g-MAHl as compatibilizer are studied by means of a capillary rheometer,scanning electron microscopy(SEM),differential scanning calorimetry (DSC)and thermogravimetric analyzer (TGA).Results suggest that the compatibility of PTT/mPE blends is improved greatly after the addition of a compatibilizer.The radius of the dispersed phase in the system decreases greatly when the compatibilizer is added into the blend.When the amount of compatibilizer exceeds 8 wt-%,the size of dispersed phase becomes larger again.This phenomena could be attributed to the higher viscosity of the EPDM-g-MAH phase,which is dispersed more difficulty in the PTT phase of lower viscosity,thus the mixing efficiency is apparently decreased during the melt blending process.Moreover,the melt viscosity of the blend reaches the maximal value in case of 4 wt-%compatibilizer content,above which it would decrease again.This result is associated with the generation of more and bigger dispersed phase inside the bulk phase,thus the grafting efficiency at the interface is decreased,which could result in lower viscosity.The DSC results suggest that the mPE component shows a nucleating effect,and could increase the overall degree and rate of PTT crystallization,while the addition of a compatibilizer might slightly diminish these effects.In addition,the blend with 4 wt-% compatibilizer shows the best thermal stability.Furthermore,the Izod impact strength and the tensile strength at room temperature of the blend are also markedly improved by the addition of a 4-8 wt-% compatibilizer.

  18. 淀粉丙烯腈接枝共聚物皂化制备吸水剂%The Preparation Technology of Water-Absorbent by the Saponification of the Graft Copolymer of Starch and Acrylonitrile

    Institute of Scientific and Technical Information of China (English)

    顾正彪; 吴嘉根

    2001-01-01

    通过对淀粉丙烯腈接枝共聚物(SPAN)皂化制备吸水剂HSPAN的研究表明:HSPAN为水不溶性凝胶,但具有很强的吸水能力.以氢氧化钾皂化,酸作沉淀剂,经洗涤、分散和干燥制备HSPAN的工艺路线较为理想.皂化工艺条件在用碱量为SPAN中接枝链部分摩尔数的1.1倍、皂化温度95°C以上、皂化时间大于3h,且HSPAN的平板干燥温度在70°C时最好.当SPAN接枝百分率在70%左右时,制得的HSPAN吸水率最高.%Studies on the Preparation Technology of Water-absorbent (HSPAN)by the Saponification of the graft Copolymer of Starch and Acrylonitrile (SPAN) showed that, HSPAN was a kind of gel which was insoluble in water but could absorb a great amount of water. The best technology for the preparation of HSPAN was that,after SPAN was saponified by potassium hydroxide, precipited by sulfuric acid, washed and dispersed in water again, HSPAN was obtained by drying it on a plate. Moreover, the best conditions were that,the quantity of potassium hydroxide used in saponification was 1.1 as much as the mole of polyacrylonitrile in SPAN, saponifying temperature over 95°C, reaction time more than 3 h and drying temperature at 70°C. In addition, the highest water-absorbing capacity could be obtained from the SPAN in which grafted ratio was 70% or so.

  19. 丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物AES的表征%Characterization of graft copolymer of styrene and acrylonitrile onto EPDM (AES)

    Institute of Scientific and Technical Information of China (English)

    董颖; 王辉; 金春玉; 赵彦广; 裴洪; 温冬梅; 刘洪伟; 邹向阳

    2012-01-01

    采用苯乙烯和丙烯腈接枝三元乙丙橡胶合成丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物AES,用其和苯乙烯-丙烯腈(SAN)树脂共混得到AES树脂.对合成的AES树脂样品进行常温相对分子质量及相对分子质量分布的测定,红外光谱、热稳定性与微观结构表征,并与目标样品进行对比.得出三元乙丙橡胶已接枝上SAN支链,即三元乙丙橡胶与苯乙烯及丙烯腈发生了接枝共聚合反应;合成样品相对分子质量及相对分子质量分布数据、热稳定性数据及微观结构与目标样品接近;合成样品AES粉料和SAN树脂基本均匀混合的结论.%In this paper, the graft copolymer of styrene and acrylonitrile onto EPDM(AES) was prepared and blended with SAN resin, the synthesized AES was characterized by infrared spectrum. Relative molecular weight and its distribution, heat stability, and microcosmic structure of the AES were determined and compared with the target AES. Results showed that the graft copolymerization of AES has happended,the properties of AES are near to that of the target AES.

  20. Dynamic mechanical analysis of binary and ternary polymer blends based on nylon copolymer/EPDM rubber and EPM grafted maleic anhydride compatibilizer

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available The dynamic mechanical properties such as storage modulus, loss modulus and damping properties of blends of nylon copolymer (PA6,66 with ethylene propylene diene (EPDM rubber was investigated with special reference to the effect of blend ratio and compatibilisation over a temperature range –100°C to 150°C at different frequencies. The effect of change in the composition of the polymer blends on tanδ was studied to understand the extent of polymer miscibility and damping characteristics. The loss tangent curve of the blends exhibited two transition peaks, corresponding to the glass transition temperature (Tg of individual components indicating incompatibility of the blend systems. The morphology of the blends has been examined by using scanning electron microscopy. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends. Finally, attempts have been made to compare the experimental data with theoretical models.

  1. Water distributions in polystyrene-block-poly[styrene-g-poly(ethylene oxide)] block grafted copolymer system in aqueous solutions revealed by contrast variation small angle neutron scattering study

    Science.gov (United States)

    Li, Xin; Hong, Kunlun; Liu, Yun; Shew, Chwen-Yang; Liu, Emily; Herwig, Kenneth W.; Smith, Gregory S.; Zhao, Junpeng; Zhang, Guangzhao; Pispas, Stergios; Chen, Wei-Ren

    2010-10-01

    We develop an experimental approach to analyze the water distribution around a core-shell micelle formed by polystyrene-block-poly[styrene-g-poly(ethylene oxide (PEO)] block copolymers in aqueous media at a fixed polymeric concentration of 10 mg/ml through contrast variation small angle neutron scattering (SANS) study. Through varying the D2O/H2O ratio, the scattering contributions from the water molecules and the micellar constituent components can be determined. Based on the commonly used core-shell model, a theoretical coherent scattering cross section incorporating the effect of water penetration is developed and used to analyze the SANS I(Q ). We have successfully quantified the intramicellar water distribution and found that the overall micellar hydration level increases with the increase in the molecular weight of hydrophilic PEO side chains. Our work presents a practical experimental means for evaluating the intramacromolecular solvent distributions of general soft matter systems.

  2. “活”的α-甲基苯乙烯共聚物:聚合反应新化学和材料工程新技术%A Novel Macroinitiator Based on the Copolymer of α-Methylstyrene Synthesis and Its Application in Preparing Block and Graft Polymers

    Institute of Scientific and Technical Information of China (English)

    马育红; 张冰; 赵长稳; 刘莲英; 蒋姗; 梁淑君; 杨万泰

    2013-01-01

    Due to the steric hindrance effects in combination with stability of the tertiary benzylic a-methylstyryl radical, there is a dynamic equilibrium between the monomer a-methylstyrene (AMS) and its polymer (PAMS) when the temperature is greater than 61 ℃ (the ceiling polymerization temperature). Based on this unique feature, a novel strategy to prepare co-polymers of AMS having liable bonds as potential macromolecular free radical initiators for synthesizing block and graft copolymers has been successfully developed in our laboratory. By conventional free radical polymerization, a series of AMS copolymers, including copolymers with (meth)acrylate, acrylic acid, styrene and maleic anhydride were synthesized. Typically, with the increasing of AMS fraction in monomer feed, the rate of copolymerization was significantly retarded and the molecular weight of the copolymers was reduced. However, the copolymer yield could be as high as 90% (w) with the increased addition of initiator, up to 4% (w), and the molar fraction of AMS structural unit in AMS copolymers could be up to 25% (mol%). It has been demonstrated that the copolymers containing AMS structural units are efficient free radical initiators when the temperature is greater than 80 ℃ (much better higher than 90 ℃). These copolymers could be exploited as macroinitiator in preparing block copolymers and core-shell polymer particles by bulk, solution and emulsion polymerization processes. In addition, the experimental results demonstrated that the molecular weight of copolymer products prepared with AMS copolymers as macromolecular initiators increased steadily with the monomer conversion. Though the polymerization initiated by AMS copolymers was not a well-controlled living system yet, it showed some characteristics of living polymerization. The ESR spectrum presented direct evidence of the generation of carbon centered radicals in the products of copolymer of AMS with glycidyl methacrylate (PAG) heated with j

  3. Grafted hydroxypropyl guargum: Development, characterization and application as flocculating agent

    Indian Academy of Sciences (India)

    B R Nayak; D R Biswal; N C Karmakar; R P Singh

    2002-11-01

    Synthesis of hydroxypropyl guargum--polyacrylamide was carried out by ceric ion induced redox polymerization technique at 28 ± 1°C. The graft copolymer was characterized by IR and thermal analysis. The flocculation performance of graft copolymer was tested in 1 wt% coal suspension.

  4. Synthesis of the amphiphilic copolymer of styrene with ethylene oxide%环氧乙烷与苯乙烯两亲性聚合物的合成

    Institute of Scientific and Technical Information of China (English)

    赵祺; 张长生; 贺传兰; 黄明; 李茂果

    2003-01-01

    Graft eopolymer eontaining poly(ethylene oxide)side chains on a polystyrene backbone were acrylamided. The amide groups in the copolymers were ionized by using potassium naphthalene, and grafting was achieved by utilizing the amide anions as initiator sites for the polymerization of ethylene oxide at 70℃. The graft copolymers was characterized with respect to molecule weight and composition using NMR, IR, GPC, and DSC. GPC result from the graft copolymer sample suggested a narrow size distribution.

  5. Development of chitosan graft pluronic®F127 copolymer nanoparticles containing DNA aptamer for paclitaxel delivery to treat breast cancer cells

    Science.gov (United States)

    Thach Nguyen, Kim; Le, Duc Vinh; Do, Dinh Ho; Huan Le, Quang

    2016-06-01

    HER-2/ErbB2/Neu(HER-2), a member of the epidermal growth factor receptor family, is specifically overexpressed on the surface of breast cancer cells and serves a therapeutic target for breast cancer. In this study, we aimed to isolate DNA aptamer (Ap) that specifically bind to a HER-2 overexpressing SK-BR-3 human breast cancer cell line, using SELEX strategy. We developed a novel multifunctional composite micelle with surface modification of Ap for targeted delivery of paclitaxel. This binary mixed system consisting of Ap modified pluronic®F127 and chitosan could enhance PTX loading capacity and increase micelle stability. Polymeric micelles had a spherical shape and were self-assemblies of block copolymers of approximately 86.22 ± 1.45 nm diameter. PTX could be loaded with high encapsulation efficiency (83.28 ± 0.13%) and loading capacity (9.12 ± 0.34%). The release profile were 29%-35% in the first 12 h and 85%-93% after 12 d at pH 7.5 of receiving media. The IC50 doses by MTT assay showed the greater activity of nanoparticles loaded paclitaxel over free paclitaxel and killed cells up to 95% after 6 h. These results demonstrated unique assembly with the capacity to function as an efficient detection and delivery vehicle in the biological living system.

  6. Contribution of hydrophobic/hydrophilic modification on cationic chains of poly(ε-caprolactone)-graft-poly(dimethylamino ethylmethacrylate) amphiphilic co-polymer in gene delivery.

    Science.gov (United States)

    Han, Shangcong; Wan, Haiying; Lin, Daoshu; Guo, Shutao; Dong, Hongxu; Zhang, Jianhua; Deng, Liandong; Liu, Ruming; Tang, Hua; Dong, Anjie

    2014-02-01

    Nanoparticles (NPs) assembled from amphiphilic polycations have been certified as potential carriers for gene delivery. Structural modification of polycation moieties may be an efficient route to further enhance gene delivery efficiency. In this study two electroneutral monomers with different hydrophobicities, 2-hydroxyethyl methacrylate (HEMA) and 2-hydroxyethyl acrylate (HEA), were incorporated into the cationic poly(dimethylamino ethyl methacrylate) (PDMAEMA) side-chains of amphiphilic poly(ε-caprolactone)-graft-poly(dimethylamino ethylmethacrylate) (PCD) by random co-polymerization, to obtain poly(ε-caprolactone)-graft-poly(dimethylamino ethyl methacrylate-co-2-hydroxyethyl methacrylate) (PCD-HEMA) and poly(ε-caprolactone)-graft-poly(dimethylamino ethyl methacrylate-co-2-hydroxyethyl acrylate) (PCD-HEA). Minimal HEA or HEMA moieties in PDMAEMA do not lead to statistically significant changes in particle size, zeta potential, DNA condensation properties and buffering capacity of the naked NPs. However, the incorporation of HEMA and HEA lead to reductions and increases, respectively, in the surface hydrophilicity of the naked NPs and NPs/DNA complexes, which was confirmed by water contact angle assay. These simple modifications of PDMAEMA with HEA and HEMA moieties significantly affect the gene transfection efficiency on HeLa cells in vitro: PCD-HEMA NP/DNA complexes show a much higher transfection efficiency than PCD NPs/DNA complexes, while PCD-HEA NPs/DNA complexes show a lower transfection efficiency than PCD NP/DNA complexes. Fluorescence activated cell sorter and confocal laser scanning microscope results indicate that the incorporation of hydrophobic HEMA moieties facilitates an enhancement in both cellular uptake and endosomal/lysosomal escape, leading to a higher transfection efficiency. Moreover, the process of endosomal/lysosomal escape confirmed in our research that PCD and its derivatives do not just rely on the proton sponge mechanism, but also

  7. Property of POE Graft Copolymer/PA6 Blends%接枝POE增韧尼龙6的性能

    Institute of Scientific and Technical Information of China (English)

    邵会菊; 秦舒浩; 张纯; 龙雪彬

    2012-01-01

    Toughening and reinforcement of PA6 were investigated by blending with POE graft and LiCl. The results showed that POE-g-GMA/PA6 blends had excellent impact strength,the influence of LiCl on reinforcement of POE-g-GMA/ PA6 were very obvious, and the crystallinity and crystal of PA6 changed. Amorphous PA6/POE-g-GMA/LiCl composite was obtained at 5 phr of LiCl.%研究了接枝POE增韧PA6及无水氯化锂增强POE接枝甲基丙烯酸环氧丙酯/尼龙6(POE-g-GMA/PA6)复合材料.结果表明:POE接枝甲基丙烯酸环氧丙酯(POE-g-GMA)对PA6具有很好的增韧效果,无水氯化锂在增强POE-g-GMA/PA6复合材料的同时,改变了PA6的结晶度和结晶形态,当氯化锂的添加量为5份时,可以得到无定形的PA6/POE-g-GMA/LiCl复合材料.

  8. GRAFT COPOLYMERIZATION OF AN ONTO CHITOSAN AND IMMOBILIZATION OF Α-AMYLASE ON THE GRAFT COPOLYMERS%壳聚糖与丙烯腈接枝共聚物的制备 及固定化α-淀粉酶研究

    Institute of Scientific and Technical Information of China (English)

    刘峥; 蒋先民

    2001-01-01

    Graft copolymerization of AN onto chitosan was carried out by using K2S2O8/NaHSO3 as an initiator. Then,α-amylase was immobilized on the AN-g-chitosan copolymer by adsorption. The effects of coupling time , pH values and the amount of α-amylase on immobilization and properties of the immobilized α-amylase was studied. The results show that the properties of immobilized α-amylase on the AN-g-chitosan was better than free α-amylase or the immobilized α-amylase on the chitosan.%本文以过硫酸钾/亚硫酸氢钠为引发体系,制备了丙烯腈接枝壳聚糖的共聚物,并以其为载体固定化α-淀粉酶,探讨了固定化酶的最佳制备条件和固定化酶的性质,并与游离酶、壳聚糖作为载体的固定化α-淀粉酶进行了比较,结果表明,丙烯腈接枝壳聚糖共聚物是固定化α-淀粉酶的优良载体。

  9. MISCIBILITY IN COPOLYMER/HOMOPOLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming

    1988-01-01

    In order to study the miscibility of a copolymer with its corresponding homopolymers, varieties of multicomponent polymers including simple graft, multibranch, diblock, triblock and four-arm block copolymers and so-called ABCPs were synthesized and characterized. The morphologies of the blends comprising the covolymers and the corresponding homopolymers were examined by electron microscopy. It is concluded that beeides molecular weight, architecture of a copolymers has apparent effect on the miscibility, i.e. the more complex is molecular architecture, the greater is conformation restriction in microdomain formation and the less is solubility of homopolymer in corresponding domains. In addition, a density gradient model is suggested for describing the segment distribution of the bound and free chains in block-homopolymer systems. Using this model, Helfand's theory is extended to the blends of copolymer and homopolymer predicting the miscibility which is in good agreement with the experimental results.

  10. Theory and Simulation Studies of Copolymer Functionalized Nanoparticles in Polymer Nanocomposites

    Science.gov (United States)

    Jayaraman, Arthi; Nair, Nitish; Seifpour, Arezou; Spicer, Philip

    2010-03-01

    Significant interest has grown around the ability to create polymer nanocomposites with controlled spatial arrangement of nanoparticles mediated by a polymer matrix. By functionalizing or grafting polymers on to nanoparticle surfaces and systematically tuning the composition, chemistry, molecular weight and grafting density of the functionalized polymers we can tailor the inter-particle interactions and precisely control the assembly/dispersion of the particles in the polymer matrix. While prior experimental and theoretical work in this area has mostly been on homopolymer grafted particles at high brush-like grafting densities, we study copolymer grafted nanoparticles at low grafting densities in a homopolymer matrix. Using an integrated approach involving Polymer Reference Interaction Site Model (PRISM) theory and Monte Carlo simulations we will present the effect of monomer sequence and molecular weight of the grafted copolymer, compatibility of the graft and matrix polymers, and nanoparticle size on the conformations of the grafted polymers, and the effective interactions between the grafted nanoparticles in the matrix.

  11. Physical properties of agave cellulose graft polymethyl methacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan [Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor (Malaysia)

    2013-11-27

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  12. Physical properties of agave cellulose graft polymethyl methacrylate

    Science.gov (United States)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-01

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm-1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  13. Preparation, investigation of metal ion removal and flocculation performances of grafted hydroxyethyl starch.

    Science.gov (United States)

    Kolya, Haradhan; Tripathy, Tridib

    2013-11-01

    Ceric ion induced graft copolymerization of N,N-dimethyl acrylamide (DMA) and acryl amide (AM) were carried out onto the hydroxyethyl starch (HES). These grafted copolymers were used for the removal of metal ions from their aqueous solutions. Flocculation performances of the synthesized graft copolymers were evaluated in 1.0 wt% silica suspensions. A comparative study of the flocculation performances of the synthetic graft copolymers was also made. The different factors affecting metal ion absorption, namely pH, treatment time, temperature and polymer dose were studied. A comparative study of the metal ion removal capacity of the two synthetic graft copolymers was also made in five metal ions namely Ni(II), Zn(II), Cu(II), Pb(II) and Hg(II). The metal ion removal capacity follows the order Hg(II)>Cu(II)>Zn(II)>Ni(II)>Pb(II) in both the two synthetic polymers. Between the two graft copolymers, graft copolymer based on AM shows better performance than that based on DMA in all the metal solutions. But the flocculation performance of DMA based graft copolymer showed better performances than that AM based graft copolymer. The former also performed best when compared to the commercial flocculants in the same suspension.

  14. 淀粉接枝丙烯酰胺聚合物处理印染废水研究%Study on dyeing wastewater treatment with acrylamide grafted starch copolymer

    Institute of Scientific and Technical Information of China (English)

    刘军海; 李志洲; 王俊宏; 刘志峰

    2016-01-01

    以玉米淀粉和丙烯酰胺作为原料,高锰酸钾作为引发剂,采用水溶液聚合法制备了淀粉接枝丙烯酰胺聚合物(S-g-PAM),并用红外光谱对产物进行表征。通过正交优化得S-g-PAM最佳制备工艺为:反应温度50℃,引发剂浓度1.8 mmol/L,m (单体)∶m(淀粉)=2∶1,反应时间120 min,pH=3。用此工艺制备的S-g-PAM处理印染废水,在pH=7,温度60℃,S-g-PAM用量0.6 g,搅拌25 min的条件下,印染废水的色度去除率达96.50%,COD去除率达93.64%,优于单独使用聚丙烯酰胺(PAM)的处理效果。%Acrylamide grafted starch copolymer was prepared by polymerization in solution method with corn starch and acrylamide as raw materials and potassium permanganate as initiator, and the product was characterized by IR. The optimum preparation conditions of S- g- PAM were obtained through the orthogonal test, the reaction temperature was 50 ℃, the concentration of initiator was 1.8 mmol/L, the ratio of starch to monomer was 2∶1, reaction time was 120 min, pH=3. S- g- PAM prepared under these conditions was ap⁃plied in printing and dyeing wastewater treatment. The color removal rate could reach 96.50% with 0.6 g of S- g- PAM at pH=7 and 60 ℃ and stirring for 25 min, and the COD removal rate was 93.64%. The treatment effect was better than that of polyacrylamide .

  15. Synthesis and characterization of graft copolymer of degraded starch and acrylamide initiated by immobilized HRP/H2O2/ACAC catalyzed system%固定化HRP/H2O2/ACAC酶促体系引发下降解淀粉接枝丙烯酰胺共聚物的合成与表征

    Institute of Scientific and Technical Information of China (English)

    闫小亮; 吕生华; 侯明明; 弓瑞

    2011-01-01

    Horseradish peroxidase(HRP)was immobilized on the surface of chitosan via glutaraldehyde crosslinking.Then a graft copolymer of degraded starch and acrylamide was synthesized by the initiation of enzyme catalysis system composed of chitosan-immobilized HRP/H2O2/acetylacetone(ACAC).The structure of the copolymer was analyzed by FTIR,UV,NMR and SEM.The results indicated that polyacrylamide(PAM)was successfully grafted onto the degraded starch.Then,the copolymer was applied as a retanning agent.The applied results showed that the retanned leather had the merits of softness,good dispersion of fiber and strong selecting filling properties.%以壳聚糖为载体、戊二醛为交联剂制备固定化辣根过氧化物酶(HRP),采用固定化HRP/H2O2/乙酰丙酮(ACAC)酶促体系制备降解淀粉-丙烯酰胺接枝共聚物(St-g-PAM),通过红外光谱、紫外光谱、核磁共振和电镜扫描等手段对接枝共聚产物进行了结构分析。结果表明,丙烯酰胺成功接枝在降解淀粉上。共聚物用做皮革复鞣剂进行了应用实验,应用结果表明复鞣后的革柔软、纤维分散好和选择填充性强。

  16. Morphological studies on block copolymer modified PA 6 blends

    Science.gov (United States)

    Poindl, M.; Bonten, C.

    2014-05-01

    Recent studies show that compounding polyamide 6 (PA 6) with a PA 6 polyether block copolymers made by reaction injection molding (RIM) or continuous anionic polymerization in a reactive extrusion process (REX) result in blends with high impact strength and high stiffness compared to conventional rubber blends. In this paper, different high impact PA 6 blends were prepared using a twin screw extruder. The different impact modifiers were an ethylene propylene copolymer, a PA PA 6 polyether block copolymer made by reaction injection molding and one made by reactive extrusion. To ensure good particle matrix bonding, the ethylene propylene copolymer was grafted with maleic anhydride (EPR-g-MA). Due to the molecular structure of the two block copolymers, a coupling agent was not necessary. The block copolymers are semi-crystalline and partially cross-linked in contrast to commonly used amorphous rubbers which are usually uncured. The combination of different analysis methods like atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) gave a detailed view in the structure of the blends. Due to the partial cross-linking, the particles of the block copolymers in the blends are not spherical like the ones of ethylene propylene copolymer. The differences in molecular structure, miscibility and grafting of the impact modifiers result in different mechanical properties and different blend morphologies.

  17. Morphological studies on block copolymer modified PA 6 blends

    Energy Technology Data Exchange (ETDEWEB)

    Poindl, M., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de; Bonten, C., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de [Institut für Kunststofftechnik, University of Stuttgart (Germany)

    2014-05-15

    Recent studies show that compounding polyamide 6 (PA 6) with a PA 6 polyether block copolymers made by reaction injection molding (RIM) or continuous anionic polymerization in a reactive extrusion process (REX) result in blends with high impact strength and high stiffness compared to conventional rubber blends. In this paper, different high impact PA 6 blends were prepared using a twin screw extruder. The different impact modifiers were an ethylene propylene copolymer, a PA PA 6 polyether block copolymer made by reaction injection molding and one made by reactive extrusion. To ensure good particle matrix bonding, the ethylene propylene copolymer was grafted with maleic anhydride (EPR-g-MA). Due to the molecular structure of the two block copolymers, a coupling agent was not necessary. The block copolymers are semi-crystalline and partially cross-linked in contrast to commonly used amorphous rubbers which are usually uncured. The combination of different analysis methods like atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) gave a detailed view in the structure of the blends. Due to the partial cross-linking, the particles of the block copolymers in the blends are not spherical like the ones of ethylene propylene copolymer. The differences in molecular structure, miscibility and grafting of the impact modifiers result in different mechanical properties and different blend morphologies.

  18. Synthesis of Polyacrylate/Polysiloxane Copolymer and Its Damping Performance

    Institute of Scientific and Technical Information of China (English)

    夏宇正; 石淑先; 焦书科; 李素青

    2003-01-01

    The copolymer of polyacrylate/polysiloxane for vibration damping materials was synthesized through emulsion polymerization. The effects of the amount of methyl methacrylate (MMA),polysiloxane containing vinyl, initiator and emulsifier on the conversion, stability of polyacrylate/polysiloxane emulsion were discussed when the emulsion was prepared by pre-emulsifying half continuous method. The graft copolymer has good vibration damping performance. The widest glass transition region of the copolymer spans 100℃, and the highest value of tanδ reached 2.0. The glass transition of the samples was examined by dynamic mechanical analysis (DMA). The vibration damping performance of the graft copolymer was affected by the amount of poly-vinyl dimethylsiloxane (PVMS).

  19. 聚乳酸接枝马来酸酐/丙烯酸丁酯共聚物的制备与性能∗%Preparation and properties of maleic anhydride/butyl acrylate grafted poly(lactic acid)copolymer

    Institute of Scientific and Technical Information of China (English)

    罗卫华; 袁彩霞; 王正良; 向世欢; 聂鹏; 袁光明

    2015-01-01

    Maleic anhydride (MAH)/butyl acrylate (BA)grafted poly(lactic acid)(PLA)copolymers (mPLAs) were prepared through solution grafting copolymerization using benzoyl peroxide as initiator,MAH and BA as monomers.The structure and properties of the graft copolymers were characterized by Fourier transform infra-red spectroscopy (FT-IR),wide-angle X-ray diffraction (WAXD),differential scanning calorimetry (DSC)and thermogravimetry (TG).The monomer graft degree on PLA first increases and then decreases with increasing mass ratio of BA to MAH.It reaches the highest value of 1.96% when the mass ratios of BA to MAH and MAH to PLA are 1/1 and 3/100 respectively.Compared with the pure PLA,mPLAs exhibit lower crystallinity and decreased thermal stability.A higher monomer graft degree was associated with a lower crystallinity of the samples.With the increase of mass ratio of BA to MAH,both the melting temperature and glass transition temperature of mPLAs have a trend of declining.%以马来酸酐(MAH)和丙烯酸丁酯(BA)为单体,通过溶液接枝法制备了聚乳酸(PLA )接枝MAH/BA共聚物(mPLA).使用红外光谱(FT-IR)、广角X 射线衍射(WAXD)、差示扫描量热仪(DSC)、热重分析仪(TG)研究了接枝共聚物的结构和性能.结果表明,随着单体质量比BA/MA H 的增加,单体在PLA 上的接枝率出现先增大后减小的趋势,当m(MAH)/m (BA )=1/1,m (MAH )/m (PLA )=3/100时,制备的 mPLA 接枝率最高为1.96%;与纯PLA相比,mPLA 的结晶度和热稳定性均比有所下降,且样品的接枝率越大其结晶度越低;随着单体中BA含量的增加,mPLA 的熔融温度和玻璃化转变温度有减小的趋势.

  20. SYNTHESIS OF ACRYLONITRILE-N-ISOPROPYLACRYLAMIDE GRAFT COPOLYMERS FOR THE PREPARATION OF THERMAL RESPONSIVE POLYACRYLONITRILE MEMBRANAES%丙烯腈-N-异丙基丙烯酰胺接枝共聚物的合成及其对聚丙烯腈分离膜的改性

    Institute of Scientific and Technical Information of China (English)

    费正东; 万灵书; 钟明强; 徐志康

    2012-01-01

    PNIPAAm with terminal amino groups was synthesized using 2-aminoethanethiol hydrochloride ( AESH) as a chain transfer agent. It was then reacted with methacryloyl chloride to result in macromer, vinly PNIPAAm. A graft copolymer,P( AN-g-NIPAAm) was synthesized through the copolymerization of acrylonitrile (AN) and vinyl PNIPAAm. Using this graft copolymer as an additive, thermal responsive PAN-based membranes were prepared by the immersion precipitation phase inversion method (IPPI). Results from FTIR and NMR indicate that the molecular weight of PNIPAAm can be effectively modulated by changing the concentration of AESH. Then, the weight average molecular weight ( Mw ) was measured by laser scattering. Results of captive bubble contact angle measurements and turbidity analysis show that the graft copolymers are still thermally responsive, which is more remarkable with higher PNIPAAm content. XPS analysis proves thatthe PNIPAAm graft chains are enriched at the membrane surface and pore surface during the course of IPPI because of the hydrophilicity of PNIPAAm. Pure water flux at 40℃ (above the LCST of PNIPAAm) is almost twice as that at 25℃ (below the LCST of PNIPAAm) ,which is due to the conformation change of PNIPAAm chains. All these results demonstrate the synthesized graft copolymers are effective additives for the preparation of thermal responsive PAN membranes.%以巯基乙胺盐酸盐( AESH)为链转移剂、2,2′-偶氮二异丁腈为引发剂,合成了具有端氨基的聚(N-异丙基丙烯酰胺)(PNIPAAm);与甲基丙烯酰氯反应,得到可聚合的PNIPAAm大分子单体;进而与丙烯腈共聚,合成了丙烯腈-N-异丙基丙烯酰胺接枝共聚物(P(AN-g-NIPAAm)).基于浸没沉淀相转化法制备了聚丙烯腈/P(AN-g-NIPAAm)共混膜.红外及核磁分析表明,通过调控AESH的浓度可制备得到不同链长的PNIPAAm大分子单体;用激光光散射进一步测定了共聚物的重均分子量;采用鼓泡接触角及浊度

  1. Multicompartment Micelles From π-Shaped ABC Block Copolymers

    Institute of Scientific and Technical Information of China (English)

    XIA Jun; ZHONG Chong-Li

    2007-01-01

    Dissipative particle dynamics simulations were performed on the morphology and structure of multicompartment micelles formed from n-shaped ABC block copolymers in water. The influences of chain architectures were studied in a systematic way, and a rich variety of morphologies were observed, such as spherical, wormlike,X-shaped, Y-shaped, ribbon-like, layered rod-like, layered disk-like, as well as network morphologies. The simulations show that the distance between the two grafts plays an important role in control of the morphology. Since π-shaped ABC block copolymers can be reduced to linear ABC and star ABC block copolymers, they are good model copolymers for studying the self-assembly of complex block copolymers into micelles. The knowledge obtained in this work as well as the new morphologies identified provide useful information for future rational design and synthesis of novel multicompartment micelles.

  2. New routes to the synthesis of amylose-block-polystyrene rod-coil block copolymers

    NARCIS (Netherlands)

    Loos, Katja; Müller, Axel H.E.

    2002-01-01

    Hybrid block copolymers amylose-block-polystyrene were synthesized by covalent attachment of maltoheptaose derivatives to end-functionalized polystyrene and subsequent enzymatic grafting from polymerization. The maltoheptaose derivatives were attached by reductive amination or hydrosilation to amino

  3. Preparation of Impact and Weather Resistant Copolymer

    Institute of Scientific and Technical Information of China (English)

    LIANG Tao

    2001-01-01

    @@ Synthesis method of the resin is that crosslinked polybutyl acrylate latex is used as base latex. Styrene (St) and acrylonitrile (AN) are grafted onto polybutyl acrylate latex particle and turn into core-shell copolymer. The resin is a good resin's impact modifier. There are study of influence regularity about additive emulsifier, initiator, monomer concentration, the ratio of St to AN, chain transfer to graft polymerization. A kind of core-shell resin used as impact modifier is obtained. (A) Preparation of Crosslinked Butyl Acrylate Rubber Latex

  4. Preparation of Impact and Weather Resistant Copolymer

    Institute of Scientific and Technical Information of China (English)

    LIANG; Tao

    2001-01-01

    Synthesis method of the resin is that crosslinked polybutyl acrylate latex is used as base latex. Styrene (St) and acrylonitrile (AN) are grafted onto polybutyl acrylate latex particle and turn into core-shell copolymer. The resin is a good resin's impact modifier. There are study of influence regularity about additive emulsifier, initiator, monomer concentration, the ratio of St to AN, chain transfer to graft polymerization. A kind of core-shell resin used as impact modifier is obtained. (A) Preparation of Crosslinked Butyl Acrylate Rubber Latex  ……

  5. Synthesis and Characterization of Chitosan-g-poly(D, L-lactic acid) Copolymer

    Institute of Scientific and Technical Information of China (English)

    Hua YANG; Shao Bing ZHOU; Xian Mo DENG

    2005-01-01

    Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.

  6. β-环糊精/木粉接枝共聚物对Pb2+的吸附动力学和热力学研究%Adsorption of Pb2+ from Aqueous Solution by β-Cyclodextrin/Wood Flour Grafted Copolymer: Kinetic and Thermodynamic Studies

    Institute of Scientific and Technical Information of China (English)

    司红燕; 李斌; 王霆; 徐祖伟

    2013-01-01

    β-cyclodextrin/wood flour (β-CD/WF) grafted copolymer was prepared by esterification- crosslinking technology, i. e. , grafting β-CD onto poplar wood flour in the presence of citric acid. The properties of this grafted copolymer were characterized by FT-IR, TGA and the technique of phenolphthalein probe respectively. The adsorption property of this copolymer for Pb2+ in a batch adsorption system as a function of contact time, pH and initial Pb2+ concentration was investigated in this study. The results showed that β-CD was not only grafted onto the surface of wood flour but also demonstrated an encapsulation activity. The kinetic data were analyzed by the pseudo-first,second-order kinetics and intraparticle diffusion, and the equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The results showed that adsorption equilibrium was reached within 30 min at 298 K under the proper pH between 4.0 and 8.0, and the adsorption capacity increased with the rise of initial Pb2+ concentration. It was found that the adsorption kinetics followed the second-order model. This suggested that the adsorption of Pb2+ by copolymer was a chemisorption process, and the intraparticle diffusion was not the primary rate-determining step. Besides, Langmuir model fitted the equilibrium data better than the Freundlich isotherm. It reflected the adsorption of Pb2+ on copolymer was monolayer adsorption. The thermodynamic properties, △GΘ, △HΘ and △SΘ showed that adsorption of Pb2+ onto β-CD/WF flour grafted copolymer was endothermic and spontaneous in the temperature range of 293 -313 K.%以柠檬酸为交联剂,利用酯化交联工艺将功能主体分子β-环糊精接枝到杨木木粉表面制备β-环糊精/木粉(β-CD/WF)接枝共聚物,并用红外光谱仪、热重分析仪和酚酞探针分子技术进行表征.以Pb2+为吸附质,β-环糊精/木粉接枝共聚物为吸附剂,系统探讨接触时间、pH值、Pb2+初始浓度对吸附效果的影

  7. Phase Transition and Micellization of Temperature Responsive Dextran-graft-poly (N-isopropylacrylamide) Polymers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Phase behavior and micellization of dextran-graft-poly (N-isopropylacrylamide) (PNIPAAm) polymers in aqueous solution are investigated in this paper using DSC and AFM methods. It is found that with the increase of grafting (G%) of the copolymers the endothermic enthalpy during the phase transition increases significantly and the transition temperature decreases slightly. The phase transition behavior of the copolymers is scanning rate dependent. Micelles are formed whenever the solution temperature is raised above the LCST of the copolymers. It is proposed that by using this thermal responsive property of the copolymers, drugs could be incorporated into the micelles without employing any organic solvent.

