Broad line .sup.1./sup.H NMR study of polymer blend composed of isotactic polypropylene and ethylene-propylene-diene terpolymer

Czech Academy of Sciences Publication Activity Database

Olčák, D.; Mucha, L.; Onufer, J.; Raab, Miroslav; Spěváček, Jiří

2002-01-01

Roč. 2, č. 3 (2002), s. 31-35 ISSN 1335-8243 R&D Projects: GA ČR GA106/02/1249 Grant - others:GA SK(SK) 1/7402/20 Institutional research plan: CEZ:AV0Z4050913 Keywords : isotactic polypropylene * EPDM rubber * polymer blend Subject RIV: JJ - Other Materials

Solid-state drawing of post-consumer isotactic poly(propylene): effect of melt filtration and carbon black on structural and mechanical properties

NARCIS (Netherlands)

Luijsterburg, B.J.; Jobse, P.S.; Spoelstra, A.B.; Goossens, J.G.P.

2016-01-01

Post-consumer plastic waste obtained via mechanical recycling is usually applied in thick-walled products, because of the low mechanical strength due to the presence of contaminants. In fact, sorted post-consumer isotactic poly(propylene) (i-PP) can be considered as a blend of 95% i-PP and 5%

Isothermal crystallization kinetics of isotactic polypropylene with inorganic fullerene-like WS2 nanoparticles

International Nuclear Information System (INIS)

Naffakh, Mohammed; Martin, Zulima; Marco, Carlos; Gomez, Marian A.; Jimenez, Ignacio

2008-01-01

Nanometric-sized inorganic fullerene-like tungsten disulfide particles (IF-WS 2 ) were used to produce new isotactic polypropylene (iPP) nanocomposites. A remarkable increase of the crystallization rate of iPP in the nanocomposites was observed by DSC and X-ray diffraction techniques using synchrotron radiation. This fact was related to the high nucleation efficiency of IF-WS 2 nanoparticles on the α-form crystals of iPP. Other parameters such as the Avrami exponent, the equilibrium melting temperature, and the fold surface free energy of crystallization of iPP chains in the nanocomposites were obtained from the calorimetric data in order to determine the effect of the nanoparticles on them. A decrease in the fold surface free energy was calculated with increasing IF-WS 2 content

Design and properties of a novel nucleating agent for isotactic polypropylene

International Nuclear Information System (INIS)

Lv, Zhiping; Yang, Yunfei; Wu, Ran; Tong, Yuchao

2012-01-01

Highlights: ► Three new nucleating agents which is structurally similar to Al-PTBBA were prepared. ► These three nucleating agents were very effective in increasing T c and X c of iPP. ► Great improvement of mechanical properties of nucleated iPP was also obtained. ► Nucleating agent TSD was the most effective nucleating agent for iPP. -- Abstract: Three new nucleating agents TB, TD and TSD (titanate of benzoate or 4-tert-Butylbenzoate) were prepared. Isotactic polypropylene (iPP) nucleated were studied by using thermogravimetry analysis (TGA), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The mechanical properties and Vicat softening temperature (VST) of iPP were also tested. The results indicated that these three nucleating agents were very effective in increasing the crystallization temperature (T c ) and crystallinity (X c ) of iPP. Mechanical properties of nucleated iPP were improved remarkably, especially nucleating agent TSD.

The effect of strain rate on the viscoplastic behavior of isotactic polypropylene at finite strains

DEFF Research Database (Denmark)

Drozdov, Aleksey D.; Christiansen, Jesper de Claville

2002-01-01

prior to testing. A constitutive model is developed for the viscoplastic behavior of isotactic polypropylene at finite strains. A semicrystalline polymer is treated as equivalent heterogeneous network of chains bridged by permanent junctions (physical cross-links and entanglements). The network...... is thought of as an ensemble of meso-regions connected with each other by links (lamellar blocks). In the sub-yield region of deformations, junctions between chains in meso-domains slide with respect to their reference positions (which reflects sliding of nodes in the amorphous phase and fine slip...... responses of non-annealed and annealed specimens: (i) necking of samples not subjected to thermal treatment precedes coarse slip and fragmentation of lamellar blocks, whereas cold-drawing of annealed specimens up to a longitudinal strain of 80% does not induce spatial heterogeneity of their deformation; (ii...

100 MeV Ag{sup 7+} ion induced physicochemical changes in isotactic polypropylene

Energy Technology Data Exchange (ETDEWEB)

Mathakari, N.L. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India); Kanjilal, D. [Inter University Accelerator Center, New Delhi (India); Bhoraskar, V.N. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India); Dhole, S.D. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India)], E-mail: sanjay@physics.unipune.ernet.in

2008-04-15

Thin films of isotactic polypropylene having 500 {mu}m thickness were irradiated with 100 MeV Ag{sup 7+} ions at the fluences varying from 10{sup 11} to 5 x 10{sup 12} ions/cm{sup 2}. The properties such as chemical, optical, structural and surface morphology were characterized by techniques namely FTIR, UV-visible, photoluminescence, XRD, SEM and contact angle method. The FTIR spectra show the scissioning of C-H and C-C bonds, whereas, in photoluminescence, the intensities of the peaks at 440 and 480 nm in emission spectra and at 236 nm in excitation spectra observed to be decreased with increase in ion fluence. This may be due to the decomposition of luminescent centers. The UV-visible spectra also show a remarkable red shift from 218 to 367 nm and the subsequent large reduction in the optical band gap from 5.37 to 3.39 eV. This attributes to the carbonization or graphitization of polypropylene. On the contrary, the intensities of XRD peaks, particularly the peak due to 1 1 0 planes, shows sufficient enhancement which signifies overall increase in crystallinity. This ascribes to relief in the local strain on the crystallites due to scissioning of tie molecules in the amorphous zones. The contact angle has increased from 78 deg. to 97 deg. which reveals the absence of hydrophilic functional groups, carbonization and surface roughening. The result is also supported by SEM analysis.

Isotactic polypropylene/carbon nanotube composites prepared by latex technology. Thermal analysis of carbon nanotube-induced nucleation

NARCIS (Netherlands)

Miltner, H.E.; Grossiord, N.; Lu, K.; Loos, J.; Koning, C.E.; Van Mele, B.

2008-01-01

During nonisothermal crystallization of highly dispersed polypropylene/carbon nanotube (CNT) composites, considerable heterogeneous nucleation is observed to an extent scaling with the CNT surface area. Saturation occurs at higher loadings, reaching a plateau value for the crystallization onset

Monotonic and cyclic responses of impact polypropylene and continuous glass fiber-reinforced impact polypropylene composites at different strain rates

KAUST Repository

Yudhanto, Arief

2016-03-08

Impact copolymer polypropylene (IPP), a blend of isotactic polypropylene and ethylene-propylene rubber, and its continuous glass fiber composite form (glass fiber-reinforced impact polypropylene, GFIPP) are promising materials for impact-prone automotive structures. However, basic mechanical properties and corresponding damage of IPP and GFIPP at different rates, which are of keen interest in the material development stage and numerical tool validation, have not been reported. Here, we applied monotonic and cyclic tensile loads to IPP and GFIPP at different strain rates (0.001/s, 0.01/s and 0.1/s) to study the mechanical properties, failure modes and the damage parameters. We used monotonic and cyclic tests to obtain mechanical properties and define damage parameters, respectively. We also used scanning electron microscopy (SEM) images to visualize the failure mode. We found that IPP generally exhibits brittle fracture (with relatively low failure strain of 2.69-3.74%) and viscoelastic-viscoplastic behavior. GFIPP [90]8 is generally insensitive to strain rate due to localized damage initiation mostly in the matrix phase leading to catastrophic transverse failure. In contrast, GFIPP [±45]s is sensitive to the strain rate as indicated by the change in shear modulus, shear strength and failure mode.

Morphology of Thermoplastic Elastomers:Stereoblock Polypropylene

Energy Technology Data Exchange (ETDEWEB)

Pople, John A

2002-08-06

The morphologies of low-density (0.86 g/cm{sup 3}), elastomeric polypropylene (ePP) derived from bis(2-arylindenyl) hafnium dichloride were investigated using a combination of polarized optical microscopy (OM), differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), Fourier transform infrared (FT-IR) spectroscopy, and tapping mode atomic force microscopy (TMAFM). These low-crystallinity polypropylenes, when crystallized isothermally from the melt, exhibit morphologies reminiscent of classical semi-crystalline polymers. The presence of lamellae, cross-hatching, hedrites, and spherulites was revealed by high resolution TM-AFM. These elastomeric polypropylenes can be fractionated into components of different average tacticities and crystallinities, but similar molecular mass. The analysis of the morphologies of all of the fractions revealed both large hierarchical structures and cross-hatching typical of the {alpha}-modification of crystalline isotactic polypropylene for all but the lowest crystalline ether soluble fraction. Evidence for high-melting crystals in all of the fractions are most consistent with a stereoblock microstructure of atactic and isotactic sequences.

Origin of toughness in .beta.-polypropylene: the effect of molecular mobility in the amorphous phase

Czech Academy of Sciences Publication Activity Database

Policianová, Olivia; Hodan, Jiří; Brus, Jiří; Kotek, Jiří

2015-01-01

Roč. 60, 9 March (2015), s. 107-114 ISSN 0032-3861 R&D Projects: GA ČR(CZ) GA13-29009S Institutional support: RVO:61389013 Keywords : isotactic polypropylene * β-modification * toughness Subject RIV: JI - Composite Materials Impact factor: 3.586, year: 2015

Degradation behavior of polymer blend of isotactic polypropylenes with and without unsaturated chain end group

International Nuclear Information System (INIS)

Nakatani, Hisayuki; Kurniawan, Dodik; Taniike, Toshiaki; Terano, Minoru

2008-01-01

In this work, the relationship between the unsaturated chain end group content and the thermal oxidative degradation rate was systematically studied with binary polymer blends of isotactic polypropylene (iPP) with and without the unsaturated chain end group. The iPPs with and without the unsaturated chain end group were synthesized by a metallocene catalyst in the absence of hydrogen and by a Ziegler catalyst in the presence of one, respectively. The thermal oxidative degradation rate of the binary iPP blends was estimated from the molecular weight and the apparent activation energy (ΔE), which were obtained through size exclusion chromatography (SEC) and thermogravimetric analysis (TGA) measurements, respectively. These values exhibited a negative correlation against the mole content of the unsaturated chain end group. The thermal oxidative degradation rate apparently depends on the content of the unsaturated chain end group. This tendency suggests that the unsaturated chain end acts as a radical initiator of the iPP degradation reaction.

Mechanical Properties of Nanofilled Polypropylene Composites

Directory of Open Access Journals (Sweden)

Cristina-Elisabeta PELIN

2015-06-01

Full Text Available The paper presents a study concerning mechanical performance of thermoplastic nanocomposites based on isotactic polypropylene matrix, nanofilled with montmorillonite modified with quaternary ammonium salt and carboxyl functionalized carbon nanotubes, respectively, added in the same concentration relative to the matrix. The nanofilled and single polymer materials were obtained by simple melt compounding through extrusion process followed by injection molding into specific shape specimens for mechanical testing of the samples. Mechanical properties were evaluated by tensile and 3 point bending tests. In terms of modulus of elasticity, the results showed overall positive effects concerning the effect of nanofiller addition to the thermoplastic polymer. The fracture cross section of the tested specimens was characterized by FT-IR spectroscopy and SEM microscopy.