  8. Grafted block complex coacervate core micelles and their effect on protein adsorption on silica and polystyrene

    NARCIS (Netherlands)

    Brzozowska, Agata M.; de Keizer, Arie; Norde, Willem; Detrembleur, Christophe; Stuart, Martien Cohen

    2010-01-01

    We have studied the formation and the stability of grafted block complex coacervate core micelles (C3Ms) in solution and the influence of grafted block C3M coatings on the adsorption of the proteins beta-lactoglobulin, bovine serum albumin, and lysozyme. The C3Ms consist of a grafted block copolymer

  9. GRAFT COPOLYMERIZATION OF ACRYLAMIDE ONTO THE UV-RAY IRRADIATED FILM OF POLYESTER-POLYETHER

    Institute of Scientific and Technical Information of China (English)

    CHEN Chuanfu; LI Xuefen; LI Zhifen

    1988-01-01

    In this paper the Ce(Ⅳ) salt initiated graft copolymerization of acrylamide onto the film of polyester-polyether block copolymer irradiated by UV-ray was reported. The UV-irradiation of the film and its graft process have been investigated by UV spectrum, ESR and ESCA and the influence of other factors on the graft copolymerization has been discussed.

  10. Synthesis and characterization of polyacrylamide-graft-poly(ethylene oxid-copropyleneoxide)

    NARCIS (Netherlands)

    de Vos, Sicco; de Vos, S.C.; Moller, M.; Möller, Martin; Visscher, K.; Mijnlieff, P.F.; Visscher, K.; Mijnlieff, P.F.

    1994-01-01

    The synthesis and first experiments on the rheological behaviour of poly(acrylamide) (PAAm) grafted with poly(ethylene oxide-co-propylene oxide) are presented. Well-defined, water-soluble graft copolymers were prepared in high yields by grafting poly(oxyalkylene) monoamines onto partly hydrolysed

  11. HRP引发酚类与淀粉接枝共聚物的制备及结构性能表征%Preparation of graft copolymer of phenols and starch by HRP-catalyzed system and characterization of structure and properties

    Institute of Scientific and Technical Information of China (English)

    吕生华; 弓瑞; 闫小亮; 张国运

    2012-01-01

    A graft copolymer was synthesized by means of radical copolymerization of phloroglucinol(PG),hydroxyl benzene sulfonic acid sodium(HBS) and degraded starch which was degraded by α-amylase and the graft copolymerization was catalyzed by horseradish peroxidase(HRP)/H2O2.It was investigated the effects of degradation degree of starch,monomer ratio of phenols,the dosage of HRP,polymerization temperature and pH value on structure and properties of modified starch.The optimum reaction conditions were obtained as follows: mass ratio of PG to HBS 12∶20,15g starch which was degraded by α-amylase,polymerization 30℃ pH 7.0 and 5mg of HRP solution.The surface tension of modified starch solution was 26.6mN/m and the shrinkage temperature(Ts) of tanned leather reached 78℃.Meanwhile the chemical structure of the graft copolymer was characterized by FT-IR,1H-NMR,UV-Vis and GPC.%降解淀粉和酚类在辣根过氧化物酶(HRP)/H2O2的催化作用下进行自由基接枝共聚反应,制备了淀粉和酚类接枝共聚物。研究了淀粉降解程度、酚类单体配比、HRP用量、反应温度和pH对接枝改性淀粉结构与性能的影响。研究结果表明,用α-淀粉酶降解后的淀粉15与12g间苯三酚(PG)和20g对羟基苯磺酸钠(HBS)在5mg HRP/H2O2引发体系下,在30℃及pH值为7.0时反应5h制备的酚类与淀粉接枝共聚物具有较好的性能,其水溶液的表面张力为26.6mN/m,所鞣制皮革收缩温度(Ts)达到了78℃。用FT-IR、1 H NMR、UV-Vis和GPC等方法对产物的化学结构进行了表征。

  12. Studies on Preparation of Poly(3,4-Dihydroxyphenylalanine-Polylactide Copolymers and the Effect of the Structure of the Copolymers on Their Properties

    Directory of Open Access Journals (Sweden)

    Dongjian Shi

    2016-03-01

    Full Text Available Properties of copolymers are generally influenced by the structure of the monomers and polymers. For the purpose of understanding the effect of polymer structure on the properties, two kinds of copolymers, poly(3,4-dihydroxyphenylalanine-g-polylactide and poly(3,4-dihydroxyphenylalanine-b-polylactide (PDOPA-g-PLA and PDOPA-b-PLA were designed and prepared by ring-opening polymerization of lactide with pre-prepared PDOPA as the initiator and the amidation of the functional PLA and PDOPA oligomer, respectively. The molecular weight and composition of the copolymers could be adjusted by changing the molar ratio of LA and DOPA and were confirmed by gel permeation chromatography (GPC and proton nuclear magnetic resonance (1H NMR spectra. The obtained copolymers with graft and block structures showed high solubility even in common organic solvents. The effects of the graft and block structures on the thermal and degradation properties were also detected. The PDOPA-g-PLA copolymers showed higher thermal stability than the PDOPA-b-PLA copolymers, due to the PDOPA-g-PLA copolymers with regular structure and strong π-π stacking interactions among the intermolecular and intramolecular chains. In addition, the degradation results showed that the PDOPA-g-PLA copolymers and the copolymers with higher DOPA composition had quicker degradation speeds. Interestingly, both two kinds of copolymers, after degradation, became undissolved in the organic solvents because of the oxidation and crosslinking formation of the catechol groups in the DOPA units during degradation in alkaline solution. Moreover, fluorescent microscopy results showed good biocompatibility of the PDOPA-g-PLA and PDOPA-b-PLA copolymers. The PDOPA and PLA copolymers have the potential applications to the biomedical and industrial fields.

  13. 丙烯酸接枝邻苯二酚衍生物的二次聚合%Novel Copolymers Synthesis by Second Polymerization of Acrylate Acid Grafted 1,2-Dihydroxylbenzene Derivatives

    Institute of Scientific and Technical Information of China (English)

    黄瑶; 朱召进; 徐景坤; 卢宝阳; 岳瑞瑞

    2012-01-01

    合成了2种聚合前驱体邻苯二丙烯酸酯(o-PDA)和2-甲氧基苯丙烯酸酯(2-MOPA),分别通过与丙烯酸(AA)自由基共聚得到邻苯二丙烯酸酯-丙烯酸共聚物(O1)和2-甲氧基苯丙烯酸酯-丙烯酸共聚物(O2).产物邻苯二酚(o-DHB)-O1(质量比1∶1)和1-羟基-2-甲氧基苯(HMOB)-O2(质量比1∶1)分别在乙腈/二氯甲烷-三氟化硼乙醚体系中直接阳极氧化聚合获得交联网状共聚物P1和P2.P1和P2均可溶于DMSO,而难溶于ACN,DCM和THF等有机溶剂.通过UV-Vis,FTIR和1H NMR对交联共聚物膜的结构进行了表征.AA的引入不仅可以增加链的柔韧性,而且提高了共聚物的力学性能.而o-DHB/HMOB的引入极大地减弱了单体的聚合位阻,实现了单体的二次聚合,同时也增强了单体及聚合物的电化学活性.荧光光谱显示,得到的2种交联共聚物膜分别在415和487 nm处有较强的发射峰,表明共聚物仍具有良好的蓝色发光性能,且聚丙烯酸结构的引入并没有对聚邻苯二酚(Po-DHB)和聚(1-羟基-2-甲氧基苯)(PHMOB)产生较大的荧光猝灭作用.热重分析曲线(TGA)表明2种交联共聚物膜均具有较高的热稳定性.%Two novel acrylate functionalized monomers o-phenylene diacrylate(o-PDA) and 2-methoxyphenyl acrylate(2-MOPA) were designed and synthesized. Through radical copolymerization of o-PDA/2-MOPA with acrylic acid( AA), two precursor polymers, oligo ( o-phenylene diacrylate-eo-acrylic acid) (01) and oligo (2-methoxyphenyl acrylate-co-acrylic acid ) ( 02 ) were obtained. Cross-linked poly ( O1-co-o-dihydroxy-benzene)(Pl) and poly(O2-co-l-hydroxy-2-methoxybenzene) (P2) films were achieved by electrochemical polymerization of monomer mixtures of o-DHB-O1 and HMOB-O2, respectively. UV-Vis, FTIR and 1H NMR spectra were used to characterize the structures of the copolymers. Since AA and o-DHB/HMOB were introduced into the polymerization processes, the steric hindrance of the monomers were weakened extremely, and

  14. Poly(amide-graft-acrylate) interfacial compounds

    Science.gov (United States)

    Zamora, Michael Perez

    Graft copolymers with segments of dissimilar chemistries have been shown to be useful in a variety of applications as surfactants, compatibilizers, impact modifiers, and surface modifiers. The most common route to well defined graft copolymers is through the use of macromonomers, polymers containing a reactive functionality and thus capable of further polymerization. However, the majority of the studies thus far have focused on the synthesis of macromonomers capable of reacting with vinyl monomers to form graft copolymers. This study focused on the synthesis of macromonomers capable of participating in condensation polymerizations. A chain transfer functionalization method was utilized. Cysteine was evaluated as a chain transfer agent for the synthesis of amino acid functionalized poly(acrylate) and poly(methacrylate) macromonomers. Low molar mass, functionalized macromonomers were produced. These macromonomers were proven to be capable of reacting with amide precursors to form poly(amide-g-acrylate) graft copolymers. Macromonomers and graft copolymers were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, elemental analysis (EA), inductively coupled plasma (ICP), and differential scanning calorimetry (DSC). The second part of this research involved poly(dimethacrylate) dental restorative materials. Volumetric shrinkage during the cure of these resins results in a poor interface between the resin and the remaining tooth structure, limiting the lifetime of these materials. Cyclic anhydrides were incorporated into common monomer compositions used in dental applications. Volume expansion from the ring opening hydrolysis of these anhydrides was shown to be feasible. The modified dental resins were characterized by swelling, extraction and ultraviolet spectroscopy (UV), and density measurements. Linear poLymers designed to model the crosslinked dental resins were

  15. Synthesis and Melt Self-Assembly of PS-PMMA-PLA Triblock Bottlebrush Copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Justin; Rzayev, Javid [Buffalo

    2014-07-03

    Polystyrene–poly(methyl methacrylate)–polylactide (PS–PMMA–PLA) triblock bottlebrush copolymer with nearly symmetric volume fractions was synthesized by grafting from a symmetrical triblock backbone and the resulting melt was characterized by scanning electron microscopy and small-angle X-ray scattering. The copolymer backbone was prepared by sequential reversible addition–fragmentation chain transfer (RAFT) polymerization of solketal methacrylate (SM), 2-(bromoisobutyryl)ethyl methacrylate (BIEM), and 5-(trimethylsilyl)-4-pentyn-1-ol methacrylate (TPYM). PMMA branches were grafted by atom transfer radical polymerization from the poly(BIEM) segment, PS branches were grafted by RAFT polymerization from the poly(TPYM) block after installment of the RAFT agents, while PLA side chains were grafted from the deprotected poly(SM) block. The resulting copolymer was found to exhibit a lamellae morphology with a domain spacing of 79 nm. Differential scanning calorimetry analysis indicated that PMMA was preferentially mixing with PS while phase separating from PLA domains.

  16. Directed self assembly of block copolymers using chemical patterns with sidewall guiding lines, backfilled with random copolymer brushes.

    Science.gov (United States)

    Pandav, Gunja; Durand, William J; Ellison, Christopher J; Willson, C Grant; Ganesan, Venkat

    2015-12-21

    Recently, alignment of block copolymer domains has been achieved using a topographically patterned substrate with a sidewall preferential to one of the blocks. This strategy has been suggested as an option to overcome the patterning resolution challenges facing chemoepitaxy strategies, which utilize chemical stripes with a width of about half the period of block copolymer to orient the equilibrium morphologies. In this work, single chain in mean field simulation methodology was used to study the self assembly of symmetric block copolymers on topographically patterned substrates with sidewall interactions. Random copolymer brushes grafted to the background region (space between patterns) were modeled explicitly. The effects of changes in pattern width, film thicknesses and strength of sidewall interaction on the resulting morphologies were examined and the conditions which led to perpendicular morphologies required for lithographic applications were identified. A number of density multiplication schemes were studied in order to gauge the efficiency with which the sidewall pattern can guide the self assembly of block copolymers. The results indicate that such a patterning technique can potentially utilize pattern widths of the order of one-two times the period of block copolymer and still be able to guide ordering of the block copolymer domains up to 8X density multiplication.

  17. Graft copolymerization of glycerol 1,3-diglycerolate diacrylate onto poly(3-hydroxyoctanoate) to improve physical properties and biocompatibility.

    Science.gov (United States)

    Kim, Hyung Woo; Chung, Moon Gyu; Kim, Young Baek; Rhee, Young Ha

    2008-10-01

    Glycerol 1,3-diglycerol diacrylate-grafted poly(3-hydroxyoctanoate) (GDD-g-PHO) copolymers were prepared by heating homogeneous solutions of PHO, GDD monomer and benzoylperoxide initiator. Experiments showed that GDD was successfully grafted onto the PHO chains and that the resulting copolymers had enhanced thermal properties and mechanical strengths. The surfaces and the bulk of GDD-g-PHO copolymers became more hydrophilic as the GDD grafting density in the copolymer increased. Measurements of the growth of Chinese hamster ovary cells and the adsorption of blood proteins and platelets in vitro showed that biocompatibility was also enhanced by grafting of GDD groups. These results indicate that the GDD-g-PHO copolymers are promising materials for biocompatible biomedical applications.

  18. Thermo-/pH-dual responsive properties of hyperbranched polyethylenimine grafted by phenylalanine.

    Science.gov (United States)

    Chen, Jie; Xia, Jialiang; Tian, Huayu; Tang, Zhaohui; He, Chaoliang; Chen, Xuesi

    2014-01-01

    Novel thermo- and pH-dual responsive amphiphilic copolymers were synthesized based on hyperbranched polyethylenimine (PEI) by grafting L-phenylalanine. The phenylalanine-modified PEI exhibited lower cytotoxicity than commercial PEI. These copolymers showed the phenomena of phase transitions in response to pH and temperature. The dilute copolymer solution at lower pH displayed the higher LCST. Furthermore, LCST increased with the increasing of phenylalanine grafting density. LCST of these copolymers were tunable from 7.2 to 59.6 °C by the degree of amidation and pH of solution. DLS and TEM experiments certified that the copolymer chains aggregated to form small size particles as increasing the temperature above LCST. For these reasons, the obtained smart copolymers were considered to be potential gene/drug carriers in biomedical field.

  19. Caraterização composicional do AES - um copolímero de enxertia de poli(estireno-co-acrilonitrila em poli(etileno-co-propileno-co-dieno Compositional characterization of AES a graft copolymer based on poly(styrene-co-acrylonitrile and poly(etyhlene-co-propylene-co-diene

    Directory of Open Access Journals (Sweden)

    Renato Turchet

    2006-06-01

    Full Text Available O objetivo deste trabalho é a caracterização do AES, um copolímero de enxertia de poli(estireno-co-acrilonitrila, SAN, em poli(etileno-co-propileno-co-dieno, EPDM. Para tanto, o AES foi submetido à extração seletiva de seus componentes: o SAN livre, o EDPM livre, e o copolímero de enxertia EPDM-g-SAN. O AES e suas frações foram caracterizados por espectroscopia de infravermelho, análise elementar, calorimetria diferencial de varredura e ressonância magnética nuclear, RMN¹H e RMN13C. O AES analisado apresenta a seguinte composição em massa: 65% de EPDM-g-SAN, 13% de EPDM livre e 22% de SAN livre. O EPDM apresenta 69,8% em massa de etileno, 26,5% em massa de propileno e 4,6% em massa do dieno, 2-etilideno-5-norboneno, ENB. O SAN apresenta razão em massa acrilonitrila/estireno de 28/72 e distribuição randômica de comonômeros de estireno e acrilonitrila. Estes resultados são concordantes com a composição do AES fornecida pelo fabricante, indicando que a metodologia proposta é adequada.This work aims the characterization of AES, a graft copolymer based on poly(styrene-co-acrylonitrile, SAN, and poly(etyhlene-co-propylene-co-diene, EPDM. AES was submitted to selective extraction of its components: free SAN, EPDM chains and the graft copolymer EPDM-g-SAN. AES and its fractions were characterized by infrared spectroscopy, elemental analysis, differential scanning calorimetry, 13C and ¹H nuclear magnetic resonance. The AES has 65 wt % of EPDM-g-SAN, 13 wt % of free EPDM and 22 wt % of free SAN. EPDM has 69.8 wt % of ethylene, 26.5 wt % of propylene and 4.6 wt % of diene, 2-ethylidene-5-norbonene ENB. SAN presents acrylonitrile/styrene mass ratio of 28/72 and a random distribution of acrylonitrile and styrene comonomers. These results are in agreement with the composition reported by the AES supplier, indicating that the proposed methodology is adequate.

  20. Preparation and Anti-Tumor Effect of Oridonin Loaded Cholesteryl Formate-Graft Chitosan Copolymer Nano-micelles%冬凌草甲素/胆固醇甲酰-壳聚糖共聚物纳米胶束的制备及其体外抗肿瘤作用

    Institute of Scientific and Technical Information of China (English)

    赵永星; 赵阳; 张振中; 张雪晓; 孙倩

    2011-01-01

    目的 制备冬凌草甲素/胆固醇甲酰-壳聚糖共聚物(ORI/CF-CS)纳米胶束并研究其体外抗肿瘤活性.方法 采用酰胺化反应合成胆固醇甲酰-壳聚糖共聚物(CF-CS);以CF-CS为载体材料制备ORI/CF-CS纳米胶束,并测定其载药量、包封率、形态、粒径和ξ电位;MTT法测定其对宫颈癌Hela肿瘤细胞的细胞毒作用.结果 ORI/CF-CS纳米胶束载药量为9.16%,包封率为48.83%,粒径控制在68.10~113.8 nm内,ξ电位为-34.97~-29.19 mV,体外释药缓慢;ORI/CF-CS纳米胶束对Hela肿瘤细胞的细胞毒作用优于冬凌草甲素溶液,且IC50值比冬凌草甲素溶液低约3倍.结论 CF-CS是冬凌草甲素的优良载体,且可提高其抗Hela肿瘤细胞的活性.%OBJECTIVE To prepare oridonin-loaded cholesteryl formate-graft chitosan copolymer (abbreviated as ORI/CF-CS) nano-micelles and study the in vitro anti-tumor activity. METHODS Cholesteryl formate-graft chitosan copolymer (abbreviated as CF-CS) was synthesized via amidation reaction. ORI/CF-CS nano-micelles were prepared by evaporating and characterized by drug loading content,entrapment efficiency, morphology, particle size,and £ potential. MTT test were applied to assess the cytotoxicity of ORI/CF-CS nano-micelles on Hela cells line. RESULTS The prepared ORI/CF-CS nanomicelles had loading content of 9.16% andentrapment efficiency of 48. 83% ,small size range of 68.10 -113. 8 nm,{j potential range of -34. 97----29. 19 mV,and slow releasein vitro. The cytotoxicity of ORI/CF-CS nanomicelles was stronger than that of oridonin solution. IC,,, value of ORI/CF-CS nanomicelles was about 3 times lower,than those of oridonin solution. CONCLUSION CF-CS nano-micelles might be used as potential carriers of oridonin for cancer therapy.

  1. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  2. Novel approach to synthesizing poly(propylene)-graft-poly(styrene) (PP-g-PS)

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel synthetic route used for preparing PP-g-PS was designed. With this synthetic route, a series of graft copolymers with different contents of PS chain were synthesized successfully, and characterized by 13C-NMR, DSC, GPC.

  3. Synthesis and Properties of Poly (n-Octyl Acrylate) with Uniform Polystyrene Grafts

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Poly (n-octyl acrylate) with uniform polystyrene grafts (POA-g-PS) was obtained by radical copolymerization of n-octyl acrylate (OA) with PS macromer, in solution. The reactivity ratio and effects of copolymerization conditions on grafting efficiency were studied. The crude products were purified by extraction with cyclohexane and n-butanol successively. POA-g-PS exhibited a very good compatibilizing effect on the acrylic rubber/polystyrene blends. 2%-3% of the graft copolymer was enough for enhancing the tensile strength of the blends. DSC and SEM demonstrated the enhancement of compatibility in the presence of the graft copolymer.

  4. Preparation of Graft Copolymer of Cellulose and N, N'-methylenebisacrylamide Using Ionic Liquid as Reaction Medium%纤维素与MBA接枝共聚物在离子液体中的制备

    Institute of Scientific and Technical Information of China (English)

    田晨; 刘明华; 林春香; 林苑

    2011-01-01

    The grafting of N, N'-methylenebisacrylamide (MBA) onto cellulose was conducted using 1-butyl-3-methylinidazolium chloride ionic liquid ([Bmim]Cl) as reaction medium and potassium peroxydisulfate as initiator. The graft conditions, i.e., reaction time, monomer concentration, reaction temperature and initiator dosage etc. on the graft efficiency were optimized by orthogonal and signal-factor experiments. The results showed that the optimal conditions included 2 h of the reaction time, 3 : 1 of the mass ratio of monomer and cellulose, 50℃ of the reaction temperature and 0.05 g of the initiator dosage. Under the above optimal conditions, the grafting efficiency of cellulose and N, N'-methylenebisacrylamide could reach 38.06%.%以N,N’-亚甲基双丙烯酰胺(MBA)为单体,过硫酸钾为引发剂,研究了MBA与纤维素在离子液体中的接枝共聚反应。通过正交单因素实验,研究了反应时间、单体用量、反应温度、引发剂用量对接枝效果的影响。实验结果表明:当反应时间为2h,单体与纤维素质量比为3:1,反应温度为50℃,引发剂用量为0.05g时,接枝效果最好。此条件下,MBA与纤维素的接枝率可达38.06%。

  5. Comb-like temperature-responsive polyhydroxyalkanoate-graft-poly(2-dimethylamino-ethylmethacrylate) for controllable protein adsorption

    DEFF Research Database (Denmark)

    Yao, Hui; Wei, Daixu; Che, Xuemei

    2016-01-01

    %. Graft copolymer PHA-g-PDMAEMA showed enhanced thermal stability, biocompatibility and controllable hydrophilicity compared with non-grafted P(3HDD-co-3H9D). The grafted material presented an obvious tendency of increasing protein adsorptions over the lower critical solution temperature (LCST 47.5 °C...... controllable protein adsorption for biomedical usages....

  6. Biodegradation of starch–graft–polystyrene and starch–graft–poly(methacrylic acid copolymers in model river water

    Directory of Open Access Journals (Sweden)

    Nikolić Vladimir

    2013-01-01

    Full Text Available In this paper the biodegradation study of grafted copolymers of polystyrene (PS and corn starch and poly(methacrylic acid and corn starch in model river water is described. These copolymers were obtained in the presence of different amine activators. The synthesized copolymers and products of degradation were characterized by Fourier Transform Infrared Spectroscopy (FTIR and Scanning Electron Microscopy (SEM. Biodegradation was monitored by mass decrease and number of microorganisms by Koch’s method. Biodegradation of both copolymers advanced with time, poly(methacrylic acid-graft-starch copolymers completely degraded after 21 day, and polystyrene-graft-starch partially degraded (45.78-93.09 % of total mass after 27 days. Differences in the degree of biodegradation are consequences of different structure of the samples, and there is a significant negative correlation between the share of polystyrene in copolymer and degree of biodegradation. The grafting degree of PS necessary to prevent biodegradation was 54 %. Based on experimental evidence, mechanisms of both biodegradation processes are proposed, and influence of degree of starch and synthetic component of copolymers on degradation were established. [Projekat Ministarstva nauke Republike Srbije, br. 172001 i br. 172062

  7. Synthesis and applications of poly(2-hydroxyethylmethacrylate) grafted agar: a microwave based approach.

    Science.gov (United States)

    Rani, G Usha; Mishra, Sumit; Pathak, Gopal; Jha, Usha; Sen, Gautam

    2013-10-01

    Synthesis of graft copolymers under the influence of microwave radiation alone is a rapid, efficient, clean, cheap, convenient, energy-saving and green method. Grafting of poly(2-hydroxyethylmethacrylate) on agar backbone was carried out under the influence of microwave radiation. The synthesis is optimized in terms of percentage grafting and intrinsic viscosity, by varying the microwave irradiation time and monomer (2-hydroxyethylmethacrylate) concentration. The synthesized graft copolymers have been characterized by intrinsic viscosity measurement, FTIR spectroscopy, UV-spectroscopy, elemental analysis (C, H, N, & S), thermal studies and scanning electron microscopy (SEM). Flocculation efficacy of the synthesized graft copolymers was studied in 0.25% kaolin and 1% coal fine suspension, through 'jar test' procedure. Further, flocculation efficacy of the best grade, coagulant (alum) and agar were studied for possible application in remediation of metals from river water.

  8. Gamma radiation-induced grafting of acrylamide and dimethyl diallyl ammonium chloride onto starch.

    Science.gov (United States)

    Lv, Xiaohua; Song, Weiqiang; Ti, Yongzhou; Qu, Lingbo; Zhao, Zhiwei; Zheng, Hongjuan

    2013-01-30

    Corn starch graft copolymers were prepared from acrylamide/dimethyl diallyl ammonium chloride binary monomers (AM/DMDAAC) by a simultaneous radiation grafting method, and were characterized by FTIR and (1)H NMR techniques, weight measurement and titration method. The copolymers with high grafting ratio and high grafting efficiency of binary monomers were achieved at absorbed doses of 2 kGy and 3 kGy using a 6:9.8:4.2 (w/w/w) ratio of starch/AM/DMDAAC, but their cationic degrees were low. Grafting ratio, grafting efficiency and cationic degree of the copolymers increased with increasing AM content in comonomer mixtures and then decreased at 3kGy using a 6:14 ratio of starch:total comonomers, but their cationic degrees generally decreased with increasing AM content. The grafting ratio, the grafting efficiency and the cationic degree of the copolymers increased, but the grafting efficiency of DMDAAC decreased with varying starch/(AM+DMDAAC) ratio from 6:3 to 6:18 at 3 kGy by using a fixed 7:3 ratio of AM:DMDAAC.

  9. SYNTHESIS AND FLOCCULABILITY OF SODIUM ALGINATE GRAFTED WITH ACRYLAMIDE

    Institute of Scientific and Technical Information of China (English)

    Kaiqiang Xu; Xiongli Xu; Zhiji Ding; Meihua Zhou

    2006-01-01

    Graft copolymers of sodium alginate (SA) with acrylamide (AM) were synthesized using aceric ion initiated solution polymerization technique. The acrylamide conversions were studied by changing reaction conditions, such as temperature, molecular weight of sodium alginate and reaction time. The flocculation performance of the graft copolymer(SAG) was investigated in kaolin suspension and also in dyeing waste water. It was found that SAG is more efficient in flocculation behavior as compared to polyacrylamide and SA in kaolin suspension, and in removal capacities for CODCr and colority in dyeing wastewater.

  10. Synthesis and Characterization of Styrene- Ethylene-Propylene-Styrene (SEPS Grafted with Maleic Anhydride (MAH for Use as Coupling Agent in Wood Polymer Composite

    Directory of Open Access Journals (Sweden)

    M. Acevedo-Morantes

    2015-10-01

    Full Text Available Styrene-Ethylene-Propylene-Styrene (SEPS block copolymer was grafted with maleic anhydride (MAH by reactive extrusion (SEPS-g-MAH using an organic peroxide as initiator in the grafting. SEPS-g-MAH was synthesized for use as coupling agent in wood polymer composite (WPC. Identification of this compatibilizer was made using Fourier transform infrared spectroscopy (FTIR and the grafting degree was determinate with titration. The characteristic peaks in FTIR analysis indicated the presence of MAH in the copolymer.

  11. Radiation-induced graft polymerization of acrylamide: Reverse osmosis properties of polyethylene-g-poly(acrylamide) membrane

    Science.gov (United States)

    Dessouki, Ahmed M.; Hegazy, El-Sayed A.; El-Assy, Nasef B.; El-Boohy, Hussein A.

    A study has been made of some properties of the graft copolymer obtained by direct radiation grafting of acrylamide (AAm) onto low density polyethylene (LDPE) films. The swelling behaviour was investigated for the grafted and alkali-treated graft copolymer and it was found that this depends mainly on the amount of hydrophilic groups and also on the type of electrolytes (K- or Nasalts). salts). Some other properties of the graft copolymer films such as dimensional change wet and dry, electrical conductivity, and mechanical properties were studied. A trial has been made of such membrane for reverse osmosis desalination of saline water. The effect of operating time, degree of grafting, applied pressure and feed concentration on the water flux and salt rejection was determined.

  12. Synthesis and Thermosensitive Behavior of Polyacrylamide Copolymers and Their Applications in Smart Textiles

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2015-05-01

    Full Text Available We tuned the lower critical solution temperature (LCST of amphiphilic poly(N-isopropylacrylamide (PNIPAAm via copolymerization with a hydrophilic comonomer of N-hydroxymethyl acrylamide (NHMAAm. A series of copolymers P(NIPAAm-co-NHMAAm were synthesized by atom transfer radical polymerization (ATRP using CuBr/(N,N,N',N',N''-Pentamethyldiethylenetriamine (PMDETA as a catalyst system and 2-bromo ethyl isobutyrate (EBiB as an initiator. The copolymers were well characterized by Fourier transform infrared spectroscopy (FT-IR, 1H Nuclear magnetic resonance (NMR, and Thermogravimetric analysis (TGA. The copolymers followed a simple rule in their thermosensitive behaviors and have a linear increase in the LCST as a function of NHMAAm mol%. The thermosensitive properties of the copolymer films were investigated and demonstrated hydrophilic-hydrophobic transitions. Finally, the copolymer was grafted onto cotton fabrics using citric acid (CA as a crosslinking agent and sodium hypophosphite (SHP as a catalyst following a two dipping, two padding process. The large number of hydroxyl groups in the copolymer makes grafting convenient and firm. The grafted cotton fabrics show obvious thermosensitive behaviors. The results demonstrate that the cotton fabrics become more hydrophobic when the temperature is higher than the LCST. This study presents a valuable route towards temperature-responsive smart textiles and their potential applications.

  13. Interfacial properties of statistical copolymer brushes in contact with homopolymer melts.

    Science.gov (United States)

    Trombly, David M; Pryamitsyn, Victor; Ganesan, Venkat

    2011-04-21

    We use polymer self-consistent field theory to quantify the interfacial properties of random copolymer brushes (AB) in contact with a homopolymer melt chemically identical to one of the blocks (A). We calculate the interfacial widths and interfacial energies between the melt and the brush as a function of the relative chain sizes, grafting densities, compositions of the random copolymer in the brush, and degree of chemical incompatibility between the A and B species. Our results indicate that the interfacial energies between the melt and the brush increase (signifying expulsion of the free chains from the brush) with increasing grafting density, chemical incompatibility between A and B components, and size of the free chains relative to the grafted chains. We also compare the interfacial energies of random copolymers of different sequence characteristics and find that, except for the case of very blocky or proteinlike chains, blockiness of the copolymer has only little effect on interfacial properties. Our results for interfacial energies are rationalized based on the concept of an "effective volume fraction" of the brush copolymers, f(eff), which quantifies the chemical composition of the brush segments in the interfacial zone between the brush and melt copolymers. Using this concept, we modify the strong-stretching theory of brush-melt interfaces to arrive at a simple model whose results qualitatively agree with our results from self-consistent field theory. We discuss the ramifications of our results for the design of neutral surfaces.

  14. 桉木木质素磺酸钙与丙烯酸接枝共聚物的分离与表征%Separation and Characterization of Graft Copolymer from Eucalyptus Calcium Lignosulfonate and Acrylic Acid

    Institute of Scientific and Technical Information of China (English)

    叶德展; 刘磊; 夏超; 代华; 张熙

    2013-01-01

    针对Fenton试剂引发桉木木质素磺酸钙(HLS-Ca)和丙烯酸(AA)单体接枝反应体系,研究了传统沉淀-索氏抽提分离方法的提纯效果,在此基础上提出了离心分离-索氏抽提联用的新分离提纯方法并对该方法的分离效果进行了考察,分析了HLS-Ca、接枝共聚物(HLS-AA)的FT-IR、UV和1H-NMR谱图特征.结果表明,离心分离-索氏抽提联用法具有优于传统沉淀-索氏抽提分离方法的分离提纯效果,可用于HLS-Ca和AA接枝共聚体系各组分的分离.HLS-AA在210 nm左右的UV吸收峰强度明显高于HLS-Ca,FT-IR谱图中1727 cm-1处的吸收峰为HLS-AA的羰基吸收峰,1H-NMR谱图中化学位移为10~14处的吸收峰为HLS-AA的特征吸收蜂.%Graft copolymerization of eucalyptus calcium lignosulfonate (HLS-Ca) with acrylic acid ( AA) was carried out using Fenton regent as a redox initiator. The separation efficiently of traditional precipitation-soxhlet extraction method was investigated, and a new centrifugal separation-combined with soxhlet extraction method was proposed. The chemical structures of HLS-Ca and the graft polymer (HLS-AA) were characterized by FT-IR, UV and 1H-NMR. The results showed that compared with traditional method, the new separation method is more effective to separate the graft polymer from homopolymer and unreacted HLS-Ca. The band at 1727 cm-1 in FT-IR spectrum is assigned to car-bonyl absorption; the stronger absorbed band at 210 nm in the UV spectrum can be observed in HLS-AA and the signals between 10 and 14, assigned to the absorption for carboxyl hydrogen, also can be observed in the 1H-NMR spectrum of HLS-AA.

  15. Potential for polyhydroxyalkanoates and policaprolactone copolymer use as tissue-engineered scaffolds in cardiovascular surgery

    Directory of Open Access Journals (Sweden)

    L. V. Antonova

    2012-01-01

    Full Text Available The absence of reliably functioning small-diameter vascular grafts for coronary artery bypass graft surgery remains one of the most important issues of cardiovascular surgery. Tissue-engineered grafts have to be characterized by highly hemocompatible, biomechanical and biocompatible properties, be quickly biodegradable and have non-toxic degradation products. This article presents polyhydroxyalkanoate and policaprolactone main characteristics and evaluates their potential use as polymers for producing vascular grafts. Biocompatibility, good physical and mechanical properties of these polymers and their better performance in copolymer scaffolds were demonstrated.

  16. Synthesis of PAA-g-PDEAEMA Dihydrophilic Graft Copolymer and Its Solution Behavior%PAA-g-PDEAEMA全亲水接枝共聚物的合成及其溶液行为

    Institute of Scientific and Technical Information of China (English)

    陆国林; 金维则; 黄晓宇

    2016-01-01

    A new acrylate monomer containing atom transfer radical polymerization (ATRP) initiation group, tert-butyl 2-((2-chloropropanoyloxy)methyl)acrylate (tBCPMA), was first prepared by Baylis-Hillman and esterification reaction. tBCPMA was homopolymerized by reversible addition-fragmentation chain transfer (RAFT) in a controlled way to obtain well-defined macroinitia-tor (PtBCPMA) with ATRP initiation group (—COCHClCH3) on each repeated unti. The PtBCPMA macroinitiator initiated ATRP of DEAEMA to synthesize PtBA-g-PDEAEMA, which was selectively hydrolyzed to obtain PAA-g-PDEAEMA dihydrophilic copolymer. Lastly, the effect of pH values on their critical micelle concentration (cmc) and micellar morphologies were investigated.%通过 Baylis-Hillman 和酯化两步反应得到一种含原子转移自由基聚合(ATRP)引发基团的含氯三官能团单体tBCPMA,通过该单体可逆加成-断裂链转移(RAFT)均聚可得到每个重复单元含有ATRP引发基团(—COCHClCH3)的大分子引发剂PtBCPMA。PtBCPMA引发单体DEAEMA的ATRP聚合得到接枝共聚物PtBA-g-PDEAEMA,选择性水解PtBA-g-PDEAEMA得到全亲水接枝共聚物PAA-g-PDEAEMA。最后研究了pH值的变化对它们的临界胶束浓度和胶束形貌的影响。

  17. Synthesis and applications of polyacrylamide grafted agar as a matrix for controlled drug release of 5-ASA.

    Science.gov (United States)

    Usha Rani, G; Konreddy, Ananda Kumar; Mishra, Sumit; Sen, Gautam

    2014-04-01

    Agar has been modified by microwave assisted grafting with acrylamide monomer, resulting in poly acrylamide grafted agar (Ag-g-PAM). The synthesized grades of Ag-g-PAM were characterized by standard physico-chemical characterization techniques (FTIR spectroscopy, elemental analysis, scanning electron microscopy (SEM)) to ascertain the intended grafting. The synthesized graft copolymer (Ag-g-PAM) has been investigated (in vitro) for controlled and colon targeted release of 5-amino salicylic acid (5-ASA).

  18. Bone graft

    Science.gov (United States)

    ... around the area. The bone graft can be held in place with pins, plates, or screws. Why ... Orthopaedic Surgery, San Francosco, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the ...