Effect of Different Nucleating Agents on the Crystallization of Ziegler-Natta Isotactic Polypropylene

Directory of Open Access Journals (Sweden)

Felipe Avalos-Belmontes

2016-01-01

Full Text Available Ziegler-Natta isotactic polypropylene (iPP was melt mixed with four different nucleating agents (carbon nanotubes (CNT, carbon nanofibers (CNF, lithium benzoate (LiBe, and a sorbitol derivative (Millad in order to study their effect on the crystallization of iPP. It was found that the four different nucleating agents promote the alpha crystalline form. At 0.01 wt%, the carbon nanoparticles produced the higher crystallization temperature “Tc” (~119°C, whereas, at 0.10 wt%, LiBe and Millad produced a markedly higher Tc (~125°C. Tc of pure iPP was 111°C. With 0.1 wt% nucleating agent, at 120°C, the crystallization half-life time of PP, when using LiBe or Millad, was 15 times faster than for pure PP, whereas, when using carbon nanoparticles, it was 20–25 times faster. At 135°C, with 0.01 wt% nucleating agent, the isothermal crystallization process of iPP was completed after 25 min, as well as with Millad. With LiBe, it was completed after just 15 min and, with any of the carbon nanoparticles, it was practically over after only a couple of minutes.

On clarification of haze in polypropylene

NARCIS (Netherlands)

Bernland, K.; Goossens, J.G.P.; Smith, P.; Tervoort, T.A.

2016-01-01

The mechanism of reducing light scattering in isotactic polypropylene (i-PP), through the addition of so-called clarifying agents, is studied with small-angle light scattering (SALS) and scanning electron microscopy (SEM). The clarifying agents used in this study depict monotectic phase behavior

Influence of the elastomeric polypropylene addition on the properties of commercial metallocenic polypropylene

Directory of Open Access Journals (Sweden)

Marques Maria de Fátima V.

2001-01-01

Full Text Available Polypropylene with special properties can be obtained by metallocenic catalysts. These catalytic systems represent the beginning of a new age in polyolefins technology. In this work, the influence of the addition of a syndiotactic polypropylene (s-PP on the processability and mechanical properties of a commercial isotactic polypropylene (i-PP obtained by metallocenic catalysts was evaluated. Increasing addition of s-PP promoted better processability, with an increase in the impact strength and a decrease in the stress at break. A reduction of the crystallinity in the polymeric blends was verified. The more significant influence of the s-PP addition was observed for the mi-PP, compared to the ZNi-PP.

Solid-state drawing of β-nucleated polypropylene : effect of additives on drawability and mechanical properties

NARCIS (Netherlands)

Luijsterburg, B.J.; Jobse, P.; Hermida Merino, D.; Peijs, A.A.J.M.; Goossens, J.G.P.

2014-01-01

Isotactic polypropylene can crystallize in different crystal modifications. In this paper, the effect of sepiolite (1D) and carbon black (3D) fillers on the solid-state drawability of i-PP is discussed. The cross-hatched structure of thermodynamically most stable a-crystal phase in isotactic i-PP

Conductive polypropylene composites

International Nuclear Information System (INIS)

Koszkul, J.

1997-01-01

The results of studies on polypropylene composites with three sorts of Polish-made carbon blacks were presented. It was found that composite of 20% black content had properties of an electrically conducting material

Radiation resistant polypropylene blended with mobilizer,. antioxidants and nucleating agent

Science.gov (United States)

Shamshad, A.; Basfar, A. A.

2000-03-01

Post-irradiation storage of medical disposables prepared from isotactic polypropylene renders them brittle due to degradation. To avoid this, isotactic polypropylene [(is)PP] was blended with a mobilizer, dioctyl pthallate (DOP), three antioxidants (hindered amines and a secondary antioxidant) and benzoic acid to obtain radiation-resistant, thermally-stable and transparent material. Different formulations prepared were subjected to gamma radiation to doses of 25 and 50 kGy. Tests of breakage on bending after ageing in an oven at 70°C up to 12 months have shown that the addition of DOP and the antioxidants imparts improved radiation and thermal stability as compared to (is)PP alone or its blend with DOP. All the formulations irradiated or otherwise demonstrated excellent colour stability even after accelerated ageing at 70°C for prolonged periods.

Plasma modification of polypropylene surfaces and its alloying with styrene in situ

Energy Technology Data Exchange (ETDEWEB)

Ma Guiqiu, E-mail: magq@tju.edu.cn [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China); Liu Ben; Li Chen; Huang Dinghai; Sheng Jing [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China)

2012-01-15

The treatment of polypropylene surfaces has been studied by dielectric barrier discharges plasma of Ar. The structure and morphology of polypropylene surfaces of Ar plasma modification are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometers and scanning electron microscope. The modified by plasma treatment of iPP (isotactic polypropylene) surface properties have been examined in a determination of free radicals. The modified active surfaces of polypropylene can induce grafting copolymerization of styrene onto polypropylene. The structure of grafting copolymer is characterized and the grafting percent of styrene onto polypropylene is calculated. The homopolymer of styrene can be formed under grafting copolymerization of styrene onto polypropylene, which follows that the alloying of polypropylene with styrene is achieved in situ.

Spray-Dried Cellulose Nanofibril-Reinforced Polypropylene Composites for Extrusion-Based Additive Manufacturing: Nonisothermal Crystallization Kinetics and Thermal Expansion

Directory of Open Access Journals (Sweden)

Lu Wang

2018-02-01

Full Text Available Isotactic polypropylene (iPP is a versatile polymer. It accounts for the second-largest polymer consumption worldwide. However, iPP is difficult to 3D print via extrusion-based processing. This is attributable to its rapid crystallization rate. In this study, spray-dried cellulose nanofibrils (SDCNF and maleic anhydride polypropylene (MAPP were investigated to reveal their effects on the nonisothermal crystallization kinetics and thermal expansion of iPP. SDCNF at 3 wt % and 30 wt % accelerated the crystallization rate of iPP, while SDCNF at 10 wt % retarded the crystallization rate by restricting crystal growth and moderately increasing the nucleation density of iPP. Additionally, adding MAPP into iPP/SDCNF composites accelerated the crystallization rate of iPP. The effective activation energy of iPP increased when more than 10 wt % SDCNF was added. Scanning electron microscopy and polarized light microscopy results indicated that high SDCNF content led to a reduced gap size among SDCNF, which hindered the iPP crystal growth. The coefficient of thermal expansion of iPP/SDCNF10% was 11.7% lower than the neat iPP. In summary, SDCNF, at 10 wt %, can be used to reduce the warping of iPP during extrusion-based additive manufacturing.

Partially-Functionalized Isotactic Polystyrene with Blocky Comonomer Segments

Science.gov (United States)

Siegel, Ariel; Powers, Wayne; Ryu, Chang Y.

2012-02-01

Isotactic polystyrenes (iPSs) have been functionalized in solution, while the accessibility of functionalizing agent is limited by the formation of crystalline domains at various temperatures. The chemical system used is the borylated isotactic polystyrene system, and we investigated the temperature effects on reaction kinetics to ultimately control the blockiness of borylated segments in the resulting copolymer. The chemical composition of partially borylated iPS reaches a steady state that is dependent on temperature. This synthesis has been performed at many different temperatures, with different steady states being reached at different temperatures. Further analysis by differential scanning calorimetry (DSC) has shown that the higher temperature reactions have greater effect on breaking down the crystal lattice structure of the isotactic polystyrene. As a result, the lower temperature reactions affect the crystalline structure less, and the resulting copolymer has more blockiness.

Oriented Crystallization and Mechanical Properties of Polypropylene Nucleated on Fibrillated Polytetrafluorethylene Scaffolds

NARCIS (Netherlands)

van der Meer, D.W.; Milazzo, Daniel; Sanguineti, Aldo; Vancso, Gyula J.

2005-01-01

It is known that friction deposited polytetrafluoroethylene (PTFE) layers are able to nucleate crystallization of thin films of isotactic polypropylene (iPP). In order to investigate the influence of PTFE on the crystallization behavior and morphology of iPP in bulk, PTFE-particles of two different

POLYPROPYLENE-MODIFIED KAOLINITE COMPOSITES: EFFECT ...

African Journals Online (AJOL)

Meziane O, Bensedira A, Guessoum M and Haddaoui N

2016-05-01

May 1, 2016 ... prepared by the melt intercalation method. ... several beneficial variations on stiffness, hardness, toughness and heat ..... Polypropylene/ untreated and treated kaolinite composites have been prepared via direct melt.

Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

DEFF Research Database (Denmark)

Stribeck, Norbert; Zeinolebadi, Ahmad; Ganjaee Sari, Morteza

2012-01-01

Small-angle X-ray scattering (SAXS) monitors tensile and load-cycling tests of metallocene isotactic polypropylene (PP), a blend of PP and montmorillonite (MMT), and two block copolymer compatibilized PP/MMT nanocomposites. Mechanical properties of the materials are similar, but the semicrystalline......%. Other results concern the evolution of Strobl’s block structure and void formation during tensile loading....

Radiation modification and interaction mechanism of polypropylene and polyethylene by protons and electrons

International Nuclear Information System (INIS)

Wang Guanghou

1988-10-01

A systematic investigation of radiation effects on isotactic polypropylene (PP) and low-density polyethylene (PE) films by protons and electrons is reported. Electrons can make polyethylene cross-linked and polypropylene crached while protons can improve the PP mechanical properties and deteriorate polyethylene with increasing the irradiation dose. The structural analysis shows that conversion between α and β phases occurs and the crystallinity remains constant in the electron-irradiated polypropylene whereas the network structure is formed by allyl-type radicals in the e - -irradiated polyethylene. The infrared spectra indicate that conformational changes have taken place in the polypropylene under proton bombardment, such as the transition from an ordered to a disordered state in the crystalline region, the formation of double bonds as well as trans-conformations. This leads to the cross-linking between macromolecules of polypropylene at the proper irradiation doses, thus enhancing its mechanical properties. The cross-linking of polypropylene by proton bombardment observed and its properties may have some potential applications

Agave nonwovens in polypropylene composites: mechanical and thermal studies

CSIR Research Space (South Africa)

John, MJ

2015-03-01

Full Text Available Blends of agave fibres with wool waste, pineapple leaf fibres and polypropylene fibres were manufactured by needle-punching technique. Composites were prepared with polypropylene matrix by the process of compression moulding. The effects of blend...

Chemical cross-linking of polypropylenes towards new shape memory polymers.

Science.gov (United States)

Raidt, Thomas; Hoeher, Robin; Katzenberg, Frank; Tiller, Joerg C

2015-04-01

In this work, syndiotactic polypropylene (sPP) as well as isotactic polypropylene (iPP) are cross-linked to gain a shape memory effect. Both prepared PP networks exhibit maximum strains of 700%, stored strains of up to 680%, and recoveries of nearly 100%. While x-iPP is stable for many cycles, x-sPP ruptures after the first shape-memory cycle. It is shown by wide-angle X-ray scattering (WAXS) experiments that cross-linked iPP exhibits homoepitaxy in the temporary, stretched shape but in contrast to previous reports it contains a higher amount of daughter than mother crystals. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The use of maleic anhydride-modified polypropylene for performance enhancement in continuous glass fiber-reinforced polypropylene composites

NARCIS (Netherlands)

Rijsdijk, H.A.; Contant, M.; Peijs, A.A.J.M.; Miravete, A.

1993-01-01

The influence of maleic anhydride-modified polypropylene (m-PP) on static mech. properties of continuous glass fiber-reinforced polypropylene (PP) composites was studied. M-PP was added to the PP homopolymer to improve the adhesion between the matrix and the glass fiber. Three-point bending tests

Coir dust reinforced recycled polypropylene composites

International Nuclear Information System (INIS)

Santos, Bianca B. dos; Costa, Marysilvia F. da; Thire, Rossana M. da S.M.

2015-01-01

The environmental impacts caused by disposed plastics encourage the search for new alternatives. Recycling polymers leads to the degradation of their mechanical properties, which can be modified by the addition of fillers. In this paper, recycled polypropylene from plastic cups with 2%, 5% and 10% of coir dust were produced with and without the addition of additives. These composites were characterized by tensile tests, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy on the fracture surface. It was verified the effectiveness of the addition of coir dust in improving the elasticity modulus of recycled polypropylene besides the effectiveness of additives used in promoting the adhesion of the powder to the matrix. However, higher levels of coir dust caused the appearance of air bubbles inside the material, which contributed to its embrittlement. The addition of coir dust promoted a decrease in the degree of polypropylene crystallinity. (author)

Preparation and Characterization of Extruded Composites Based on Polypropylene and Chitosan Compatibilized with Polypropylene-Graft-Maleic Anhydride

Science.gov (United States)

Carrasco-Guigón, Fernando Javier; Rodríguez-Félix, Dora Evelia; Castillo-Ortega, María Mónica; Santacruz-Ortega, Hisila C.; Burruel-Ibarra, Silvia E.; Encinas-Encinas, Jose Carmelo; Plascencia-Jatomea, Maribel; Herrera-Franco, Pedro Jesus; Madera-Santana, Tomas Jesus

2017-01-01

The preparation of composites of synthetic and natural polymers represent an interesting option to combine properties; in this manner, polypropylene and chitosan extruded films using a different proportion of components and polypropylene-graft-maleic anhydride (PPgMA) as compatibilizer were prepared. The effect of the content of the biopolymer in the polypropylene (PP) matrix, the addition of compatibilizer, and the particle size on the properties of the composites was analyzed using characterization by fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile strength, and contact angle, finding that in general, the addition of the compatibilizer and reducing the particle size of the chitosan, favored the physicochemical and morphological properties of the films. PMID:28772464

A Study on Creep Behavior of Wood Flour- Recycled Polypropylene Composite

Directory of Open Access Journals (Sweden)

Saman Ghahri

2013-06-01

Full Text Available The creep behavior of wood flour- recycled polypropylene composites (with and without compatibilizer has been evaluated in this study. For this purpose, virgin polypropylene (PP was thermo-mechanically degraded by five times of extrusion under controlled conditions in a twin-screw extruder at a rotor speed of 100 rpm and at temperature of 1900C. The virgin and recycled polypropylene were mixed with the wood flour (50/50% W/W as well as the compatibilizer (0, 2% W/W by a counter-rotating twin-screw extruder to manufacture the wood flour-PP composites (WPCs samples. The nominal cross section of the manufactured composites was 70×10 mm2. Short term flexural creep test at 30% of ultimate bending load was performed by using flexural creep equipment. The total time to complete every test was 120 min (60 min creep and 60 min recovery. Results revealed that recycling of the PP reduced the creep resistance in composites containing recycled polypropylene. Also results have shown that with the presence of compatibilizer (MAPP creep deflection, creep factor and relative creep decrease and creep modulus increase. The composites containing virgin PP and MAPP exhibited higher creep resistance than those containing recycled PP.

The mechanical properties of unidirectional all-polypropylene composites

NARCIS (Netherlands)

Alcock, B.; Cabrera, N.O.; Barkoula, N.M.; Loos, J.; Peijs, A.A.J.M.

2006-01-01

The creation of highly oriented, co-extruded polypropylene (PP) tapes allows the production of recyclable ‘all-polypropylene’ composites, with a large temperature processing window (>30 °C) and a high volume fraction of highly oriented PP (>90%). These composites show little deviation of mechanical

Chemical modification of flax reinforced polypropylene composites

CSIR Research Space (South Africa)

Jacob John, Maya

2009-04-01

Full Text Available This paper presents an experimental study on the static and dynamic mechanical properties of nonwoven based flax fibre reinforced polypropylene composites. The effect of zein modification on flax fibres is also reported. Flax nonwovens were treated...

Development of foams from linear polypropylene (PP) and high melt strength polypropylene (HMSPP) polymeric blends

International Nuclear Information System (INIS)

Cardoso, Elisabeth Carvalho Leite

2009-01-01

Foamed polymers are future materials, with a comprehensive application field. They can be used in order to improve appearance of insulation structures, for example, or to reduce costs involving materials. This work address to Isotactic Polypropylene / High Melt Strength Polypropylene blends, for foams production. Rheological behavior of polymer melt, especially referring to viscosity in processing temperature, plays a decisive role in applications where dominates extensional flow, as in case of foaming. If the viscosity is very low, it will correspond to a low melt strength, as in case of linear homopolymer (Isotact PP), and the foam will be prejudiced, due to the impossibility of expansion. Otherwise, if the viscosity is very high, with a high melt strength, the foam will collapse immediately after its formation. In order to get foams with an homogeneous and defined cellular structure, there were accomplished blends, 50% in weight, between linear homopolymer (isotactic PP) and HMSPP, from PP modified as per gamma radiation, in acetylene environment and at a 12.5 kGy doses. Extrusion process used a soluble foaming methodology, according to a processing/dissolution principle, which involves the dissolution of a Physical Blowing Agent (PBA), under 30 bar pressure, homogeneously mixed with polymeric melt. Extrusion conditions, that generally involve temperature, pressure and viscoelastic material flow control were experimentally investigated to define prevalent characteristics for producing foams. Nitrogen was the used PBA and process extrusion parameters were adapted to PP, HMSPP and their 50% in weight mixtures thereof. Major PP and HMSPP characteristics were obtained via melt Index and melt strength and thermal analyses (DSC/TGA), in order to make viable and to reproduce foaming as per extrusion process. Foams cellular morphology of PP, HMSPP and their 50% in weight mixtures thereof was investigated, with and without talc addition, as nucleating agent, by using

Acoustic properties of polypropylene composites reinforced with stone groundwood

Directory of Open Access Journals (Sweden)

Joan Pere López

2012-11-01

Full Text Available Currently, acoustic isolation is one of the problems raised with building construction in Spain. The publication of the Basic Document for the protection against noise of the Technical Building Code has increased the demand of comfort for citizens. This has created the need to seek new composite materials that meet the new required acoustical building codes. In this paper we report the results of the newly developed composites that are able to improve the acoustic isolation of airborne noise. These composites were prepared from polypropylene (PP reinforced with mechanical pulp fibers from softwood (Pinus radiata. Mechanical and acoustical properties of the composites from mechanical pulp (MP and polypropylene (PP have been investigated and compared to fiberglass (FG composites. MP composites had lower tensile properties compared with FG composites, although these properties can be improved by incorporation of a coupling agent. The results of acoustical properties of MP composites were reported and compared with the conventional composites based on fiberglass and gypsum plasterboards. Finally, we suggest the application of MP composites as a light-weight building material to reduce acoustic transmitions.

Morphology and crystalline-phase-dependent electrical insulating properties in tailored polypropylene for HVDC cables

Science.gov (United States)

Zha, Jun-Wei; Yan, Hong-Da; Li, Wei-Kang; Dang, Zhi-Min

2016-11-01

Polypropylene (PP) has become one promising material to potentially replace the cross-link polyethylene used for high voltage direct current cables. Besides the isotactic polypropylene, the block polypropylene (b-PP) and random polypropylene (r-PP) can be synthesized through the copolymerization of ethylene and propylene molecules. In this letter, the effect of morphology and crystalline phases on the insulating electrical properties of PP was investigated. It was found that the introduction of polyethylene monomer resulted in the formation of β and γ phases in b-PP and r-PP. The results from the characteristic trap energy levels indicated that the β and γ phases could induce deep electron traps which enable to capture the carriers. And the space charge accumulation was obviously suppressed. Besides, the decreased electrical conductivity was observed in b-PP and r-PP. It is attributed to the existence of deep traps which can effectively reduce the carrier mobility and density in materials.

The effect of temperature and strain rate on the mechanical properties of highly oriented polypropylene tapes and all-polypropylene composites

NARCIS (Netherlands)

Alcock, B.; Cabrera, N.O.; Barkoula, N.M.; Reynolds, C.T.; Govaert, L.E.; Peijs, A.A.J.M.

2007-01-01

The creation of highly oriented, co-extruded polypropylene (PP) tapes allows the production of recyclable "all-polypropylene" (all-PP) composites, with a large temperature processing window and a high volume fraction of highly oriented PP (>90%). The wholly thermoplastic nature of these

Rheological and Thermal Behavior of Polypropylene-Kaolin Composites

International Nuclear Information System (INIS)

Teng, S.T.; Nor Azura Abdul Rahim; Lan, D.N.U

2014-01-01

Kaolins effect on rheological behaviour of polypropylene-kaolin composites was investigated. The research found that not only the kaolin content influence the rheological behaviour but also the compounding using internal mixer and twin screw extruder. In details, viscosity and shear stress increased with addition of kaolin content. These characteristics also exhibited higher in polypropylene-kaolin composite suspensions compounded using twin screw extruder than using internal mixer. Chain scission was assumed to occur and affect the melt properties. Further justification characterized by Differential Scanning Calorimeter (DSC) showed that the effect of kaolin and loading content were more evident on the onset melting temperature and crystallinity. Besides, due to the different cooling operation in both processes, the effect of compounding on melting characteristic was conspicuous. (author)

Mechanical properties of pineapple leaf fibre reinforced polypropylene composites

International Nuclear Information System (INIS)

Arib, R.M.N.; Sapuan, S.M.; Ahmad, M.M.H.M.; Paridah, M.T.; Zaman, H.M.D. Khairul

2006-01-01

Pineapple leaf fibre, which is rich in cellulose, relative inexpensive and abundantly available has the potential for polymer-reinforced composite. The present study investigates the tensile and flexural behaviours of pineapple leaf fibre-polypropylene composites as a function of volume fraction. The tensile modulus and tensile strength of the composites were found to be increasing with fibre content in accordance with the rule of mixtures. The tensile modulus and tensile strength with a volume fraction 10.8% are 687.02 and 37.28 MPa, respectively. The flexural modulus gives higher value at 2.7% volume fraction. The flexural strength of the composites containing 5.4% volume fraction was found to be higher than that of pure polypropylene resin by 5.1%. Scanning electron microscopic studies were carried out to understand the fibre-matrix adhesion and fibre breakage

Mechanical properties of pineapple leaf fibre reinforced polypropylene composites

Energy Technology Data Exchange (ETDEWEB)

Arib, R.M.N. [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapuan, S.M. [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)]. E-mail: sapuan@eng.upm.edu.my; Ahmad, M.M.H.M. [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Paridah, M.T. [Faculty of Forestry, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Zaman, H.M.D. Khairul [Radiation Processing Technology Division, Malaysian Institute for Nuclear Technology Research (MINT), Bangi 43000 Kajang, Selangor (Malaysia)

2006-07-01

Pineapple leaf fibre, which is rich in cellulose, relative inexpensive and abundantly available has the potential for polymer-reinforced composite. The present study investigates the tensile and flexural behaviours of pineapple leaf fibre-polypropylene composites as a function of volume fraction. The tensile modulus and tensile strength of the composites were found to be increasing with fibre content in accordance with the rule of mixtures. The tensile modulus and tensile strength with a volume fraction 10.8% are 687.02 and 37.28 MPa, respectively. The flexural modulus gives higher value at 2.7% volume fraction. The flexural strength of the composites containing 5.4% volume fraction was found to be higher than that of pure polypropylene resin by 5.1%. Scanning electron microscopic studies were carried out to understand the fibre-matrix adhesion and fibre breakage.

Study of structural modifications in the stretched polypropylene (PP) film for various ratios

International Nuclear Information System (INIS)

Melinte, S.; Leanca, M.; Moise, M.; Mateescu, N.

1979-01-01

The initial spherolitic structure of isotactic polypropylene films changes as a result of their plastic deformation. The fibrous structure fraction increases with the draw ratio. Interfibrillar ranges, formed by molecules binding adjacent microfibrils, also develop. Along interfibrillar borders there occur voids which have a special role in lending properties to the film. Amorphous orientation rises proportionally to the draw degree while the crystal lattice orientation quickly grows and is almost completed for lambda = 5. (author)

Effect of compatibilization and reprocessing on the isothermal crystallization kinetics of polypropylene/wood flour composites

Directory of Open Access Journals (Sweden)

Arieny Rodrigues

2013-01-01

Full Text Available Numerous studies have focused on polymer mixtures aimed at the potential applications of these materials. This work analyzed the effect of polymer reprocessing and the type and concentration of compatibilizer on the isothermal crystallization kinetics of polypropylene/wood flour composites. The composites, which were polypropylene grafted with acrylic acid (PP-g-AA and maleic anhydride (PP-g-MA, were processed in a twin screw extruder with and without compatibilizer. Reprocessed polypropylene reached complete crystallization in less time than the composites with virgin polypropylene. The addition of wood flour to the composites did not change the kinetics significantly compared to that of the pure polymers, but the compatibilizers did, particularly PP-g-AA. The nucleation exponent (n and crystallization rate (K were calculated from Avrami plots. The values of n ranged from 2 to 3, indicating instantaneous to sporadic nucleation. The crystallization half-time of reprocessed polypropylene was shorter than that of virgin polypropylene and of the compositions containing PP-g-AA compatibilizer. The activation energy of crystallization and the equilibrium melting temperature were calculated, respectively, from Arrhenius and Hoffman-Weeks plots. Both of these parameters showed lower values in the composites, particularly in the ones containing compatibilizers.