  19. Application of grafted polysaccharides for treatment of coal washery effluent - a case study

    Energy Technology Data Exchange (ETDEWEB)

    Karmakar, N.C. [Indian School of Mines, Dhanbad (India)

    2002-07-01

    Four new generation graft copolymers of polyacrylamide (PAM) grafted on the backbone of polysaccharides, namely starch, amylopectin, sodium alginate and carboxymethyl cellulose have been tested for their performance as flocculant in the treatment of coal washery effluent. For this purpose standard jar test and column settling test were carried on the effluent collected from a semi-coking coal washery plant. The performance of the graft copolymers was compared against the commercial flocculant Nalco-8873 that was being used in the plant. The study reveals that all the graft copolymers, in general, possess good flocculation quality. In the jar test starch based graft copolymers performed on a par with the commercial flocculant. In the column settling test, amylopectin-g-PAM performed much better than Nalco-8873 in terms of supernatant turbidity. As to the settling velocity, though performance of Nalco 8873 was somewhat close to the graft copolymer amylopectin-g-PAM, the latter had an edge over the former exhibiting more or less constant high performance over a wide range of dosage. 3 refs., 4 figs., 1 tab.

  20. Preparation of amphoteric polyacrylamide-grafted starch copolymer and its application in coal slurry wastewater treatment%两性型淀粉-丙烯酰胺接枝共聚物的合成与在煤泥水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    高明; 徐志强

    2013-01-01

    以过硫酸铵/尿素为引发剂,淀粉(St)、丙烯酰胺(AM)、甲基丙烯酰氧乙基三甲基氯化铵(DMC,阳离子单体)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS,阴离子单体)为原料,通过溶液聚合方法合成了两性型淀粉-丙烯酰胺接枝共聚物(St-g-AM-DMC-AMPS),并采用红外光谱和热重分析对接枝共聚物进行了表征,将其应用于煤泥水的絮凝试验,考察了絮凝剂用量、温度和pH 对絮凝效果的影响。%A polyacrylamide-grafted starch (St-g-AM-DMC-AMPS)copolymer,was pre-pared by using corn starch (St),ammonium persulfate-urea as initiator,acrylamide (AM)as monomer,methyl acryloyloxyethy trimethyl ammonium chloride (DMC)as cationic monomer, 2-acrylamido-2-methyl acrylate sulfonic acid (AMPS,anionic monomer)as raw materials through solution polymerization· The structure of the synthesized St-g-AM-DMC-AMPS was character-ized by FT-IR and TG· The effects of the flocculant concentration,temperature,and pH on floc-culation capability were investigated.

  1. A facile metal-free "grafting-from" route from acrylamide-based substrate toward complex macromolecular combs

    KAUST Repository

    Zhao, Junpeng

    2013-01-01

    High-molecular-weight poly(N,N-dimethylacrylamide-co-acrylamide) was used as a model functional substrate to investigate phosphazene base (t-BuP 4)-promoted metal-free anionic graft polymerization utilizing primary amide moieties as initiating sites. The (co)polymerization of epoxides was proven to be effective, leading to macromolecular combs with side chains being single- or double-graft homopolymer, block copolymer and statistical copolymer. © 2013 The Royal Society of Chemistry.

  2. Chitosan-graft-poly(L-glutamic acid) Hybrid Material and Its Self-assembly

    Institute of Scientific and Technical Information of China (English)

    LIU Ye-zhuo; YAO Jin-rong; CAO Heng; LENG Bo-xun; SHAO Zheng-zhong; CHEN Xin

    2012-01-01

    Chitosan-graft-poly(L-glutamic acid)(CS-g-PGA) copolymer was successfully synthesized by grafting polymerization of γ-benzyl-L-glutamate N-carboxyanhydride onto the modified chitosan chains.The self-assembly behavior of such a CS-g-PGA amphiphilic copolymer was studied.The results show that spherical nanoparticles have been formed.The size of CS-g-PGA nanoparticles is found to be controlled by the grafting ratio of PGA.These bio-based polysaccharide/polypeptide hybrid nanoparticles with controllable size may have great potential application in biomedical fields,such as drug delivery systems.

  3. Grafting copolymerization of natural rubber with 2-hydroxyethyl methacrylate for plywood adhesion improvement

    Directory of Open Access Journals (Sweden)

    Yoopadee Promdum

    2009-10-01

    Full Text Available The graft copolymer of natural rubber (NR and 2-hydroxyethyl methacrylate (HEMA was prepared by seeded emulsion polymerization using cumene hydroperoxide (CHP and tetraethylene pentamine TEPA as an initiator system. The structures of the copolymers were characterized by FT-IR and 1H-NMR spectroscopy techniques. The adhesion properties of NR-g-HEMA were examined. The effects of monomer concentration, initiator concentration, reaction temperature,reaction time and the agitation speed on grafting and grafting efficiency were investigated. It was found that the optimumconditions for preparing NR-g-HEMA when 5 phr of HEMA with 0.15mol% of initiator was used were 60oC for 90 min under agitation speed of 50 rpm. Furthermore, the adhesion properties to plywood of the graft copolymers are higher than those of original NR.

  4. Radiation-induced graft copolymerization of binary monomer mixture containing acrylonitrile onto polyethylene films

    Science.gov (United States)

    Choi, Seong-Ho; Nho, Young Chang

    2000-04-01

    Graft copolymerization of acrylonitrile (AN)/acrylic acid (AA), acrylonitrile (AN)/methacrylic acid (MA), and acrylonitrile (AN)/glycidyl methacrylate (GMA) onto pre-irradiated polyethylene (PE) films were studied. The effect of reaction conditions such as solvents, additives, and monomer composition on the grafting yields was investigated. The extent of grafting was found to increase with increasing sulfuric acid concentration when sulfuric acid as an additive was added to the grafting solution. In AN/AA mixture, the proportion of acrylonitrile in the copolymer increased with an increasing AN component in feed monomers. On the other hand, in AN/MA mixture, acrylonitrile component in copolymer was very slight in spite of the increase AN component in feed monomers. In the AN/GMA mixture, the proportion of acrylonitrile in the copolymer increased with increasing acrylonitrile component in AN/GMA feed monomer.

  5. Iodinated glycidyl methacrylate copolymer as a radiopaque material for biomedical applications.

    Science.gov (United States)

    Dawlee, S; Jayabalan, M

    2013-07-01

    Polymeric biomaterial was synthesized by copolymerizing 50:50 mol% of monomers, glycidyl methacrylate and methyl methacrylate. Iodine atoms were then grafted to the epoxide groups of glycidyl methacrylate units, rendering the copolymer radiopaque. The percentage weight of iodine in the present copolymer was found to be as high as 23%. The iodinated copolymer showed higher glass transition temperature and thermal stability in comparison with unmodified polymer. Radiographic analysis showed that the copolymer possessed excellent radiopacity. The iodinated copolymer was cytocompatible to L929 mouse fibroblast cells. The in vivo toxicological evaluation by intracutaneous reactivity test of the copolymer extracts has revealed that the material was nontoxic. Subcutaneous implantation of iodinated copolymer in rats has shown that the material was well tolerated. Upon explantation and histological examination, no hemorrhage, infection or necrosis was observed. The samples were found to be surrounded by a vascularized capsule consisting of connective tissue cells. The results indicate that the iodinated copolymer is biocompatible and may have suitable applications as implantable materials.

  6. Modification of polyethylene by radiation-induced graft polymerization of acrylic acid

    Science.gov (United States)

    Sidorova, L. P.; Aliev, A. D.; Zlobin, V. B.; Aliev, R. E.; Chalykh, A. E.; Kabanov, V. Ya.

    The kinetics investigation of the radiation-induced graft polymerization of acrylic acid onto low density polyethylene by direct method in aqueous solution in the presence of Mohr's salt, was performed. The technique of the contrasting of polyacrylic acid (PAA) graft layer was worked out by Ag +-ions. The structural and morphological peculiarities of grafted copolymers of PE with PAA were determined by the method of electron probe, and X-ray microanalysis by means of the electron microscopy.

  7. Investigation of thermal oxidative break-down of polyethylene films modified with grafted polyacrylonitrile. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Krul, L.P.; Gert, E.V. (Belorusskij Gosudarstvennyj Univ., Minsk)

    1981-11-01

    Thermal oxidative destruction of polyethylene (PE) films modified by radiation (..gamma..-radiation, dose rate is 0.56 Mrad/hr) liquid-phase graft polymerization of acrylonitrile (AN) has been studied. Comparative stability of grafted copolymers, homopolymers and mechanical mixtures of PE and PAN (polyacrylonitrile) to thermal oxidative destruction is studied using the derivatographic method. It is shown that graft of PAN considerably decelerates the development of oxidative and destructive processes in PE, at that, the efficiency of PE chain stabilization increases with the increase of grafted PAN amount. The sample with PAN content x=0.367 (in parts of the mass of grafted film) possesses the highest stability.

  8. Ceric ion initiated synthesis of polyacrylamide grafted oatmeal: Its application as flocculant for wastewater treatment.

    Science.gov (United States)

    Bharti, Srijita; Mishra, Sumit; Sen, Gautam

    2013-04-01

    Polyacrylamide grafted oatmeal (OAT-g-PAM) was synthesized by conventional method. The grafting of the PAM chains on the biomaterial backbone was confirmed through intrinsic viscosity study, FTIR spectroscopy, elemental analysis (C, H, N, S and O), SEM morphology and TGA study. The intrinsic viscosity of oatmeal appreciably improved on grafting of PAM chains, thus resulting grafted product with potential application as superior viscosifier. Further, flocculation efficacy of the graft copolymer was studied in coal fine suspension, kaolin suspension, iron-ore suspension and then in municipal wastewater through 'jar test' procedure.

  9. Optimization of cellulose acrylate and grafted 4-vinylpyridine and 1-vinylimidazole synthesis

    Directory of Open Access Journals (Sweden)

    Bojanić Vaso

    2010-01-01

    Full Text Available Optimization of cellulose acrylate synthesis by reaction with sodium cellulosate and acryloyl chloride was carried out. Optimal conditions for conducting the synthesis reaction of cellulose acrylate were as follows: the molar ratio of cellulose/potassium-t-butoxide/acryloyl chloride was 1:3:10 and the optimal reaction time was 10 h. On the basis of elemental analysis with optimal conditions for conducting the reaction of cellulose acrylate, the percentage of substitution of glucose units in cellulose Y = 80.7%, and the degree of substitution of cellulose acrylate DS = 2.4 was determined. The grafting reaction of acrylate vinyl monomers onto cellulose in acetonitrile with initiator azoisobutyronitrile (AIBN in a nitrogen atmosphere was performed, by mixing for 5 h at acetonitrile boiling temperature. Radical copolymerization of synthesized cellulose acrylate and 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-2-pyrrolidinone and 9-vinylcarbazole, cellulose-poly-4-vinylpyridine (Cell-PVP, cellulose-poly-1- vinylimidazole (Cell-PVIm and cellulose-poly-1-vinyl-2-pyrrolidinone (Cell-P1V2P and cellulose-poly-9-vinylcarbazole (Cell-P9VK were synthesized. Acrylate cellulose and cellulose grafted copolymers were confirmed by IR spectroscopy, based on elementary analysis and the characteristics of grafted copolymers of cellulose were determined. The mass share of grafted copolymers, X, the relationship of derivative parts/cellulose vinyl group, Z, and the degree of grafting copolymers of cellulose (mass% were determined. In reaction of methyl iodide and cellulose-poly-4-vinylpyridine (Cell-PVP the cellulose-1-methyl-poly-4-vinylpyridine iodide (Cell-1-Me-PVPJ was synthesized. Cellulose acrylate and grafted copolymers were obtained with better thermal, electrochemical and ion-emulation properties for bonding of noble metals Au, Pt, Pd from water solutions. The synthesis optimization of cellulose acrylate was applied as a model for the synthesis of grafted

  10. Block coordination copolymers

    Science.gov (United States)

    Koh, Kyoung Moo; Wong-Foy, Antek G; Matzger, Adam J; Benin, Annabelle I; Willis, Richard R

    2012-11-13

    The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

  11. 离子液体中自由基反应制备纤维素接枝共聚物%Preparation of a Novel Cellulose Graft Copolymers by Radical Polymerization in Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    朱虎; 李友明; 万小芳; 刘晓雯; 吴良玉

    2012-01-01

    Quaternization of methylimidazole was carried out to make ionic liquids, 1-butyl-3-methylimidazolium chloride, and 13↑C NMR proved the target product. Degreasing cotton was dissolved and regenerated in 1-butyl-3- methylimidazolium chloride, to study its capability of dissolving cellulose and the changes of cellulose during the dissolving process. Homogeneous graft copolymerization of cellulose and acrylamide in ionic liquids was carried out. FT -IR demonstrated that the product was cellulose-g-polyacrylamide, and the rate graftin dahl method. The result of orthogonal test illustrated the order of the effects of factors : the cellulose 〉 reaction time 〉 mass ratio of monomer to cellulose 〉 reaction temperature. g reached 60% by Kjel- mass ratio of initiator to cellulose 〉 reaction time 〉 mass ratio of monomer to cellulose 〉 reaction temperature.%通过季胺化反应合成离子型液体1-丁基,3-甲基氯化咪唑[Bmin]Cl,13C NMR结果表明有效地合成了目标产物。将脱脂棉纤维素溶解于合成的离子液体中,研究讨论了[Bmin]Cl对其溶解性能及溶解前后纤维素的变化。基于自由基聚合反应的原理,使纤维素在[Bmin]Cl中均相与丙烯酰胺接枝共聚,FT-IR证明了接枝产物的生成,凯氏定氮法测量计算得接枝率达60%。正交试验结果表明各因素对接枝率的影响的主次顺序为:引发剂与纤维素的质量比〉反应时间〉单体与纤维素的质量比〉反应温度。

  12. Preparation of Cationic Fluorinated Styrene-Butyl Acrylate Graft Copolymer and Its Application as Surface Sizing Agent%阳离子含氟苯丙共聚物表面施胶剂的制备及应用

    Institute of Scientific and Technical Information of China (English)

    赵方; 张光华; 刘龙; 郭锦鸽

    2012-01-01

    The corrugated board surface sizing agent was synthesized by soap-free radical polymerization using styrene (St), butyl acrylate (BA), dodecafluoro-heptyl methacrylate (FM), N-hydroxymethyl acrylamide (HMAM) and dimethyl diallyl ammonium chloride (DMDAAC) as graft monomers in oxidation-reduction initiator system, and the surface sizing agent was characterized with infrared spectrum(FTIR), static contact angle and SEM. The optimum synthesis conditions are as follows: m(persulfate): m(starch) dosage being 0.5, m(monomer): m(starch) dosage being 2, m(St): m(BA) dosage being 2.5, and FM dosage being 0.3%. The sizing degree is more than 5 minutes when the sizing content is 0.6%.%在氧化还原体系中,以淀粉为主链,苯乙烯(st)、丙烯酸丁酯(BA)、甲基丙烯酸十二氟庚酯(FM)、N-羟甲基丙烯酰胺(HMAM)和二甲基二烯丙基氯化铵(DMDAAC)为单体,通过无皂乳液聚合制备了阳离子含氟苯丙共聚物瓦楞纸表面施胶剂,并通过红外光谱(FT-IR)、静态接触角和扫描电镜(SEM)进行了表征。结果表明,最佳合成工艺是m(单体):m(淀粉)=2,m(St)聊(BA)=2.5,m(过硫酸钾):m(淀粉)=0.5,w(VM)=0.3%。当施胶浓度为0.6%时,施胶度可达5min。

  13. Reduction of CT beam hardening artefacts of ethylene vinyl alcohol copolymer by variation of the tantalum content: evaluation in a standardized aortic endoleak phantom

    Energy Technology Data Exchange (ETDEWEB)

    Treitl, Karla M.; Scherr, Michael; Foerth, Monika; Braun, Franziska; Maxien, Daniel; Treitl, Marcus [Hospitals of the Ludwig-Maximilians-University of Munich, Institute for Clinical Radiology, Munich (Germany)

    2014-10-16

    Our aim was to develop an aortic stent graft phantom to simulate endoleak treatment and to find a tantalum content (TC) of ethylene-vinyl-alcohol-copolymer that causes fewer computed tomography (CT) beam hardening artefacts, but still allows for fluoroscopic visualization. Ethylene-vinyl-alcohol-copolymer specimens of different TC (10-50 %, and 100 %) were injected in an aortic phantom bearing a stent graft and endoleak cavities with simulated re-perfusion. Fluoroscopic visibility of the ethylene-vinyl-alcohol-copolymer specimens was analyzed. In addition, six radiologists analyzed endoleak visibility, and artefact intensity of ethylene-vinyl-alcohol-copolymer in CT. Reduction of TC significantly decreased CT artefact intensity of ethylene-vinyl-alcohol-copolymer and increased visibility of endoleak re-perfusion (p < 0.000). It also significantly decreased fluoroscopic visibility of ethylene-vinyl-alcohol-copolymer (R = 0.883, p ≤ 0.01), and increased the active embolic volumes prior to visualization (Δ ≥ 40 μl). Ethylene-vinyl-alcohol-copolymer specimens with a TC of 45-50 % exhibited reasonable visibility, a low active embolic volume and a tolerable CT artefact intensity. The developed aortic stent graft phantom allows for a reproducible simulation of embolization of endoleaks. The data suggest a reduction of the TC of ethylene-vinyl-alcohol-copolymer to 45 -50 % of the original, to interfere less with diagnostic imaging in follow-up CT examinations, while still allowing for fluoroscopic visualization. (orig.)

  14. 乙二胺改性淀粉GMA共聚物对Pb(Ⅱ)的吸附性能%Adsorption of Pb( Ⅱ ) on copolymer of glycidyl methacrylete grafted on starch modified with ethylenediamine

    Institute of Scientific and Technical Information of China (English)

    谢国仁; 尚小琴; 刘汝峰; 胡晶; 胡卓

    2011-01-01

    以木薯淀粉为原料,通过接枝共聚、环氧开环反应,得到富含-NH2官能团的新型氨基改性淀粉(AMS),用FT-IR、SEM和XRD对其结构进行表征.在静态条件下,研究了AMS对水溶液中Pb(Ⅱ)的吸附性能和吸附热力学,考察了溶液pH值、吸附时间、Pb(Ⅱ)初始浓度及温度对AMS吸附性能的影响.结果表明:pH值对AMS的吸附性能有显著影响;该吸附是一个快速吸附过程,符合准二级动力学方程,以化学吸附为主;吸附等温线用Langmuir方程拟合效果优于Freundlich方程;分离因子在0~1之间;在初始浓度100mg·L1,pH值为6.0、25℃下的最大吸附容量为0.481 mmol·g-1;吸附为自发、吸热的熵增加过程,升温有利于吸附;AMS可重复使用5次以七.%A novel amino modified starch (AMS) adsorbent modified with ethylenediamine was obtained via grafting polymerization and ring-opening reactions using cassava starch as raw material. The adsorbent was characterized by FT-IR, XRD and SEM. The absorption performance and adsorption thermodynamics were studied in the adsorption process of Pb( Ⅱ ) ions in aqueous solution on the AMS. The effects of pH value, adsorption time, temperature and initial concentration were investigated. It is found that the effect of pH on the adsorption is significant. The adsorption is fast and follows a pseudo-second order process. Chemical adsorption is the main process and the equilibrium isotherm is well described by the Langmuir model rather than the Freundlich model. The separation factors are in the range of 0-1. The maximum adsorption capacity of 0. 481 mmol · g-1 is obtained at initial concentration of 100 mg· L-1 , pH 6.0 and 25℃. The adsorption is a spontaneous and endothermic process with increased entropy, and higher temperature will benefit the adsorption. The adsorbent can be reused for more than five cycles withoutdecreasing its adsorption efficiency.

  15. PLANTAGO PSYLLIUM-GRAFTED-POLYACRYLONITRILE: SYNTHESIS,CHARACTERIZATION AND ITS USE FOR SOLID REMOVAL FROM SEWAGE WASTEWATER

    Institute of Scientific and Technical Information of China (English)

    Anuradha Mishra; Alpa Yadav; Monika Agarwal; Rajani Srinivasan

    2005-01-01

    Plantago psyllium mucilage (PSY), an anionic natural polysaccharide consisting of pentosan and uronic acid obtained from the seeds of Plantago psyllium (Plantago family), was grafted with acrylonitrile (AN). Graft copolymers were prepared by ceric ion initiated solution polymerization technique and were characterized by FT-IR spectroscopy, scanning electron microscopy and differential scanning calorimetry. These copolymers are good flocculating agents for removal of suspended (SS) and total dissolved solid (TDS) in sewage wastewater treatment. The effects of copolymer dose, pH and contact time on flocculation capacity of one selected copolymer sample were studied by jar test method. The suitable pH range for maximum solid removal was 7.0 to 9.2 and the optimum copolymer dose was 1.2 mg/L. The overall process for solid removal took 4 h. X-ray diffraction (XRD) patterns of grafted copolymer, PSY grafted polyacrylonitrile (PSY-g-PAN)and solid waste, before and after treatment are used to suggest the interaction of the solid waste with PSY-g-PAN copolymer.

  16. Radiation-grafted polymers for biomaterial applications. I. 2-hydroxyethyl methacrylate: ethyl methacrylate grafting onto low density polyethylene films

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, D.; Hoffman, A.S.; Ratner, B.D.

    1984-08-01

    Studies were conducted on the radiation grafting of 2-hydroxyethyl methacrylate (HEMA) and ethyl methacrylate (EMA) by the mutual irradation technique onto low density polyethylene. Four different solution concentrations were used, and radiation doses ranged from 0.03 to 0.50 Mrad. Four copolymer compositions having different HEMA:EMA ratios were also studied using two total monomer concentrations. The kinetics of the grafting process demonstrated by the two monomers were basically different. While EMA showed a typical diffusion-controlled kinetic pattern, HEMA exhibited a more complex behavior, the main features of which were an induction period, a slight autoacceleration and a significant drop in graft level after a maximum is reached. The difference in behavior was interpreted in terms of partitioning of monomers into the polyethlene substrate. The surface topography of the grafted films was studied by means of scanning electron microscopy. A mechanism based on osmotic cell formation was suggested for the HEMA graft system. The copolymer systems investigated showed that the graft reaction is faster in the initial stages for higher percentages of EMA in the monomer mixtures; as grafting proceeds the trend is reversed. 24 references, 16 figures, 2 tables.

  17. Polypeptide Grafted Hyaluronan: Synthesis and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaojun [ORNL; Messman, Jamie M [ORNL; Mays, Jimmy [ORNL; Baskaran, Durairaj [University of Tennessee, Knoxville (UTK)

    2010-01-01

    Poly(L-leucine) grafted hyaluronan (HA-g-PLeu) has been synthesized via a Michael addition reaction between primary amine terminated poly(L-leucine) and acrylate-functionalized HA (TBAHA-acrylate). The precursor hyaluronan was first functionalized with acrylate groups by reaction with acryloyl chloride in the presence of triethylamine in N,N-dimethylformamide. 1H NMR analysis of the resulting product indicated that an increase in the concentration of acryloylchoride with respect to hydroxyl groups on HA has only a moderate effect on functionalization efficiency, f. A precise control of stoichiometry was not achieved, which could be attributed to partial solubility of intermolecular aggregates and the hygroscopic nature of HA. Michael addition at high [PLeu- NH2]/[acrylate]TBAHA ratios gave a molar grafting ratio of only 0.20 with respect to the repeat unit of HA, indicating grafting limitation due to insolubility of the grafted HA-g-PLeu. Soluble HA-g-PLeu graft copolymers were obtained for low grafting ratios (<0.039) with <8.6% by mass of PLeu and were characterized thoroughly using light scattering, 1H NMR, FT-IR, and AFM techniques. Light scattering experiments showed a strong hydrophobic interaction between PLeu chains, resulting in aggregates with segregated nongrafted HA segments. This yields local networks of aggregates, as demonstrated by atomic force microscopy. Circular dichroism spectroscopy showed a -sheet conformation for aggregates of poly(L-leucine).

  18. STUDY ON PET-PA66 COPOLYMER

    Institute of Scientific and Technical Information of China (English)

    WU Rongrui; SHI Weitong

    1992-01-01

    In this work the PET-PA66 copolymers are obtained. The characterization of chemical structure of copolymer chain by NMR method is also given . It is shown that when the 66 Nylon salt is added in the copolycondensation, the adipic acid and hexamethylenediamine reacted mainly by itself and the obtained copolymer is a random copolymer, and when the Nylon 66 oligomer is added, the obtained copolymer is a block copolymer. The result of NMR analysis is demonstrated by properties investigation.

  19. Block copolymer battery separator

    Energy Technology Data Exchange (ETDEWEB)

    Wong, David; Balsara, Nitash Pervez

    2016-04-26

    The invention herein described is the use of a block copolymer/homopolymer blend for creating nanoporous materials for transport applications. Specifically, this is demonstrated by using the block copolymer poly(styrene-block-ethylene-block-styrene) (SES) and blending it with homopolymer polystyrene (PS). After blending the polymers, a film is cast, and the film is submerged in tetrahydrofuran, which removes the PS. This creates a nanoporous polymer film, whereby the holes are lined with PS. Control of morphology of the system is achieved by manipulating the amount of PS added and the relative size of the PS added. The porous nature of these films was demonstrated by measuring the ionic conductivity in a traditional battery electrolyte, 1M LiPF.sub.6 in EC/DEC (1:1 v/v) using AC impedance spectroscopy and comparing these results to commercially available battery separators.

  20. Block copolymer battery separator

    Science.gov (United States)

    Wong, David; Balsara, Nitash Pervez

    2016-04-26

    The invention herein described is the use of a block copolymer/homopolymer blend for creating nanoporous materials for transport applications. Specifically, this is demonstrated by using the block copolymer poly(styrene-block-ethylene-block-styrene) (SES) and blending it with homopolymer polystyrene (PS). After blending the polymers, a film is cast, and the film is submerged in tetrahydrofuran, which removes the PS. This creates a nanoporous polymer film, whereby the holes are lined with PS. Control of morphology of the system is achieved by manipulating the amount of PS added and the relative size of the PS added. The porous nature of these films was demonstrated by measuring the ionic conductivity in a traditional battery electrolyte, 1M LiPF.sub.6 in EC/DEC (1:1 v/v) using AC impedance spectroscopy and comparing these results to commercially available battery separators.

  1. Synthesis and Characterization of Konjac Glucomannan-Graft-Polyacrylamide via γ-Irradiation

    Directory of Open Access Journals (Sweden)

    Jie Pang

    2008-03-01

    Full Text Available The synthesis of konjac glucomannan-graft-polyacrylamide (KGM-g-PAM wascarried out at 25°C by γ-irradiation under a N2 atmosphere. The effects of absorbedradiation dosage and monomer concentration on grafting yield and water absorbency werestudied. The grafted copolymers were characterized using Fourier Transform Infrared(FTIR spectroscopy, nuclear magnetic resonance (NMR, x-ray diffraction (XRD,thermogravimetric analysis (TGA and gel permeation chromatography (GPC. Thegrafting yield was observed to increase with increasing absorbed dosage and monomerconcentration. Compared with the original KGM, the grafted copolymers exhibited betterthermal stability and water absorbency. The results suggest that γ-irradiation is convenientand efficient for inducing graft copolymerization of KGM and acrylamide (AM.

  2. Preparation of metal adsorbent from poly(methyl acrylate)-grafted-cassava starch via gamma irradiation

    Science.gov (United States)

    Suwanmala, Phiriyatorn; Hemvichian, Kasinee; Hoshina, Hiroyuki; Srinuttrakul, Wannee; Seko, Noriaki

    2012-08-01

    Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, % Dg=191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum condition. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15 and 1.6 mmol/g-adsorbent for Cd2+, Al3+, UO22+, V5+ and Pb2+, respectively, in the batch mode adsorption.

  3. Synthesis and self-assembly of Chitosan-g-Polystyrene copolymer: A new route for the preparation of heavy metal nanoparticles

    KAUST Repository

    Francis, Raju S.

    2015-01-01

    Amphiphilic graft copolymers made of a Chitosan (CS) backbone and three arm polystyrene (PS) grafts were prepared by "grafting onto" strategy using Toluene Diisocyanate. IR spectroscopy and SEC show the successful grafting process. SEM pictures of Chitosan-g-Polystyrene (CS-g-PS) indicate a spherulite like surface and exhibit properties that result from the disappearance of Chitosan crystallinity. The introduced polystyrene star grafts units improve hydrophobic properties considerably as confirmed by the very high solubility of (CS-g-PS) in organic solvents. The graft copolymer which self-assembles into polymeric micelles in organic media demonstrates much better adsorption of transition and inner transition metal ions than pure Chitosan whose amine groups are not necessarily available due to crystallinity.

  4. Synthesis and self-assembly of chitosan-g-polystyrene copolymer: a new route for the preparation of heavy metal nanoparticles.

    Science.gov (United States)

    Francis, Raju; Baby, Deepa K; Gnanou, Yves

    2015-01-15

    Amphiphilic graft copolymers made of a Chitosan (CS) backbone and three arm polystyrene (PS) grafts were prepared by "grafting onto" strategy using Toluene Diisocyanate. IR spectroscopy and SEC show the successful grafting process. SEM pictures of Chitosan-g-Polystyrene (CS-g-PS) indicate a spherulite like surface and exhibit properties that result from the disappearance of Chitosan crystallinity. The introduced polystyrene star grafts units improve hydrophobic properties considerably as confirmed by the very high solubility of (CS-g-PS) in organic solvents. The graft copolymer which self-assembles into polymeric micelles in organic media demonstrates much better adsorption of transition and inner transition metal ions than pure Chitosan whose amine groups are not necessarily available due to crystallinity.

  5. Microwave assisted synthesis and characterization of sodium alginate-graft-poly(N,N'-dimethylacrylamide).

    Science.gov (United States)

    Akın, Alper; Işıklan, Nuran

    2016-01-01

    Modification of sodium alginate (NaAlg) was carried out using N,N'-dimethylacrylamide (DMAAm) as a monomer and azobisizobutyronitrile (AIBN) as an initiator under microwave irradiation. The effect of reaction conditions such as concentrations of DMAAm, AIBN, NaAlg as well as microwave power and temperature on grafting and grafting efficiency has been explored. Maximum grafting and grafting efficiency has been observed at 1h of grafting time, 0.291 M of DMAAm concentration, 500 W microwave irradiation power, 0.134 M of AIBN concentration, 75°C of reaction temperature and 0.5 g/dL of NaAlg concentration. The grafted copolymer has been characterized by FTIR, DSC, TGA, (13)C NMR, XRD, SEM, and GPC analysis. Cytotoxicity as standard MTT assay, apoptotic and necrotic effects of graft copolymer were investigated on L929 fibroblast cell. It has been found that the grafted copolymer is biocompatible and thermally more stable than the ungrafted alginate. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Preparation and characterization of lignin based macromonomer and its copolymers with butyl methacrylate.

    Science.gov (United States)

    Liu, Xiaohuan; Wang, Jifu; Yu, Juan; Zhang, Mingming; Wang, Chunpeng; Xu, Yuzhi; Chu, Fuxiang

    2013-09-01

    Copolymerization of butyl methacrylate (BMA) with biobutanol lignin (BBL) was achieved by free-radical polymerization (FRP) using a lignin-based macromonomer. The lignin-based macromonomer containing acrylic groups was prepared by reacting acryloyl chloride with biobutanol lignin using triethylamine (TEA) as absorb acid agentin. From the results of elemental analysis and GPC, the average degree of polymerization (DP) of BBL was estimated to be five. A detailed molecular characterization has been performed, including techniques such as (1)H NMR, (13)C NMR and UV-vis spectroscopies, which provided quantitative information about the composition of the copolymers. The changes in the solubility of lignin-g-poly(BMA) copolymers in ethyl ether were dependent on the length of poly(BMA) side chain. TGA analysis indicated that the lignin-containing poly(BMA) graft copolymers exhibited high thermal stability. The bulky aromatic group of lignin increased the glass-transition temperature of poly(BMA). In order to confirm the main structure of copolymer, (AC-g-BBL)-co-BMA copolymer was also synthesized by atom transfer radical polymerization (ATRP), and the results revealed that the copolymer prepared by ATRP had the same solution behavior as that prepared by FRP, and the lignin-based macromonomer showed no homopolymerizability due to the steric hindrance. In addition, the lignin-co-BMA copolymer had a surprisingly higher molecular weight than poly(BMA) under the same reaction condition, suggesting that a branched lignin based polymer could be formed.

  7. The study on grafting comonomer of n-butyl acrylate and styrene onto poly(ethylene terephthalate) film by gamma-ray induced graft copolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Ping Xiang; Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ge Xuewu, E-mail: xwge@ustc.edu.c [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2010-09-15

    Poly(ethylene terephthalate) (PET) film was successfully grafted with n-butyl acrylate and styrene comonomer through gamma-ray induced graft copolymerization. The degree of grafting (DG) and the composition of grafted side chain were characterized by {sup 1}H NMR. It was found that St can inhibit the homopolymerization of BA effectively and increase the DG when the concentration of comonomer mixture is kept constant. The proportion of St to BA in grafted side chain has a positive dependence on the feed ratio of St, which ultimately approaches the feed ratio. The thermal properties of poly(ethylene terephthalate)-graft-poly(n-butyl acrylate-co-styrene) (PET-g-P(BA-co-St)) films were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The T{sub g} of PET decreases with the DG, indicating that the grafted P(BA-co-St) copolymer has good compatibility with PET backbone.

  8. Hydrolyzed polyacrylamide grafted maize starch based microbeads: application in pH responsive drug delivery.

    Science.gov (United States)

    Setty, C Mallikarjuna; Deshmukh, Anand S; Badiger, Aravind M

    2014-09-01

    The present study details the synthesis, characterization and pharmaceutical application of hydrolysed polyacrylamide grafted maize starch (HPam-g-MS) as promising polymeric material for the development of pH responsive microbeads. Different grades of graft copolymer were synthesized by changing the net microwave irradiation time, while keeping all other factors constant. Acute oral toxicity study performed in rodents ensured the bio-safety of graft copolymer for clinical application. Various batches of aceclofenac loaded microbeads were prepared by ionic gelation method using synthesized graft copolymers and evaluated for formulation parameters. FTIR spectroscopy confirmed the chemical compatibility between drug and graft copolymer. Results of in vitro release study (USP type-II) carried out in two different pH media (pH 1.2 acid buffer and pH 7.4 phosphate buffer) showed that release rate of drug from developed microbeads was a function of both: (a) surrounding pH and (b) the matrix composition. The drug release was relatively higher at alkaline pH as compared to acidic pH and this feature is desirable from viewpoint of site specific drug delivery. A direct correlation was observed between percentage grafting and microbeads performance and it presents a scope for further research on application and optimization of HPam-g-MS based microbeads as drug delivery carriers.

  9. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Luzhong; Dou, Sufeng [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China); Li, Yan [College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Yuan, Ying; Ji, Yawei [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China); Wang, Yaling [College of Chemistry and Chemical Engineering, Nantong University, Nantong 226001 (China); Yang, Yumin, E-mail: yangym@ntu.edu.cn [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China)

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields. - Highlights: ► Chitosan-g-poly(glycolic acid) copolymer was prepared without using a catalyst. ► Degradation rate of copolymer increased dramatically compared with that of chitosan. ► Degradation rate was controlled by the molar ratio of glycolic acid to chitosan. ► In vitro cytotoxicity tests revealed that the copolymer has good biocompatibility. ► The copolymer has a great potential to meet diverse needs in biomedical fields.

  10. STUDIES ON ULTRASONIC GRAFTING OF POLY(VINYL ACETATE) WITH POLY(ETHYLENE OXIDE)

    Institute of Scientific and Technical Information of China (English)

    LI Wenduan; XU Xi; Tu Hong; Tang Zuyao

    1983-01-01

    The ultrasonic degradation of poly(ethylene oxide) and poly(vinyl acetate) in benzene solution, and grafting reaction of poly(vinyl acetate) with poly(ethylene oxide) were studied. It is found that the chain-scission reactions follow the course suggested by D. W. Ovenall. The structure of the copolymer was identified by IR, NMR and DTA, showing that the copolymer prepared is a graft copolymer mainly. The copolymer formed by irradiating 1 % PEO/PVAc solution (PEO/PVAc:1/1 by weight) for a period of 10 min at 18.2 kHz with 2.0 A input current on reversed main circuit, amounts to 10.5%.

  11. Stent graft placement for dysfunctional arteriovenous grafts

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2015-07-15

    This study aimed to evaluate the usefulness and outcomes of stent graft use in dysfunctional arteriovenous grafts. Eleven patients who underwent stent graft placement for a dysfunctional hemodialysis graft were included in this retrospective study. Expanded polytetrafluoroethylene covered stent grafts were placed at the venous anastomosis site in case of pseudoaneurysm, venous laceration, elastic recoil or residual restenosis despite the repeated angioplasty. The patency of the arteriovenous graft was evaluated using Kaplan-Meier analysis. Primary and secondary mean patency was 363 days and 741 days. Primary patency at 3, 6, and 12 months was 82%, 73%, and 32%, respectively. Secondary patency at the 3, 6, 12, 24, and 36 months was improved to 91%, 82%, 82%, 50%, and 25%, respectively. Fractures of the stent graft were observed in 2 patients, but had no effect on the patency. Stent graft placement in dysfunctional arteriovenous graft is useful and effective in prolonging graft patency.