Essential work of fracture analysis for starch filled poly(propylene carbonate) composites

International Nuclear Information System (INIS)

Wang, X.L.; Li, R.K.Y.; Cao, Y.X.; Meng, Y.Z.

2007-01-01

Starch filled poly(propylene carbonate) composites are environmental friendly materials. In this study, the fracture toughness of composites under mode I loading was determined by the essential work of fracture concept. The specific essential fracture work of the poly(propylene carbonate)/starch composites decreases with increasing the starch content, while the non-essential work term, βw p increases with increasing the starch content. In addition, the morphologies, thermal properties, thermo-mechanical properties were studied by scanning electron microscope, thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry, respectively. The thermal and thermo-mechanical measurements revealed that increasing starch content led to an increase in glass transition temperature and thermal stability. Morphology observation indicates that poly(propylene carbonate) and starch have weak interfacial adhesion

Preparation of organophilic clays and polypropylene nano composites

International Nuclear Information System (INIS)

Lima, Martha Fogliato S.; Nascimento, Vinicius G. do; Lenz, Denise M.; Schenato, Flavia

2011-01-01

Polypropylene/montmorillonite nano composites were prepared by the melt intercalation technique. The clay was organically modified with different quaternary ammonium salts to obtain the organo clay. The modified clays with the quaternary ammonium salts were introduced in a polypropylene matrix with 3 wt. % of clay. The interlayer distance (d001) of the clay particles were obtained by X- ray diffraction and the thermal stability of the systems were investigated by thermogravimetry. The organo clay presence in the polymer matrix increased the degradation temperature in relation to the pure polymer. (author)

A novel insight into the origin of toughness in polypropylene-calcium carbonate microcomposites: multivariate analysis of ss-NMR spectra

Czech Academy of Sciences Publication Activity Database

Kukačková, Olivia; Nguyen, Viet Dung; Abbrent, Sabina; Urbanová, Martina; Kotek, Jiří; Brus, Jiří

2017-01-01

Roč. 132, 6 December (2017), s. 106-113 ISSN 0032-3861 R&D Projects: GA ČR(CZ) GA16-04109S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : isotactic polypropylene microcomposites * CaCO3 * toughness Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer sci ence Impact factor: 3.684, year: 2016

Study of gel formation in polypropylene modified by gamma irradiation

International Nuclear Information System (INIS)

Oliani, W.L.; Parra, D.F.; Fermino, D.M.; Lima, L.F.C.P.; Lugao, A.B.; Riella, H.G.

2010-01-01

The linearity of the chains of iPP (isotactic polypropylene) confers to this, low melt strength. This fact limits the use of iPP in processes that demand high stretching. The graft of branches confers improvements in its extensional viscosity, resulting in Polypropylene with High Melt Strength (HMS-PP). Preparation process of the HMS-PP, included iPP in pellets, conditioned in plastic container containing acetylene under pressure of 110 kPa and radiation with γ source of 60 Co in the doses of 5, 12.5 and 20 kGy. The gel fraction of the samples was determined by the extraction of soluble components in xylene under boiling for 12 hours at 138 deg C. The soluble part of the samples was decanted with the total volatilization of the xylene to the room temperature (25 deg C) and deposition in glass blades. These samples had been characterized by Optic Microscopy, Scanning Electron Microscopy and Infrared Spectroscopy. In this study of the morphology, we obtained the formation of gel and microgel of polypropylene with higher incidence in HMS-PP 20 kGy. (author)

Tensile strength characteristics of polypropylene composites reinforced with stone groundwood fibers from softwood

OpenAIRE

López, Joan Pere; Méndez González, José Alberto; Espinach Orús, Xavier; Julián Pérez, Fernando; Mutjé Pujol, Pere; Vilaseca Morera, Fabiola

2012-01-01

The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW) is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP) composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composit...

Development and characterisation of injection moulded, all-polypropylene composites

Directory of Open Access Journals (Sweden)

A. Kmetty

2013-02-01

Full Text Available In this work, all-polypropylene composites (all-PP composites were manufactured by injection moulding. Prior to injection moulding, pre-impregnated pellets were prepared by a three-step process (filament winding, compression moulding and pelletizing. A highly oriented polypropylene multifilament was used as the reinforcement material, and a random polypropylene copolymer (with ethylene was used as the matrix material. Plaque specimens were injection moulded from the pellets with either a film gate or a fan gate. The compression moulded sheets and injection moulding plaques were characterised by shrinkage tests, static tensile tests, dynamic mechanical analysis and falling weight impact tests; the fibre distribution and fibre/matrix adhesion were analysed with light microscopy and scanning electron microscopy. The results showed that with increasing fibre content, both the yield stress and the perforation energy significantly increased. Of the two types of gates used, the fan gate caused the mechanical properties of the plaque specimens to become more homogeneous (i.e., the differences in behaviour parallel and perpendicular to the flow direction became negligible.

Kenaf/PP and EFB/PP: Effect of fibre loading on the mechanical properties of polypropylene composites

Science.gov (United States)

Anuar, N. I. S.; Zakaria, S.; Harun, J.; Wang, C.

2017-07-01

Kenaf and empty fruit bunch (EFB) fibre which are the important natural fibres in Malaysia were studied as nonwoven polymer composites. The effect of fibre loading on kenaf polypropylene and EFB polypropylene nonwoven composite was studied at different mixture ratio. Kenaf polypropylene nonwoven composite (KPNC) and EFB polypropylene nonwoven composite (EPNC) were prepared by carding and needle-punching techniques, followed by a compression moulding at 6 mm thickness. This study was conducted to identify the optimum fibre loading of nonwoven polypropylene composite and their effect on the mechanical strength. The study was designed at 40%, 50%, 60% and 70% of fibre content in nonwoven mat and composite. The tensile strength, flexural strength and compression strength were tested to evaluate the composite mechanical properties. It was found that the mechanical properties for both kenaf and EFB nonwoven composites were influenced by the fibre content. KPNC showed higher mechanical strength than EPNC. The highest flexural strength was obtained at 60% KPNC and the lowest value was showed by 40% EPNC. The tensile and flexural strength for both KPNC and EPNC decreased after the fibre loading of 60%.

Kenaf Fibre Reinforced Polypropylene Composites: Effect of Cyclic Immersion on Tensile Properties

Directory of Open Access Journals (Sweden)

W. H. Haniffah

2015-01-01

Full Text Available This research studied the degradation of tensile properties of kenaf fibre reinforced polypropylene composites due to cyclic immersion into two different solutions, as well as comparison of the developed composites’ tensile properties under continuous and cyclic immersion. Composites with 40% and 60% fibre loadings were immersed in tap water and bleach for 4 cycles. Each cycle consisted of 3 days of immersion and 4 days of conditioning in room temperature (28°C and 55% humidity. The tensile strength and modulus of composites were affected by fibre composition, type of liquid of immersion, and number of cycles. The number of immersion cycles and conditioning caused degradation to tensile strength and modulus of kenaf fibre reinforced polypropylene composites. Continuous and cyclic immersion in bleach caused tensile strength of the composites to differ significantly whereas, for tensile modulus, the difference was insignificant in any immersion and fibre loadings. However, continuous immersion in the bleach reduced the tensile strength of composites more compared to cyclic immersion. These preliminary results suggest further evaluation of the suitability of kenaf fibre reinforced polypropylene composites for potential bathroom application where the composites will be exposed to water/liquid in cyclic manner due to discontinuous usage of bathroom.

Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites

Directory of Open Access Journals (Sweden)

Alejandra J. Monsiváis-Barrón

2014-10-01

Full Text Available Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified halloysite, carbon nanotubes and functionalized halloysite and carbon nanotubes. Morphological characterization in SEM and STEM/TEM showed dispersion in the polypropylene matrix. According to TGA and DSC measurements thermal behavior remain similar for all the composites. Mechanical test in tension demonstrate that modulus of the composites increases for all samples with a major impact for materials containing silanol groups synthetized in formic acid. Rheological measurements show a significantly increment in viscosity for samples containing unmodified and modified carbon nanotubes. No difference was found for samples containing silanol groups and halloysite when compared to neat polypropylene. Finally, the oxygen transmission rate increased for all samples showing high barrier properties only for samples containing natural and functionalized halloysite nanotubes.

Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites.

Science.gov (United States)

Monsiváis-Barrón, Alejandra J; Bonilla-Rios, Jaime; Sánchez-Fernández, Antonio

2014-10-20

Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified halloysite, carbon nanotubes and functionalized halloysite and carbon nanotubes. Morphological characterization in SEM and STEM/TEM showed dispersion in the polypropylene matrix. According to TGA and DSC measurements thermal behavior remain similar for all the composites. Mechanical test in tension demonstrate that modulus of the composites increases for all samples with a major impact for materials containing silanol groups synthetized in formic acid. Rheological measurements show a significantly increment in viscosity for samples containing unmodified and modified carbon nanotubes. No difference was found for samples containing silanol groups and halloysite when compared to neat polypropylene. Finally, the oxygen transmission rate increased for all samples showing high barrier properties only for samples containing natural and functionalized halloysite nanotubes.

A novel test method for quantifying surface tack of polypropylene compound surfaces

Directory of Open Access Journals (Sweden)

2011-11-01

Full Text Available While adhesiveness is required for polymer surfaces in special applications, tacky surfaces are generally undesirable in many applications like automotive interior parts. The tackiness of polymer surface results from a combination of composition and additivation, and it can change significantly in natural or accelerated ageing. Since there is no established, uniform method to characterize surface tack, the major focus of the present work was on the development of an objective quantification method. A setup having a soft die tip attached to a standard tensile tester was developed aiming for correlation to the human sense of touch. Three different model thermoplastic polyolefin (TPO compound formulations based on a high-impact isotactic polypropylene (iPP composition with varying amounts and types of anti-scratch additives were used for these investigations. As the surface tack phenomenon is related to ageing and weathering, the material’s examination was also performed after various intervals of weathering. The developed method allows a fast assessment of the effect of polymer composition variations and different additive formulations on surface tack and gives identical rankings as the standardized haptic panel.

Effect of nano-scaled styrene butadiene rubber based nucleating agent on the thermal, crystallization and physical properties of isotactic polypropylene

Energy Technology Data Exchange (ETDEWEB)

Petchwattana, Nawadon [Division of Polymer Materials Technology, Faculty of Agricultural Product Innovation and Technology, Srinakharinwirot University, Sukhumvit 23, Wattana, Bangkok 10110 (Thailand); Covavisaruch, Sirijutaratana, E-mail: sirijutaratana.c@chula.ac.th [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Pathumwan, Bangkok 10330 (Thailand); Sripanya, Panjapong [Thai Oleochemicals Company Limited (A Subsidiary of PTT Global Chemical Public Company Limited), Mueang Rayong, Rayong 21150 (Thailand)

2014-01-05

Highlights: • The effect of a SBR based β-NA on the properties iPP was investigated. • The addition of β-NA led to higher population of nuclei and smaller spherulites. • β to α phase transformation was observed when re-extrusion process was applied. • Impact strength was increased when the β-NA was added from 0.10 to 0.20 wt%. -- Abstract: The influence of a specific nano-scaled styrene butadiene rubber based β-nucleating agent (β-NA) on the properties of isotactic polypropylene (iPP) was investigated in the current research. β-NA was applied at the concentration ranged from 0.05 to 0.50 wt%. Microscopic observation revealed that the neat iPP crystals grew very slowly; they ranged in size from 100 to 200 μm. The addition of β-NA led to higher population of nuclei and smaller spherulites than those found in neat iPP. The addition of only 0.05 wt% β-NA significantly decreased the sizes of the spherulites down to 5 μm; the crystal grew very rapidly, leading to extremely fine morphology. Analysis by X-ray diffraction (XRD) confirmed that iPP/β-NA constituted mainly of β-crystal structure. The transformation of β to α phase was observed upon re-extrusion, it was verified by the lowered fraction of the β-crystalline phase (K{sub β}) although the total degree of crystallinity remained unchanged. A significant improvement in the impact strength of the iPP/β-NA was observed when the β-NA was employed from 0.10 to 0.20 wt%, leading to the formation of tough β-crystals in the β-NA nucleated iPP. The color measurement implied that the iPP nucleated with β-NA was superior in terms of whiteness but it was less transparent, as was evident by the increased haze.

Fabrication of polypropylene/silver nanocomposites for biocidal applications

Energy Technology Data Exchange (ETDEWEB)

Oliani, Washington Luiz, E-mail: washoliani@usp.br [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242 – Cidade Universitária – CEP, 05508-000 São Paulo (Brazil); Parra, Duclerc Fernandes; Komatsu, Luiz Gustavo Hiroki [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242 – Cidade Universitária – CEP, 05508-000 São Paulo (Brazil); Lincopan, Nilton [Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, 05508-000, São Paulo (Brazil); Department of Clinical Analysis, School of Pharmacy, University of São Paulo, 05508-000, São Paulo (Brazil); Rangari, Vijaya Kumar [Department of Materials Science and Engineering, Tuskegee University, AL 36088 (United States); Lugao, Ademar Benevolo [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242 – Cidade Universitária – CEP, 05508-000 São Paulo (Brazil)

2017-06-01

This paper presents a study on biocidal effect of polymer nanocomposite films of gamma irradiated polypropylene (PP) and silver nanoparticles. The modified polypropylene was obtained from isotactic polypropylene (iPP) in pellets form by irradiation with gamma rays in the presence of acetylene. A new morphology with long chain branching of PP and distinct rheology is obtained by this process. The blend of 50/50 wt% neat PP and PP modified by gamma radiation were further mixed using a twin screw extruder. The AgNPs were infused into this polymer blend at different concentrations of: 0.1%; 0.25%; 0.5%; 1.0%; 1.0% (PVP), 2.0% and 4.0% by wt%. These polymer nanocomposites were characterized by Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), cytotoxicity test and Kirby-Bauer disk diffusion techniques. The bactericidal effect of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) were assessed in detail. - Highlights: • PP film was obtained from iPP in pellets form by γ rays with acetylene and AgNPs • Bactericidal effect of P aeruginosa and S aureus were assessed.

Structural changes of PP with different isotacticity induced by γ-irradiation

International Nuclear Information System (INIS)

Wang Shaofeng; Wei Genshuan; Qiao Jinliang

2000-01-01

The morphology of i-PP with different isotacticity under high absorbed dose were studied with the measurements of crystallinity, crystallite size, melting heat and melting point by x-ray diffraction and DSC methods respectively. The results indicate that the changes are not only related to the heat history but also related to the isotacticity of i-PP. In generally, the higher the isotacticity of i-PP, the less morphology changes, and the morphology of annealing samples change less than the virgin powder samples. It means that the annealed i-PP with higher isotacticity is more stable to radiation both in air and vacuum conditions. (author)

Properties analysis of tensile strength, crystallinity degree and microstructure of polymer composite polypropylene-sand

International Nuclear Information System (INIS)

Sudirman; Karo-Karo, Aloma; Ari-Handayani; Bambang-Sugeng; Rukihati; Mashuri

2004-01-01

Materials modification base on polymer toward polymer composite is needed by addition of filler. Mechanical properties such as tensile strength, crystallinity degree and microstructure of polymer composite based on polypropylene with sand filler have been investigated. In this work, the polymer composite has been made by mixing the matrix of polypropylene melt flow 2 (PP MF2) or polypropylene melt flow 10 (PP MF 10) with sand filler in a labo plastomill. The composition of sand filler was varied to 10, 30, 40 and 50 % v/v, a then the composite were casted to the film sheets form. The sheets were characterized mechanically i.e tensile strength, crystallinity degree and microstructure. The result showed that the tensile strength decreased by increasing the volume fraction of sand filler, in accordance with microstructure investigation that the matrix area under zone plastic deformation (more cracks), while the filler experienced elastic deformation, so that the strength mechanism of filler did not achieved with expectation (Danusso and Tieghi theory). For filler more than 30 % of volume fraction, the tensile strength of polypropylene melt flow 10 (PP MF 10) was greater than that polypropylene melt flow 2 (PP MF2). It was caused by plasticities in PP MF 10. The tensile strength of PP MF2 was greater than that PP MF 10 for volume fraction of sand filler less than 30 %. It was caused by PP MF2 to be have more degree of crystallinity

Flexural creep behaviour of jute polypropylene composites

Science.gov (United States)

Chandekar, Harichandra; Chaudhari, Vikas

2016-09-01

Present study is about the flexural creep behaviour of jute fabric reinforced polypropylene (Jute-PP) composites. The PP sheet and alkali treated jute fabric is stacked alternately and hot pressed in compression molding machine to get Jute-PP composite laminate. The flexural creep study is carried out on dynamic mechanical analyzer. The creep behaviour of the composite is modeled using four-parameter Burgers model. Short-term accelerated creep testing is conducted which is later used to predict long term creep behaviour. The feasibility of the construction of a master curve using the time-temperature superposition (TTS) principle to predict long term creep behavior of unreinforced PP and Jute-PP composite is investigated.

Susceptibility to scratch surface damage of wollastonite- and talc-containing polypropylene micrometric composites

International Nuclear Information System (INIS)

Hadal, R.; Dasari, A.; Rohrmann, J.; Misra, R.D.K.

2004-01-01

The paper describes the effect of wollastonite and talc on the scratch deformation behavior of low and high crystallinity polypropylenes under identical test conditions. The vertical resolution of atomic force microscopy and lateral resolution of scanning electron microscopy is utilized to examine the characteristics of scratch damage. Contrary to the expectations that high crystallinity and stiffness of polypropylene composites should increase resistance to scratch deformation, the susceptibility to mechanical deformation depends on bonding of mineral particles to the polymer matrix. Scratch deformed regions in neat polypropylenes were free of voids and grooves, while reinforced-polypropylenes exhibited voids and debonding/detachment of filler particles. The severity of plastic deformation in reinforced polypropylenes is a function of debonding/detachment of mineral particles, which is comparatively more for talc-reinforced polypropylenes than wollastonite-reinforced polypropylenes because of the layered structure of talc that encourages delamination. Usage of coating and coupling agents improved the resistance to scratch deformation by promoting adhesion and bonding between the reinforcement and matrix

Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

Energy Technology Data Exchange (ETDEWEB)

Sosiati, H., E-mail: hsosiati@gmail.com [Nanomaterials Research Group, LPPT Universitas Gadjah Mada (Indonesia); Nahyudin, A., E-mail: ahmadnahyudin@yahoo.co.id; Fauzi, I., E-mail: ikhsannurfauzi@gmail.com; Wijayanti, D. A., E-mail: wijayantidwiastuti@gmail.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Gadjah Mada University (Indonesia); Triyana, K., E-mail: triyana@ugm.ac.id [Nanomaterials Research Group, LPPT Universitas Gadjah Mada (Indonesia); Department of Physics, Faculty of Mathematics and Natural Sciences, Gadjah Mada University (Indonesia)

2016-04-19

Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

International Nuclear Information System (INIS)

Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

2016-01-01

Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

Science.gov (United States)

Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

2016-04-01

Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

A novel approach in organic waste utilization through biochar addition in wood/polypropylene composites

Energy Technology Data Exchange (ETDEWEB)

Das, Oisik [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Sarmah, Ajit K., E-mail: a.sarmah@auckland.ac.nz [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Bhattacharyya, Debes [Department of Mechanical Engineering, Center for Advanced Composite Materials, University of Auckland, Auckland 1142 (New Zealand)

2015-04-15

Highlights: • Biochar made from waste wood was added with wood polypropylene composites. • 24% biochar gave the best mechanical properties. • 6% biochar had no effect on physico-mechanical properties of composites. • Coupling agent remained unreacted in composites having higher amount of biochar. - Abstract: In an attempt to concurrently address the issues related to landfill gas emission and utilization of organic wastes, a relatively novel idea is introduced to develop biocomposites where biochar made from pyrolysis of waste wood (Pinus radiata) is added with the same wood, plastic/polymer (polypropylene) and maleated anhydride polypropylene (MAPP). Experiments were conducted by manufacturing wood and polypropylene composites (WPCs) mixed with 6 wt%, 12 wt%, 18 wt%, 24 wt%, and 30 wt% biochar. Though 6 wt% addition had similar properties to that of the control (composite without biochar), increasing biochar content to 24 wt% improved the composite’s tensile/flexural strengths and moduli. The biochar, having high surface area due to fine particles and being highly carbonised, acted as reinforcing filler in the biocomposite. Composites having 12 wt% and 18 wt% of biochar were found to be the most ductile and thermally stable, respectively. This study demonstrates that, WPCs added with biochar has good potential to mitigate wastes while simultaneously producing biocomposites having properties that might be suited for various end applications.

A novel approach in organic waste utilization through biochar addition in wood/polypropylene composites

International Nuclear Information System (INIS)

Das, Oisik; Sarmah, Ajit K.; Bhattacharyya, Debes

2015-01-01

Highlights: • Biochar made from waste wood was added with wood polypropylene composites. • 24% biochar gave the best mechanical properties. • 6% biochar had no effect on physico-mechanical properties of composites. • Coupling agent remained unreacted in composites having higher amount of biochar. - Abstract: In an attempt to concurrently address the issues related to landfill gas emission and utilization of organic wastes, a relatively novel idea is introduced to develop biocomposites where biochar made from pyrolysis of waste wood (Pinus radiata) is added with the same wood, plastic/polymer (polypropylene) and maleated anhydride polypropylene (MAPP). Experiments were conducted by manufacturing wood and polypropylene composites (WPCs) mixed with 6 wt%, 12 wt%, 18 wt%, 24 wt%, and 30 wt% biochar. Though 6 wt% addition had similar properties to that of the control (composite without biochar), increasing biochar content to 24 wt% improved the composite’s tensile/flexural strengths and moduli. The biochar, having high surface area due to fine particles and being highly carbonised, acted as reinforcing filler in the biocomposite. Composites having 12 wt% and 18 wt% of biochar were found to be the most ductile and thermally stable, respectively. This study demonstrates that, WPCs added with biochar has good potential to mitigate wastes while simultaneously producing biocomposites having properties that might be suited for various end applications

Effect of particles size on mechanical properties of polypropylene particulate composites

Czech Academy of Sciences Publication Activity Database

Nezbedová, E.; Krčma, F.; Majer, Z.; Hutař, Pavel

2016-01-01

Roč. 7, č. 5 (2016), s. 690-699 ISSN 1757-9864 Institutional support: RVO:68081723 Keywords : Morphology * Mechanical properties * Numerical simulation * Polypropylene particulate composite s * Plasma surface treatment Subject RIV: JI - Composite Material s www.emeraldinsight.com/1757-9864.htm

Mechanical and thermal behaviour of isotactic polypropylene reinforced with inorganic fullerene-like WS2 nanoparticles: Effect of filler loading and temperature

International Nuclear Information System (INIS)

Díez-Pascual, Ana M.; Naffakh, Mohammed

2013-01-01

The thermal and mechanical behaviour of isotactic polypropylene (iPP) nanocomposites reinforced with different loadings of inorganic fullerene-like tungsten disulfide (IF-WS 2 ) nanoparticles was investigated. The IF-WS 2 noticeably enhanced the polymer stiffness and strength, ascribed to their uniform dispersion, the formation of a large nanoparticle–matrix interface combined with a nucleating effect on iPP crystallization. Their reinforcement effect was more pronounced at high temperatures. However, a drop in ductility and toughness was found at higher IF-WS 2 concentrations. The tensile behaviour of the nanocomposites was extremely sensitive to the strain rate and temperature, and their yield strength was properly described by the Eyring's equation. The activation energy increased while the activation volume decreased with increasing nanoparticle loading, indicating a reduction in polymer chain motion. The nanoparticles improved the thermomechanical properties of iPP: raised the glass transition and heat deflection temperatures while decreased the coefficient of thermal expansion. The nanocomposites also displayed superior flame retardancy with longer ignition time and reduced peak heat release rate. Further, a gradual rise in thermal conductivity was found with increasing IF-WS 2 loading both in the glassy and rubbery states. The results presented herein highlight the benefits and high potential of using IF-nanoparticles for enhancing the thermomechanical properties of thermoplastic polymers compared to other nanoscale fillers. - Graphical abstract: Display Omitted - Highlights: • The thermal and mechanical behaviour of iPP/IF-WS 2 nanocomposites was studied. • Low IF-WS 2 contents provide a good balance between stiffness, strength and toughness. • Their tensile behaviour is sensitive to the strain rate and temperature. • The nanocomposites exhibit superior thermal conductivity and flame retardancy than iPP. • The benefits of using IF-WS 2 compared

Solid-state drawing of post-consumer isotactic poly(propylene): Effect of melt filtration and carbon black on structural and mechanical properties.