  12. A rare example of the formation of polystyrene-grafted aliphatic polyester in one-pot by radical polymerization.

    Science.gov (United States)

    Shi, Yinfeng; Zheng, Zhicheng; Agarwal, Seema

    2014-06-10

    The radical copolymerization of cyclic ester β-propiolactone (β-PL) with styrene (St) at 120 °C, with a complete range of monomer ratios, is a rare example of a system providing graft copolymers (PSt-g-β-PL) in one pot. The structure of the resulting β-PL-St copolymers was proven by using a combination of different characterization techniques, such as 1D and 2D NMR spectroscopy and gel permeation chromatography (GPC), before and after alkaline hydrolysis of the polymers. The number of grafting points increased with an increasing amount of β-PL in the feed. A significant difference in the reactivity of St and β-PL and radical chain-transfer reactions at the polystyrene (PSt) backbone, followed by combination with the active growing poly(β-PL) chains, led to the formation of graft copolymers by a grafting-onto mechanism.

  13. Characterization of methyl methacrylate grafting onto preirradiated biodegradable lignocellulose fiber by gamma-radiation.

    Science.gov (United States)

    Khan, Ferdous

    2005-01-14

    Gamma-radiation-induced graft copolymerization of methyl methacrylate onto natural lignocellulose (jute) fiber was carried out by the preirradiation method in an aqueous medium by using octylphenoxy-polyethoxyethanol as an emulsifier. The different factors that influenced the graft copolymer reaction process were investigated. In the case of radiation-dose-dependent grafting, samples irradiated in the presence of air produced up to 73% graft weight compared to 53% obtained in the case of irradiation in a nitrogen environment. By assuming Arrhenius reaction kinetics, the activation energy (E(a)) of the grafting reaction process was evaluated for different reaction temperatures. Moreover, the graft copolymer reaction was controlled by incorporating a homopolymer-inhibiting agent and three different chain-transfer agents in the reaction medium. The mechanical and thermal properties of jute fiber 'as received' and jute-graft-poly(methyl methacrylate) were also investigated. The results showed that the percentage of grafting with jute fiber has a significant effect on the properties. The kinetic parameters were evaluated from TGA thermograms by using Broido's method in the temperature range 240-350 degrees C. Scanning electron micrographs show that the structural changes on the surface of jute fibers were induced by graft copolymerization of methyl methacrylate monomer. Fiber-fiber surface friction was measured in terms of the average maximum load and the kinetic friction. SEM of jute-graft-poly(methyl methacrylate).

  14. Surface modification of polyethylene by radiation-induced grafting for adhesive bonding. III. Oxidative degradation and stabilization of grafted layer

    Energy Technology Data Exchange (ETDEWEB)

    Yamakawa, S.; Yamamoto, F.

    1978-09-01

    Vapor-phase mutual grafting of methyl acrylate (MA) onto polyethylene (PE) and subsequent saponification treatment produce a surface graft having a high adhesive bondability, which results from the presence of a hydrolized homopolymer layer (consisting of only monomer componenet) on an inner graft copolymer layer consisting of both PE and monomer components. The oxidative deterioration and the stabilization of the grated surface layer have been investigated to clarify the long-term stability of the adhesive bondability. The bondability rapidly disappears with accelerated weatherly followed by acetone extraction treatment, whereas it is kept unchanged during thermal-oxidative aging at 100/sup 0/C. Microscopic and attenuated total resonance (ATR) infrared spectroscopic observations of the degreaded surfaces show that the bondability loss is due to degradiative removal of the surface homopolymer layer. The addition of combinations of conventional antioxidants and ultraviolet absorbers stabilizes the grafted surface layer against thermal-oxidative and photo-oxidative degradation and thus extends the bondability rentention time. The stabilization is more effective in the grafts of carbon black-containing PE, where carbon black is present in the inner-graft copolymer layer.

  15. Nitroxide mediated and atom transfer radical graft polymerization of atactic polymers onto syndiotactic polystyrene

    Directory of Open Access Journals (Sweden)

    M. Abbasian

    2012-06-01

    Full Text Available 'Living' radical graft polymerization was employed to prepare graft copolymers with nitroxide-mediated arylated syndiotactic polystyrene as the backbone and polystyrene (PS, poly(p-methylstyrene (PMS and poly(methylmethacrylate (PMMA as branches. A two-stage process has been developed to synthesize the macroinitiator. First, syndiotactic polystyrene (sPS was modified by the Friedel-Crafts reaction to introduce chlorine; second, the chlorine groups were converted to nitroxide mediated groups by coupling with 1-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO-OH. The resulting macroinitiator (sPS-TEMPO for 'living' free radical polymerization was then heated in the presence of styrene and p-methylstyrene to form graft and block copolymers. We used the obtained copolymer and N-bromosuccinimide as brominating agent to achieve polymers with bromine groups. This brominated copolymer was used as a macroinitiator for polymerizing methyl methacrylate in the presence of the CuBr/bpy catalyst system. The formation of the graft and block copolymers was confirmed by DSC, ¹H NMR and FTIR spectroscopy. This approach using macroinitiators is an effective method for the preparation of new materials.

  16. Nitroxide mediated and atom transfer radical graft polymerization of atactic polymers onto syndiotactic polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, M. [Department of Basic Science, Payame Noor University, Tehran (Iran, Islamic Republic of); Shoja, S. Esmaeily [Lab. of Materials, Faculty of Engineering, Islamic Azad University, Bonab (Iran, Islamic Republic of)

    2012-04-15

    'Living' radical graft polymerization was employed to prepare graft copolymers with nitroxide mediated arylated syndiotactic polystyrene as the backbone and polystyrene (PS), poly(p-methylstyrene) (PMS) and poly(methylmethacrylate) (PMMA) as branches. A two-stage process has been developed to synthesize the macroinitiator. First, syndiotactic polystyrene (sPS) was modified by the Friedel-Crafts reaction to introduce chlorine; second, the chlorine groups were converted to nitroxide mediated groups by coupling with 1-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO-OH). The resulting macroinitiator (sPSTEMPO) for 'living' free radical polymerization was then heated in the presence of styrene and pmethylstyrene to form graft and block copolymers. We used the obtained copolymer and N-bromosuccinimide as brominating agent to achieve polymers with bromine groups. This brominated copolymer was used as a macroinitiator for polymerizing methyl methacrylate in the presence of the CuBr/bpy catalyst system. The formation of the graft and block copolymers was confirmed by DSC, {sup 1}H NMR and FTIR spectroscopy. This approach using macroinitiators is an effective method for the preparation of new materials. (author)

  17. Synthesis of New Elastomers with Controlled Structures Based on Alkylene Oxides, Grafted by ROMP

    Science.gov (United States)

    Spurcaciu, Bogdan; Dragutan, Ileana; Nicolae, Cristian-Andi; Buzdugan, Emil; Dragutan, Valerian

    Poly(propylene oxide-ran-allyl glycidyl ether) (PPO-AGE) copolymers have been prepared using as initiating system an alkyl aluminum compound, controlled amounts of water and different organic compounds that act as cocatalysts, e.g. ethers, diols, phosphines, salicylic acid derivatives, and organozinc compounds. Among the investigated catalysts the most productive systems showed to be the ternary systems derived from triisobutylaluminum (TIBA) and water having Zn(acac)2 as a third component. These copolymers have subsequently been grafted by ringopening metathesis polymerization (ROMP) with cyclooctene in the presence of Grubbs first-generation ruthenium (Ru) catalyst to produce new comblike copolymers.

  18. Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaomeng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Luan Shifang, E-mail: sfluan@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yang Huawei; Shi Hengchong; Zhao Jie; Jin Jing [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy)

    2012-01-15

    Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.

  19. Synthesis of polyaniline catalysed by Cu(I), Ni(II) and Fe(II) supported on the polyethylene-i-acrylic acid copolymer; Sintesis de polianilina catalizada por Cu(I), Ni(II) y Fe(II), soportados en el copolimero polietileno-i-acido acrilico

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, L.; Urena, F.; Lopez, R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    In this study the active sites of acrylic acid (AA) were grafted in low density polyethylene (PEBD) using gamma radiation. Subsequently, the graft copolymer PEBD-i-AA was coordinated with different metals such as copper, nickel and iron. The organometallic copolymers so formed were used as catalysts in the aniline polymerization reaction. Finally, it was realized the characterization of the obtained products, determining their thermal properties, copolymer graft percentage, quantification of the metal contained in the complex as well as polymerization and electric conductivity percentages of the poly aniline film. (Author)

  20. Peroxydisulfate initiated synthesis of potato starch-graft-poly(acrylonitrile under microwave irradiation

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Potato starch-graft-poly(acrylonitrile could be efficiently synthesized using small concentration of ammonium peroxydisulfate (0.0014M in aqueous medium under microwave irradiation. A representative microwave synthesized graft copolymer was characterized using Fourier Transform Infrared Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and Thermogravimetric Analysis. Under microwave conditions oxygen removal from the reaction vessel was not required and the graft copolymer was obtained in high yield using very small amount of ammonium peroxydisulfate, however using the same amount of ammonium peroxydisulfate (0.0014M on thermostatic water bath no grafting was observed up to 98°C (even in inert atmosphere. Raising the concentration of the initiator to 0.24 M resulted into 10% grafting at 50 °C but in inert atmosphere.The viscosity/shear stability of the grafted starch (aqueous solution and water/saline retention ability of the microwave synthesized graft copolymer were also studied and compared with that of the native potato starch.

  1. Morphology and Properties of Model Block and Graft Copolymers

    Science.gov (United States)

    2007-11-02

    run and 2nd run) Interestingly, PCHD shows a strong exothermic peak on first heating in DSC. This suggests the presence of formation of higher...ARL scientists on SABRE to help a company (Boston Scientific Inc., Natick, Massachusetts) better understand their polymer coated heart stents .

  2. Modulation of graft architectures for enhancing hydrophobic interaction of biomolecules with thermoresponsive polymer-grafted surfaces.

    Science.gov (United States)

    Idota, Naokazu; Kikuchi, Akihiko; Kobayashi, Jun; Sakai, Kiyotaka; Okano, Teruo

    2012-11-01

    This paper describes the effects of graft architecture of poly(N-isopropylacrylamide) (PIPAAm) brush surfaces on thermoresponsive aqueous wettability changes and the temperature-dependent hydrophobic interaction of steroids in silica capillaries (I.D.: 50 μm). PIPAAm brushes were grafted onto glass substrates by surface-initiated atom transfer radical polymerization (ATRP) that is one of the living radical polymerization techniques. Increases in the graft density and chain length of PIPAAm brushes increased the hydration of polymer brushes, resulting in the increased hydrophilic properties of the surface below the transition temperature of PIPAAm at 32 °C. More hydrophobic surface properties were also observed on surfaces modified with the block copolymers of IPAAm and n-butyl methacrylate (BMA) than that with IPAAm homopolymer-grafted surfaces over the transition temperature. Using PBMA-b-PIPAAm-grafted silica capillaries, the baseline separation of steroids was successfully achieved by only changing temperature. The incorporation of hydrophobic PBMA chains in grafted PIPAAm enhanced the hydrophobic interaction with testosterone above the transition temperature. The surface modification of hydrophobicity-enhanced thermoresponsive polymers is a promising method for the preparation of thermoresponsive biointerfaces that can effectively modulated their biomolecule and cell adsorption with the wide dynamic range of hydrophilic/hydrophobic property change across the transition temperature.

  3. Preparation of hydrophilic vinyl chloride copolymer hollow fiber membranes with antifouling properties

    Science.gov (United States)

    Rajabzadeh, Saeid; Sano, Rie; Ishigami, Toru; Kakihana, Yuriko; Ohmukai, Yoshikage; Matsuyama, Hideto

    2015-01-01

    Hydrophilic vinyl chloride copolymer hollow fiber membranes with antifouling properties were prepared from brominated vinyl chloride-hydroxyethyl methacrylate copolymer (poly(VC-co-HEMA-Br)). The base membrane was grafted with two different zwitterionic monomers, (2-methacryloyloxyethylphosphorylcholine) (MPC) and [2-(methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) ammonium hydroxide) (MEDSAH), and poly(ethylene glycol) methyl ether methacrylate (PEGMA). The effect of the grafting on the base membrane hydrophilicity and antifouling properties was investigated. For comparison of the results, the pure water permeabilities and pore sizes at the outer surfaces of the grafted hollow fiber membranes were controlled to be similar. A poly(VC-co-HEMA-Br) hollow fiber membrane with similar pure water permeability and pore size was also prepared as a control membrane. A BSA solution was used as a model fouling solution for evaluation of the antifouling properties. Grafting with zwitterionic monomers and PEGMA improved the antifouling properties compared with the control membrane. The PEGMA grafted membrane showed the best antifouling properties among the grafted membranes

  4. Magnetic silica hybrids modified with guanidine containing co-polymers for drug delivery applications

    Energy Technology Data Exchange (ETDEWEB)

    Timin, Alexander S., E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); RASA Center in Tomsk, Tomsk Polytechnic University, 30, Lenin Avenue, 634500 Tomsk (Russian Federation); Khashirova, Svetlana Yu. [Kabardino-Balkar State University, ul. Chernyshevskogo 173, Nal' chik, 360004 Kabardino-Balkaria (Russian Federation); Rumyantsev, Evgeniy V.; Goncharenko, Alexander A. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation)

    2016-07-01

    Guanidine containing co-polymers grafted onto silica nanoparticles to form core-shell structure were prepared by sol-gel method in the presence of γ-Fe{sub 2}O{sub 3} nanoparticles. The morphological features for uncoated and coated silica particles have been characterized with scanning electron microscopy. The results show that the polymer coated silicas exhibit spherical morphology with rough polymeric surface covered by γ-Fe{sub 2}O{sub 3} nanoparticles. The grafting amount of guanidine containing co-polymers evaluated by thermogravimetric analysis was in the range from 17 to 30%. Then, the drug loading properties and cumulative release of silica hybrids modified with guanidine containing co-polymers were evaluated using molsidomine as a model drug. It was shown that after polymer grafting the loading content of molsidomine could reach up to 3.42 ± 0.21 and 2.34 ± 0.14 mg/g respectively. The maximum drug release of molsidomine is achieved at pH 1.6 (approximately 71–75% release at 37 °C), whereas at pH 7.4 drug release is lower (50.4–59.6% release at 37 °C). These results have an important implication that our magneto-controlled silica hybrids modified with guanidine containing co-polymers are promising as drug carriers with controlled behaviour under influence of magnetic field. - Highlights: • Polymer coated silica hybrids containing γ-Fe{sub 2}O{sub 3} were prepared via sol–gel method. • Polymer grafting influences pH-response and surface properties of final products. • Molsidomine as a model drug was effectively loaded into polymer coated silicas. • The drug loading depends on the nature of grafted polymer and its content.

  5. Deformation mechanism in swollen radiation-grafted polyethylene

    Science.gov (United States)

    Ungar, G.; Dlugosz, J.; Ranogajec, F.

    Stress-strain behaviour of anisotropic polyethylene (PE) film radiation-grafted with styrene was studied with the samples immersed in xylene. The glassy polystyrene (PS) phase (1) is softened by swelling. Whereas the tensile modulus of dry graft increases somewhat with increasing PS content, for the swollen graft it decreases sharply. However the yield stress and the elongation at break remain fairly large. For highly grafted films (PS/PE > 1) deformation is almost fully reversible and proceeds without necking up to draw ratios as high as 5:1. With the aid of additional X-ray diffraction and transmission electron microscopy results the deformation mechanism is interpreted in terms of the known morphology of the copolymer.

  6. Invertase immobilization onto radiation-induced graft copolymerized polyethylene pellets

    Science.gov (United States)

    de Queiroz, Alvaro Antonio Alencar; Vitolo, Michele; de Oliveira, Rômulo Cesar; Higa, Olga Zazuco

    1996-06-01

    The graft copolymer poly(ethylene-g-acrylic acid) (LDPE-g-AA) was prepared by radiation-induced graft copolymerization of acrylic acid onto low density polyethylene (LDPE) pellets, and characterized by infrared photoacoustic spectroscopy and scanning electron microscopy (SEM). The presence of the grafted poly(acrylic acid) (PAA) was established. Invertase was immobilized onto the graft polymer and the thermodynamic parameters of the soluble and immobilized enzyme were determined. The Michaelis constant, Km, and the maximum reaction velocity, Vmax, were determined for the free and the immobilized invertase. The Michaelis constant, Km was larger for the immobilized invertase than for the free enzyme, whereas Vmax was smaller for the immobilized invertase. The thermal stability of the immobilized invertase was higher than that of the free enzyme.

  7. Deformation mechanism in swollen radiation-grafted polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Ungar, G.; Ranogajec, F. (Institut Rudjer Boskovic, Zagreb (Yugoslavia)); Dlugosz, J. (Bristol Univ. (UK). H.H. Wills Physics Lab.)

    1981-01-01

    Stress-strain behaviour of anisotropic polyethylene (PE) film radiation-grafted with styrene was studied with the samples immersed in xylene. The glassy polystyrene (PS) phase is softened by swelling. Whereas the tensile modulus of dry graft increases somewhat with increasing PS content, for the swollen graft it decreases sharply. However the yield stress and the elongation at break remain fairly large. For highly grafted films (PS/PE > 1) deformation is almost fully reversible and proceeds without necking up to draw ratios as high as 5:1. With the aid of additional X-ray diffraction and transmission electron microscopy results the deformation mechanism is interpreted in terms of the known morphology of the copolymer.

  8. EPR investigation on radiation-induced graft copolymerization of styrene onto polyethylene: Energy transfer effects

    Science.gov (United States)

    Salih, M. A.; Buttafava, A.; Ravasio, U.; Mariani, M.; Faucitano, A.

    2007-08-01

    In this paper, energy transfer phenomena concerning the in-source graft copolymerization of styrene onto LDPE were investigated through the EPR analysis of the radical intermediates. The model solution experiments have shown a substantial deviation of the experimental G (radicals) values with respect to the additivity law, which reflect the negative effect of the styrene monomer concentration on the initiation rate of the graft copolymerization. The EPR measurements performed on polyethylene- co-styrene graft copolymers of various composition following low-temperature vacuum gamma irradiation have confirmed the decrease of the total radical yields with increasing the styrene concentration. The effect was partly attributed to the heterogeneity of the graft copolymer matrix and to the lack of molecular mobility in the solid state at low temperature, which prevents the attainment of the favourable geometrical configurations in intermolecular energy and charge transfer events.

  9. BIODEGRADATION BEHAVIOR OF POLY(METHYL METHACRYLATE GRAFTED SAGO STARCH BIOPOLYMER

    Directory of Open Access Journals (Sweden)

    Isam Yassin Qudsieh

    2010-09-01

    Full Text Available The graft copolymerization of poly(methyl methacrylate (PMMA onto sago starch (sago starch-g-PMMA was carried out using ceric ammonium nitrate (CAN as an initiator. PMMA was grafted onto sago starch using CAN as an initiator under nitrogen gas atmosphere. The maximum percentage of grafting (%G was determined to be 246% at the optimum conditions. The copolymers produced were characterized by Fourier Transform Infrared Spectrophotometry (FTIR, The FTIR spectra of the copolymers clearly indicated the presence of characteristic peaks of PMMA and sago starch, which suggested that PMMA had been successfully grafted on the sago starch. Biodegradability studies of sago starch-g-PMMA and sago starch were carried out by ?-amylase enzyme. Maximum biodegradation of the biopolymer was achieved after 3 days of incubation, while for the product was 7 days. The maximum production of glucose was achieved when the concentration of -amylase was 50 ppm.

  10. Cytotoxicity of copolymer PHEMA-g-LDPE obtained for ionizing radiation; Citotoxicidade de copolimero de PEBD-e-PHEMA obtido por radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Lorenzetti, Solange G.; Camillo, Maria A.P.; Higa, Olga Z. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Biologia Molecular]. E-mail: solangl@ig.com.br; Queiroz, Alvaro A.A. de [Universidade Federal de Itajuba, MG (Brazil). Dept. de Fisica e Quimica

    2005-07-01

    Polymeric biomaterials are the polymers described in the literature which are employed in medicine and biotechnology. The aim of the work was the preparation of biocompatible polymeric surface for the posterior immobilization of protein compounds using grafted copolymers obtained by ionizing radiation. The copolymers was obtained by gamma irradiation induced grafting of 2-hydroxyethyl methacrylate (HEMA) onto low density polyethylene (LDPE) in different conditions.. The grafting yield ranged from 2% to 50%. The copolymers were analysed by infrared spectroscopy (FTIR). MEV micrographs showed a smooth surface for the virgin LDPE and rough surface for the copolymers due to the grafted PHEMA. The hydrophilic property appeared with the grafting increase of PHEMA onto LDPE. The diffusion coefficient was determined. Cytotoxicity assay was performed for the evaluation of biocompatibility. The method is based on the quantitative assesment of surviving viable cells upon exposure of CHO cells to the material extract and incubation with the supravital dye MTS. The amount of MTS, taken up by the population of cells is directly proportional to the number of viable cells in culture. The grafted polymers were not cytotoxic and will be used for the chemical immobilization of the enzyme phospholipase A2, purified from the rattlesnake venom. (author)

  11. Pressure induced graft-co-polymerization of acrylonitrile onto Saccharum cilliare fibre and evaluation of some properties of grafted fibre

    Indian Academy of Sciences (India)

    A S Singha; Anjali Shama; Vijay Kumar Thakur

    2008-02-01

    In the present work, graft co-polymerization of acrylonitrile (AN) onto Saccharum cilliare fibre has been carried out in the presence of potassium persulphate and ferrous ammonium sulphate (FAS–KPS) as redox initiator. The reactions were carried out under pressure in an autoclave. Various reaction parameters such as pressure, time, pH, concentrations of initiator and monomer were optimized to get maximum graft yield (35.59%). Grafted and ungrafted Saccharum cilliare fibres were then subjected to evaluation of some of their properties like swelling behaviour in different solvents, moisture absorbance under different humidity levels, water uptake and resistance towards chemicals such as hydrochloric acid and sodium hydroxide. The characterization of the graft copolymers were carried out by FTIR spectrophotometer, X-ray diffraction (XRD) and scanning electron microscopic (SEM) studies.

  12. A NEW METHOD TO SYNTHESIZE THE CATIONIC GRAFT STARCH

    Institute of Scientific and Technical Information of China (English)

    Lin Li; Bingyue Liu; Yafeng Cao

    2004-01-01

    The cationic graft copolymer was synthesized by reversed phase emulsion copolymerization of starch with diallydimethyl ammoniumlchlorid (DADMAC)and acrylamide (AM). The copolymerization was carried out using (NH4)2S2O8-NH2CONH2 redox as initiator and selecting Span-20 as emulsifier. The effects of emulsifier content in oil phase, volume ratio of oil to water, initiator concentration and mole ratio of DADMAC to AM on the graft copolymerization were discussed. The optimum condition of synthetics was found with the orthogonal test method.

  13. Synthesis and characterization of non-toxic and thermo-sensitive poly(N-isopropylacrylamide)-grafted cashew gum nanoparticles as a potential epirubicin delivery matrix.

    Science.gov (United States)

    Abreu, Clara M W S; Paula, Haroldo C B; Seabra, Vitor; Feitosa, Judith P A; Sarmento, Bruno; de Paula, Regina C M

    2016-12-10

    Cashew gum (CG) was grafted with N-isopropylacrylamide (NIPA) by radical polymerization to originate a stimuli-sensitive copolymer for drug delivery purposes. NMR and IR spectroscopy confirmed the insertion of NIPA onto the cashew gum chains. The graft copolymer (CG:NIPA) demonstrated thermal responsiveness. The critical aggregation concentration of the copolymers at 25°C was higher than at 50°C. At temperatures lower than the LCST, the nanoparticle size ranged from 12 to 21nm, depending on the CG:NIPA ratio, but above the LCST the particles aggregated, increasing the particle size. Regarding the potential for future oral application, the nanoparticles showed no cytotoxic activity against the Caco-2 and HT29-MTX intestine cell lines. Epirubicin was encapsulated into nanoparticles of CG-NIPA (1:1), resulting in a 64% association efficiency and 22% loading capacity. Thus, the CG:NIPA graft copolymer demonstrates good potential for used in controlled drug delivery systems.

  14. A NEW METHOD TO SYNTHESIZE THE CATIONIC GRAFT STARCH

    Institute of Scientific and Technical Information of China (English)

    LinLi; BingyueLiu; YafengCao

    2004-01-01

    The cationic graft copolymer was synthesized byreversed phase emulsion copolymerization of starchwith diallydimethyl ammoniumlchlorid (DADMAC)and acrylamide (AM). The copolymerization wascarried out using (NH4)2S2Os-NH2CONH2 redox asinitiator and selecting Span-20 as emulsifier. Theeffects of emulsifier content in oil phase, volumeratio of oil to water, initiator concentration and moleratio of DADMAC to AM on the graftcopolymerization were discussed. The optimumcondition of synthetics was found with theorthogonal test method.

  15. Development of novel melt-compounded starch-grafted polypropylene/polypropylene-grafted maleic anhydride/organoclay ternary hybrids

    Directory of Open Access Journals (Sweden)

    E. Lafranche

    2012-11-01

    Full Text Available Starch-grafted polypropylene (PP-g-starch/organoclay nanocomposites were melt-compounded using a corotating twin-screw extruder. Homopolymer or copolymer-based polypropylene-grafted maleic anhydrides (PP-g-MA with different molecular weights and different maleic anhydride (MA grafting levels were added at different weight contents as compatibilizer. Two organo-modified montmorillonites were used, the first one containing polar functional groups (Cloisite®30B having affinity to the starch phase, and the other one containing non polar-groups (Cloisite®20A having affinity to the polypropylene phase of the polymer matrix. Whatever the MA grafting level and the molecular weight and content of PP-g-MA, no significant immiscibility of PP-g-starch/PP-g-MA blends is evidenced. Regarding clay dispersion, adding a low content of ethylene-propylene copolymer-based PP-g-MA compatibilizer having a high MA-grafting level, and a polar organoclay (Cloisite®30B is the most desirable formulation to optimize clay intercalation and exfoliation in PP-g-starch. Nevertheless, regarding the reinforcement effect, whatever the PP-g-MA compatibilizer, the addition of non polar organoclay (Cloisite®20A is preferably recommended to reach higher tensile properties (modulus, yield stress, strength without significant loss of ductility.

  16. Radiation graft copolymerization of butyl methacrylate and acrylamide onto low density polyethylene and polypropylene films, and its application in wastewater treatment

    Science.gov (United States)

    Abdel Ghaffar, A. M.; El-Arnaouty, M. B.; Aboulfotouh, Maysara E.; Taher, N. H.; Taha, Ahmed A.

    2014-09-01

    Butyl methacrylate and acrylamide (BMA/AAm) comonomers were grafted onto low-density polyethylene (LDPE) and polypropylene (PP) films using the mutual gamma radiation grafting technique. The influences of grafting conditions such as solvent, monomer concentration, monomer composition, and irradiation dose on the grafting yield were determined. It was found that using dimethyl formamide as a solvent enhanced the copolymerization process. The grafting yield increases as the comonomer concentration increases up to 60%. Also it was found that the degree of grafting of BMA/AAm onto both LDPE and PP films increases as the AAm content increases till an optimum value at 50:50 wt%. The grafting yield of the comonomers was found to increase with increase in the radiation dose. It was observed that the degree of grafting of polyethylene films is higher than that of polypropylene (PP) films at the same conditions. Some selected properties of the graft copolymers, such as water uptake and thermal properties, were determined using thermogravimetric analysis. The morphology and structure of the grafted films were investigated using scanning electron microscopy, infra-red, and X-ray diffraction. Improvement in such properties of the prepared copolymers was observed which offers possible uses in some practical applications such as the removal of some heavy metals from wastewater. It was found that the maximum metal uptake by the copolymer followed the order Cu2+>Co2+>Ni2+ ions.

  17. High durability and low toxicity antimicrobial coatings fabricated by quaternary ammonium silane copolymers.

    Science.gov (United States)

    Li, Hairui; Bao, Hongqian; Bok, Ke Xin; Lee, Chi-Ying; Li, Bo; Zin, Melvin T; Kang, Lifeng

    2016-02-01

    Adhesion and subsequent growth of microorganisms on material surfaces are a major concern in many biomedical applications. Currently, various polymers are immobilized on material surfaces to prevent microbial colonization. However, there are several challenges with regard to the coating materials, including their inability to kill microorganisms, complexity of surface grafting, limited durability and toxicity towards humans. To address these challenges, we synthesize a novel quaternary ammonium silane (QAS) antimicrobial copolymer to confer the antimicrobial effect via a simple thermal-curing coating process. The QAS copolymers were less toxic to 3 human cell lines than a commercial antimicrobial QAS monomeric agent, namely, dimethyloctadecyl[3-(trimethoxysilyl) propyl]ammonium chloride (DTPAC). Moreover, the QAS coatings demonstrated superior antimicrobial efficacy and durability than those of the DTPAC coatings. In conclusion, the novel QAS copolymers are useful to prevent substrates from microbial infections, yet with low toxicity to humans and long durability. In addition, the synthetic process is potentially scalable for industrial applications.

  18. Biomimetic potential of some methacrylate-based copolymers: a comparative study.

    Science.gov (United States)

    Zecheru, Teodora; Filmon, Robert; Rusen, Edina; Mărculescu, Bogdan; Zerroukhi, Amar; Cincu, Corneliu; Chappard, Daniel

    2009-11-01

    Preparation of new biocompatible materials for bone recovery has consistently gained interest in the last few decades. Special attention was given to polymers that contain negatively charged groups, such as phosphate, carboxyl, and sulfonic groups toward calcification. This present paper work demonstrates that other functional groups present also potential application in bone pathology. New copolymers of 2-hydroxyethyl methacrylate with diallyldimethylammonium chloride (DADMAC), glycidyl methacrylate (GlyMA), methacrylic acid (MAA), 2-methacryloyloxymethyl acetoacetate (MOEAA), 2-methacryloyloxyethyltriethylammonium chloride (MOETAC), and tetrahydrofurfuryl methacrylate (THFMA) were obtained. The copolymers were characterized by FTIR, swelling potential, and they were submitted to in vitro tests for calcification and cytotoxicity evaluation. GlyMA and MOETAC-containing copolymers show promising results for further in vivo mineralization tests, as a potential alternative to the classical bone grafts, in bone tissue engineering.

  19. Grafting of vinyl acetate-ethylacrylate binary monomer mixture onto guar gum.

    Science.gov (United States)

    Singh, Vandana; Singh, Angela; Joshi, Sneha; Malviya, Tulika

    2016-03-01

    Present article reports on guar gum (GG) functionalization through graftcopolymerization of vinylacetate (VAC) and ethylacrylate (EA) from their binary mixtures. The potassium persulfate/ascorbic acid (KPS/AA) redox initiator system has been used for the binary grafting under the previously optimized conditions for VAC grafting at guar gum. The concentration of ascorbic acid (AA), persulfate (KPS), and grafting temperature were varied to optimize the binary grafting. A preliminary investigation revealed that the copolymer has excellent ability to capture Hg(II) from aqueous solution. It was observed that the optimum % grafting sample (CP3) was best at Hg(II) adsorption. CP3 and mercury loaded CP3 (CP3-Hg) have been extensively characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Thermo gravimetric analysis (TGA) and a plausible mechanism for the grafting has been proposed.

  20. Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

    Science.gov (United States)

    Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

    2015-07-01

    Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

  1. THE EFFECTS OF MAGNETIC FIELD ON GRAFT COPOLYMERIZATION OF METHYL METHACRYLATE ONTO POLYVINYL ALCOHOL IN THE PRESENCE OF BENZOPHENONE DURING UV IRRADIATION

    Institute of Scientific and Technical Information of China (English)

    HUANG Junlian; WU Qingfong

    1990-01-01

    The effects of magnetic field on the graft ratio and stereoregularity of grafts of PVA-g-MMA in the presence of benzophenone during UV irradiation are discussed. By means of IR, it was found that the graft ratio was increased with the increment of magnetic field strength. Furthermore, application of relative weak magnetic field of 0.4 Tesla had been shown to substantially enhance the stereo-regularity of graft copolymer. The maximum stereo-regularity appeared when the graft ratio approached to 85% with the magnetic field of 1.2 Tesla (T). The resistance to moisture and heat resistance of the grafted copolymer in the presence of magnetic field were also improved.

  2. Magnetic core–bilayer shell complex of magnetite nanoparticle stabilized with mPEG–polyester amphiphilic block copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Mekkapat, Supachai; Thong-On, Bandit; Rutnakornpituk, Boonjira; Wichai, Uthai; Rutnakornpituk, Metha, E-mail: methar@nu.ac.th [Naresuan University, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science (Thailand)

    2013-11-15

    In this article, we report the synthesis of magnetite nanoparticles (Fe{sub 3}O{sub 4}) coated with methoxy poly(ethylene glycol) (mPEG)–polyester amphiphilic block copolymers. The coating polymer layer contains a hydrophobic inner layer of polyester and a hydrophilic corona of mPEG. The copolymers were first prepared via a direct condensation between diacid, diol compounds and mPEG oligomer to obtain a hydrophobic polyester block and hydrophilic mPEG block and then “grafted onto” a magnetite nanoparticle surface. The copolymer composition was varied by changing the structure of the diacid, diol, and the molecular weight ( M-bar {sub n} ) of the mPEG such that particles with good dispersibility and stability in water were obtained. It was found that the copolymer prepared from 1,6-hexanediol can effectively stabilize the particles in water regardless of the types of diacid and M-bar {sub n} of mPEG used. The particle size was approximately 10 nm in diameter, and the particle dispersibility in water was quite dependent on the type and concentration of the copolymer used. Thermogravimetric analysis revealed the presence of less than 37 % Fe{sub 3}O{sub 4} and about 48–53 % of the copolymer in the complexes. The percent entrapment efficiency and loading efficiency of indomethacin model drug in the copolymer-coated magnetite nanoparticles were 19 and 77 %, respectively.

  3. Bone grafting: An overview

    Directory of Open Access Journals (Sweden)

    D. O. Joshi

    2010-08-01

    Full Text Available Bone grafting is the process by which bone is transferred from a source (donor to site (recipient. Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of

  4. Biodegradable p(DLLA-epsilon-CL) nerve guides versus autologous nerve grafts : Electromyographic and video analysis

    NARCIS (Netherlands)

    Meek, MF; Nicolai, JPA; Gramsbergen, A; van der Werf, J.F.A.

    2001-01-01

    The aim of this study was to evaluate the functional effects of bridging a gap in the sciatic nerve of the rat with either a biodegradable copolymer of (DL)-lactide and epsilon -caprolactone [p(DLLA-epsilon -CL)] nerve guide or an autologous nerve graft. Electromyograms (EMGs) of the gastrocnemius (

  5. Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid

    NARCIS (Netherlands)

    Witono, J. R.; Noordergraaf, Inge; Heeres, H. J.; Janssen, L. P. B. M.; Heeres, Hero

    2014-01-01

    An important application of starch grafted with copolymers from unsaturated organic acids is the use as water absorbent. Although much research has been published in recent years, the kinetics of water absorption and the swelling behavior of starch based superabsorbents are relatively unexplored. Al

  6. Sulfonated Poly(styrene) Chains Grafted on Magnetic Nanoparticles

    Science.gov (United States)

    Jiao, Yang; Yevelev, Anton; Parra, Javier; Akcora, Pinar; Stevens Institute of Technology Team

    2014-03-01

    Iron oxide nanoparticles functionalized with poly(styrene) (PS) chains at various grafting densities and loadings present stable and ordered nanostructures for tuning the mechanical and conductive properties in polymer composites. Strings, spherical and anisotropic clusters and well-dispersed particles are achieved with PS-grafted Fe3O4 nanoparticles in PS matrices upon varying the system parameters. In this work, we report the effect of sulfonic group locations on the aggregation state of polymer-grafted nanoparticles. Structures formed by the random and diblock copolymers of PS-poly(styrene sulfonate) (PSS) grafted particles will be discussed with small-angle x-ray scattering (SAXS) measurements in solution and melts. The conformational changes in PS-grafted chains and ion-containing grafts will be also presented in small-angle neutron-scattering (SANS) results to understand the role of polymer on the assembly of particles at the low grafting density. We acknowledge support by NSF-CAREER-DMR (#1048865).

  7. Enhanced infarct myocardium repair mediated by thermosensitive copolymer hydrogel-based stem cell transplantation

    OpenAIRE

    Xia, Yu; Zhu, Kai; Lai, Hao; Lang, Meidong; Xiao, Yan; Lian, Sheng; Guo, Changfa; Wang, Chunsheng

    2015-01-01

    Mesenchymal stem cell (MSC) transplantation by intramyocardial injection has been proposed as a promising therapy strategy for cardiac repair after myocardium infarction. However, low retention and survival of grafted MSCs hinder its further application. In this study, copolymer with N-isopropylacrylamide/acrylic acid/2-hydroxylethyl methacrylate-poly(ɛ-caprolactone) ratio of 88:9.6:2.4 was bioconjugated with type I collagen to construct a novel injectable thermosensitive hydrogel. The inject...