Science.gov (United States)

Luijsterburg, B J; Jobse, P S; Spoelstra, A B; Goossens, J G P

2016-08-01

Post-consumer plastic waste obtained via mechanical recycling is usually applied in thick-walled products, because of the low mechanical strength due to the presence of contaminants. In fact, sorted post-consumer isotactic poly(propylene) (i-PP) can be considered as a blend of 95% i-PP and 5% poly(ethylene), with traces of poly(ethylene terephthalate) (PET). By applying a treatment such as solid-state drawing (SSD) after melt extrusion, the polymer chains can be oriented in one direction, thereby improving the stiffness and tensile strength. In this research, molecular processes such as crystal break-up and chain orientation of these complex blends were monitored as a function of draw ratio. The melt filter mesh size - used to exclude rigid PET particles - and the addition of carbon black (CB) - often added for coloration in the recycling industry - were varied to investigate their influence on the SSD process. This research shows that despite the blend complexity, the molecular processes during SSD compare to virgin i-PP and that similar draw ratios can be obtained (λmax=20), albeit at reduced stiffness and strength as a result of the foreign polymers present in post-consumer i-PP. It is observed that the process stability improves with decreasing mesh size and that higher draw ratios can be obtained. The addition of carbon black, which resides in the dispersed PE phase, also stabilizes the SSD process. Compared to isotropic post-consumer i-PP, the stiffness can be improved by a factor 10 to over 11GPa, while the tensile strength can be improved by a factor 15-385MPa, which is approx. 70% of the maximum tensile strength achieved for virgin i-PP. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coir fiber reinforced polypropylene composite panel for automotive interior applications

Science.gov (United States)

Nadir Ayrilmis; Songklod Jarusombuti; Vallayuth Fueangvivat; Piyawade Bauchongkol; Robert H. White

2011-01-01

In this study, physical, mechanical, and flammability properties of coconut fiber reinforced polypropylene (PP) composite panels were evaluated. Four levels of the coir fiber content (40, 50, 60, and 70 % based on the composition by weight) were mixed with the PP powder and a coupling agent, 3 wt % maleic anhydride grafted PP (MAPP) powder. The water resistance and the...

Dynamic Mechanical and Thermal Properties of Bagasse/Glass Fiber/Polypropylene Hybrid Composites

Directory of Open Access Journals (Sweden)

Mehdi Roohani

2016-06-01

Full Text Available This work aims to evaluate the thermal and dynamic mechanical properties of bagasse/glass fiber/polypropylene hybrid composites. Composites were prepared by the melt compounding method and their properties were characterized by differential scanning calorimetry (DSC and dynamic mechanical analysis (DMA. DSC results found that with incorporation of bagasse and glass fiber the melting temperature (Tm and the crystallisation temperature (Tc shift to higher temperatures and the degree of crystallinity (Xc increase. These findings suggest that the fibers played the role of a nucleating agent in composites. Dynamic mechanical analysis indicated that by the incorporation of bagasse and glass fiber into polypropylene, the storage modulus ( and the loss modulus ( increase whereas the mechanical loss factor (tanδ decrease. To assess the effect of reinforcement with increasing temperature, the effectiveness coefficient C was calculated at different temperature ranges and revealed that, at the elevated temperatures, improvement of mechanical properties due to the presence of fibers was more noticeable. The fiber-matrix adhesion efficiency determined by calculating of adhesion factor A in terms of the relative damping of the composite (tan δc and the polymer (tan δpand volume fraction of the fibers (Фf. Calculated adhesion factor A values indicated that by adding glass fiber to bagasse/polypropylene system, the fiber-matrix adhesion improve. Hybrid composite containing 25% bagasse and 15% glass fiber showed better fiber-matrix adhesion.

Evaluation of Properties of Unidirectional Hemp/Polypropylene Composites: Influence of Fiber Content and Fiber/Matrix Interface Variables

DEFF Research Database (Denmark)

Plackett, David; Løgstrup Andersen, Tom; Lilholt, Hans

2002-01-01

Flament-wound textile hemp yarn was used in combination with unmodified or maleated polypropylene (PP) films to produce plates of unidirectional composites.......Flament-wound textile hemp yarn was used in combination with unmodified or maleated polypropylene (PP) films to produce plates of unidirectional composites....

Recycling of asbestos tailings used as reinforcing fillers in polypropylene based composites.

Science.gov (United States)

Zhai, Wensi; Wang, Yao; Deng, Yuan; Gao, Hongli; Lin, Zhen; Li, Mao

2014-04-15

In this work, asbestos tailings were recycled and used as reinforcing fillers to enhance the mechanical properties of polypropylene (PP). A silane coupling agent was used to chemically modify the asbestos tailings to increase the compatibility between asbestos tailings and polypropylene matrix. Both raw and chemically treated asbestos tailings with different loading levels (from 3 to 30 wt%) were utilized to fabricate composites. Mechanical properties of these composites have been investigated by dynamic mechanical analysis, tensile test and notched impact test. Results showed that hybridization of asbestos tailings in the composites enhanced the mechanical properties of neat PP evidently, and treated asbestos tailings/PP composites yielded even better mechanical properties compared with those of raw asbestos tailings/PP composites. This recycling method of asbestos tailings not only reduces disposal costs and avoids secondary pollution but also produces a new PP-based composite material with enhanced mechanical properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Crystallization and melting behavior of isotactic polypropylene composites filled by zeolite supported β-nucleator

International Nuclear Information System (INIS)

Jiang, Juan; Li, Gu; Tan, Nanshu; Ding, Qian; Mai, Kancheng

2012-01-01

Highlights: ► The supported calcium pimelate β-zeolite was prepared. ► The β-nucleation of zeolite was enhanced dramatically through reaction. ► High β-phase content iPP composites were obtained by introducing the β-zeolite into iPP. - Abstract: In order to prepare the zeolite filled β-iPP composites, the calcium pimelate as β-nucleator supported on the surface of zeolite (β-zeolite) was prepared by the interaction between calcified zeolite and pimelic acid. The β-nucleation, crystallization behavior and melting characteristic of zeolite, calcified zeolite and β-zeolite filled iPP composites were investigated by differential scanning calorimetry and wide-angle X-ray diffractometer. The results indicated that addition of the zeolite and calcified zeolite as well as β-zeolite increased the crystallization temperature of iPP. The zeolite and calcified zeolite filled iPP composites mainly crystallized in the α-crystal form and the strong β-heterogeneous nucleation of β-zeolite results in the formation of only β-crystal in β-zeolite filled iPP composites. The zeolite filled β-iPP composites with high β-crystal contents (above 0.90) can be easily obtained by adding β-zeolite into iPP matrix.

Mechanical and dielectric characterization of hemp fibre reinforced polypropylene (HFRPP by dry impregnation process

Directory of Open Access Journals (Sweden)

2010-03-01

Full Text Available Natural fibres such as jute, coir, sisal, bamboo and pineapple are known to have high specific strength and can be effectively used in composites in various applications. The use of hemp fibres to reinforce the polymer aroused great interest and expectations amongst scientists and materials engineers. In this paper, composites with isotactic polypropylene (iPP matrix and hemp fibres were studied. These materials were manufactured via the patented FIBROLINE process based on the principle of the dry impregnation of a fibre assembly with a thermoplastic powder (iPP, using an alternating electric field. The aim of this paper is to show the influence of fibre/matrix interfaces on dielectric properties coupled with mechanical behaviours. Fibres or more probably the fibre/matrix interfaces allow the diffusion of electric charges and delocalise the polarisation energy. In this way, damages are limited during mechanical loading and the mechanical properties of the composites increase. The structure of composite samples was investigated by X-ray and FTIR analysis. The mechanical properties were analysed by quasistatic and dynamic tests. The dielectric investigations were carried out using the SEMME (Scanning Electron Microscope Mirror Effect method coupled with the measurement of the induced current (ICM.

Effect of Reinforcement of Hydrophobic Grade Banana (Musa ornata Bark Fiber on the Physicomechanical Properties of Isotactic Polypropylene

Directory of Open Access Journals (Sweden)

Md. Mamunur Rashid

2016-01-01

Full Text Available This research studied the physicomechanical as well as morphological properties of alkali treated (NaOH and KMnO4 and untreated banana bark fiber (BBF reinforced polypropylene composites. A detailed structural and morphological characterization was performed using Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM, and mechanical properties testing (tensile strength, flexural strength, and microhardness. Chemical treatments improved the hydrophobic property of the fiber and it is found to be better for KMnO4 treatment. Composites with 0, 5, 10, and 15 wt.% loadings were then compared for water uptake studies and revealed that KMnO4 treated fiber composites absorb less water compared to others. KMnO4 treatment with 15% fiber loading improved the tensile strength, flexural strength, and microhardness of the composites compared to raw and NaOH treated fiber loadings. TGA analysis also shows onset temperature at 400~500°C that is associated with the decomposition of the banana fibers constituents including lignin, cellulose, and hemicelluloses which suggests better thermomechanical stability. All of the values suggest that 15% KMnO4 treated banana bark fiber (BBF/PP composites were found to be better than those of the raw and NaOH treated ones.

Spatially Resolved Characterization of Cellulose Nanocrystal-Polypropylene Composite by Confocal Raman Microscopy

Science.gov (United States)

Umesh P. Agarwal; Ronald Sabo; Richard S. Reiner; Craig M. Clemons; Alan W. Rudie

2012-01-01

Raman spectroscopy was used to analyze cellulose nanocrystal (CNC)–polypropylene (PP) composites and to investigate the spatial distribution of CNCs in extruded composite filaments. Three composites were made from two forms of nanocellulose (CNCs from wood pulp and the nanoscale fraction of microcrystalline cellulose) and two of the three composites investigated used...

Analysis of Nanodomain Composition in High-Impact Polypropylene by Atomic Force Microscopy-Infrared.

Science.gov (United States)

Tang, Fuguang; Bao, Peite; Su, Zhaohui

2016-05-03

In this paper, compositions of nanodomains in a commercial high-impact polypropylene (HIPP) were investigated by an atomic force microscopy-infrared (AFM-IR) technique. An AFM-IR quantitative analysis method was established for the first time, which was then employed to analyze the polyethylene content in the nanoscopic domains of the rubber particles dispersed in the polypropylene matrix. It was found that the polyethylene content in the matrix was close to zero and was high in the rubbery intermediate layers, both as expected. However, the major component of the rigid cores of the rubber particles was found to be polypropylene rather than polyethylene, contrary to what was previously believed. The finding provides new insight into the complicated structure of HIPPs, and the AFM-IR quantitative method reported here offers a useful tool for assessing compositions of nanoscopic domains in complex polymeric systems.

Interfacial enhancement of polypropylene composites modified with sorbitol derivatives and siloxane-silsesquioxane resin

Science.gov (United States)

Dobrzyńska-Mizera, Monika; Dutkiewicz, Michał; Sterzyński, Tomasz; Di Lorenzo, Maria Laura

2015-12-01

Composites based on polypropylene (iPP) modified with a sorbitol derivative (NX8000) and siloxane-silsesquioxane resin (SiOPh) containing maleated polypropylene (MAPP) as compatibilizer were prepared by melt extrusion. Calorimetric investigations were carried out using differential scanning calorimetry (DSC), whereas the morphological and mechanical properties were investigated by scanning electron microscopy (SEM) and static tensile tests. DSC measurements revealed no influence of SiOPh and a slight effect of MAPP addition on the crystallization kinetics of polypropylene. Additionally, the introduction of MAPP into the iPP+NX8000+SiOPh composites increased plastic properties of the samples. All the above was attributed to the compatibilizing effect of MAPP which improved interfacial adhesion between iPP, NX8000 and SiOPh. This phenomenon was also confirmed by the SEM images illustrating more homogenous distribution of the filler in the compatibilized samples.

Morphology and properties of recycled polypropylene/bamboo fibers composites

International Nuclear Information System (INIS)

Phuong, Nguyen Tri; Guinault, Alain; Sollogoub, Cyrille; Chuong, Bui

2011-01-01

Polypropylene (PP) is among the most widely used thermoplastics in many industrial fields. However, like other recycled polymers, its properties usually decrease after recycling process and sometimes are degraded to poor properties level for direct re-employment. The recycled products, in general, need to be reinforced to have competitive properties. Short bamboo fibers (BF) have been added in a recycled PP (RPP) with and without compatibilizer type maleic anhydride polypropylene (MAPP). Several properties of composite materials, such as helium gas permeability and mechanical properties before and after ageing in water, were examined. The effects of bamboo fiber content and fiber chemical treatment have been also investigated. We showed that the helium permeability increases if fiber content is higher than 30% because of a poor adhesion between untreated bamboo fiber and polymer matrix. The composites reinforced by acetylated bamboo fibers show better helium permeability due to grafting of acetyl groups onto cellulose fibers surface and thus improves compatibility between bamboo fibers and matrix, which has been shown by microscopic observations. Besides, mechanical properties of composite decrease with ageing in water but the effect is less pronounced with low bamboo fiber content.

Thermal analysis of polypropylene modified by gamma irradiation composites under outdoor conditions

International Nuclear Information System (INIS)

Komatsu, Luiz G.H.; Oliani, Washington L.; Lugao, Ademar B.; Parra, Duclerc F.

2015-01-01

This work reports the influence of the clay in the degradation process of the HMSPP.The polypropylene (PP) was irradiated under acetylene atmosphere in gamma irradiation source ( 60 Co) to obtain the HMSPP (high melt strength polypropylene). Composites of HMSPP were processed in twin-screw extruder with clay Cloisite 20A and Maleic Anhydride (PP-g-MA) as coupling agent. The obtained composites were exposed under outdoor conditions for 6 months. The ageing effects were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetry Analysis (TGA). Chemical oxidation was evaluated by Carbonyl Index (IC) through infrared Spectroscopy (FT-IR). The results showed correlation between carbonyl index and ageing time. (author)

Thermal analysis of polypropylene modified by gamma irradiation composites under outdoor conditions

Energy Technology Data Exchange (ETDEWEB)

Komatsu, Luiz G.H.; Oliani, Washington L.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: dfparra@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

This work reports the influence of the clay in the degradation process of the HMSPP.The polypropylene (PP) was irradiated under acetylene atmosphere in gamma irradiation source ({sup 60}Co) to obtain the HMSPP (high melt strength polypropylene). Composites of HMSPP were processed in twin-screw extruder with clay Cloisite 20A and Maleic Anhydride (PP-g-MA) as coupling agent. The obtained composites were exposed under outdoor conditions for 6 months. The ageing effects were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetry Analysis (TGA). Chemical oxidation was evaluated by Carbonyl Index (IC) through infrared Spectroscopy (FT-IR). The results showed correlation between carbonyl index and ageing time. (author)

Thermal degradation and tensile strength of sansevieria trifasciata-polypropylene composites

Science.gov (United States)

Abral, H.; Kenedy, E.

2015-07-01

The paper exhibits thermal degradation and tensile strength of Sansevieria Trifasciata (ST) fibers and polypropylene (PP) composites. Thermal degradation of ST fibers PP composites was conducted by using thermogravimetry (TGA) instrument, meanwhile tensile strength of the composite was done by using tensile equipment. The results show that the thermal resistance of ST fibers PP composites was higher than that of virgin PP only. Increases in volume fraction of fibers in the composites enhance the tensile strength. Scanning Electron Microscope (SEM) observation exhibits good interface bonding between ST fibers and PP matrix.

Thermal degradation and tensile strength of sansevieria trifasciata-polypropylene composites

International Nuclear Information System (INIS)

Abral, H; Kenedy, E

2015-01-01

The paper exhibits thermal degradation and tensile strength of Sansevieria Trifasciata (ST) fibers and polypropylene (PP) composites. Thermal degradation of ST fibers PP composites was conducted by using thermogravimetry (TGA) instrument, meanwhile tensile strength of the composite was done by using tensile equipment. The results show that the thermal resistance of ST fibers PP composites was higher than that of virgin PP only. Increases in volume fraction of fibers in the composites enhance the tensile strength. Scanning Electron Microscope (SEM) observation exhibits good interface bonding between ST fibers and PP matrix. (paper)

Stone-ground wood pulp-reinforced polypropylene composites: Water uptake and thermal properties

Directory of Open Access Journals (Sweden)

Joan Pere López

2012-11-01

Full Text Available Two of the drawbacks of using natural-based composites in industrial applications are thermal instability and water uptake capacity. In this work, mechanical wood pulp was used to reinforce polypropylene at a level of 20 to 50 wt. %. Composites were mixed by means of a Brabender internal mixer for both non-coupled and coupled formulations. Differential scanning calorimetry (DSC and thermogravimetric analysis (TGA were used to determine the thermal properties of the composites. The water uptake behavior was evaluated by immersion of the composites in water until an equilibrium state was reached. Results of water absorption tests revealed that the amount of water absorption was clearly dependent upon the fiber content. The coupled composites showed lower water absorption compared to the uncoupled composites. The incorporation of mechanical wood pulp into the polypropylene matrix produced a clear nucleating effect by increasing the crystallinity degree of the polymer and also increasing the temperature of polymer degradation. The maximum degradation temperature for stone ground wood pulp–reinforced composites was in the range of 330 to 345 ºC.

Surface modification and micromechanical properties of jute fiber mat reinforced polypropylene composites

Directory of Open Access Journals (Sweden)

2007-05-01

Full Text Available A new treating method using sodium hydroxide (NaOH and Maleic anhydride-grafted polypropylene (MPP emulsion was introduced to treat jute fiber mat in order to enhance the performance of jute/polypropylene (PP composite prepared by film stacking method. The surface modifications of jute fiber mat have been found to be very effective in improving the fiber-matrix adhesion. It was shown that treatments changed not only the surface topography but also the distribution of diameter and strength for the jute fibers, which was analyzed by using a two-parameter Weibull distribution model. Consequently, the interfacial shear strength, flexural and tensile strength of the composites all increased, but the impact strength decreased slightly. These results have demonstrated a new approach to use natural materials to enhance the mechanical performances of composites.

Evaluation of the thermal properties of polypropylene reinforced with palm fibers composites

International Nuclear Information System (INIS)

Capri, M.R.; Santana, L.C.; Mulinari, D.R.

2016-01-01

The aim of this study was to characterize polypropylene reinforced with palm composites. Of this form, it was studied physical and chemical modifications of the in nature fibers, washed with hot water and mercerized. The composites of polypropylene reinforced with 5%, 10% and 20% (wt /wt) in nature fibers and mercerized were evaluated thermally. The fibers were characterized by SEM XRD and TGA / DSC techniques. Results revealed that the mercerized fibers presented higher crystallinity when compared to others, as well as increased roughness, facilitating interlacing with the reinforcement matrix. Thermal studies of the fibers showed that the mercerization caused displacement curves paragraph higher temperatures. The composites reinforced with treated fibers presented largest temperatures and enthalpies of degradation. The content of fiber influenced in enthalpy degradation and reduction in fusion temperature. (author)

Study of Tensile Properties and Deflection Temperature of Polypropylene/Subang Pineapple Leaf Fiber Composites

Science.gov (United States)

Hafizhah, R.; Juwono, A. L.; Roseno, S.

2017-05-01

The development of eco-friendly composites has been increasing in the past four decades because the requirement of eco-friendly materials has been increasing. Indonesia has a lot of natural fiber resources and, pineapple leaf fiber is one of those fibers. This study aimed to determine the influence of weight fraction of pineapple leaf fibers, that were grown at Subang, to the tensile properties and the deflection temperature of polypropylene/Subang pineapple leaf fiber composites. Pineapple leaf fibers were pretreated by alkalization, while polypropylene pellets, as the matrix, were extruded into sheets. Hot press method was used to fabricate the composites. The results of the tensile test and Heat Deflection Temperature (HDT) test showed that the composites that contained of 30 wt.% pineapple leaf fiber was the best composite. The values of tensile strength, modulus of elasticity and deflection temperature were (64.04 ± 3.91) MPa; (3.98 ± 0.55) GPa and (156.05 ± 1.77) °C respectively, in which increased 187.36%, 198.60%, 264.72% respectively from the pristine polypropylene. The results of the observation on the fracture surfaces showed that the failure modes were fiber breakage and matrix failure.

Irradiation and processing of oil palm empty fruit bunch fibres - polypropylene composites

International Nuclear Information System (INIS)

Khairul Zaman Mohd Dahlan; Syarifah Hanisah Syed Abdul Aziz

2000-01-01

In this study, polypropylene was blended with oil palm empty fruit bunch fibres at a ratio of 60 to 40 by weight, respectively. Trimethylolpropane triacrylate (TMPTA) was used as the crosslinking agent. Homopolymer Polypropylene of MFI 14.0 and EFB fibres of 0.5 -1.0 mm sizes were used through out the experiment. Processing parameters such as temperature, rotor speed and processing time were optimized. Modes of irradiation were established to determine the optimum properties of the composites. The mechanical properties of the composite such as tensile strength, tensile modulus, flexural strength and flexural modulus were measured. The results indicate that temperature, 185 degree C, with a rotor speed of 40 rpm and 9 minutes processing time are sufficient to produce the optimum mechanical properties of PP/EFB composite. Modes of adding TMPTA into the blend and modes of irradiation also have influenced the properties of the composites

Tough and Reinforced Polypropylene/Kaolin Composites using Modified Kaolin

Science.gov (United States)

Yao, J. L.; Zhu, H. X.; Qi, Y. B.; Guo, M. J.; Hu, Q.; Gao, L.

2018-05-01

Polypropylene (PP)/kaolin composites have been prepared by filling modified kaolin with diethylenetriaminepentaacetic acid (DTPA) into the PP matrix. The surface modification of kaolin particles effectively improves the compatibility between kaolin and PP matrix. It is conducive for uniform dispersion of inorganic particles in the matrix, and enhances the mechanical performance of the composites. Compared with plain kaolin, the mechanical properties of the modified composites exhibit higher tensile strength, bending strength, impact strength and melt index simultaneously. The DTPA modification of kaolin overall enhances the mechanical properties of PP composites. It meets the requirements in various applications, and makes the modified experiment interesting in modern teaching.

Ziegler-Natta catalysts for the preparation of polypropylene clay nanocomposites from magnesium ethoxide

International Nuclear Information System (INIS)

Marques, Maria de Fatima V.; Silva, Micheli G. da; Ferreira, Ana Luiza R.