  8. Synthesis and characterization of biodegradable amphiphilic PEG-grafted poly(DTC-co-CL)

    Institute of Scientific and Technical Information of China (English)

    Qiu Jin Zhang; Wei Pu Zhu; Zhi Quan Shen

    2010-01-01

    A novel biodegradable copolymer,poly(5,5-dibromomethyltrimethylene carbonate-co-ε-caprolactone)(poly(DBTC-co-CL))with pendant bromine groups,was synthesized via ring-opening polymerization(ROP)of ε-caprolactone(CL)and 5,5-dibromomethyltrimethylene carbonate(DBTC)using stannous octoate(Sn(Oct)2)as catalyst.Then the pendant bromine groups were completely converted into azide form,which permitted"click"reaction with alkyne-terminated polyethylene(A-PEG)by Huisgen 1,3-dipolar cycloadditions preparing biodegradable amphiphilic poly(DTC-co-CL)-g-PEG graft copolymer.The graft copolymer was characterized by nuclear magnetic resonance(NMR)and size-exclusion chromatography(SEC).

  9. Copolymères greffés porteurs d'OLA optiquement purs : De la synthèse aux propriétés de stéréocomplexation pour générer des films multicouches

    OpenAIRE

    Bahloul, Mohamed

    2015-01-01

    This work is devoted to the exploitation of the mixture of stéréocomplexation oligolactate of opposite chirality (OLLA and ODLA) to construct multilayer films through deposition technique layer by layer (LbL). In the literature, this interaction based on the phenomenon of co-crystallization, was used to prepare supramolecular assemblies (micelles, gels) in a solvent medium, in particular through the synthesis of graft or block copolymers containing segments OLA. In this context, graft copolym...

  10. Study of polystyrene-poly(ethylene oxide) diblock copolymer monolayers as barriers to protein adsorption

    Science.gov (United States)

    Jogikalmath, Gangadhar

    Protein adsorption resistant surfaces find use in many biomedical applications, such as catheters, dialysis devices and biosensors that involve blood contacting surfaces. To ensure long-term functioning of a device in an environment containing protein, there is a need to produce homogeneous surfaces that are resistant to protein adsorption. A polymer brush covered surface, produced by either physical adsorption or chemical grafting of hydrophilic polymers to surfaces, is one of the approaches used in creating such surfaces. High grafting densities needed to make an effective barrier are usually not realized in chemical grafting/adsorption from solution, due to self-exclusion of surface grafted molecules. In this dissertation polymer brush surfaces formed by chemically grafted PEO molecules and transferred monolayers of PS-b-PEO diblock copolymers are investigated using atomic force microscopy (AFM), surface plasmon resonance (SPR) and surface pressure measurement techniques. An AFM adhesion mapping technique was used to evaluate the surface heterogeneity of chemically modified PEO and transferred diblock copolymer monolayer surfaces. The behavior of PS-b-PEO molecules at the air-water interface was studied using Langmuir trough. The stability of transferred diblock copolymer monolayers was investigated using AFM. Using SPR, protein adsorption to the diblock copolymer layers was investigated as a function of protein size (using HSA and ferritin) as a function of grafting density of PEO in the monolayer. It was seen that a lower density of the PS-b-PEO monolayer was sufficient to prevent ferritin adsorption (larger protein) while a higher density brush layer was required to achieve complete prevention of HSA adsorption to the surface. The effect of mobility of the polymer brush layer on protein adsorption prevention was analyzed using SPR and surface pressure measurements. It was seen that the copolymer monolayer (at the air-buffer interface) rearranged itself to

  11. BARRIER PROPERTIES OF VINYLIDENE CHLORIDE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    LI Yuesheng; WENG Zhixue; HUANG Zhiming; PAN Zuren

    1996-01-01

    The permeability coefficients of a series of copolymers of vinylidene chloride (VDC)with methyl acrylate (MA), butyl acrylate (BA) or vinyl chloride (VC) (as comonomer)to oxygen and carbon dioxide have been measured at 1.0 MPa and 30℃, while those to water vapor have been measured at 30℃ and 100% relative humidity. All the copolymers are semicrystalline. VDC/MA copolymers have lower melting temperature compared with VDC/BA copolymers, while that melting temperature of VDC/VC copolymer is higher than that of VDC/acrylate copolymers with the same VDC content. The barrier property of the copolymers is predominantly controlled by crystallite, free volume fraction, and cohesive energy. The permeability coefficients of VDC/MA copolymers to oxygen, carbon dioxide, and water vapor were successfully correlated with the ratio of free volume to cohesive energy.

  12. GRAFT POLYMERIZATION OF ACRYLAMIDE ONTO HOMOPOLYMER OF 5-METHYL-5-HEXEN-2, 4-DIONE INITIATED BY CERIC ION

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jingbo; ZHAO Tong; QIU Kunyuan

    1997-01-01

    The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA),a vinyl monomer having β-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamide initiated by ceric ion onto the homopolymer film was investigated and the mechanism of the grafting reaction was proposed on the basis of ESR study. The grafted copolymer was characterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.

  13. Micellization and Dynamics of a Block Copolymer

    DEFF Research Database (Denmark)

    Hvidt, Søren

    2006-01-01

    Triblock copolymers of the type EPE, where E and P denote ethylene oxide and propylene oxide blocks, respectively, are industrially important copolymers often called Pluronics or Poloxamers. EPE copolymers form micelles with a core of P blocks and different micellar shapes depending on block leng...

  14. Micellization and Dynamics of a Block Copolymer

    DEFF Research Database (Denmark)

    Hvidt, Søren

    2006-01-01

    Triblock copolymers of the type EPE, where E and P denote ethylene oxide and propylene oxide blocks, respectively, are industrially important copolymers often called Pluronics or Poloxamers. EPE copolymers form micelles with a core of P blocks and different micellar shapes depending on block length...

  15. Graft Copolymerization of Styrene from Poly(vinyl alcohol via RAFT Process

    Directory of Open Access Journals (Sweden)

    Gholam Ali Koohmareh

    2011-01-01

    Full Text Available Polystyrene, PS, was grafted from poly(vinyl alcohol, PVA, backbone by reversible addition-fragmentation chain transfer (RAFT polymerization. The hydroxyl groups of the PVA were converted into aromatic dithioester RAFT agent and polymerization began in the presence of this agent. The structure of compounds was confirmed by FT-IR and 1HNMR spectroscopy. The graft copolymer was characterized by thermogravimetric analysis (TGA, X-ray diffraction (XRD, and scanning electron microscopy (SEM. Grafted polystyrene chains were cleaved from the PVA backbone by acidic hydrolysis of the PVA-g-PS, and its polydispersity index, PDI, was determined by gel permeation chromatography (GPC showing narrow molecular weight distribution.

  16. GRAFT COPOLYMERIZATION OF ACRYLAMIDE ONTO POLY(N-PARA-TOLYLACRYLAMIDE) FILMS INITIATED BY CERIC ION

    Institute of Scientific and Technical Information of China (English)

    QIU Kunyuan; SONG Ye

    1988-01-01

    Functional monomers having phenylcarbarnoyl and p-tolylcarbamoyl were synthesized. Binary initiation system consisted of Ce4+ andthese functional monomers could initiate acrylamide polymerization.It was found that acrylamide could graft copolymerize onto macromolecules having these functional monomers units. The formation of graft copolymer has been verified by its percentage of water absorption,contact angle with water, XPS and SEM photographs. The reaction mechanism was proposed and the main reactive site of graft copolymerization initiated by Ce4+ would take place predominantly at the functional pendant group.

  17. Preparation and characterizations of naproxen-loaded magnetic nanoparticles coated with PLA- g-chitosan copolymer

    Science.gov (United States)

    Thammawong, C.; Sreearunothai, P.; Petchsuk, A.; Tangboriboonrat, P.; Pimpha, N.; Opaprakasit, P.

    2012-08-01

    Naproxen (NPX) drug-loaded magnetic nanoparticles (MNPs) have been prepared in a one-step process utilizing a biocompatible polylactide-grafted-chitosan copolymer. The copolymer serves both as a NPX drug carrier as well as a polymeric surfactant for the synthesis of MNPs without the use of any additional surfactant. Highly stable MNPs with high magnetization in the form of maghemite (γ-Fe2O3) are prepared in aqueous media. Effects of preparation conditions on structures and properties of the copolymer-coated and drug-loaded MNPs are investigated by employing particle size and zeta potential measurements, transmission electron microscopy, vibrating sample magnetometer, X-ray diffraction, Fourier-transform infrared, nuclear magnetic resonance, and confocal Raman spectroscopy. The results show that average particle size (150-300 nm), coating efficiency, and coating structures of the resulting MNPs materials are strongly dependent on MNP/copolymer and MNP/NPX ratios in feed. It is also observed that NPX acts as co-surfactant in the drug-loading process, resulting in different encapsulating structures with the variation in the MNP/copolymer and MNP/NPX ratios. Properties of the MNPs materials can be further optimized for use in specific biomedical applications.

  18. SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Jian-hua Li; You-yi Xu; Jian-hua Wang; Chun-hui Du

    2009-01-01

    The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4-hydroxyphenyl) maleimide) (SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate (PEGMA) side groups was achieved by atom transfer radical polymerization (ATRP). The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC). From thermogravimetric analysis (TGA), the decomposition temperature of SHMI-g-PEGMA is lower than that of SHMI, and the graft ratio of PEGMA in the SHMI is 18.6%. The experimental results of solubilities showed that SHMI, SHMI-Br and SHMI-g-PEGMA had excellent solubility in polar solvents, such as DMF, DMSO and NMP. SHMI-g-PEGMA had higher solubilities in H_2O and methanol, while lower solubility in CHCl_3 than SHMI and SHMI-Br. PVDF blend membranes were prepared via the standard immersion precipitation phase inversion process, using amphiphilic SHMI-g-PEGMA copolymer as additives. The morphology and hydrophilicity of the blend membrane surfaces were characterized by SEM and water contact angle. It is demonstrated that the blend membranes display enhanced hydrophilicity compared to unmodified PVDF membranes. Finally, the permeation and anti-fouling properties were investigated. The result shows that amphiphilic SHMI-g-PEGMA copolymer increases the permeatability and anti-fouling property of PVDF membranes greatly.

  19. Preparation and characterizations of naproxen-loaded magnetic nanoparticles coated with PLA-g-chitosan copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Thammawong, C.; Sreearunothai, P. [Thammasat University, School of Bio-Chemical Engineering and Technology, Sirindhorn International Institute of Technology (SIIT) (Thailand); Petchsuk, A. [National Metal and Materials Technology Center (MTEC) (Thailand); Tangboriboonrat, P. [Mahidol University, Department of Chemistry, Faculty of Science (Thailand); Pimpha, N. [National Nanotechnology Center (NANOTEC) (Thailand); Opaprakasit, P., E-mail: pakorn@siit.tu.ac.th [Thammasat University, School of Bio-Chemical Engineering and Technology, Sirindhorn International Institute of Technology (SIIT) (Thailand)

    2012-08-15

    Naproxen (NPX) drug-loaded magnetic nanoparticles (MNPs) have been prepared in a one-step process utilizing a biocompatible polylactide-grafted-chitosan copolymer. The copolymer serves both as a NPX drug carrier as well as a polymeric surfactant for the synthesis of MNPs without the use of any additional surfactant. Highly stable MNPs with high magnetization in the form of maghemite ({gamma}-Fe{sub 2}O{sub 3}) are prepared in aqueous media. Effects of preparation conditions on structures and properties of the copolymer-coated and drug-loaded MNPs are investigated by employing particle size and zeta potential measurements, transmission electron microscopy, vibrating sample magnetometer, X-ray diffraction, Fourier-transform infrared, nuclear magnetic resonance, and confocal Raman spectroscopy. The results show that average particle size (150-300 nm), coating efficiency, and coating structures of the resulting MNPs materials are strongly dependent on MNP/copolymer and MNP/NPX ratios in feed. It is also observed that NPX acts as co-surfactant in the drug-loading process, resulting in different encapsulating structures with the variation in the MNP/copolymer and MNP/NPX ratios. Properties of the MNPs materials can be further optimized for use in specific biomedical applications.

  20. Copolymers For Capillary Gel Electrophoresis

    Science.gov (United States)

    Liu, Changsheng; Li, Qingbo

    2005-08-09

    This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

  1. Polyethylene-Based Tadpole Copolymers

    KAUST Repository

    Alkayal, Nazeeha

    2017-02-15

    Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser coupling reaction. The -OH groups of the 3-miktoarm star copolymers (PE-OH)-b-PS, synthesized by polyhomologation and ATRP, are transformed to alkyne groups by esterification with propiolic acid, followed by Glaser cyclization and removal of the unreacted linear with Merrifield\\'s resin-azide. The characterization results of intermediates and final products by high-temperature size exclusion chromatography, H NMR spectroscopy, and differential scanning calorimetry confirm the tadpole topology.

  2. Homogeneous Modification of Sugarcane Bagasse by Graft Copolymerization in Ionic Liquid for Oil Absorption Application

    Directory of Open Access Journals (Sweden)

    Ming-Jie Chen

    2016-01-01

    Full Text Available Sugarcane bagasse, lignocellulosic residue from the sugar industry, is an abundant and renewable bioresource on the earth. The application of ionic liquids in sugarcane bagasse biorefinery is gaining increasing interest. The homogeneous modification of sugarcane bagasse by free radical initiated graft copolymerization of acrylate monomers using 1-allyl-3-methylimidazolium chloride as solvent was performed. A variety of sugarcane bagasse graft copolymers with different weight percent gain were prepared via adjusting the monomer dosage. FT-IR studies confirmed the success in attaching the poly(acrylate side chains onto sugarcane bagasse. Oil absorbency studies suggested that the sugarcane bagasse graft copolymers were potential biobased materials for effective treatment of ester-based oils. SEM studies showed that the sugarcane bagasse graft copolymers displayed a dense morphology structure. Thermogravimetric analysis demonstrated that the thermal stability of sugarcane bagasse decreased after the homogeneous modification by the graft copolymerization. The present study provides an alternative strategy to convert sugarcane bagasse into a value-added functional biobased material.

  3. Bone grafts in dentistry

    Directory of Open Access Journals (Sweden)

    Prasanna Kumar

    2013-01-01

    Full Text Available Bone grafts are used as a filler and scaffold to facilitate bone formation and promote wound healing. These grafts are bioresorbable and have no antigen-antibody reaction. These bone grafts act as a mineral reservoir which induces new bone formation.

  4. PREPARATION OF NOVEL POLYETHYLENE-graft- POLY(4-VINYLPYRIDINE)-SUPPORTED METALLOCENE CATALYSTS FOR ETHYLENE POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Ning Zhu; Yong Chen; Zi-long Li; Yuan-xia Liu; Yu-cai Ke; Wen-Hua Sun

    2003-01-01

    Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by the irradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for Cp2ZrCl2 catalyst. Results of X-ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, ultraviolet spectroscopy and scanning electron microscope measurements show that the catalytic sites have been linked through MAO on the PE-graft-4-vinylpyridine (PEVP). The percentages of grafting 4-vinylpyridine and supported Cp2ZrCl2 depend on the size of polyethylene powder. The smaller the polyethylene powder, the more percent of 4-vinylpyridine groups and Cp2ZrCl2 exist on the polyethylene chains, and the PEVP-supported catalyst has a relatively high activity for ethylene polymerization.

  5. MODIFICATION OF SILK FIBER via EMULSION GRAFT COPOLYMERIZATION WITH FLUOROACRYLATE

    Institute of Scientific and Technical Information of China (English)

    Zhan-xiong Li; Fei-fei Jin; Ben-wen Cao; Xiao-fei Wang

    2008-01-01

    2,2,3,3,4,4,5,5-Octafluoropentyl acrylate was grafted onto silk fiber in a two-step heterogeneous system through the vinyl bonds of acryloyloxyethyl isocyanate modified on the silk. The grafted copolymer was analyzed by FTIR and WAXD, and the results revealed that the fluoroacrylate was successfully grafted onto silk fiber and the crystalline structure of silk fibroin with β-sheet structure was not changed after graft copolymerization. The FT-IR corrected method was used to simulate the grafting yield onto silk compared with the weight increasing method. The results obtained from these two methods were roughly consistent. The influence of the initiator concentration, monomer concentration, react time and temperature on the graft yield was also investigated. The experimental data of thermogravimetry (TG) and differential thermal analysis (DTA) showed that the thermal stability of the modified silk fibers was improved due to the introduction of fluoroacrylate. In comparison with the untreated silk fibers, the water repellence of the modified silk fibers was also improved.

  6. Olecranon bone graft: revisited.

    Science.gov (United States)

    Mersa, Berkan; Ozcelik, Ismail Bulent; Kabakas, Fatih; Sacak, Bulent; Aydin, Atakan

    2010-09-01

    Autogenous bone grafts are frequently in use in the field of reconstructive upper extremity surgery. Cancellous bone grafts are applied to traumatic osseous defects, nonunions, defects after the resection of benign bone tumors, arthrodesis, and osteotomy procedures. Cancellous bone grafts do not only have benefits such as rapid revascularization, but they also have mechanical advantages. Despite the proximity to the primary surgical field, cancellous olecranon grafts have not gained the popularity they deserve in the field of reconstructive hand surgery. In this study, the properties, advantages, and technical details of harvesting cancellous olecranon grafts are discussed.

  7. Liquid ethylene-propylene copolymers

    Science.gov (United States)

    Rhein, R. A.; Ingham, J. D.; Humphrey, M. F.

    1975-01-01

    Oligomers are prepared by heating solid ethylene-propylene rubber in container that retains solid and permits liquid product to flow out as it is formed. Molecular weight and viscosity of liquids can be predetermined by process temperature. Copolymers have low viscosity for given molecular weight.

  8. Control of Grafting Density and Distribution in Graft Polymers by Living Ring-Opening Metathesis Copolymerization.

    Science.gov (United States)

    Lin, Tzu-Pin; Chang, Alice B; Chen, Hsiang-Yun; Liberman-Martin, Allegra L; Bates, Christopher M; Voegtle, Matthew J; Bauer, Christina A; Grubbs, Robert H

    2017-03-15

    Control over polymer sequence and architecture is crucial to both understanding structure-property relationships and designing functional materials. In pursuit of these goals, we developed a new synthetic approach that enables facile manipulation of the density and distribution of grafts in polymers via living ring-opening metathesis polymerization (ROMP). Discrete endo,exo-norbornenyl dialkylesters (dimethyl DME, diethyl DEE, di-n-butyl DBE) were strategically designed to copolymerize with a norbornene-functionalized polystyrene (PS), polylactide (PLA), or polydimethylsiloxane (PDMS) macromonomer mediated by the third-generation metathesis catalyst (G3). The small-molecule diesters act as diluents that increase the average distance between grafted side chains, generating polymers with variable grafting density. The grafting density (number of side chains/number of norbornene backbone repeats) could be straightforwardly controlled by the macromonomer/diluent feed ratio. To gain insight into the copolymer sequence and architecture, self-propagation and cross-propagation rate constants were determined according to a terminal copolymerization model. These kinetic analyses suggest that copolymerizing a macromonomer/diluent pair with evenly matched self-propagation rate constants favors randomly distributed side chains. As the disparity between macromonomer and diluent homopolymerization rates increases, the reactivity ratios depart from unity, leading to an increase in gradient tendency. To demonstrate the effectiveness of our method, an array of monodisperse polymers (PLA(x)-ran-DME(1-x))n bearing variable grafting densities (x = 1.0, 0.75, 0.5, 0.25) and total backbone degrees of polymerization (n = 167, 133, 100, 67, 33) were synthesized. The approach disclosed in this work therefore constitutes a powerful strategy for the synthesis of polymers spanning the linear-to-bottlebrush regimes with controlled grafting density and side chain distribution, molecular

  9. Neutral wetting brush layers for block copolymer thin films using homopolymer blends processed at high temperatures.

    Science.gov (United States)

    Ceresoli, M; Palermo, M; Ferrarese Lupi, F; Seguini, G; Perego, M; Zuccheri, G; Phadatare, S D; Antonioli, D; Gianotti, V; Sparnacci, K; Laus, M

    2015-10-16

    Binary homopolymer blends of two hydroxyl-terminated polystyrene (PS-OH) and polymethylmethacrylate (PMMA-OH) homopolymers (Mn ∼ 16000 g mol(-1)) were grafted on SiO2 substrates by high-temperature (T > 150 °C), short-time (t layer was tested to screen preferential interactions of the SiO2 substrate with the different symmetric and asymmetric PS-b-PMMA block copolymers deposited on top of the grafted molecules. By properly adjusting the blend composition and the processing parameters, an efficient surface neutralization path was identified, enabling the formation, in the block copolymer film, of homogeneous textures of lamellae or cylinders perpendicularly oriented with respect to the substrate. A critical interplay between the phase segregation of the homopolymer blends and their grafting process on the SiO2 was observed. In fact, the polar SiO2 is preferential for the PMMA-rich phase that forms a homogeneous layer on the substrate, while the PS-rich phase is located at the polymer-air interface. During the thermal treatment, phase segregation and grafting proceed simultaneously. Complete wetting of the PS rich phase on the PMMA rich phase leads to the formation of a PS/PMMA bilayer. In this case, the progressive diffusion of PS chains toward the polymer-SiO2 interface during the thermal treatment allows tuning of the brush layer composition.

  10. Radiation-induced graft polymerization of chitosan onto poly(3-hydroxybutyrate).

    Science.gov (United States)

    Torres, Maykel González; Muñoz, Susana Vargas; Rosales, Silvia G Solís; Carreón-Castro, Ma del Pilar; Muñoz, Rodrigo Alonso Esparza; González, Roberto Olayo; González, Miriam Rocío Estévez; Talavera, Rogelio Rodríguez

    2015-11-20

    Chitosan is among the most studied biopolymers and offers important advantages, such as biodegradability, biocompatibility and nontoxicity. In this study, this polysaccharide was grafted onto poly(3-hydroxybutyrate) using the simultaneous gamma-irradiation-initiated polymerization method. The polyester was immersed in diverse solvents, which allowed the preparation of graft copolymers with different yields and crystallinities. A successful synthesis and the estimation of the degree of crystallinity were verified by spectroscopic and calorimetric techniques. The most suitable method was found to be the thermoanalytical approach because it displayed a linear relationship between the degree of crystallinity and the increasing degree of grafting. The results also indicated that the lowest degree of grafting was seen for acetic acid (14.27%), while the highest degree corresponded to ethyl acetate (32.11%). The mechanism of grafting was proposed on the basis of the experimental results.

  11. Preparation and Structural Characterization of Hydroxylethyl Methacrylate Grafted Natural Rubber Latex

    Directory of Open Access Journals (Sweden)

    Feiyun Wei

    2014-06-01

    Full Text Available The graft copolymer with semi-interpenetrating polymer networks (semi-IPNs from 2-hydroxyethyl methacrylate (HEMA and natural rubber (NR latex was prepared using cumene hydroperoxide and tetraethylene pentamine redox initiator system. The changes of grafting ratios and grafting efficiency with the reaction time and temperature, the concentration of crosslinking agent, initiator and monomer were investigated. The appropriate amounts of crosslinking agent (0.1phr, initiator (0.2phr and monomer (20phr and the optimum reaction conditions of 16ºC×8h were determined. The swelling temperature and times of monomers against NR latex particles were found to be significant for the grafting copolymerization and the appropriate swelling conditions were 16ºC×20h. The water contact angle measurement and platelet adhesion evaluation indicated that the hydrophilicity and blood compatibility of NR latex could be improved by grafting copolymerization with HEMA.

  12. Functionalization of magnetic nanoparticles with dendritic-linear-brush-like triblock copolymers and their drug release properties.

    Science.gov (United States)

    He, Xiaohua; Wu, Xiaomeng; Cai, Xin; Lin, Shaoliang; Xie, Meiran; Zhu, Xinyuan; Yan, Deyue

    2012-08-14

    Novel water-soluble dendritic-linear-brush-like triblock copolymer polyamidoamine-b-poly(2-(dimethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (PAMAM-b-PDMAEMA-b-PPEGMA)-grafted superparamagnetic iron oxide nanoparticles (SPIONs) were successfully prepared via a two-step copper-mediated atom transfer radical polymerization (ATRP) method. The macroinitiators were immobilized on the surface of Fe(3)O(4) nanoparticles via effective ligand exchange of oleic acid with the propargyl focal point PAMAM-typed dendron (generation 2.0, denoted as propargyl-D(2.0)) containing four carboxyl acid end groups, following a click reaction with 2'-azidoethyl-2-bromoisobutylate (AEBIB). PDMAEMA and PPEGMA were grown gradually from nanoparticle surfaces using the "grafting from" approach, which rendered the SPIONs soluble in water and reversed aggregation. To the best of our knowledge, this is the first report that describes the functionalization of magnetic nanoparticles with dendritic-linear-brush-like triblock copolymers. The modified nanoparticles were systematically studied via TEM, FT-IR, DLS, XRD, NMR, TGA, and magnetization measurements. DLS measurement confirmed that the obtained dendritic-linear-brush-like triblock copolymer-grafted SPIONs had a uniform hydrodynamic particle size of average diameter less than 30 nm. The dendritic-linear-brush-like triblock copolymer-grafted SPIONs possessed excellent biocompatibility by methyl tetrazolium (MTT) assays against NIH3T3 cells and hemolysis assays with rabbit erythrocytes. Furthermore, an anticancer drug, doxorubicin (Dox), was used as a model drug and loaded into the dendritic-linear-brush-like triblock copolymer-grafted SPIONs, and subsequently, the drug releases were performed in phosphoric acid buffer solution pH = 4.7, 7.4, or 11.0 at 37 °C. The results verify that the dendritic-linear-brush-like triblock copolymer-grafted SPIONs possess pH-responsive drug release behavior. The Dox dose

  13. Impacts of Repeat Unit Structure and Copolymer Architecture on Thermal and Solution Properties in Homopolymers, Copolymers, and Copolymer Blends

    Science.gov (United States)

    Marrou, Stephen Raye

    Gradient copolymers are a relatively new type of copolymer architecture in which the distribution of comonomers gradually varies over the length of the copolymer chain, resulting in a number of unusual properties derived from the arrangement of repeat units. For example, nanophase-segregated gradient copolymers exhibit extremely broad glass transition temperatures (Tgs) resulting from the wide range of compositions present in the nanostructure. This dissertation presents a number of studies on how repeat unit structure and copolymer architecture dictate bulk and solution properties, specifically taking inspiration from the gradient copolymer architecture and comparing the response from this compositionally heterogeneous material to other more conventional materials. The glass transition behavior of a range of common homopolymers was studied to determine the effects of subunit structure on Tg breadth, observing a significant increase in T g breadth with increasing side chain length in methacrylate-based homopolymers and random copolymers. Additionally, increasing the composition distribution of copolymers, either by blending individual random copolymers of different overall composition or synthesizing random copolymers to high conversion, resulted in significant increases to Tg breadth. Plasticization of homopolymers and random copolymers with low molecular weight additives also served to increase the Tg breadth; the most dramatic effect was observed in the selective plasticization of a styrene/4-vinylpyridine gradient copolymer with increases in T g breadth to values above 100 °C. In addition, the effects of repeat unit structure and copolymer architecture on other polymer properties besides Tg were also investigated. The intrinsic fluorescence of styrene units in styrene-containing copolymers was studied, noting the impact of repeat unit structure and copolymer architecture on the resulting fluorescence spectra in solution. The impact of repeat unit structure on

  14. Obtention and characterization of acrylic acid-i-polyethylene organometallic copolymers with Mo, Fe, Co, Zn, and Ni; Obtencion y caracterizacion de copolimeros organometalicos de acido acrilico-i-polietileno, con Mo, Fe, Co, Zn y Ni

    Energy Technology Data Exchange (ETDEWEB)

    Dorantes, G.; Urena, F.; Lopez, R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Lopez, R. [Universidad Autonoma del Estado de Mexico (Mexico)

    1997-07-01

    In this study a graft acrylic acid (AA) in low density polyethylene (PEBD) copolymers were prepared, using as reaction initiator, gamma radiation at different doses. These copolymers were coordinated with molybdenum, cobalt, iron, zinc and nickel. the obtained polymeric materials were characterized by conventional analysis techniques. It was studied the measurement parameter variation of the positron annihilation when they inter activated with this type of materials and so obtaining information about microstructure of these polymers. (Author)

  15. Synthesis, Characterization and Application of Thermoresponsive Polyhydroxyalkanoate-graft-Poly(N-isopropylacrylamide)

    DEFF Research Database (Denmark)

    Ma, Yi-Ming; Wei, Dai-Xu; Yao, Hui

    2016-01-01

    (3HDD-co-3H10U), a random copolymer of 3-hydroxydodecanoate (3HDD) and 3-hydroxy-10-undecylenate (3H10U), via a thiol–ene click reaction. Enhanced hydrophilicity and thermoresponsive property of the resulted PHA-g-PNIPAm were confirmed by water contact angle studies. The biocompatibility of PHA......A thermoresponsive graft copolymer polyhydroxyalkanoate-g-poly(N-isopropylacrylamide) or short as PHA-g-PNIPAm, was successfully synthesized via a three-step reaction. First, PNIPAm oligomer with a trithiocarbonate-based chain transfer agent (CTA), short as PNIPAm-CTA, with designed polymerization...

  16. Volatile organic compound detection using nanostructured copolymers.

    Science.gov (United States)

    Li, Bo; Sauvé, Genevieve; Iovu, Mihaela C; Jeffries-El, Malika; Zhang, Rui; Cooper, Jessica; Santhanam, Suresh; Schultz, Lawrence; Revelli, Joseph C; Kusne, Aaron G; Kowalewski, Tomasz; Snyder, Jay L; Weiss, Lee E; Fedder, Gary K; McCullough, Richard D; Lambeth, David N

    2006-08-01

    Regioregular polythiophene-based conductive copolymers with highly crystalline nanostructures are shown to hold considerable promise as the active layer in volatile organic compound (VOC) chemresistor sensors. While the regioregular polythiophene polymer chain provides a charge conduction path, its chemical sensing selectivity and sensitivity can be altered either by incorporating a second polymer to form a block copolymer or by making a random copolymer of polythiophene with different alkyl side chains. The copolymers were exposed to a variety of VOC vapors, and the electrical conductivity of these copolymers increased or decreased depending upon the polymer composition and the specific analytes. Measurements were made at room temperature, and the responses were found to be fast and appeared to be completely reversible. Using various copolymers of polythiophene in a sensor array can provide much better discrimination to various analytes than existing solid state sensors. Our data strongly indicate that several sensing mechanisms are at play simultaneously, and we briefly discuss some of them.

  17. Bioinspired catecholic copolymers for antifouling surface coatings.

    Science.gov (United States)

    Cho, Joon Hee; Shanmuganathan, Kadhiravan; Ellison, Christopher J

    2013-05-01

    We report here a synthetic approach to prepare poly(methyl methacrylate)-polydopamine diblock (PMMA-PDA) and triblock (PDA-PMMA-PDA) copolymers combining mussel-inspired catecholic oxidative chemistry and atom transfer radical polymerization (ATRP). These copolymers display very good solubility in a range of organic solvents and also a broad band photo absorbance that increases with increasing PDA content in the copolymer. Spin-cast thin films of the copolymer were stable in water and showed a sharp reduction (by up to 50%) in protein adsorption compared to those of neat PMMA. Also the peak decomposition temperature of the copolymers was up to 43°C higher than neat PMMA. The enhanced solvent processability, thermal stability and low protein adsorption characteristics of this copolymer makes it attractive for variety of applications including antifouling coatings on large surfaces such as ship hulls, buoys, and wave energy converters.

  18. Acrylic acid polymerization and its graft copolymerization to poly(ethylene oxide) by gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Hochberg, A.

    1984-01-01

    Free radical initiated polymerization of acrylic acid was investigated in methanol-water solutions with and without poly(ethylene oxide) (PEO). The formation of poly(acrylic acid) (PAA) initiated both by gamma irradiation and water soluble azo initiators was found to follow classical free radical kinetics. A significant increase in the rate of the propagation step (together with the degree of polymerization) was observed as the water fraction of the medium increased. During homogeneous polymerization of acrylic acid in methanol-water solutions containing poly(ethylene oxide), PAA grafting efficiency was found to be 67% and independent of initiation rate and yield. A mechanism of grafting to poly(ethylene oxide) was proposed. Chain transfer to PEO (K/sub tr/ = 6.5 x 10/sup -5/) was found to be the dominant mechanism for graft formation. Drag reduction characteristics of these PEO-PAA graft copolymers were measured in dilute aqueous solutions as a function of Reynolds number and solution pH. PEO graft copolymers containing 45% by mole PAA graft had, in neutral and basic solutions, drag reduction characteristics equivalent on a mass basis to the initial PEO. However at low pH, drag reduction characteristics disappeared as the PEO-PAA coacervate formed.

  19. Synthesis and characterization of PEPO grafted carboxymethyl guar and carboxymethyl tamarind as new thermo-associating polymers.

    Science.gov (United States)

    Gupta, Nivika R; Torris A T, Arun; Wadgaonkar, Prakash P; Rajamohanan, P R; Ducouret, Guylaine; Hourdet, Dominique; Creton, Costantino; Badiger, Manohar V

    2015-03-06

    New thermo associating polymers were designed and synthesized by grafting amino terminated poly(ethylene oxide-co-propylene oxide) (PEPO) onto carboxymethyl guar (CMG) and carboxymethyl tamarind (CMT). The grafting was performed by coupling reaction between NH2 groups of PEPO and COOH groups of CMG and CMT using water-soluble EDC/NHS as coupling agents. The grafting efficiency and the temperature of thermo-association, T(assoc) in the copolymer were studied by NMR spectroscopy. The graft copolymers, CMG-g-PEPO and CMT-g-PEPO exhibited interesting thermo-associating behavior which was evidenced by the detailed rheological and fluorescence measurements. The visco-elastic properties (storage modulus, G'; loss modulus, G") of the copolymer solutions were investigated using oscillatory shear experiments. The influence of salt and surfactant on the T(assoc) was also studied by rheology, where the phenomenon of "Salting out" and "Salting in" was observed for salt and surfactant, respectively, which can give an easy access to tunable properties of these copolymers. These thermo-associating polymers with biodegradable nature of CMG and CMT can have potential applications as smart injectables in controlled release technology and as thickeners in cosmetics and pharmaceutical formulations.

  20. Clear antismudge unimolecular coatings of diblock copolymers on glass plates.

    Science.gov (United States)

    Macoretta, Danielle; Rabnawaz, Muhammad; Grozea, Claudia M; Liu, Guojun; Wang, Yu; Crumblehulme, Alison; Wyer, Martin

    2014-12-10

    Two poly[3-(triisopropyloxysilyl)propyl methacrylate]-block-poly[2-(perfluorooctyl)ethyl methacrylate] (PIPSMA-b-PFOEMA) samples and one poly(perfluoropropylene oxide)-block-poly-[3-(triisopropyloxysilyl)propyl methacrylate] (PFPO-b-PIPSMA) sample were synthesized, characterized, and used to coat glass plates. These coatings were formed by evaporating a dilute polymer solution containing HCl, which catalyzed PIPSMA's sol-gel chemistry. Polymer usage was minimized by targeting at diblock copolymer unimolecular (brush) layers that consisted of a sol-gelled grafted PIPSMA layer and an oil- and water-repellant fluorinated surface layer. Investigated is the effect of varying the catalyst amount, polymer amount, as well as block copolymer type and composition on the structure, morphology, and oil- and water-repellency of the coatings. Under optimized conditions, the prepared coatings were optically clear and resistant to writing by a permanent marker. The marker's trace was the faintest on PFPO-b-PIPSMA coatings. In addition, the PFPO-b-PIPSMA coatings were far more wear-resistant than the PIPSMA-b-PFOEMA coatings.

  1. The influence of chain stretching on the phase behavior of multiblock copolymer and comb copolymer melts

    NARCIS (Netherlands)

    Angerman, HJ; ten Brinke, G

    2003-01-01

    The subject of this paper is inspired by microphase-separated copolymer melts in which a small-scale structure is present inside one of the phases of a large-scale structure. Such a situation can arise in a diblock copolymer melt, if one of the blocks of the diblock is in itself a multiblock copolym

  2. Blends of Styrene-Butadiene-Styrene Triblock Copolymer with Random Styrene-Maleic Anhydride Copolymers

    NARCIS (Netherlands)

    Piccini, Maria Teresa; Ruggeri, Giacomo; Passaglia, Elisa; Picchioni, Francesco; Aglietto, Mauro

    2002-01-01

    Blends of styrene-butadiene-styrene triblock copolymer (SBS) with random styrene-maleic anhydride copolymers (PS-co-MA), having different MA content, were prepared in a Brabender Plastigraph mixer. The presence of polystyrene (PS) blocks in the SBS copolymer and the high styrene content (93 and 86 w

  3. Effects of Substrate Interactions on Out-of-Plane Order in Thin Films of Lamellar Copolymers

    Science.gov (United States)

    Mitra, Indranil; Mahadevapuram, Nikhila; Bozhchenko, Alona; Strzalka, Joseph; Stein, Gila E.

    2014-03-01

    Block copolymer (BCP) thin films are widely studied and applied for low cost, large area nanopatterning of semiconductor devices and has a very low tolerance for both in-plane or out of plane defects. Here we study, defects in lamellar diblock copolymers as a function of film thickness and the types of interactions at the substrate interface. Thin films of poly (styrene-b-methyl methacrylate) (PS-PMMA) with equilibrium periodicity 46nm were prepared and annealed on silicon substrates that were functionalized with a random copolymer P(s-r-MMA) brush. The resulting structures were evaluated with optical, scanning force and, scanning electron microscopy, along with grazing-incidence small-angle X-ray scattering (GISAXS). The in-plane correlation length (OCL) increased with brush grafting density, and increased with distance from the substrate interface. Out-of-plane order improved with brush grafting density, but thick films always contain a high density of misoriented domains. Based on these findings, we propose that (1) substrate pinning either induces or traps the mis-oriented domains, and (2) out-of-plane orientation defects are difficult to remove, from a thick film, because the energetic penalty for bending a ``tall'' domain is very low. Funding from NHARP and the Department of Chemical and Biomolecular Engineering, University of Houston.

  4. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...... a viscoclastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel. (C) 2004 Elsevier Ltd. All rights reserved....

  5. Copolymers of fluorinated polydienes and sulfonated polystyrene

    Science.gov (United States)

    Mays, Jimmy W.; Gido, Samuel P.; Huang, Tianzi; Hong, Kunlun

    2009-11-17

    Copolymers of fluorinated polydienes and sulfonated polystyrene and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization.

  6. SOME ASPECTS OF MORPHOLOGIES AND INTERFACES IN COPOLYMER/HOMOPOLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming; CAO Xianyi; YU Tongyin

    1988-01-01

    Based on a series of morphological studies of blends of homopolymer (Homo) and a variety of block and graft copolymers (Cop), the nature of phase separation, interface, emulsification and inner morphology of copolymer-dispersed phase etc. in the blends are discussed. In the cases of Cop AB/Homo A/Homo B systems,in which one homopolymer forms matrix, it is observed that the dispersed homopolymer phase is exclusively associated with Cop AB, i.e. no Homo A-Homo B interface exists. This phenomenon is believed to be caused by minimizing the interfacial energy of the systems. Meanwhile, preferential solubilization or anchoring of the like chains of copolymer into homopolymer matrix leads to stabilization of the dispersed phase in the matrix.In addition, regular variation of the inner morphology of the dispersed copolymer phase with the composition and molecular parameters of the component polymers is observed. When the two components have comparable proportions, alternating concentric shells are the most common feature which is associated with minimizing the interfacial energy in the Cop/Homo systems.

  7. Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.

    Science.gov (United States)

    Samitier, Gonzalo; Alentorn-Geli, Eduard; Taylor, Dean C; Rill, Brian; Lock, Terrence; Moutzouros, Vasilius; Kolowich, Patricia

    2015-01-01

    To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV). The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation. Systematic review of level II-IV studies, Level IV.

  8. Comparison of PEI-PEG and PLL-PEG copolymer coatings on the prevention of protein fouling.

    Science.gov (United States)

    Bergstrand, Anna; Rahmani-Monfared, Ghazal; Ostlund, Asa; Nydén, Magnus; Holmberg, Krister

    2009-03-01

    The effect of surface charge on the protein resistance of adsorbed layers of poly(ethylene imine)-[g]-poly(ethylene glycol), PEI-PEG, and poly(L-lysine)-[g]-poly(ethylene glycol), PLL-PEG, was studied. Mixed and monofunctional self-assembled monolayers, SAMs, on gold were obtained by adsorption of 16-mercapto-1-hexadecanoic acid and 16-mercapto-1-hexadecanol. The surface charge was systematically varied by changing the ratio of the two alkanethiols. The graft copolymers PEI-PEG and PLL-PEG were adsorbed at the SAMs and tested for resistance towards human serum albumin and fibrinogen. The adsorbed amount of copolymers increased with increasing negative surface charge. However, the best protein resistance was found at an intermediate surface charge. The PLL-PEG covered surfaces showed better protein resistance than the PEI-PEG covered surfaces. Thus, this work demonstrates that an adsorbed layer of PEG-grafted PEI and, in particular, PEG-grafted PLL is efficient in preventing protein adsorption when there is charge neutralization between the copolymer and the underlying surface. (c) 2008 Wiley Periodicals, Inc.

  9. A surface interaction model for self-assembly of block copolymers under soft confinement

    Science.gov (United States)

    Song, Jun-Qing; Liu, Yi-Xin; Zhang, Hong-Dong

    2016-12-01

    The surface interaction between substrates and block copolymers is one of the most important factors that control the alignment of self-assembled domains under thin film confinement. Most previous studies simply modeled substrates modified by grafting polymers as a hard wall with a specified surface energy, leading to an incomplete understanding of the role of grafted polymers. In this study, we propose a general model of surface interactions where the role of grafted polymers is decomposed into two independent contributions: the surface preference and the surface softness. Based on this model, we perform a numerical analysis of the stability competition between perpendicular and parallel lamellae of symmetric diblock copolymers on substrates modified by homopolymers using self-consistent field theory. The effects of the surface preference and the surface softness on the alignment of lamellar domains are carefully examined. A phase diagram of the alignment in the plane of the surface preference parameter and the surface softness parameter is constructed, which reveals a considerable parameter window for preparing stable perpendicular lamellae even on highly preferential substrates.

  10. Functionalization of poly(dimethylsiloxane) surfaces with maleic anhydride copolymer films.

    Science.gov (United States)

    Cordeiro, Ana L; Zschoche, Stefan; Janke, Andreas; Nitschke, Mirko; Werner, Carsten

    2009-02-01

    Combining advantageous bulk properties of polymeric materials with surface-selective chemical conversions is required in numerous advanced technologies. For that aim, we investigate strategies to graft maleic anhydride (MA) copolymer films onto poly(dimethylsiloxane) (PDMS) precoatings. Amino groups allowing the covalent attachment of the MA copolymer films to the PDMS (Sylgard 184) surface were introduced either by low-pressure ammonia plasma treatment, or by attachment of 3-aminopropyltriethoxysilane (APTES) onto air plasma-treated PDMS. The resultant coatings were extensively characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contact angle measurements, and atomic force microscopy (AFM). The results show that the impact of the plasma treatment on the physical properties on the topmost surface of the PDMS is critically important for the characteristics of the layered coatings.

  11. Micellization and Characterization of Block Copolymer Detergents

    DEFF Research Database (Denmark)

    Hvidt, Søren

    Triblock copolymers of the type EPE, where E and P denote ethylene oxide and propylene oxide blocks, respectively, are used widely in industry as emulsifiers, anti-foaming agents, and in delayed drug release. EPE copolymers form micelles with a core of P blocks and different micellar shapes depen...

  12. Micellization and Characterization of Block Copolymer Detergents

    DEFF Research Database (Denmark)

    Hvidt, Søren

    Triblock copolymers of the type EPE, where E and P denote ethylene oxide and propylene oxide blocks, respectively, are used widely in industry as emulsifiers, anti-foaming agents, and in delayed drug release. EPE copolymers form micelles with a core of P blocks and different micellar shapes...

  13. Copolymers at the solid - liquid interface

    NARCIS (Netherlands)

    Wijmans, C.M.

    1994-01-01

    Copolymers consisting of both adsorbing and nonadsorbing segments can show an adsorption behaviour which is very different from that of homopolymers. We have mainly investigated the adsorption of AB diblock copolymers, which have one adsorbing block (anchor) and one nonadsorbing block

  14. Drug targeting to tumors using HPMA copolymers

    NARCIS (Netherlands)

    Lammers, T.G.G.M.

    2009-01-01

    Copolymers based on N-(2-hydroxypropyl)methacrylamide (HPMA) are prototypic and well-characterized polymeric drug carriers that have been broadly implemented in the delivery of anticancer agents. HPMA copolymers circulate for prolonged periods of time, and by means of the Enhance Permeability and Re

  15. Process-Accessible States of Block Copolymers

    Science.gov (United States)

    Sun, De-Wen; Müller, Marcus

    2017-02-01

    Process-directed self-assembly of block copolymers refers to thermodynamic processes that reproducibly direct the kinetics of structure formation from a starting, unstable state into a selected, metastable mesostructure. We investigate the kinetics of self-assembly of linear A C B triblock copolymers after a rapid transformation of the middle C block from B to A . This prototypical process (e.g., photochemical transformation) converts the initial, equilibrium mesophase of the A B B copolymer into a well-defined but unstable, starting state of the A A B copolymer. The spontaneous structure formation that ensues from this unstable state becomes trapped in a metastable mesostructure, and we systematically explore which metastable mesostructures can be fabricated by varying the block copolymer composition of the initial and final states. In addition to the equilibrium mesophases of linear A B diblock copolymers, this diagram of process-accessible states includes 7 metastable periodic mesostructures, inter alia, Schoen's F-RD periodic minimal surface. Generally, we observe that the final, metastable mesostructure of the A A B copolymer possesses the same symmetry as the initial, equilibrium mesophase of the A B B copolymer.

  16. Thermochemical characteristics of chitosan-polylactide copolymers

    Science.gov (United States)

    Goruynova, P. E.; Larina, V. N.; Smirnova, N. N.; Tsverova, N. E.; Smirnova, L. A.

    2016-05-01

    The energies of combustion of chitosan and its block-copolymers with different polylactide contents are determined in a static bomb calorimeter. Standard enthalpies of combustion and formation are calculated for these substances. The dependences of the thermochemical characteristics on block-copolymer composition are determined and discussed.

  17. PEO-related block copolymer surfactants

    DEFF Research Database (Denmark)

    Mortensen, K.

    2001-01-01

    Non-ionic block copolymer systems based on hydrophilic poly(ethylene oxide) and more hydrophobic co-polymer blocks are used intensively in a variety of industrial and personal applications. A brief description on the applications is presented. The physical properties of more simple model systems ...

  18. Copolymers of various architectures containing ethylene and 5-norbornen-2-yl derivatives

    Science.gov (United States)

    Diamanti, Steve Jon

    Polyolefins are a class of materials with enormous economic impact. Tailoring of polyolefin bulk properties by synthetic control is a major focus of many industrial and academic research groups. Polar functionalities within the hydrophobic polyolefin backbone can change important properties, such as, toughness, adhesion, solvent resistance, blend compatibility with other functional polymers, and rheological properties. Functional polyolefin materials with block or graft architectures are the most desirable structures as the pure polyolefin block maintains its intrinsic properties. Our initial work elucidated a neutral nickel based catalyst system capable of catalyzing the "quasi-living" homopolymerization of ethylene and the "quasi-living" copolymerization of ethylene with 5-norbornen-2-yl acetate (NBA), a polar comonomer. Through testing the effect of several reaction variables on the copolymerization of ethylene with NBA it was found that changing ethylene pressure causes a large change in the content of NBA in the copolymer chain. This change in NBA content, in turn, drastically affects the physical and thermal properties of these polymers. Understanding the impact of such reaction variables on copolymer properties made it possible to design more sophisticated architectures. This catalytic system has since been used to synthesize block copolymers and tapered block copolymers of ethylene and NBA. Block copolymers of ethylene and NBA have been synthesized by a method utilizing ethylene pressure variation to create two distinct copolymeric blocks that are able to order into microphase-separated structures. The block structure of these materials has been proven by 1H-NMR spectroscopy, thermal analysis, GPC, AFM, and TEM. The synthesis, characterization, and bulk and thermal properties of tapered block copolymers containing ethylene and NBA, has also been performed. The final structure of the tapered block polymer is a polar amorphous chain (rich in NBA) on one

  19. Synthesis and properties of silane-fluoroacrylate grafted starch.

    Science.gov (United States)

    Qu, Jia; He, Ling

    2013-10-15

    The latex of silane-fluoroacrylate grafted starch for coating materials, VTMS-starch/P(MMA/BA/3FMA), is obtained by two step grafting reactions. Vinyltrimethoxysilane (VTMS) is primarily grafted onto starch by condensation between Si-OH and C-OH at 120 °C, and then the copolymer of methyl methacrylate (MMA), butyl acrylate (BA) and 2,2,2-trifluoroethyl methacrylate (3FMA) is grafted onto the VTMS-starch by emulsion polymerization. Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to confirm the chemically grafting reactions in every step. The conversion percent, grafting percent and grafting efficiency for VTMS-starch/p(MMA/BA/3FMA) latex indicate that the optimum conditions should be controlled at 75 °C for 1h as VTMS-starch/P(MMA/BA/3FMA) in 1/3 weight ratio. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis have revealed that the latexes exhibit the uniform spherical particles of 40-60 nm in a narrow size distribution. The latex films perform the obvious hydrophobic (107°) property, lower surface free energy (25-35 mN/m) and the higher thermostability (330-440 °C) than starch (51°, 51.32 mN/m, 100-330 °C). Dynamic thermomechanical analysis (DMA) shows that the latex film could gain considerable toughness and strength with an elongation at break of 39.45% and a tensile strength of 11.97 MPa.

  20. Grafting of PEG400 onto the surface of LLDPE/SMA film

    Institute of Scientific and Technical Information of China (English)

    CHEN Gufeng; ZHANG Yi; ZHU Yafei; XU Jiarui

    2007-01-01

    Linear low-density polyethylene (LLDPE)was melt and blended with styrene-maleic anhydride copolymer (SMA).The blending films were then immersed in poly(ethylene glycol)400 (PEG400) at room temperature.The surface composition of the blend films was determined by Fourier transform infra-red spectroscopy coupled with a variable incidence angle attenuated total reflection accessory (ATR-FTIR).Results show that PEG400 can be grafted onto the surface of the films via esterification with SMA.The immersion of PEG promotes the enrichment of SMA onto the surface of the films.The water contact angle data show that grafting of PEG400 onto PE can greatly improve the hydrophilicity of the PE surface.These experiments show that surface functionalization of polyethylene films by blending SMA and then surface grafting of PEG is feasible,which suggest an effective and simple route for PE surface modification via blending and grafting.

  1. Lysozyme immobilization onto PVC catheters grafted with NVCL and HEMA for reduction of bacterial adhesion

    Science.gov (United States)

    Guadarrama-Zempoalteca, Yesica; Díaz-Gómez, Luis; Meléndez-Ortiz, H. Iván; Concheiro, Angel; Alvarez-Lorenzo, Carmen; Bucio, Emilio

    2016-09-01

    The aim of the present work was to functionalize poly(vinyl chloride) (PVC) urinary catheters with grafted copolymers that can improve the biocompatibility and serve as binding points of lysozyme. PVC catheters were modified by grafting a mixture of N-vinylcaprolactam (NVCL) and 2-hydroxyethylmethacrylate (HEMA) applying a gamma-ray pre-irradiation method. The effect of absorbed dose, monomer concentration, temperature, and reaction time on the grafting percentage was evaluated. The grafted catheters were characterized regarding surface composition (FTIR-ATR spectroscopy), thermal properties (DSC and TGA) and swelling in aqueous medium. Lysozyme was directly coupled onto PVC-g-(NVCL/HEMA) previously activated using carbonyldiimidazole. Antimicrobial lytic activity of the modified catheters over time was tested against Micrococcus lysodeikticus. Lysozyme diminished the adhesion of Staphylococcus aureus onto the functionalized catheters, which may be suitable to prevent biofilm formation.

  2. Study of polyacrylamide grafted starch based algal flocculation towards applications in algal biomass harvesting.

    Science.gov (United States)

    Banerjee, Chiranjib; Gupta, Pratibha; Mishra, Sumit; Sen, Gautam; Shukla, Pratyoosh; Bandopadhyay, Rajib

    2012-11-01

    Microalgae may be the source of high amount of lipid and protein. It has the property for carbon dioxide sequestration, recycling and also can remove pollutants from wastewater. Using traditional methods, collection of algal biomass is either cost effective, time consuming or may be toxic due to use of chemical salts. The aim of this study is to harvest freshwater microalgae (Chlorella sp. CB4) biomass by using polymer. Polyacrylamide grafted starch (St-g-PAM) has been synthesized by microwave assisted method involving a synergism of microwave radiation and ceric ammonium nitrate (CAN) to initiate the grafting reaction. The synthesis was optimized in terms of CAN and monomer (acrylamide) concentration. The algal flocculation efficacy of all the grades of this graft copolymer was studied through standard 'Jar test' procedure. Effects of percentage grafting, pH and zeta potential on percentage recovery of algal biomass were thoroughly investigated.

  3. Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

    Directory of Open Access Journals (Sweden)

    X. D. Zhou

    2013-11-01

    Full Text Available Carbon fibers chemically grafted with hydroxyl-terminated diblock copolymer poly (n-butylacrylate-b-poly (glycidyl methacrylate (OH-PnBA-b-PGMA, were used as the reinforcement for epoxy composites. The multi-filament composite specimens were prepared and measured by dynamic mechanical analysis (DMA, to study the interfacial toughness of carbon fiber reinforced epoxy composites with the diblock copolymers. The loss modulus and loss factor peaks of β-relaxation indicated that composites with diblock copolymers could dissipate more energy at small strain and possess better interfacial toughness, whereas composites without the ductile block PnBA having the worse interfacial toughness. The glass transition temperature and the apparent activation energy calculated from the glass transition showed that the strong interfacial adhesion existed in the composites with diblock copolymers, corresponding with the value of interfacial shear strength. Therefore, a strengthening and toughening interfacial structure in carbon fiber/epoxy composites was achieved by introducing the diblock copolymer OH-PnBA-b-PGMA. The resulting impact toughness, characterized with an Izod impact tester, was better than that of composite without the ductile block PnBA.

  4. STUDY ON POLYSULFONE-POLYESTER BLOCK COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    DING Youjun; QI Daquan

    1988-01-01

    Synthesis and characterization of a series of Polysulfone (PSF)-Polyester (PEs) block copolymers were studied.The degree of randomness (B) of these block copolymers was calculated from the intensities of their proton signals in 1H NMR spectra and lies in the region of 0 < B < 1. It was shown that the degree of randomness (B) and the average sequence length (L) in block copolymers were relatively dependent on the reaction conditions, various feed ratios and structure of diols.The phenomenon was observed, when the PSF-PEs block copolymers dissolved in different solvents they had different viscosities and molecular conformations.The PSF-PEs block copolymers had better solvent resistance than homo-polysulfone.

  5. STUDIES ON THE OXIDATION AND GRAFT COPOLYMERIZATION OF POLY(ETHER-URETHANE)

    Institute of Scientific and Technical Information of China (English)

    SUN Yanhui; QIU Kunyuan; FENG Xinde

    1983-01-01

    A new method of graft copolymerization of acrylamide (AAM) on poly(ether-urethane) (PEU)which was prepared from poly(tetramethylene ether) glycol (PTMG), 4,4'-diphenylmethane diisocyanate (MDI) and ethylene diamine or butanediol extender was investigated. Hydroperoxide group was first introduced onto the surface of PEU through photo-oxidation in the presence of hydrogen peroxide, then it was reacted with ferrous ion or N,N-dimethyl toluidine (DMT) to initiate AAM graft copolymerization on PEU surface. The graft reaction could be carried out effectively at low temperature. The formation of graft copolymer has been verified by its water absorption % and the scanning electron microscopy photographs. Some model compounds of PEU soft segment and hard segment were synthesized in order to clarify the site of graft reaction. The results of oxidation and graft copolymerization of model compounds showed that this graft copolymerization possesses higher selectivity, and it takes place predominately at the polyether segments, because the ether linkage in soft segment is very sensitive to oxidation and can form hydroperoxide easily. Thus,the grafting site appears to be at a-carbon of the ether linkage.

  6. A facile method for construction of antifouling surfaces by self-assembled polymeric monolayers of PEG-silane copolymers formed in aqueous medium.

    Science.gov (United States)

    Park, Sangjin; Chi, Young Shik; Choi, Insung S; Seong, Jiehyun; Jon, Sangyong

    2006-11-01

    Self-assembled polymeric monolayers (PMs) on Si/SiO2 wafers were prepared in water from a series of random copolymers of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3-(trimethoxysilyl)propyl methacrylate (TMSMA), denoted as poly(TMSMA-r-PEGMA). Four polymers of poly(TMSMA-r-PEGMA) were synthesized by free radical polymerization with a systematic variation of co-monomer feed ratios. Regardless of PEG grafting density in the copolymers, all PMs formed approximately 1 nm-thick film as measured by ellipsometry. However, the PMs with a higher grafting density of PEG resulted in more hydrophilic surfaces in terms of water contact angle. The protein resistance of the PMs was evaluated using bovine serum albumin (BSA) as a model protein. Analyses by ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) showed that the PMs of the copolymers markedly reduced the nonspecific adsorption of proteins compared to the unmodified Si/SiO2 wafers. The study also revealed that the PMs prepared from the copolymers with a higher PEG grafting density were more effective in resisting the nonspecific protein adsorption.

  7. STUDIES ON THE OXIDATION AND GRAFT COPOLYMERIZATION OF POLYETHERS

    Institute of Scientific and Technical Information of China (English)

    SUN Yanhui; QIU Kunyuan; FENG Xinde VOONG Sing-tuh

    1984-01-01

    Polyethers could form hydroperoxide under air-oxidation or photo-oxidation in the presence of H2O2. The scission of ether linkage induced by moderate oxidation was prevented by controlling the reaction time and hydroperoxide concentration. The oxidation rate was affected by the end groups of polyethers. The decreasing order of oxidation rate for various poly(tetramethylene ether) glycol derivatives having different end groups are as follows: poly(tetramethylene ether) glycol (PTMG)> poly(tetramethylene ether)acetate (PTMGAC) > poly(tetramethylene ether) phenyl carbamate (PTMGPC). The urethane end groups in PTMGPC increase the resistance toward oxidation. Polyether hydroperoxide reacts with ferrous ion or N,N-dimethyl toluidine (DMT) to form polymericoxy radical which then initiates the graft copolymerization of vinyl monomers at low temperature,and was devoid of homopolymerization. The copolymer after separation and purification was proved to be a graft one by IR analysis and elemental analysis.

  8. SYNTHESIS OF POLY(METHYL METHACRYLATE)-graft-POLYSTYRENE BY ATOM TRANSFER RADICAL POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Sheng-min Gong; Qun-sheng Li; Yan Shi; Zhi-feng Fu; Shu-ke Jiao; Wan-tai Yang

    2003-01-01

    The radical copolymerization of methyl methacrylate and 2-hydroxyethyl methacrylate was carried out via atom complex. This polymerization proceeds in a living fashion with controlled molecular weight and low polydispersity. The obtained copolymer was esterified with 2-bromoisobutylryl bromide yielding a macroinitiator, poly(methyl methacrylate-co-2-hydroxyethyl methacrylate-co-2-(2-bromoisobutyryloxy)ethyl methacrylate), and its structure was characterized by 1HNMR. This macroinitiator was used for ATRP of styrene to synthesize poly(methyl methacrylate)-grafi-polystyrene. The molecular weight of graft copolymer increased with the monomer conversion, and the polydispersity remained relatively low.The individual grafted polystyrene chains were cleaved from the macroinitiator backbone by hydrolysis and the hydrolyzed product was characterized by 1H-NMR and GPC.

  9. GRAFTING OF PEROXIDE-INITIATED MALEIC ANHYDRIDE ON SPHERICAL PE/PP IN-REACTOR BLEND GRANULES

    Institute of Scientific and Technical Information of China (English)

    Yan-zhong Zhang; Zhi-qiang Fan; Bai-geng Wu; Jun-ting Xu; Qi Wang

    2004-01-01

    Spherical polyethylene/polypropylene (PE/PP) in-reactor blend granules with various ethylene/propylene molar ratios and high porosity were synthesized using a high yield TiCl4/MgCl2 supported catalyst. A solution of benzoyl peroxide (BPO)/maleic anhydride (MAH)/xylene (interfacial reagent) or BPO/MAH/St (comonomer) was absorbed onto the PE/PP inreactor blend granules, and solid phase graft polymerization of MAH on PE/PP was conducted. The amount of grafted MAH on PE/PP was measured through chemical titration. The results showed that solid phase graft polymerization of MAH in PE/PP in-reactor blend granules produced graft copolymer with high amount of grafted MAH, and the amount of grafted MAH was raised slightly when St was introduced as comonomer. The graft in-reactor blend was fractionated into five fractions through temperature-gradient extraction fractionation (TGEF), and the fractions were analyzed by FTIR. The results revealed that MAH is mainly grafted on the PE segments, whereas MAH was predominantly grafted on the PP segments when St was present in the graft polymerization system. In addition, the final product is still in the form of regular spherical granules, which is beneficial for industrial processing.

  10. Analysis and evaluation of starch - styrene grafting polymerization%淀粉-苯乙烯接枝共聚的分析与评定

    Institute of Scientific and Technical Information of China (English)

    吴柏生

    2011-01-01

    The soluble starch was modified by means of graft copolymerization using suspension polymerization in experiment, in order to prepare grafted copolymer that possessed both favorable qualities of starch and monomers.%采用悬浮聚合的方法,对淀粉进行接枝共聚改性,制得的接枝共聚物具有淀粉和单体的双重优良性能.

  11. Rapid self-assembly of block copolymers to photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yan; Sveinbjornsson, Benjamin R; Grubbs, Robert H; Weitekamp, Raymond; Miyake, Garret M; Atwater, Harry A; Piunova, Victoria; Daeffler, Christopher Scot; Hong, Sung Woo; Gu, Weiyin; Russell, Thomas P.

    2016-07-05

    The invention provides a class of copolymers having useful properties, including brush block copolymers, wedge-type block copolymers and hybrid wedge and polymer block copolymers. In an embodiment, for example, block copolymers of the invention incorporate chemically different blocks comprising polymer size chain groups and/or wedge groups that significantly inhibit chain entanglement, thereby enhancing molecular self-assembly processes for generating a range of supramolecular structures, such as periodic nanostructures and microstructures. The present invention also provides useful methods of making and using copolymers, including block copolymers.

  12. Electrospun mats from styrene/maleic anhydride copolymers: modification with amines and assessment of antimicrobial activity.

    Science.gov (United States)

    Ignatova, Milena; Stoilova, Olya; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2010-08-11

    New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M-600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8-hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5-amino-8-hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.

  13. Mechanism in determining pretilt angle of liquid crystals aligned on fluorinated copolymer films

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hsin-Ying; Wang, Chih-Yu; Lin, Chia-Jen; Pan, Ru-Pin [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan 30010 (China); Lin, Song-Shiang; Lee, Chein-Dhau [Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan 31040 (China); Kou, Chwung-Shan, E-mail: rpchao@mail.nctu.edu.t [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 30013 (China)

    2009-08-07

    This work explores the surface treatment of copolymer materials with fluorinated carbonyl groups in various mole fractions by ultraviolet irradiation and ion-beam (IB) bombardment and its effect on liquid crystal (LC) surface alignments. X-ray photoemission spectroscopic analysis confirms that the content of the grafted CF{sub 2} side chains dominates the pretilt angle. A significant increase in oxygen content is responsible for the increase in the polar surface energy during IB treatment. Finally, the polar component of the surface energy dominates the pretilt angle of the LCs.

  14. Fluorinated ethylene propylene copolymer coating for the stability enhancement of electroactive and photoactive systems

    Science.gov (United States)

    Zhao, Luping; Neoh, K. G.; Zhang, Yan; Kang, E. T.

    2003-11-01

    The effectiveness of radio frequency sputtered fluorinated ethylene propylene copolymer (FEP) for the stability enhancement of electroactive and photoactive systems was investigated. Two kinds of electroactive polymer systems, polyaniline (PANI) coated low density polyethylene (LDPE) film and PANI-viologen assembly, were tested. In both cases, a sputtered FEP coating of coating of 40-50 nm in thickness. The deposition of a FEP coating on the photoactive viologen system (viologen grafted on LDPE film) prolonged its photochromic effect by inhibiting the diffusion of oxygen, and hence the reoxidation of the highly colored viologen radical cations to the dication state.

  15. NANOSTRUCTURES OF FUNCTIONAL BLOCK COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Guojun Liu

    2000-01-01

    Nanostructure fabrication from block copolymers in my group normally involves polymer design, synthesis, selfassembly, selective domain crosslinking, and sometimes selective domain removal. Preparation of thin films with nanochannels was used to illustrate the strategy we took. In this particular case, a linear triblock copolymer polyisopreneblock-poly(2-cinnamoylethyl methacrylate)-block-poly(t-butyl acrylate), PI-b-PCEMA-b-PtBA, was used. Films, 25 to50μm thick, were prepared from casting on glass slides a toluene solution of PI-b-PCEMA-b-PtBA and PtBA homopolymer,hPtBA, where hPtBA is shorter than the PtBA block. At the hPtBA mass fraction of 20% relative to the triblock or the total PtBA (hPtBA and PtBA block) volume fraction of 0.44, hPtBA and PtBA formed a seemingly continuous phase in the matrix of PCEMA and PI. Such a block segregation pattern was locked in by photocrosslinking the PCEMA domain. Nanochannels were formed by extracting out hPtBA with solvent. Alternatively, larger channels were obtained from extracting out hPtBA and hydrolyzing the t-butyl groups of the PtBA block. Such membranes were not liquid permeable but had gas permeability constants ~6 orders of magnitude higher than that of low-density polyethylene films.

  16. Coarse Grained Simulation of Lipid Membrane and Triblock Copolymers

    Science.gov (United States)

    Hatakeyama, Masaomi; Faller, Roland

    2008-02-01

    We investigated the interaction between DPPC (Dipalmitoyl phosphatidylcholine) bilayer and polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) triblock copolymers using coarse grained simulation. We simulated two systems of DPPC bilayer and PEO-PPO-PEO triblock copolymer containing different mole fractions, and simulated DPPC vesicle with the copolymers. We found different adsorption mechanisms of triblock copolymers depending on concentration. And we also observed docking process between a lipid vesicle and a micelle of the copolymers.

  17. Block copolymer membranes for aqueous solution applications

    KAUST Repository

    Nunes, Suzana Pereira

    2016-03-22

    Block copolymers are known for their intricate morphology. We review the state of the art of block copolymer membranes and discuss perspectives in this field. The main focus is on pore morphology tuning with a short introduction on non-porous membranes. The two main strategies for pore formation in block copolymer membranes are (i) film casting and selective block sacrifice and (ii) self-assembly and non-solvent induced phase separation (SNIPS). Different fundamental aspects involved in the manufacture of block copolymer membranes are considered, including factors affecting the equilibrium morphology in solid films, self-assembly of copolymer in solutions and macrophase separation by solvent-non-solvent exchange. Different mechanisms are proposed for different depths of the SNIPS membrane. Block copolymer membranes can be prepared with much narrower pore size distribution than homopolymer membranes. Open questions and indications of what we consider the next development steps are finally discussed. They include the synthesis and application of new copolymers and specific functionalization, adding characteristics to respond to stimuli and chemical environment, polymerization-induced phase separation, and the manufacture of organic-inorganic hybrids.

  18. Skin graft - slideshow

    Science.gov (United States)

    ... ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features on this page, ... 2017 Updated by: Debra G. Wechter, MD, FACS, general surgery practice specializing in breast cancer, Virginia Mason ...

  19. BIRCH XYLAN GRAFTED WITH PLA BRANCHES OF PREDICTABLE LENGTH

    Directory of Open Access Journals (Sweden)

    Johanna Persson,

    2012-06-01

    Full Text Available Birch xylan (4-O-methylglucuronoxylan isolated from a kraft cooking liquor was delignified and grafted with polylactide of predictable branch length. This graft copolymerization resulted in very high total yields, greater than 90%, and with less than 10% polylactide homopolymer byproducts. Mild reaction conditions (40°C, 5 to 120 minutes were used, which was believed to limit transesterification reactions and thus make it possible to reach good predictability of the polylactide branch length. The thermal properties of the polylactide-grafted xylan depended on the branch length. Short branches resulted in fully amorphous materials with a glass transition temperature of about 48 to 55°C, whereas long polylactide branches resulted in semi-crystalline materials with melting points of about 130°C. Using mixtures of L-lactide and D/L-lactide in the monomer feed further altered the thermal properties. The degradation temperatures of the polylactide-grafted xylans were higher than that of the unmodified xylan, with degradation temperatures of about 300°C and 250°C, respectively. Tensile testing showed increased elongation at break with increasing branch length. The proposed method thus enables tailor-making of copolymers with specific thermal and mechanical properties.

  20. Injectible bodily prosthetics employing methacrylic copolymer gels

    Science.gov (United States)

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  1. Enhanced infarct myocardium repair mediated by thermosensitive copolymer hydrogel-based stem cell transplantation.

    Science.gov (United States)

    Xia, Yu; Zhu, Kai; Lai, Hao; Lang, Meidong; Xiao, Yan; Lian, Sheng; Guo, Changfa; Wang, Chunsheng

    2015-05-01

    Mesenchymal stem cell (MSC) transplantation by intramyocardial injection has been proposed as a promising therapy strategy for cardiac repair after myocardium infarction. However, low retention and survival of grafted MSCs hinder its further application. In this study, copolymer with N-isopropylacrylamide/acrylic acid/2-hydroxylethyl methacrylate-poly(ɛ-caprolactone) ratio of 88:9.6:2.4 was bioconjugated with type I collagen to construct a novel injectable thermosensitive hydrogel. The injectable and biocompatible hydrogel-mediated MSC transplantation could enhance the grafted cell survival in the myocardium, which contributed to the increased neovascularization, decreased interstitial fibrosis, and ultimately improved heart function to a significantly greater degree than regular MSC transplantation. We suggest that this novel hydrogel has the potential for future stem cell transplantation.

  2. Enhanced infarct myocardium repair mediated by thermosensitive copolymer hydrogel-based stem cell transplantation

    Science.gov (United States)

    Xia, Yu; Zhu, Kai; Lai, Hao; Lang, Meidong; Xiao, Yan; Lian, Sheng

    2015-01-01

    Mesenchymal stem cell (MSC) transplantation by intramyocardial injection has been proposed as a promising therapy strategy for cardiac repair after myocardium infarction. However, low retention and survival of grafted MSCs hinder its further application. In this study, copolymer with N-isopropylacrylamide/acrylic acid/2-hydroxylethyl methacrylate-poly(ɛ-caprolactone) ratio of 88:9.6:2.4 was bioconjugated with type I collagen to construct a novel injectable thermosensitive hydrogel. The injectable and biocompatible hydrogel-mediated MSC transplantation could enhance the grafted cell survival in the myocardium, which contributed to the increased neovascularization, decreased interstitial fibrosis, and ultimately improved heart function to a significantly greater degree than regular MSC transplantation. We suggest that this novel hydrogel has the potential for future stem cell transplantation. PMID:25432986

  3. Methods of fiber surface grafting for interphase design and tailored composite response

    Science.gov (United States)

    Arnold, Jesse Judson

    1997-11-01

    surface conformation of the grafts using a 'hard-sphere' model. Finally, three styrene/acrylonitrile/butyl acrylate interphases, each with a different copolymer composition, were grafted to evaluate the effect of interphase mechanics on the reinforcing and impact properties of woven-fiber-reinforced, three-phase composites. Accordingly, the interfacial and composite properties were tailored by varying the graft composition as well as the grafting efficiency. Moreover, the grafted interphases elicited a synergistic response in terms of the reinforcement and impact properties, a result previously unobtainable by oxidative-type surface treatments.

  4. Study of Graft Copolymerization of Acrylic Acid Onto Nata De Coco and its Application as Microfiltration Membrane

    Directory of Open Access Journals (Sweden)

    T. Puspitasari

    2006-07-01

    Full Text Available Chemical and physical modifications of membrane can be carried out by radiation induced graft copolymerization. The aim of this research is to prepare graft copolymers of acrylic acid onto nata de coco (NDC-g-AAc by radiation and to study the performance of grafted copolymer as microfiltration membrane. Using a total dose of 30 kGy, the highest degree of grafting obtained were 209% and 142% for r (weight ratio of monomers to nata de coco equal to 61.3 and 35.7 respectively. The increasing degree of grafting resulted in decreasing flux due to high hydrogen bonding between grafted acrylic groups and water. It was found that the degree of swelling of NDC-g-AAc membrane with r = 35.7 was higher than that of r = 63.1. The changes of chemical structure of membrane were characterized by FTIR spectroscopy which showed a new band at 1720 cm-1 attributed to the carbonyl group of acrylic acid

  5. Hydroxyalkylation and polyether polyol grafting of graphene tailored for graphene/polyurethane nanocomposites.

    Science.gov (United States)

    Appel, Anna-Katharina; Thomann, Ralf; Mülhaupt, Rolf

    2013-08-01

    Graphene functionalization by hydroxyalkylation and grafting with polyether polyols enables polyurethane (PU) nanocomposites formation by in situ polymerization with isocyanates combined with effective covalent interfacial coupling. Functionalized graphene (FG) hydroxylation is achieved either by alkylation, transesterification, or grafting of thermally reduced graphite oxide. In the presence of K2 CO3 as catalyst the reaction of FG-OH with ethylene carbonate at 180 °C affords hydroxyethylated FG, whereas transesterification with castor oil produces riconoleiate-modified FG polyols. In the "grafting-from" process, FG-alkoholate macro initiators initiate the graft polymerization of propylene oxide to produce hybrid FG polyols containing 38 and 59 wt% oligopropylene oxide. In the "grafting-to" process 3-ethyl-3-hydroxymethyl-oxetane is cationically polymerized onto FG-OH, producing novel hyperbranched FG-based polyether polyols. Whereas hydroxylation and grafting of FG greatly improve FG dispersion in organic solvents, polyols and even PU, as confirmed by transmission electron microscopy, matrix reinforcement of FG/PU is impaired by increasing alkyl chain length and polyol graft copolymer content. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Barleany, Dhena Ria, E-mail: dbarleany@yahoo.com; Ulfiyani, Fida; Istiqomah, Shafina; Rahmayetty [Department of Chemical Engineering, University of Sultan Ageng Tirtayasa, Cilegon, Banten (Indonesia); Heriyanto, Heri; Erizal [Centre for Application of Isotopes and Radiation, Jakarta (Indonesia)

    2015-12-29

    Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w{sup −1} acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g{sup −1} of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g{sup −1} and 523 g g{sup −1} for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM)

  7. Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

    Science.gov (United States)

    Barleany, Dhena Ria; Ulfiyani, Fida; Istiqomah, Shafina; Heriyanto, Heri; Rahmayetty, Erizal

    2015-12-01

    Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w-1 acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g-1 of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g-1 and 523 g g-1 for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).

  8. Studies on preparing and adsorption property of grafting terpolymer microbeads of PEI-GMA/AM/MBA for bilirubin.

    Science.gov (United States)

    Gao, Baojiao; Lei, Haibo; Jiang, Liding; Zhu, Yong

    2007-06-15

    Crosslinking copolymer microbeads with a diameter range of 100-150 microm were synthesized by suspension copolymerization of glycidyl methacrylate (GMA), acrylamide (AM) and N,N'-methylene bisacrylamide (MBA). Subsequently, polyethyleneimine (PEI) was grafted on the surfaces of the terpolymer microbeads GMA/AM/MBA via the ring-opening reaction of the epoxy groups, and the grafting microbeads PEI-GMA/AM/MBA were prepared. In this paper, the adsorption property of the grafting microbeads for bilirubin was mainly investigated, and the effects of various factors, such as pH value, ionic strength and grafting degree of PEI on the surface of grafting microbeads and the adsorption capacity of the grafting microbeads for bilirubin were examined. The batch adsorption experiment results show that by right of the action of grafted polyamine macromolecules PEI, the grafting microbeads PEI-GMA/AM/MBA have quite strong adsorption ability for bilirubin; the isotherm adsorption conforms to Freundlich equation. The pH value of the medium affects the adsorption capacity greatly, As in the nearly neutral solutions with pH 6, the grafting microbeads have the strongest adsorption ability for bilirubin, whereas in acidic and basic solutions their adsorption ability is weak. The ionic strength hardly affects the adsorption ability of the grafting microbeads. The grafting degree of PEI on the surfaces of the grafting microbeads also has a great effect on the adsorption capacity, and higher the grafting degree of PEI on the surface of the microbead PEI-GMA/AM/MBA, the stronger is the adsorption ability of the microbeads.

  9. Block Copolymers: Synthesis and Applications in Nanotechnology

    Science.gov (United States)

    Lou, Qin

    This study is focused on the synthesis and study of (block) copolymers using reversible deactivation radical polymerizations (RDRPs), including atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. In particular, two primary areas of study are undertaken: (1) a proof-of-concept application of lithographic block copolymers, and (2) the mechanistic study of the deposition of titania into block copolymer templates for the production of well-ordered titania nanostructures. Block copolymers have the ability to undergo microphase separation, with an average size of each microphase ranging from tens to hundreds of nanometers. As such, block copolymers have been widely considered for nanotechnological applications over the past two decades. The development of materials for various nanotechnologies has become an increasingly studied area as improvements in many applications, such as those found in the semiconductor and photovoltaic industries are constantly being sought. Significant growth in developments of new synthetic methods ( i.e. RDRPs) has allowed the production of block copolymers with molecular (and sometimes atomic) definition. In turn, this has greatly expanded the use of block copolymers in nanotechnology. Herein, we describe the synthesis of statistical and block copolymers of 193 nm photolithography methacrylate and acrylate resist monomers with norbornyl and adamantyl moieties using RAFT polymerization.. For these resist (block) copolymers, the phase separation behaviors were examined by atomic force microscopy (AFM). End groups were removed from the polymers to avoid complications during the photolithography since RAFT end groups absorb visible light. Poly(glycidyl methacrylate-block-polystyrene) (PGMA-b-PS) was synthesize by ATRP and demonstrated that this block copolymer acts as both a lithographic UV (365 nm) photoresist and a self-assembly material. The PGMA segments can undergo cationic

  10. Silicone containing copolymers: Synthesis, properties and applications

    OpenAIRE

    Yılgör, Emel; Yılgör, İskender

    2013-01-01

    Accepted Manuscript Title: Silicone containing copolymers: Synthesis, properties and applications Author: Emel Yilgor Iskender Yilgor PII: S0079-6700(13)00141-X DOI: http://dx.doi.org/doi:10.1016/j.progpolymsci.2013.11.003 Reference: JPPS 848 To appear in: Progress in Polymer Science Received date: 1-8-2013 Revised date: 4-11-2013 Accepted date: 8-11-2013 Please cite this article as: Yilgor E, Yilgor I, Silicone containing copolymers: Synthesis, properties ...

  11. Amphiphilic diblock copolymers for molecular recognition

    OpenAIRE

    Nehring, Rainer

    2009-01-01

    In this thesis, the synthesis and the characterization of poly(butadiene)-blockpoly( ethylene oxide) copolymers with terminal Me2+-NTA groups (copper or nickel) is described for the first time. A convenient “one-pot” procedure that allows control over the individual block lengths of the copolymer and the end-group functionalization was successfully established. The formation of the metal-polymer complex has been confirmed by EPR and UV/VIS spectroscopy. Mixing of the Ni2+-NT...

  12. Drug targeting to tumors using HPMA copolymers

    OpenAIRE

    Lammers, T.G.G.M.

    2009-01-01

    Copolymers based on N-(2-hydroxypropyl)methacrylamide (HPMA) are prototypic and well-characterized polymeric drug carriers that have been broadly implemented in the delivery of anticancer agents. HPMA copolymers circulate for prolonged periods of time, and by means of the Enhance Permeability and Retention (EPR) effect, they localize to tumors both effectively and selectively. As a consequence, the concentrations of attached active agents in tumors can be increased, and their accumulation in ...

  13. Responsive Copolymers for Enhanced Petroleum Recovery

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, C.; Hester, R.

    2001-02-27

    The objectives of this work was to: synthesize responsive copolymer systems; characterize molecular structure and solution behavior; measure rheological properties of aqueous fluids in fixed geometry flow profiles; and to tailor final polymer compositions for in situ rheology control under simulated conditions. This report focuses on the synthesis and characterization of novel stimuli responsive copolymers, the investigation of dilute polymer solutions in extensional flow and the design of a rheometer capable of measuring very dilute aqueous polymer solutions at low torque.

  14. Fabrication of Thiol-Ene "Clickable" Copolymer-Brush Nanostructures on Polymeric Substrates via Extreme Ultraviolet Interference Lithography.

    Science.gov (United States)

    Dübner, Matthias; Gevrek, Tugce N; Sanyal, Amitav; Spencer, Nicholas D; Padeste, Celestino

    2015-06-03

    We demonstrate a new approach to grafting thiol-reactive nanopatterned copolymer-brush structures on polymeric substrates by means of extreme ultraviolet (EUV) interference lithography. The copolymer brushes were designed to contain maleimide functional groups as thiol-reactive centers. Fluoropolymer films were exposed to EUV radiation at the X-ray interference lithography beamline (XIL-II) at the Swiss Light Source, in order to create radical patterns on their surfaces. The radicals served as initiators for the copolymerization of thiol-ene "clickable" brushes, composed of a furan-protected maleimide monomer (FuMaMA) and different methacrylates, namely, methyl methacrylate (MMA), ethylene glycol methyl ether methacrylate (EGMA), or poly(ethylene glycol) methyl ether methacrylate (PEGMA). Copolymerization with ethylene-glycol-containing monomers provides antibiofouling properties to these surfaces. The number of reactive centers on the grafted brush structures can be tailored by varying the monomer ratios in the feed. Grafted copolymers were characterized by using attenuated total reflection infrared (ATR-IR) spectroscopy. The reactive maleimide methacrylate (MaMA) units were utilized to conjugate thiol-containing moieties using the nucleophilic Michael-addition reaction, which proceeds at room temperature without the need for any metal-based catalyst. Using this approach, a variety of functionalities was introduced to yield polyelectrolytes, as well as fluorescent and light-responsive polymer-brush structures. Functionalization of the brush structures was demonstrated via ATR-IR and UV-vis spectroscopy and fluorescence microscopy, and was also indicated by a color switch. Furthermore, grafted surfaces were generated via plasma activation, showing a strongly increased wettability for polyelectrolytes and a reversible switch in static water contact angle (CA) of up to 18° for P(EGMA-co-MaMA-SP) brushes, upon exposure to alternating visible and UV-light irradiation.

  15. Tuning the strength of chemical patterns for directed self-assembly of block copolymers

    Science.gov (United States)

    Williamson, Lance; Lin, Guanyang; Cao, Yi; Gronheid, Roel; Nealey, Paul

    2014-03-01

    Directed self-assembly (DSA) of block copolymers (BCP) via chemo-epitaxy is a potential lithographic solution to patterns of dense features. The LiNe (Liu-Nealey) flow was used to fabricate the chemical pattern, which guides the BCP due to the different wetting behavior of the materials. Fine control of both the chemical pattern chemistry and geometry are important for DSA of BCP. Furthermore, wetting behavior considerations for DSA extend beyond pattern design and include the surrounding region. BCP DSA would be easier to integrate into device design if the patterned region were isolated with a featureless region (horizontal lamellar BCP assembly) rather than undirected BCP fingerprint structures. This paper addresses two processing steps found to be modifying the guide material. For one, the backfill brush grafts to the cross-linked polystyrene (XPS), albeit at a lower rate than the brush grafts to the exposed substrate. Undersaturating the backfill brush only moderately improves the XPS wetting behavior, but also negatively impacts the background region of the chemical pattern. Replacing the brush grafting functionality so that the brush grafts at lower annealing conditions also did not avoid the side reaction between the brush and the XPS. The other step modifying the XPS is the trim etch. Replacing the trim etch process was effective at generating a chemical pattern that can orient the BCP horizontally on a stripe 11 L0 wide passing through a field of chemical pattern.

  16. Using click chemistry to modify block copolymers and their morphologies

    Science.gov (United States)

    Wollbold, Johannes

    Microphase separated block copolymers (BCPs) are emerging as promising templates and scaffolds for the fabrication of nanostructured materials. To achieve the desired nanostructures, it is necessary to establish convenient approaches to control the morphology of BCPs. It remains challenging to induce morphological transitions of BCPs via external fields. Click chemistry, especially alkyne/azide click chemistry, has been widely used to synthesize novel functionalized materials. Here, we demonstrate that alkyne/azide click chemistry can be used as an efficient approach to chemically modify BCPs and therefore induce morphological transitions. Alkyne-functionalized diblock copolymers (di-BCPs) poly(ethylene oxide)- block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) have been successfully synthesized. When the di-BCP is blended with an azide additive Rhodamine B azide and annealed at elevated temperatures, click reaction occurs between the two components. With the Rhodamine B structure attached to the polymer backbone, the di-BCP shows dramatic change in the interactions between the two blocks and the volume fraction of each block. As a result, morphological transitions, such as disorder-to-order transitions (DOTs) and order-to-order transitions (OOTs), are observed. The reaction kinetics and morphology evolution during the click chemistry induced DOTs have been investigated by in-situ and ex-situ characterizations, and fast kinetics properties are observed. Microphase separated morphologies after the DOTs or OOTs are dictated by the composition of neat di-BCPs and the mole ratio between the alkyne and azide groups. The DOTs of PEO-b-P(nBMA-r-PgMA) di-BCPs induced by alkyne/azide click chemistry have also been achieved in thin film geometries, with comparable kinetics to bulk samples. The orientation of the microdomains is dependent on the grafting density of Rhodamine B structure as well as film thickness. At higher grafting densities

  17. Superselective arterial embolisation with a liquid polyvinyl alcohol copolymer in patients with acute gastrointestinal haemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Lenhart, Markus; Schneider, Hans [Sozialstiftung Bamberg, Department of Diagnostic and Interventional Radiology, Bamberg (Germany); Paetzel, Christian [Klinikum Weiden, Department of Radiology, Weiden (Germany); Sackmann, Michael [Sozialstiftung Bamberg, Department of Gastroenterology, Bamberg (Germany); Jung, Ernst Michael; Schreyer, Andreas G.; Feuerbach, Stefan; Zorger, Niels [University of Regensburg, Department of Radiology, Regensburg (Germany)

    2010-08-15

    To evaluate the results of emergency embolisation in acute arterial bleeding of the gastrointestinal tract with a liquid polyvinyl alcohol copolymer from two centres. We retrospectively analysed 16 cases (15 patients) of acute arterial bleeding of the gastrointestinal tract where emergency embolotherapy was performed by using the copolymer when acute haemorrhage was not treatable with endoscopic techniques alone. Cause of haemorrhage and technical and clinical success were documented. Arterial embolotherapy was successful in all 16 cases. The technical success rate was 100%. The cause of bleeding was pancreatitis in four, graft-versus-host disease (GVHD) of the colon in three, malignancy in three, angiodysplasia in two, ulcer in two and panarteritis no dosa and trauma in one each. There were no procedure-related complications. No bowel necrosis occurred because of embolisation. In 13 cases, the patients were discharged in good condition (81%); the three patients with GVHD died because of the underlying disease. The copolymer seems to have great potential in embolotherapy of acute arterial gastrointestinal bleeding. In our series none of the patients had rebleeding at the site of embolisation and no clinically obvious bowel necrosis occurred. (orig.)

  18. Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

    Science.gov (United States)

    Li, Jian-Hua; Li, Mi-Zi; Miao, Jing; Wang, Jia-Bin; Shao, Xi-Sheng; Zhang, Qi-Qing

    2012-06-01

    An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

  19. Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianhua, E-mail: jhli_2005@163.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Zhang Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China) and Institute of Biomedical Engineering, Chinese Academy of Medical Science, Peking Union Medical College, Tianjin 300192 (China)

    2012-06-15

    An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

  20. Hydrogen-bond interaction assisted branched copolymer HILIC material for separation and N-glycopeptides enrichment.

    Science.gov (United States)

    Shao, Wenya; Liu, Jianxi; Yang, Kaiguang; Liang, Yu; Weng, Yejing; Li, Senwu; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-09-01

    Hydrophilic interaction chromatography (HILIC) has attracted increasing attention in recent years due to its efficient application in the separation of polar compounds and the enrichment of glycopeptides. However, HILIC materials are still of weak hydrophilicity and thereby present weak retention and selectivity. In this work, branched copolymer modified hydrophilic material Sil@Poly(THMA-co-MBAAm), with high hydrophilicity and unique "claw-like" polyhydric groups, were prepared by "grafting from" thiol-ene click reaction. Due to the abundant functional groups provided by branched copolymer, the material showed excellent retention for nucleosides, necleobases, acidic compounds, sugars and peptides. Furthermore, Sil@Poly(THMA-co-MBAAm) was also applied for the N-glycosylation sites profiling towards the digests of the mouse brain, and 1997N-glycosylated peptides were identified, corresponding to 686 glycoprotein groups. Due to the assisted hydrogen-bond interaction, the selectivity for glycopeptide enrichment in the real sample reached 94.6%, which was the highest as far as we know. All these results indicated that such hydrogen-bond interaction assisted branched copolymer HILIC material possessed great potential for the separation and large scale glycoproteomics analysis.

  1. SELF ASSEMBLY OF ABC TRIBLOCK COPOLYMER THIN FILMS ON A BRUSH-COATED SUBSTRATE

    Institute of Scientific and Technical Information of China (English)

    Zhi-bin Jiang; Rong Wang; Gi Xue

    2009-01-01

    Self assemblies of ABC triblock copolymer thin films on a densely brush-coated substrate were investigated by using the self-consistent field theory. The middle block B and the coated polymer form one phase and the alternating phase A and phase C occur when the film is very thin either for the neutral or selective hard surface (which is opposite to the brush-coated substrate). The lamellar phase is stable on the hard surface when it is neutral and interestingly, the short block tends to stay on this hard surface. The rippled structure forms when the cylindrical phase exists near the surface between grafted polymers and ABC block copolymers. Due to the existence of the hydrophilic brush-coated surface serving as a soft surface of the film, the energy fluctuation existing in the film confined by two hard surfaces disappears. The results are helpful for designing the nanopattern of the film and realizing the functional thin film, such as adding the functional short block A to the BC diblock copolymer.

  2. The influence of chain stretching on the phase behavior of multiblock copolymer and comb copolymer melts

    NARCIS (Netherlands)

    Angerman, HJ; ten Brinke, G

    The subject of this paper is inspired by microphase-separated copolymer melts in which a small-scale structure is present inside one of the phases of a large-scale structure. Such a situation can arise in a diblock copolymer melt, if one of the blocks of the diblock is in itself a multiblock

  3. Biodegradable IPN hydrogel beads of pectin and grafted alginate for controlled delivery of diclofenac sodium.

    Science.gov (United States)

    Giri, Tapan Kumar; Thakur, Deepa; Alexander, Amit; Ajazuddin; Badwaik, Hemant; Tripathy, Minaketan; Tripathi, Dulal Krishna

    2013-05-01

    A novel diclofenac sodium (DS) loaded interpenetrating polymer network (IPN) beads of pectin and hydrolyzed polyacrylamide-graft-sodium alginate (PAAm-g-SA) was developed through ionotropic gelation and covalent cross-linking. The graft copolymer was synthesized by free radical polymerization under the nitrogen atmosphere followed by alkaline hydrolysis. The grafting, alkaline hydrolysis, and characterization of beads were confirmed by Fourier transforms infrared spectroscopy. The crystalline structure of drug after encapsulation into IPN beads were evaluated by differential scanning colorimetry and X-ray diffraction analyses. DS encapsulation was up to 96.45 %. The effect of hydrolyzed graft copolymer/pectin ratios and glutaraldehyde concentration on drug release in acidic and phosphate buffer solutions were investigated. The release of drug was significantly increased with increase of pH. The release of drug depends on the extent of cross-linking. The results indicated that IPN beads of hydrolyzed PAAm-g-SA and pectin could be used for sustained release of DS.

  4. Sorption studies on Cr (VI) removal from aqueous solution using cellulose grafted with acrylonitrile monomer.

    Science.gov (United States)

    Hajeeth, T; Sudha, P N; Vijayalakshmi, K; Gomathi, T

    2014-05-01

    Graft copolymerization of acrylonitrile on to cellulosic material derived from sisal fiber can be initiated effectively with ceric ammonium nitrate. The grafting conditions were optimized by changing the concentration of initiator and monomer. The change in crystallinity of the grafted polymeric samples was concluded from the XRD patterns. The prepared cellulose grafted acrylonitrile copolymer was used as an adsorbent to remove Cr (VI) ions from aqueous solutions. The efficiency of the adsorbent was identified from the variation in the percentage of adsorption with contact time, adsorbent dose and pH. From the observed results it was evident that the adsorption of metal ions increases with the increase in contact time and metal ion concentration. An optimum pH was found to be 5.0 for the removal of Cr (VI) from the aqueous solution. The results of the Langmuir, Freundlich, and pseudo first- and second-order studies revealed that the adsorption was found to fit well with Freundlich isotherm and follows pseudo second-order kinetics. From the above results, it was concluded that the cellulose-g-acrylonitrile copolymer was found to be an efficient adsorbent for the removal of Cr (VI) from aqueous waste generated from industries.

  5. [Chickenpox, burns and grafts].

    Science.gov (United States)

    Rojas Zegers, J; Fidel Avendaño, L

    1979-01-01

    An outbreak of chickenpox that occurred at the Burns Repair Surgery Unit, Department of Children's Surgery, Hospital R. del Río, between June and November, 1975, is reported. 27 cases of burned children were studied, including analysis of correlations of the stages and outcome of the disease (varicela), the trauma (burns) and the graft (repair surgery). As a result, the authors emphasize the following findings: 1. Burns and their repair are not aggravating factors for varicella. In a small number of cases the exanthema looked more confluent in the graft surgical areas and in the first degree burns healing spontaneously. 2. Usually there was an uneventful outcome of graft repair surgery on a varicella patient, either during the incubation period, the acme or the convalescence. 3. The fact that the outmost intensity of secondary viremia of varicella occurs before the onset of exanthemia, that is, during the late incubation period, is confirmed.

  6. Alveolar bone grafting

    Directory of Open Access Journals (Sweden)

    Lilja Jan

    2009-10-01

    Full Text Available In patients with cleft lip and palate, bone grafting in the mixed dentition in the residual alveolar cleft has become a well-established procedure. The main advantages can be summarised as follows: stabilisation of the maxillary arch; facilitation of eruption of the canine and sometimes facilitation of the lateral incisor eruption; providing bony support to the teeth adjacent to the cleft; raising the alar base of the nose; facilitation of closure of an oro-nasal fistula; making it possible to insert a titanium fixture in the grafted site and to obtain favourable periodontal conditions of the teeth within and adjacent to the cleft. The timing of the ABG surgery take into consideration not only eruption of the canine but also that of the lateral incisor, if present. The best time for bone grafting surgery is when a thin shell of bone still covers the soon erupting lateral incisor or canine tooth close to the cleft.

  7. Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

    Science.gov (United States)

    Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si; Wang, Jin; Huang, Nan

    2016-11-01

    Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

  8. Arteriovenous shunt graft ulceration with sinus and graft epithelialization

    Directory of Open Access Journals (Sweden)

    Pooja Singhal

    2015-03-01

    Full Text Available Arteriovenous fistula and grafts are used as access sites for patients with chronic kidney disease and are prone for complications. Stent grafts are used to treat access site complications. We report a rare and unusual finding of epithelialization of the sinus tract and the lumen of a polytetrafluoroethylene graft, following ulceration of the overlying skin.

  9. Polyhydroxyalkanoate copolymers from forest biomass.

    Science.gov (United States)

    Keenan, Thomas M; Nakas, James P; Tanenbaum, Stuart W

    2006-07-01

    The potential for the use of woody biomass in poly-beta-hydroxyalkanoate (PHA) biosynthesis is reviewed. Based on previously cited work indicating incorporation of xylose or levulinic acid (LA) into PHAs by several bacterial strains, we have initiated a study for exploring bioconversion of forest resources to technically relevant copolymers. Initially, PHA was synthesized in shake-flask cultures of Burkholderia cepacia grown on 2.2% (w/v) xylose, periodically amended with varying concentrations of levulinic acid [0.07-0.67% (w/v)]. Yields of poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) [P(3HB-co-3HV)] from 1.3 to 4.2 g/l were obtained and could be modulated to contain from 1.0 to 61 mol% 3-hydroxyvalerate (3HV), as determined by 1H and 13C NMR analyses. No evidence for either the 3HB or 4HV monomers was found. Characterization of these P(3HB-co-3HV) samples, which ranged in molecular mass (viscometric, Mv) from 511-919 kDa, by differential scanning calorimetry and thermogravimetric analyses (TGA) provided data which were in agreement for previously reported P(3HB-co-3HV) copolymers. For these samples, it was noted that melting temperature (Tm) and glass transition temperature (Tg) decreased as a function of 3HVcontent, with Tm demonstrating a pseudoeutectic profile as a function of mol% 3HV content. In order to extend these findings to the use of hemicellulosic process streams as an inexpensive carbon source, a detoxification procedure involving sequential overliming and activated charcoal treatments was developed. Two such detoxified process hydrolysates (NREL CF: aspen and CESF: maple) were each fermented with appropriate LA supplementation. For the NREL CF hydrolysate-based cultures amended with 0.25-0.5% LA, P(3HB-co-3HV) yields, PHA contents (PHA as percent of dry biomass), and mol% 3HV compositions of 2.0 g/l, 40% (w/w), and 16-52 mol% were obtained, respectively. Similarly, the CESF hydrolysate-based shake-flask cultures yielded 1.6 g/l PHA, 39% (w

  10. Cross-linked nanoassemblies from poly(ethylene glycol)-poly(aspartate) block copolymers as stable supramolecular templates for particulate drug delivery.

    Science.gov (United States)

    Lee, Hyun Jin; Bae, Younsoo

    2011-07-11

    Block copolymer cross-linked nanoassemblies (CNAs) were developed as stable supramolecular templates for particulate drug delivery. Poly(ethylene glycol)-poly(aspartate) [PEG-p(Asp)] block copolymers, consisting of PEG (5 or 12 kDa) and Asp (5, 14, 25, 33, and 37 repeating units), were used as scaffolds and grafts in combination to prepare a nanoassembly library of grafted nanoassemblies (GNAs) and CNAs. Four synthesis routes were tested to maximize the number of drug-binding Asp units per nanoassembly. Grafting-onto-scaffold and grafting-from-scaffold methods were used for GNA synthesis. Either partially or completely deprotected PEG-p(Asp) was cross-linked with diamine compounds to prepare CNAs. (1)H NMR and GPC measurements showed that GNAs and CNAs contained the maximum 183 and 253 Asp units, respectively. Initial screening of the nanoassemblies revealed that GNAs would be impractical for further development as drug carriers due to variable grafting efficiency and low product yields. CNAs were obtained in high yields and identified as a promising supramolecular template that can entrap and release ionizable drugs (doxorubicin), enhancing the particle stability of nanoassemblies in the pharmaceutically relevant pH ranges between 4 and 9. Light scattering measurements demonstrated that the particle size of CNAs remained uniform before and after drug entrapment, causing neither aggregation nor dissociation (<5 mg/mL).

  11. Surface modification by γ-ray-induced grafting of PDMAEMA/PEGMEMA onto PE films

    Science.gov (United States)

    Titaux, G. A.; Contreras-García, A.; Bucio, E.

    2009-07-01

    Radiation grafting of poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) onto polyethylene (PE) films was synthesized using gamma radiation from a 60Co source. PE was modified by the PDMAEMA and PEGMEMA by pre-irradiation and one-step method. Grafting as a function of the pre-irradiation dose between 50 and 200 kGy, dose rate of 9 kGy h -1, and monomer concentration 50% of PDMAEMA/PEGMEMA (1/1) in toluene. The characterization of the graft copolymer obtained was carried out by FTIR-ATR, TGA, and DSC. Stimuli-responsive behavior and critical pH point were studied by swelling in water, pH and thermo-responsive films of PE-g-(DMAEMA/PEGMEMA) presented a lower critical solution temperature (LCST) of 55 °C and critical pH point around 8.5.

  12. Grafting amphiphilic brushes onto halloysite nanotubes via a living RAFT polymerization and their Pickering emulsification behavior.

    Science.gov (United States)

    Hou, Yifan; Jiang, Junqing; Li, Kai; Zhang, Yanwu; Liu, Jindun

    2014-02-20

    Amphiphilic brushes of poly(4-vinylpyridine)-block-polystyrene (P4VP-b-PS) and polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) are grafted onto halloysite nanotubes (HNTs) via a surface reversible addition-fragmentation chain transfer (RAFT) living polymerization through anchoring R group in RAFT agent S-1-dodecyl-S'-(R,R'-dimethyl-R″-acetic acid) trithiocarbonates (DDMAT). The characterization of TGA, TEM, and GPC show that amphiphilic brushes are successfully grafted onto HNTs in a living manner. To verify the amphiphilicity of HNTs grafted with block copolymers, their Pickering emulsification behavior in water/soybean oil diphase mixture is studied. The results show that modified HNTs can emulsify water/soybean oil diphase mixture and the emulsification performance is dependent on microstructure of amphiphilic brushes such as hydrophilic/hydrophobic segment size and sequence.

  13. Surface modification by {gamma}-ray-induced grafting of PDMAEMA/PEGMEMA onto PE films

    Energy Technology Data Exchange (ETDEWEB)

    Titaux, G.A. [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico); Contreras-Garcia, A. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico); Bucio, E. [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico DF 04510 (Mexico)], E-mail: ebucio@nucleares.unam.mx

    2009-07-15

    Radiation grafting of poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) onto polyethylene (PE) films was synthesized using gamma radiation from a {sup 60}Co source. PE was modified by the PDMAEMA and PEGMEMA by pre-irradiation and one-step method. Grafting as a function of the pre-irradiation dose between 50 and 200 kGy, dose rate of 9 kGy h{sup -1}, and monomer concentration 50% of PDMAEMA/PEGMEMA (1/1) in toluene. The characterization of the graft copolymer obtained was carried out by FTIR-ATR, TGA, and DSC. Stimuli-responsive behavior and critical pH point were studied by swelling in water, pH and thermo-responsive films of PE-g-(DMAEMA/PEGMEMA) presented a lower critical solution temperature (LCST) of 55 deg. C and critical pH point around 8.5.

  14. Polyamide copolymers having 2,5-furan dicarboxamide units

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Bret Ja; Samanta, Satyabrata

    2017-09-19

    Polyamide copolymers, and methods of making and using polyamide copolymers, having 2,5-furan dicarboxamide units are disclosed herein. Such polymers can be useful for engineering thermoplastics having advantageous physical and/or chemical properties.

  15. Primary renal graft thrombosis

    NARCIS (Netherlands)

    Bakir, N; Sluiter, WJ; Ploeg, RJ; van Son, WJ; Tegzess, Adam

    1996-01-01

    Background. Renal allograft thrombosis is a serious complication of kidney transplantation that ultimately leads to graft loss. Its association with acute and hyperacute rejection is well documented; however, in a large proportion of patients the precise cause remains obscure. The exact incidence an

  16. Photo-induced Synthesis and Characterization of Poly(methyl methacrylate) Grafted Sodium Salt of Partially Carboxymethylated Guar Gum

    Institute of Scientific and Technical Information of China (English)

    J.H.Trivedi; M.D.Thaker; H.C.Trivedi

    2014-01-01

    Photo-induced graft copolymerization of methyl methacrylate (MMA) onto sodium salt of partially carboxymethylated guar gum (Na-PCMGG,DS =0.291) was carried out in an aqueous medium using ceric ammonium nitrate (CAN) as photoinitiator to synthesize a novel graft copolymer,Na-PCMGG-g-PMMA,which may find its potential application as a metal adsorbent.The influences of synthesis variables such as concentrations of photoinitiator (CAN),nitric acid and monomer (MMA) as well as reaction time,temperature and amount of substrate on the grafting yields were studied and the reaction conditions for optimum photo-grafting were evaluated.At optimum concentration,the maximum values of the grafting yields achieved were G =271.61% and GE =63.89%.The experimental results were found to be in very good agreement with the proposed kinetic scheme.The photo-graft copolymerization of MMA onto Na-PCMGG (DS =0.291) was also carried out in the presence and absence of ultraviolet radiation for studying the efficiency of the photoinitiator.The influence of carboxymethyl groups introduced onto the guar gum molecules with regard to its behavior towards ultra-violet radiation induced grafting with MMA was also investigated.Photo-grafting process was confirmed and the products were characterized with the help of the spectroscopic (1H-NMR and FTIR) and SEM techniques.

  17. Exploring the effect of hydrophilic and hydrophobic structure of grafted polymeric micelles on drug loading.

    Science.gov (United States)

    Shi, Chenjun; Sun, Yujiao; Wu, Haiyang; Zhu, Chengyun; Wei, Guoguang; Li, Jinfeng; Chan, Tenglan; Ouyang, Defang; Mao, Shirui

    2016-10-15

    The objective of this paper is to explore the effect of hydrophilic and hydrophobic structure of grafted polymeric micelles on drug loading, and elucidate whether drug-polymer compatibility, as predicted by Hansen solubility parameters (HSPs), can be used as a tool for drug-polymer pairs screening and guide the design of grafted polymeric micelles. HSPs of 27 drugs and three grafted copolymers were calculated according to group contribution method. The drug-polymer compatibilities were evaluated using the approaches of Flory-Huggins interaction parameters (χFH) and polarity difference (△Xp). Two models, model A and B, were put forward for drug-polymer compatibility prediction. In model A, hydrophilic/hydrophobic part as a whole was regarded as one segment. And, in model B, hydrophilic and hydrophobic segments were evaluated individually. First of all, using chitosan (CS)-grafted-glyceryl monooeate (GMO) based micelle as an example, the suitability of model A and model B for predicating drug-polymer compatibility was evaluated theoretically. Thereafter, corresponding experiments were carried out to check the validity of the theoretical prediction. It was demonstrated that Model B, which evaluates drug compatibility with both hydrophilic and hydrophobic segments of the copolymer, is more reliable for drug-polymer compatibility prediction. Moreover, the approach of model B allows for the selection of a defined grafted polymer with for a specific drug and vice versa. Thus, drug compatibility evaluation via HSPs with both hydrophilic and hydrophobic segments is a suitable tool for the rational design of grafted polymeric micelles. The molecular dynamics (MD) simulation study provided further support to the established model and experimental results.

  18. Oil recovery with vinyl sulfonic acid-acrylamide copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Norton, C.J.; Falk, D.O.

    1973-12-18

    An aqueous polymer flood containing sulfomethylated alkali metal vinyl sulfonate-acrylamide copolymers was proposed for use in secondary or tertiary enhanced oil recovery. The sulfonate groups on the copolymers sustain the viscosity of the flood in the presence of brine and lime. Injection of the copolymer solution into a waterflooded Berea core, produced 30.5 percent of the residual oil. It is preferred that the copolymers are partially hydrolyzed.

  19. Chain exchange in block copolymer micelles

    Science.gov (United States)

    Lu, Jie; Bates, Frank; Lodge, Timothy

    2014-03-01

    Block copolymer micelles are aggregates formed by self-assembly of amphiphilic copolymers dispersed in a selective solvent, driven by unfavorable interactions between the solvent and the core-forming block. Due to the relatively long chains being subject to additional thermodynamic and dynamic constraints (e.g., entanglements, crystallinity, vitrification), block copolymer micelles exhibit significantly slower equilibration kinetics than small molecule surfactants. As a result, details of the mechanism(s) of equilibration in block copolymer micelles remain unclear. This present works focuses on the chain exchange kinetics of poly(styrene-b-ethylenepropylene) block copolymers in squalane (C30H62) using time-resolved small angle neutron scattering (TR-SANS). A mixture of h-squalane and d-squalane is chosen so that it contrast matches a mixed 50/50 h/d polystyrene micelle core. When the temperature is appropriate and isotopically labeled chains undergo mixing, the mean core contrast with respect to the solvent decreases, and the scattering intensity is therefore reduced. This strategy allows direct probing of chain exchange rate from the time dependent scattering intensity I(q, t).

  20. Thermoreversible copolymer gels for extracellular matrix.

    Science.gov (United States)

    Vernon, B; Kim, S W; Bae, Y H

    2000-07-01

    To improve the properties of a reversible synthetic extracellular matrix based on a thermally reversible polymer, copolymers of N-isopropylacrylamide and acrylic acid were prepared in benzene with varying contents of acrylic acid (0 to 3%) and the thermal properties were evaluated. The poly(N-isopropylacrylamide) and copolymers made with acrylic acid had molecular weights from 0.8 to 1.7 x10(6) D. Differential scanning calorimetry (DSC) showed the high-molecular-weight acrylic acid copolymers had similar onset temperatures to the homopolymers, but the peak width was considerably increased with increasing acrylic acid content. DSC and cloud point measurements showed that polymers with 0 to 3% acrylic acid exhibit a lower critical solution temperature (LCST) transition between 30 degrees and 37 degrees C. In swelling studies, the homopolymer showed significant syneresis at temperatures above 31 degrees C. Copolymers with 1 and 1.5% showed syneresis beginning at 32 degrees and 37 degrees C, respectively. At 37 degrees C the copolymers with 1.5-3% acrylic acid showed little or no syneresis. Due to the high water content and a transition near physiologic conditions (below 37 degrees C), the polymers with 1.5-2.0% acrylic acid exhibited properties that would be useful in the development of a refillable synthetic extracellular matrix. Such a matrix could be applied to several cell types, including islets of Langerhans, for a biohybrid artificial pancreas.

  1. Charge Transport in Conjugated Block Copolymers

    Science.gov (United States)

    Smith, Brandon; Le, Thinh; Lee, Youngmin; Gomez, Enrique

    Interest in conjugated block copolymers for high performance organic photovoltaic applications has increased considerably in recent years. Polymer/fullerene mixtures for conventional bulk heterojunction devices, such as P3HT:PCBM, are severely limited in control over interfaces and domain length scales. In contrast, microphase separated block copolymers self-assemble to form lamellar morphologies with alternating electron donor and acceptor domains, thereby maximizing electronic coupling and local order at interfaces. Efficiencies as high as 3% have been reported in solar cells for one block copolymer, P3HT-PFTBT, but the details concerning charge transport within copolymers have not been explored. To fill this gap, we probed the transport characteristics with thin-film transistors. Excellent charge mobility values for electron transport have been observed on aluminum source and drain contacts in a bottom gate, bottom contact transistor configuration. Evidence of high mobility in ordered PFTBT phases has also been obtained following thermal annealing. The insights gleaned from our investigation serve as useful guideposts, revealing the significance of the interplay between charge mobility, interfacial order, and optimal domain size in organic block copolymer semiconductors.

  2. Multifaceted prospects of nanocomposites for cardiovascular grafts and stents.

    Science.gov (United States)

    Vellayappan, Muthu Vignesh; Balaji, Arunpandian; Subramanian, Aruna Priyadarshini; John, Agnes Aruna; Jaganathan, Saravana Kumar; Murugesan, Selvakumar; Supriyanto, Eko; Yusof, Mustafa

    2015-01-01

    Cardiovascular disease is the leading cause of death across the globe. The use of synthetic materials is indispensable in the treatment of cardiovascular disease. Major drawbacks related to the use of biomaterials are their mechanical properties and biocompatibility, and these have to be circumvented before promoting the material to the market or clinical setting. Revolutionary advancements in nanotechnology have introduced a novel class of materials called nanocomposites which have superior properties for biomedical applications. Recently, there has been a widespread recognition of the nanocomposites utilizing polyhedral oligomeric silsesquioxane, bacterial cellulose, silk fibroin, iron oxide magnetic nanoparticles, and carbon nanotubes in cardiovascular grafts and stents. The unique characteristics of these nanocomposites have led to the development of a wide range of nanostructured copolymers with appreciably enhanced properties, such as improved mechanical, chemical, and physical characteristics suitable for cardiovascular implants. The incorporation of advanced nanocomposite materials in cardiovascular grafts and stents improves hemocompatibility, enhances antithrombogenicity, improves mechanical and surface properties, and decreases the microbial response to the cardiovascular implants. A thorough attempt is made to summarize the various applications of nanocomposites for cardiovascular graft and stent applications. This review will highlight the recent advances in nanocomposites and also address the need of future research in promoting nanocomposites as plausible candidates in a campaign against cardiovascular disease.

  3. SCATTERING BY CYCLIC POLYMERS AND COPOLYMERS AT LARGE SCATTERING VECTORS

    NARCIS (Netherlands)

    KOSMAS, M; BENOIT, H; HADZIIOANNOU, G

    1994-01-01

    General formulae allowing the evaluation of the form factors of cyclic block copolymers are established and graphs for cyclic copolymers of the form (A-B)(N) are shown. When N is large, the linear and the cyclic copolymer have the same behaviour. It is possible to extend at large angle an analytical

  4. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as a food-contact surface of articles intended for...

  5. 21 CFR 173.60 - Dimethylamine-epichlorohydrin copolymer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dimethylamine-epichlorohydrin copolymer. 173.60... HUMAN CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.60 Dimethylamine-epichlorohydrin copolymer. Dimethylamine-epichlorohydrin copolymer (CAS Reg. No. 25988-97-0) may be safely used in...

  6. SCATTERING BY CYCLIC POLYMERS AND COPOLYMERS AT LARGE SCATTERING VECTORS

    NARCIS (Netherlands)

    KOSMAS, M; BENOIT, H; HADZIIOANNOU, G

    1994-01-01

    General formulae allowing the evaluation of the form factors of cyclic block copolymers are established and graphs for cyclic copolymers of the form (A-B)(N) are shown. When N is large, the linear and the cyclic copolymer have the same behaviour. It is possible to extend at large angle an analytical

  7. 21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate copolymers. 177.1350 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate copolymers may be safely used as articles or components of...

  8. Cyclen Grafted with poly[(Aspartic acid)-co-Lysine]: Preparation, Assembly with Plasmid DNA, and in Vitro Transfection Studies.

    Science.gov (United States)

    Ma, Chunying; Zhang, Jin; Guo, Liwen; Du, Changguo; Song, Ping; Zhao, Baojing; Li, Ling; Li, Chao; Qiao, Renzhong

    2016-01-04

    Development of safe and effective gene carriers is the key to the success of gene therapy. Nowadays, it is still required to develop new methods to improve nonviral gene delivery efficiency. Herein, copolymers of poly[(aspartic acid)-co-lysine] grafted with cyclen (cyclen-pAL) were designed and evaluated for efficient gene delivery. Two copolymers with different Asp/Lys block ratios were prepared and characterized by NMR and gel permeation chromatography analysis. Agarose gel retardation, circular dichroism, and fluorescent quenching assays showed the strong DNA-binding and protection ability for the title compounds. Atomic force microscopy studies clearly delineated uniform DNA globules with a diameter around 100 nm, induced by cyclen-pAL. By grafting cyclen on Asp, relatively high gene delivery efficiency and low cytotoxicity of the modified copolymers were achieved compared with their parent compounds. The present work might help to develop strategies for design and modification of polypeptide copolymers, which may also be applied to favorable gene expression and delivery.

  9. Preparation of end-grafted polymer brushes by nitroxide-mediated free radical polymerization of vaporized vinyl monomers.

    Science.gov (United States)

    Li, Jun; Chen, Xiaoru; Chang, Ying-Chih

    2005-10-11

    In this work, we report a gas-phase polymerization approach to create end-grafted vinyl based polymer films on silicon oxide based substrates. The "surface-initiated vapor deposition polymerization" (SI-VDP) of vaporized vinyl monomers, via the nitroxide-mediated free radical polymerization mechanism, was developed to fabricate various homo- and block copolymer brushes from surface-bound initiators, 1-(4'-oxa-2'-phenyl-12'-trimethoxysilyldodecyloxy)-2,2,6,6-tetra-methylpiperidine ("TEMPO"). The resulting polymer thin films were characterized by the Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ellipsometry, and contact angle goniometry, respectively, to identify the surface composition, film thickness, surface coverage, and water contact angles. Through the SI-VDP, end-grafted polymer films of polystyrene (PSt), poly(acrylic acid) (PAAc), poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA), and poly(N-isopropylacrylamide) (PNIPAAm) with 10-200 nm thicknesses were fabricated. Furthermore, the block copolymer films of PAAc (1st block)-b-PSt (2nd block), PSt (1st block)-b-PAAc (2nd block), and a triblock copolymer film of PAAc (1st)-b-PSt (2nd)-b-PHPMA (3rd), were also fabricated, suggesting the "renewability" of the TEMPO-initiated polymerization in the SI-VDP scheme. It is also noticed that the SI-VDP is more efficient than the conventional solution phase polymerization in producing functional polymer brushes such as PNIPAAm, PAAc, or PAAc-b-PSt end-grafted films. In summary, our studies have shown clear advantages of the SI-VDP setup for the nitroxide-mediated polymerization scheme in controlling synthesis of end-grafted homo- and copolymer thin films.

  10. Stable dropwise condensation for enhancing heat transfer via the initiated chemical vapor deposition (iCVD) of grafted polymer films.

    Science.gov (United States)

    Paxson, Adam T; Yagüe, Jose L; Gleason, Karen K; Varanasi, Kripa K

    2014-01-22

    Ultra-thin copolymer films are deposited by initiated chemical deposition (iCVD) to investigate their performance under the condensation of water vapor. By forming a grafted interface between the coating and the substrate, the films exhibit stable dropwise condensation even when subjected to 100 °C steam. The applicability of the iCVD to complex substrate geometries is demonstrated on a copper condenser coil.

  11. Effect of the hydrophobic basal layer of thermoresponsive block co-polymer brushes on thermally-induced cell sheet harvest.

    Science.gov (United States)

    Matsuzaka, Naoki; Takahashi, Hironobu; Nakayama, Masamichi; Kikuchi, Akihiko; Okano, Teruo

    2012-01-01

    Thermoresponsive poly(benzyl methacrylate)-b-poly(N-isopropylacrylamide) (PBzMA-b-PIPAAm) block co-polymer brush surfaces were prepared by surface-initiated two-step reversible addition-fragmentation chain transfer radical (RAFT) polymerization. PBzMA brushes were fabricated on azoinitiator-immobilized glass substrates in the presence of dithiobenzoate (DTB) compound as a RAFT agent. The amount of grafted polymer was regulated by initial monomer concentrations. The second thermoresponsive blocks were added to the RAFT-related DTB groups located at PBzMA termini through the propagation of PIPAAm chains, resulting in formation of PBzMA-b-PIPAAm brushes. Surface characteristics of the block co-polymer brushes and its influence on thermally regulated cellular behavior were investigated using bovine carotid artery endothelial cells (BAECs), compared with PIPAAm brush surfaces. Cell adhesion/detachment behavior on thermoresponsive polymer brush surfaces significantly depended on their individual polymer architectures and chemical compositions of grafted polymers. Low-temperature treatment at 20°C, below the phase-transition temperature of PIPAAm, induced the spontaneous detachment of adhering cells from the PBzMA-b-PIPAAm brush surfaces with a higher rate than that from PIPAAm brush surfaces. In addition, the cell-repellent effect of the hydrophobic basal layer successfully accelerated for harvesting BAEC sheets from the block co-polymer brush surfaces. Unique features of thermoresponsive block co-polymer brush architectures can be applied to control cell-adhesion strength for enhancing cell adhesion or accelerating cell detachment.

  12. Polyethylene glycol-grafted polyethylenimine used to enhance adenovirus gene delivery.

    Science.gov (United States)

    Singarapu, Kumar; Pal, Ivy; Ramsey, Joshua D

    2013-07-01

    An improved adenoviral-based gene delivery vector was developed by complexing adenovirus (Ad) with a biocompatible, grafted copolymer PEG-g-PEI composed of polyethylene glycol (PEG) and polyethylenimine (PEI). Although an Ad-based gene vector is considered relatively safe, its native tropism, tendency to elicit an immune response, and susceptibility to inactivating antibodies makes the virus less than ideal. The goal of the current study was to determine whether Ad could be complexed with a PEG-g-PEI copolymer that would enable the virus to transduce cells lacking the Ad receptor, while avoiding the issues commonly associated with PEI. A copolymer library was synthesized using 2 kDa PEG and either linear or branched PEI (25 kDa) with a PEG to PEI grafting ratio of 10, 20, or 30. The results of the study indicate that PEG-g-PEI/Ad complexes are indeed able to transduce CAR-negative NIH 3T3 cells. The results also demonstrate that the PEG-g-PEI/Ad complexes are less toxic, less hemolytic, and more appropriately sized than PEI/Ad complexes.

  13. Synthesis of amphiphilic diblock copolymer for surface modification of Ethylene-Norbornene copolymers

    DEFF Research Database (Denmark)

    Levinsen, Simon; Svendsen, Winnie Edith; Horsewell, Andy

    2014-01-01

    -norbornene copolymer TOPAS. Through matching of the radius of gyration for the model polymer and TOPAS the miscibility was achieved. The poly(ethylene-1-butene) polymer was synthesized from a hydrogenated anionic polymerized polybutadiene polymer. As hydrophilic block poly(ethylene oxide) was subsequently added also...... consisting of a bulk material compatible block and a hydrophilic block. To utilize the possibility of incorporating diblock copolymers into ethylenenorbornene copolymers, we have in this work developed a model poly(ethylene-1-butene) polymer compatible with the commercial available ethylene...

  14. Functionalization of Block Copolymer Vesicle Surfaces

    Directory of Open Access Journals (Sweden)

    Wolfgang Meier

    2011-01-01

    Full Text Available In dilute aqueous solutions certain amphiphilic block copolymers self-assemble into vesicles that enclose a small pool of water with a membrane. Such polymersomes have promising applications ranging from targeted drug-delivery devices, to biosensors, and nanoreactors. Interactions between block copolymer membranes and their surroundings are important factors that determine their potential biomedical applications. Such interactions are influenced predominantly by the membrane surface. We review methods to functionalize block copolymer vesicle surfaces by chemical means with ligands such as antibodies, adhesion moieties, enzymes, carbohydrates and fluorophores. Furthermore, surface-functionalization can be achieved by self-assembly of polymers that carry ligands at their chain ends or in their hydrophilic blocks. While this review focuses on the strategies to functionalize vesicle surfaces, the applications realized by, and envisioned for, such functional polymersomes are also highlighted.

  15. Additive-driven assembly of block copolymers

    Science.gov (United States)

    Lin, Ying; Daga, Vikram; Anderson, Eric; Watkins, James

    2011-03-01

    One challenge to the formation of well ordered hybrid materials is the incorporation of nanoscale additives including metal, semiconductor and dielectric nanoparticles at high loadings while maintaining strong segregation. Here we describe the molecular and functional design of small molecule and nanoparticle additives that enhance phase segregation in their block copolymer host and enable high additive loadings. Our approach includes the use of hydrogen bond interactions between the functional groups on the additive or particle that serve as hydrogen bond donors and one segment of the block copolymer containing hydrogen bond acceptors. Further, the additives show strong selectively towards the targeted domains, leading to enhancements in contrast between properties of the phases. In addition to structural changes, we explore how large changes in the thermal and mechanical properties occur upon incorporation of the additives. Generalization of this additive-induced ordering strategy to various block copolymers will be discussed.

  16. Nanoscale Ionic Aggregate Morphology in Zwitterionic Copolymers

    Science.gov (United States)

    Choi, Jae-Hong; Huyck, Rebecca; Salas-de La Cruz, David; Long, Timothy E.; Winey, Karen I.

    2009-03-01

    The morphology of two different zwitterionic copolymers, poly(sulfobetaine methacrylate-ran-butyl acrylate), and poly(sulfobetaine methacrylamide-ran-butyl acrylate) are investigated as a function of the mol % content of SBMA (7 and 9 mol %) and SBMAm (6, 10 and 13 mol %), respectively. In both copolymers, X-ray scattering results show a new structure in the material arising from ionic aggregates. The sizes of the ionic aggregates are obtained through the scattering model. The sizes of the ionic aggregates increase as the ion content increases. The application of scanning transmission electron microscopy to the study of ionomer morphology has enabled direct, model-independent visualization of the ionic aggregates. The correlation between X-ray scattering results and the real space imaging for morphology of these zwitterionic copolymers will be presented.

  17. Optical properties of coumarins containing copolymers

    Science.gov (United States)

    Skowronski, L.; Krupka, O.; Smokal, V.; Grabowski, A.; Naparty, M.; Derkowska-Zielinska, B.

    2015-09-01

    We investigate the optical properties such as absorption coefficient, refractive index, real and imaginary parts of dielectric function and energy band gap of coumarin-containing copolymers thin films by means of spectroscopic ellipsometry (SE) combined with transmittance measurements (T) and atomic force microscopy (AFM). We found that the optical properties of coumarin-containing copolymers strongly depend from length of alkyl spacer as well as the type of substitution in coumarin moiety. In our case the refractive index as well as the energy band gap of coumarin-containing copolymer decrease with increase the length of alkyl spacer. Additionally, the lengthening of the alkyl spacer brings the bathochromic shifts of the absorption spectra towards longer wavelengths.

  18. Dynamics of Block Copolymer Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Mochrie, Simon G. J.

    2014-09-09

    A detailed study of the dynamics of cadmium sulfide nanoparticles suspended in polystyrene homopolymer matrices was carried out using X-ray photon correlation spectroscopy for temperatures between 120 and 180 °C. For low molecular weight polystyrene homopolymers, the observed dynamics show a crossover from diffusive to hyper-diffusive behavior with decreasing temperatures. For higher molecular weight polystyrene, the nanoparticle dynamics appear hyper-diffusive at all temperatures studied. The relaxation time and characteristic velocity determined from the measured hyper-diffusive dynamics reveal that the activation energy and underlying forces determined are on the order of 2.14 × 10-19 J and 87 pN, respectively. We also carried out a detailed X-ray scattering study of the static and dynamic behavior of a styrene– isoprene diblock copolymer melt with a styrene volume fraction of 0.3468. At 115 and 120 °C, we observe splitting of the principal Bragg peak, which we attribute to phase coexistence of hexagonal cylindrical and cubic double- gyroid structure. In the disordered phase, above 130 °C, we have characterized the dynamics of composition fluctuations via X-ray photon correlation spectroscopy. Near the peak of the static structure factor, these fluctuations show stretched-exponential relaxations, characterized by a stretching exponent of about 0.36 for a range of temperatures immediately above the MST. The corresponding characteristic relaxation times vary exponentially with temperature, changing by a factor of 2 for each 2 °C change in temperature. At low wavevectors, the measured relaxations are diffusive with relaxation times that change by a factor of 2 for each 8 °C change in temperature.

  19. Graft copolymerization of acrylo–nitrile onto delignified native bamboo (Bambusa vulgaris cellulosic and its utilization potential for heavy metal uptake from aqueous medium

    Directory of Open Access Journals (Sweden)

    M.O. EKEBAFE

    2011-06-01

    Full Text Available Graft polymerization of acrylonitrile onto delingnified cellulosic material obtained from Nigeria grown bamboo (Bambusa vulgaris could be initiated by a ceric ammonium nitrate redox system. Optimization of grafting of acrylonitrile onto cellulosic material was performed by varying the reaction conditions, such as the duration of soaking of cellulosic material in ceric ammonium nitrate solution, concentration of ceric ammonium nitrate solution, polymerization time, temperature of reaction, and acrylonitrile concentration and saponification time, in order to study their influence on percent grafting yield and grafting efficiency. The resulting cellulosic-g-polyacrylonitrile (PAN copolymers were fractionated by extraction at 33 C with N,N’-dimethylformamide. Fractions were characterized by determining both the % add-on and the free polymer. Saponification of grafted copolymer was done by reaction with sodium hydroxide followed by methanol precipitation. The absorbent polymer so produced gave fair water retention values. The optimum reaction conditions obtained were: 20 mmol/L ceric ammonium nitrate solution in 1% nitric acid, soaking duration of 0.5 h at 40 C for a polymerization time of 2 h and saponification time of 3 h. The percent grafting was 167.89%, grafting efficiency was 93.52% and water retention value was 389 g/g. The grafting was confirmed using FTIR. Sorption of different metal ions in the mixture, e.g. Cr, Mn, Ni, Cu and Pb, by grafted cellulosic and the hydrogel was also investigated. Hydrolysis increases the sorption affinity of grafted cellulose toward water and metal ions.

  20. Substrate tolerant direct block copolymer nanolithography

    DEFF Research Database (Denmark)

    Li, Tao; Wang, Zhongli; Schulte, Lars

    2016-01-01

    Block copolymer (BC) self-assembly constitutes a powerful platform for nanolithography. However, there is a need for a general approach to BC lithography that critically considers all the steps from substrate preparation to the final pattern transfer. We present a procedure that significantly...... simplifies the main stream BC lithography process, showing a broad substrate tolerance and allowing for efficient pattern transfer over wafer scale. PDMS-rich poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) copolymers are directly applied on substrates including polymers, silicon and graphene. A single oxygen...

  1. Polaronic Tunnelling in Organic Triblock Copolymers

    Institute of Scientific and Technical Information of China (English)

    LIU De-Sheng; ZHANG Da-Cheng; XIE Shi-Jie; MEI Liang-Mo

    2005-01-01

    @@ Polaron tunnelling is studied in xPA/nPPP/xPA (PA for polyacetylene and PPP poly (p-phenylene)) triblock copolymer, which has a well-barrier-well structure. An extended tight-binding Hamiltonian including external electric field is adopted. Without electric field, the injected electrons would not extend over the whole copolymer chain but instead be confined in the segments of PA. This is different from the behaviour of the traditional semiconductors. It is found that the polaron can transfer to the potential barrier-PPP segment when the applied electric field reaches a certain value. The critical polaron tunnelling electric fields depend upon the lengths of PPP segments.

  2. Co-polymer Films for Sensors

    Science.gov (United States)

    Ryan, Margaret A. (Inventor); Homer, Margie L. (Inventor); Yen, Shiao-Pin S. (Inventor); Kisor, Adam (Inventor); Jewell, April D. (Inventor); Shevade, Abhijit V. (Inventor); Manatt, Kenneth S. (Inventor); Taylor, Charles (Inventor); Blanco, Mario (Inventor); Goddard, William A. (Inventor)

    2012-01-01

    Embodiments include a sensor comprising a co-polymer, the co-polymer comprising a first monomer and a second monomer. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is polystyrene and the second monomer is poly-2-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium benzylamine chloride. Other embodiments are described and claimed.

  3. Ordering phenomena in ABA triblock copolymer gels

    DEFF Research Database (Denmark)

    Reynders, K.; Mischenko, N.; Kleppinger, R.

    1997-01-01

    Temperature and concentration dependencies of the degree of order in ABA triblock copolymer gels are discussed. Two factors can influence the ordering phenomena: the conformation of the midblocks (links of the network) and the polydispersity of the endblock domains (nodes of the network). The lat......Temperature and concentration dependencies of the degree of order in ABA triblock copolymer gels are discussed. Two factors can influence the ordering phenomena: the conformation of the midblocks (links of the network) and the polydispersity of the endblock domains (nodes of the network...

  4. [Grafting of carotid arteries].

    Science.gov (United States)

    Belov, Iu V; Stepanenko, A B; Gens, A P; Bazylev, V V; Seleznev, M N; Savichev, D D

    2005-01-01

    Over 5-years, 167 reconstructive surgeries for stenosis of internal carotid arteries (ICA) were performed in 124 patients. Mean age of the patients was 63.5 years. One hundred and twenty-nine carotid endarterectomies (CEAE) in 86 patients and 38 reconstructive operations of ICA in 38 patients were performed. There were no lethal outcomes in short- and long-term postoperative period. In short-term period after prosthesis of ICA restenosis was revealed in 3% patients, after eversion CEAE in 3% patients the embolism was seen, after standard CEAE restenosis were diagnosed in 8% patients and thrombosis -- in 3%. In long-term period after grafting of ICA the strokes were seen in 3%, stenosis -- in 6% patients, after eversion endarterectomy -- in 0 and 3% patients, and after standard CEAE -- in 3 and 24% patients, respectively. It is concluded that grafting of ICA is adequate surgical method of reconstruction and stroke prevention in specific variants of carotid atherosclerosis.

  5. Electrochemical and spectroscopic characterization of poly (bithiophene + 2-methylfuran) copolymer

    Science.gov (United States)

    Lamiri, Leila; Nessark, Belkacem; Habelhames, Farid; Sibous, Lakhdar

    2017-09-01

    In this work, Poly(bithiophene + 2-methylfuran) copolymer was successfully synthetized by an electrochemical polymerization of two monomers, bithiophene and 2-methylfuran in acetonitrile containing lithium perchlorate. The obtained copolymer was characterized via cyclic voltammetry, impedance spectroscopy, UV-visible, scanning electron microscope, conductivity and photocurrent measurements. The cyclic voltammetry study showed two redox couples characteristic of Poly (bithiophene + 2-methylfuran) copolymer. The impedance spectroscopy study revealed that the resistance of the copolymer film increases with the addition of 2-methylfuran. The photocurrent measurement showed good photoelectrochemical properties, making this copolymer an ideal candidate for photovoltaic cell applications.

  6. Drug governs the morphology of polyalkylated block copolymer aggregates.

    Science.gov (United States)

    Le Dévédec, F; Her, S; Vogtt, K; Won, A; Li, X; Beaucage, G; Yip, C; Allen, C

    2017-02-16

    Polyalkylated copolymers based on mPEG-b-(AGE-C6,12 or 18)25 have been used to formulate clinically relevant concentrations of doxorubicin (DOX) and the impact of drug incorporation on copolymer aggregation behaviour was examined. The copolymer aggregates were analyzed by various microscopy techniques (TEM, cryo-TEM and AFM) and scattering methods (SANS, DLS). In the absence of the drug, the copolymers formed largely non-spherical aggregates (i.e. cylinders, vesicles). Drug incorporation during copolymer aggregate formation directed the formation of only spherical aggregates. As well, the nature of the core-forming block was found to influence drug release and cytotoxicity of the formulations.

  7. Buccal Mucosal Graft Urethroplasty

    Directory of Open Access Journals (Sweden)

    Angela M. Arlen

    2010-01-01

    Full Text Available At our institution, the majority of buccal mucosal graft urethroplasties are performed using a two-team approach with an otolaryngologic surgeon. We report our two-surgeon experience with buccal mucosal grafting for reconstruction of all anterior urethral strictures. Twenty-four men underwent autologous buccal mucosal graft urethroplasty between October 2001 and September 2008 for recurrent urethral stricture disease. Twenty-two underwent a single-stage repair and two underwent a two-stage repair. Medical charts were retrospectively reviewed for demographics, comorbidities, etiology, location and length of stricture, and prior interventions in order to identify predictors of buccal urethroplasty success, defined as no evidence of stricture recurrence. All patients underwent retrograde urethrogram and cystoscopy. Operative and anesthesia times were evaluated. We determined an overall success rate of 83.3% (20 of 24 cases. Mean anesthesia time for single-stage urethroplasty was 155 min and mean operative time was 123 min. One of the two two-stage urethroplasties experienced stricture recurrence (50%. The single-stage buccal graft success rate was 86.4% (19 of 22 cases. Two of the four who developed recurrent stricture disease that required intervention had undergone a previous mesh urethroplasty. Complications developed in four of 24 patients (16.6%, including superficial wound infection (one, superficial wound dehiscence (two, and abscess/fistula formation requiring reoperation (one. The buccal mucosa is an ideal tissue for both single- and two-stage substitution urethroplasty for patients with recurrent stricture disease. Our two-surgeon technique minimizes anesthesia and operative times, and contributes to the overall high success rate and relatively low complication rate.

  8. Block Copolymers of Ethylene Oxide and Styrene Oxide.New Copolymer Surfactants(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    Zhuo Yang; David Attwood; Colin Booth

    2003-01-01

    @@ 3.2. Association Number Figure 5 shows the dependence of the weight-average association number (Nw,measured by static light scattering, solution temperature 30 °C) on hydrophobe block length for ES and ESEblock copolymers.

  9. Molecular Interaction Control in Diblock Copolymer Blends and Multiblock Copolymers with Opposite Phase Behaviors

    Science.gov (United States)

    Cho, Junhan

    2014-03-01

    Here we show how to control molecular interactions via mixing AB and AC diblock copolymers, where one copolymer exhibits upper order-disorder transition and the other does lower disorder-order transition. Linear ABC triblock copolymers possessing both barotropic and baroplastic pairs are also taken into account. A recently developed random-phase approximation (RPA) theory and the self-consistent field theory (SCFT) for general compressible mixtures are used to analyze stability criteria and morphologies for the given systems. It is demonstrated that the copolymer systems can yield a variety of phase behaviors in their temperature and pressure dependence upon proper mixing conditions and compositions, which is caused by the delicate force fields generated in the systems. We acknowledge the financial support from National Research Foundation of Korea and Center for Photofunctional Energy Materials.

  10. Synthesis and self-assembly behavior of a biodegradable and sustainable soybean oil-based copolymer nanomicelle

    Science.gov (United States)

    Bao, Lixia; Bian, Longchun; Zhao, Mimi; Lei, Jingxin; Wang, Jiliang

    2014-08-01

    Herein, we report a novel amphiphilic biodegradable and sustainable soybean oil-based copolymer (SBC) prepared by grafting hydrophilic and biocompatible hydroxyethyl acrylate (HEA) polymeric segments onto the natural hydrophobic soybean oil chains. FTIR, H1-NMR, and GPC measurements have been used to investigate the molecular structure of the obtained SBC macromolecules. Self-assembly behaviors of the prepared SBC in aqueous solution have also been extensively evaluated by fluorescence spectroscopy and transmission electron microscopy. The prepared SBC nanocarrier with the size range of 40 to 80 nm has a potential application in the biomedical field.

  11. Preparation of epoxy resin copolymers with low luminous decay%低光衰环氧树脂共聚物的制备

    Institute of Scientific and Technical Information of China (English)

    冯钠; 张小扉; 张桂霞; 陈涛; 王旭

    2011-01-01

    Copolymers of epoxy resin grafted by hydroxy-terminated silicone(EP-g-HTPDMS) with low luminous decay were prepared by graft condensation polymerization from EP and HTPDMS. The structure of the EP-g-HTPDMS copolymers was characterized by Fourier transform infrared spectroscopy(FTIR) and therm ogravimetric(TG) analysis. The EP-g-HTPDMS copolymers were applied to package of light-emitting diode, and its optical properties were studied by luminous decay and refractive index test. The mechanical properties and micro-morphology of the copolymers were analyzed by hardness tester and scanning electron microscope(SEM). The results indicate that HTPDMS is successfully incorporated into EP molecular chain.Adding HTPDMS has unobvious effect on the refractive index of the copolymers. When HTPDMS mass content is less than 9%, the relative light output of the EP-g-HTPDMS copolymers is higher than that of unmodified EP and luminous decay reduces significantly. The hardness of the copolymers decreases with increasing HTPDMS mass content. The introduction of HTPDMS makes the copolymer exhibit the features of tough fracture, lowers the internal stress in the system and improves the resistance to cracking.%采用接枝缩聚的方法,将端羟基硅酮(HTPDMS)与环氧树脂(EP)反应,制备低光衰HTPDMS接枝EP(EP-g-HTPDMS)共聚物.利用傅里叶变换红外光谱和热重分析表征其结构,并将制备的EP-g-HTPDMS共聚物应用于发光二级管封装,通过测试光衰和折射率分析其光学性能,同时利用硬度测试仪和扫描电子显微镜研究其力学性能和微观结构.结果表明:HTPDMS成功接枝在EP分子链中;引入HTPDMS对共聚物折射率的影响并不明显,当w(HTPDMS)小于9%时,共聚物的相对输出功率均高于EP,光衰明显降低;随着w(HTPDMS)增加,共聚物的硬度减小;引入HTPDMS使共聚物断面呈韧性断裂,体系的内应力降低,抗开裂性能得到改善.

  12. FTIR Spectroscopy characterization of PVC films grafted and heparinized by gamma radiation; Caracterizacao de fimes de PVC enxertados e heparinizados via radiacao gama por espectroscopia FTIR

    Energy Technology Data Exchange (ETDEWEB)

    Panzarini, Luz C.G.A. [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil). Dept. de Engenharia Quimica]. E-mail: luz_con@yahoo.com.br; Guedes, Selma M.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2005-07-01

    Polymeric biomaterials with surface hemo compatibility properties had been successfully synthesized by the grafting of hydrophilic monomers onto commercial polymeric films by the simultaneous gamma irradiation process. In this work was studied the simultaneous gamma irradiation of flexible PVC films in systems containing the hydrophilic monomer DMAEMA in different concentrations (30% and 45%) and heparin sodium salt aqueous solution (0,25% w/v). The irradiation of the samples was carried out in a {sup 60}Co source, with doses of 0-16 kGy and dose rates of 0,5 to 0,8 kGy h{sup -1}. The grafted copolymers obtained by this method were characterized by FTIR-ATR and PAS spectroscopy in both DMAEMA studied concentrations. The graft copolymer characterization, accomplished by FTIR-PAS evidenced the largest grafting levels for the irradiated samples with 45% of DMAEMA, however heparin presence was only evident on irradiated samples with 30% of DMAEMA. This studies shows that the grafting of the monomer occurs in the surface of the films and the excess of the grafting difficult the heparin linkages in the polymeric matrix. (author)

  13. Nylon 46-polytetramethylene oxide segmented block copolymers

    NARCIS (Netherlands)

    Gaymans, R.J.; Schwering, P.; Haan, de J.L.

    1989-01-01

    Block copolymers were synthesized from amine-terminated polytetramethylene oxide (PMTO) (Mw 800 and 1130) and polyamide 4,6 salt. First prepolymers were prepared at 200–210°C in the presence of a solvent (pyrrolidone). The prepolymers were postcondensed at 255°C (where possible in the solid state) t

  14. Shear instability of a gyroid diblock copolymer

    DEFF Research Database (Denmark)

    Eskimergen, Rüya; Mortensen, Kell; Vigild, Martin Etchells

    2005-01-01

    -induced destabilization is discussed in relation to analogous observations on shear-induced order-to-order and disorder-to-order transitions observed in related block copolymer systems and in microemulsions. It is discussed whether these phenomena originate in shear-reduced fluctuations or shear-induced dislocations....

  15. CONJUGATED BLOCK-COPOLYMERS FOR ELECTROLUMINESCENT DIODES

    NARCIS (Netherlands)

    Hilberer, A; Gill, R.E; Herrema, J.K; Malliaras, G.G; Wildeman, J.; Hadziioannou, G

    1995-01-01

    In this article we review results obtained in our laboratory on the design and study of new light-emitting polymers. We are interested in the synthesis and characterisation of block copolymers with regularly alternating conjugated and non conjugated sequences. The blocks giving rise to luminescence

  16. Gyroid Membranes made from Nanoporous Blck Copolymers

    DEFF Research Database (Denmark)

    Szewczykowski, Piotr Plzemystaw; Vigild, Martin Etchells; Ndoni, Sokol;

    2007-01-01

    of the membrane and its nanoporosity is e.g. obtained by cross-linking the majority blocks and selectively etching the minority blocks. Here we report on ultrafiltration membranes prepared from a 1,2-polybutadiene-b-polydimethylsiloxane diblock copolymer with gyroid structure. Different experimental methods...

  17. Glycine/Glycolic acid based copolymers

    NARCIS (Netherlands)

    in 't Veld, P.J.A.; in 't Veld, Peter J.A.; Shen, Zheng-Rong; Shen, Z.; Takens, Gijsbert A.J.; Takens, G.A.J.; Dijkstra, Pieter J.; Feijen, Jan

    1994-01-01

    Glycine/glycolic acid based biodegradable copolymers have been prepared by ring-opening homopolymerization of morpholine-2,5-dione, and ring-opening copolymerization of morpholine-2,5-dione and glycolide. The homopolymerization of morpholine-2,5-dione was carried out in the melt at 200°C for 3 min

  18. Helical Ordering in Chiral Block Copolymers

    Science.gov (United States)

    Zhao, Wei; Hong, Sung Woo; Chen, Dian; Grason, Gregory; Russell, Thomas

    2012-02-01

    Introducing molecular chirality into the segments of block copolymers can influence the nature of the resultant morphology. Such an effect was found for poly(styrene-b-L-lactide) (PS-b-PLLA) diblock copolymers where hexagonally packed PLLA helical microdomains (H* phase) form in a PS matrix. However, molecular ordering of PLLA within the helical microdomains and the transfer of chirality from the segmental level to the mesoscale is still not well understood. We developed a field theoretic model to describe the interactions between segments of chiral blocks, which have the tendency to form a ``cholesteric'' texture. Based on the model, we calculated the bulk morphologies of chiral AB diblock copolymers using self-consistent field theory (SCFT). Experiments show that the H* phase only forms when microphase separation between PS and PLLA block happens first and crystallization of PLLA block is suppressed or happens within confined microdomain. Hence, crystalline ordering is not necessary for H* phase formation. The SCFT offers the chance to explore the range of thermodynamic stability of helical structures in the phase diagram of chiral block copolymer melts, by tuning parameters not only like the block segregation strength and composition, but also new parameters such as the ratio between preferred helical pitch to the radius of gyration and the Frank elastic constant for inter-segment distortions.

  19. CONJUGATED BLOCK-COPOLYMERS FOR ELECTROLUMINESCENT DIODES

    NARCIS (Netherlands)

    Hilberer, A; Gill, R.E; Herrema, J.K; Malliaras, G.G; Wildeman, J.; Hadziioannou, G

    1995-01-01

    In this article we review results obtained in our laboratory on the design and study of new light-emitting polymers. We are interested in the synthesis and characterisation of block copolymers with regularly alternating conjugated and non conjugated sequences. The blocks giving rise to luminescence

  20. Chiral Block Copolymer Structures for Metamaterial Applications

    Science.gov (United States)

    2015-01-27

    MONITOR’S REPORT NUMBER(S) AOARD-114078 12. DISTRIBUTION/AVAILABILITY STATEMENT Distribution A: Approved for public release. Distribtion is...researchers focused o synthesis and processing, morphology and physical characterization of chiral block copolymer (BCP) materials. Such materials a...developed a platform process technology that can fabricate novel netwo morphologies from initial bicontinuous cubic phases through supergroup/subgroup