2009-01-01

In the present work, the process for the preparation of Ziegler-Natta catalysts based on MgCl 2 /TiCl 4 was evaluated on the synthesis of isotactic polypropylene. The catalysts were produced by the chemical activation process aiming the morphology control, in order to obtain catalyst particles with spherical form. The synthesis of the catalytic support was accomplished from magnesium ethoxide at different preparation conditions. Commercial clays were also added in the preparation of ZN catalysts, which were employed in propylene polymerization. The purpose was to synthesizing polypropylene nanocomposites by in situ polymerization technique. The results indicated that the developed methods of catalyst preparation were effective, since they have shown high activities and they produced PP with high melting temperatures. It was possible to verify by XRD that the catalytic components were inserted in the clays galleries and the polymers obtained by means of those catalysts are possibly exfoliated nanocomposites. (author)

The effect of specific beta-nucleation on morphology and mechanical behavior of isotactic polypropylene

Czech Academy of Sciences Publication Activity Database

Kotek, Jiří; Raab, Miroslav; Baldrian, Josef; Grellmann, W.

2002-01-01

Roč. 85, č. 6 (2002), s. 1174-1184 ISSN 0021-8995 R&D Projects: GA ČR GA106/99/P011; GA ČR GA106/98/0718; GA AV ČR IAA4050904 Institutional research plan: CEZ:AV0Z4050913 Keywords : polypropylene * morphology * beta-nucleation Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.927, year: 2002

Studies on improvement of mechanical properties of Kenaf-reinforced polypropylene composites

International Nuclear Information System (INIS)

Sarifah Hanisah Syed Abd Aziz; Khairul Zaman Mohd Dahlan

2006-01-01

At present, research in composite materials is being directed at using natural fibres instead of synthetic fibres. Kenaf which is extensively grown in the Far East including Malaysia, has been identified as a bast (stem) fibre with significant market potential. In this work, long and random kenaf fibres were used in the as-received condition and alkalized with a 0.06 M NaOH solution. They were combined with polypropylene thin sheets, sandwiched between layers of kenaf fibres and hot-pressed to form natural fibre composites. The mechanical properties of the composites were investigated to observe the effect of fibre alignment, fibre treatment, the addition of coupling agent and pre-irradiation method used. A general trend was observed whereby alkalized and long fibre composites gave higher flexural modulus and flexural strength compared with random mat and untreated fibres. The long fibre composites also gave a higher work of fracture. However, the correlation between fibre surface treatment and the work of fracture was less clear. The addition of coupling agent at 1% showed a slight improvement on the mechanical performance of the composites whereas pre-irradiation on the polypropylene pellets and fibres before the composite is manufactured showed significant improvement on the mechanical properties. However, the method of moulding used need to be improved to optimize the performance of the composites. (Author)

Benzothiazole sulfide compatibilized polypropylene/halloysite nanotubes composites

Energy Technology Data Exchange (ETDEWEB)

Liu Mingxian [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Guo Baochun, E-mail: psbcguo@scut.edu.cn [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Lei Yanda; Du Mingliang; Jia Demin [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China)

2009-02-15

Clay-philic benzothiazole sulfide, capable of donating electrons, is grafted onto polypropylene (PP) backbones when N-cyclohexyl-2-benzothiazole sulfonamide (CBS), a commonly used accelerator in the tire industry, is included in the processing of PP/halloysite nanotubes (HNTs) composites. CBS decomposes at elevated temperature and yields benzothiazole sulfide radicals, which react with the PP polymeric free radicals generated during the processing of the composites. On the other hand, the benzothiazole group of CBS is reactive to HNTs via electron transferring. The compatibilization between HNTs and PP is thus realized via interfacial grafting and electron transferring mechanism. The interfacial interactions in the compatibilized systems were fully characterized. Compared with the control sample, the dispersion of HNTs and the interfacial bonding are enhanced substantially in the compatibilized composites. The significantly improved mechanical properties and thermal properties of benzothiazole sulfide compatibilized PP/HNTs composites are correlated to the enhanced interfacial property. The present work demonstrates a novel interfacial design via interfacial grafting/electron transferring for the compatibilization of PP/clay composites.

Chapter 1.4: Spatially Resolved Characterization of CNC-Polypropylene composite by Confocal Raman Microscopy

Science.gov (United States)

Umesh Agarwal; Ronald Sabo; Richard Reiner; Craig Clemons; Alan Rudie

2013-01-01

Raman spectroscopy was used to analyze cellulose nanocrystal (CNC)-polypropylene (PP) composites and to investigate the spatial distribution of CNCs in extruded composite filaments. Three composites were made from two forms of nanocellulose (CNCs from wood pulp and the nanoscale fraction of microcrystalline cellulose), and two of the three composites...

Bio-composites based on polypropylene reinforced with Almond Shells particles: Mechanical and thermal properties

International Nuclear Information System (INIS)

Essabir, H.; Nekhlaoui, S.; Malha, M.; Bensalah, M.O.; Arrakhiz, F.Z.; Qaiss, A.; Bouhfid, R.

2013-01-01

Highlights: • Almond Shells (ASs) particles have been used as reinforcement in polypropylene matrix. • The SEBS-g-MA has been used to improve the adhesion between matrix and particles. • The mechanical and thermal properties of the composite have been improved by the AS. - Abstract: In this work, Almond Shells (ASs) particles are used as reinforcement in a thermoplastic matrix as polypropylene (PP). Composites containing Almond Shells (ASs) particles with and without compatibilizer (maleic anhydride grafted polypropylene; SEBS-g-MA) for various particle content (5, 10, 15, 20, 25, 30 wt.%) was investigated by means of studying their mechanical, thermal and rheological properties. The composites were prepared in a twin-screw extruder and assessed by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), tensile testing and Dynamic Mechanical Analysis (DMA). Results show a clear improvement in mechanical and rheological properties from the use of Almond Shells particles in the matrix without and with maleic anhydride compatibilizer, corresponding to a gain in Young’s modulus of 56.2% and 35% respectively, at 30 wt.% particle loading. Thermal analysis revealed that incorporation of particle in the composites resulted in increase in the initial thermal decomposition temperatures

Topological and thermal properties of polypropylene composites based on oil palm biomass

Energy Technology Data Exchange (ETDEWEB)

Bhat, A. H., E-mail: aamir.bhat@petronas.com.my, E-mail: anie-yal88@yahoo.com; Dasan, Y. K., E-mail: aamir.bhat@petronas.com.my, E-mail: anie-yal88@yahoo.com [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, 31750 Perak (Malaysia)

2014-10-24

Roughness on pristine and polymer composite surfaces is of enormous practical importance for polymer applications. This study deals with the use of varying quantity of oil palm ash as a nanofiller in a polypropylene based matrix. The oil palm ash sample was preprocessed to break the particles into small diameter by using ultra sonication before using microfluidizer for further deduction in size and homogenization. The oil palm ash was made to undergo many passes through the microfluidizer for fine distribution of particles. Polypropylene based composites containing different loading percentage oil palm ash was granulated by twin screw extruder and then injection molded. The surface morphology of the OPA passed through microfluidizer was analyzed by Tapping Mode - Atomic Force Microscopy (TMAFM). Thermal analysis results showed an increase in the activation energy values. The thermal stability of the composite samples showed improvement as compared to the virgin polymer as corroborated by the on-set degradation temperatures and the temperatures at which 50% degradation occurred.

Topological and thermal properties of polypropylene composites based on oil palm biomass

International Nuclear Information System (INIS)

Bhat, A. H.; Dasan, Y. K.

2014-01-01

Roughness on pristine and polymer composite surfaces is of enormous practical importance for polymer applications. This study deals with the use of varying quantity of oil palm ash as a nanofiller in a polypropylene based matrix. The oil palm ash sample was preprocessed to break the particles into small diameter by using ultra sonication before using microfluidizer for further deduction in size and homogenization. The oil palm ash was made to undergo many passes through the microfluidizer for fine distribution of particles. Polypropylene based composites containing different loading percentage oil palm ash was granulated by twin screw extruder and then injection molded. The surface morphology of the OPA passed through microfluidizer was analyzed by Tapping Mode - Atomic Force Microscopy (TMAFM). Thermal analysis results showed an increase in the activation energy values. The thermal stability of the composite samples showed improvement as compared to the virgin polymer as corroborated by the on-set degradation temperatures and the temperatures at which 50% degradation occurred

Physicochemical Study of Irradiated polypropylene/Organo :Modified Montmorillonite Composites by Using Electron Beam Irradiation Technique

International Nuclear Information System (INIS)

Hassan, M.S.

2008-01-01

Polypropylene/ Organo modified montmorillonite composites (PP/ OMMT) were prepared by melt blending with a twin screw extruder. The thermal properties by thermo gravimetric analysis (TGA), the dispersion of OMMT of macromolecules by X-ray diffraction (XRD), mechanical properties and the morphology by scanning electron microscopy (SEM) were investigated. The effect of electron beam irradiation on these properties was also studied. The results showed an intercalation between the silicate layers and the PP polymer matrix. The (PP/ OMMT) composites exhibit higher thermal stability and lower mechanical properties than pure polypropylene

Analysis and optimization of machining parameters of laser cutting for polypropylene composite

Science.gov (United States)

Deepa, A.; Padmanabhan, K.; Kuppan, P.

2017-11-01

Present works explains about machining of self-reinforced Polypropylene composite fabricated using hot compaction method. The objective of the experiment is to find optimum machining parameters for Polypropylene (PP). Laser power and Machining speed were the parameters considered in response to tensile test and Flexure test. Taguchi method is used for experimentation. Grey Relational Analysis (GRA) is used for multiple process parameter optimization. ANOVA (Analysis of Variance) is used to find impact for process parameter. Polypropylene has got the great application in various fields like, it is used in the form of foam in model aircraft and other radio-controlled vehicles, thin sheets (∼2-20μm) used as a dielectric, PP is also used in piping system, it is also been used in hernia and pelvic organ repair or protect new herrnis in the same location.

Effect of boron and phosphate compounds on physical, mechanical, and fire properties of wood-polypropylene composites

Science.gov (United States)

Nadir Ayrilmis; Turgay Akbulut; Turker Dundar; Robert H. White; Fatih Mengeloglu; Umit Buyuksari; Zeki Candan; Erkan Avci

2012-01-01

Physical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites incorporated with different contents of boron compounds; borax/boric acid and zinc borate, and phosphate compounds; mono and diammonium phosphates were investigated. The effect of the coupling agent content, maleic anhydride-grafted polypropylene, on the properties of...

Switchgrass (Panicum virgatum L.) as a reinforcing fibre in polypropylene composites

NARCIS (Netherlands)

Oever, van den M.J.A.; Elbersen, H.W.; Keijsers, E.R.P.; Gosselink, R.J.A.; Klerk-Engels, de B.

2003-01-01

In this study the switchgrass (Panicum virgatum L.), a biomass crop being developed in North America and Europe, was tested as a stiffening and reinforcing agent in polypropylene (PP) composites with and without maleic anhydride grafted PP (MAPP) as a compatibiliser and to evaluate the effect of

Effect of ionizing radiation on polypropylene composites reinforced with coconut fibers

Energy Technology Data Exchange (ETDEWEB)

Miranda, Leila F.; Pereira, Nilson C.; Faldini, Sonia B.; Masson, Terezinha J.; Silveira, Luiz H., E-mail: lfmiranda@sti.com.b [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Escola de Engenharia. Curso de Engenharia de Materiais; Silva, Leonardo G. de Andrade e, E-mail: lgasilva@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2009-07-01

The use of the polymeric composite materials has been increasing but these materials have environmental problems related to the discard. To reduce the discard deleterious effect, coconuts, sisal, as well as sugar cane pulp natural based fiber have been studied to replace the synthetic ones. These fibers embedded in a polymeric matrix plays a similar role as the synthetic ones, in terms of mechanical and thermal properties. The natural fibers are environmentally friendly, easy to recycle and biodegradable. The aim of this work is the study of ionizing radiation effects on the properties of recycled polypropylene composites, reinforced with 10%, 15% and 20% of the coconut fibers, using as coupling agent a substance based on maleic anhydride (MAPP) graphitized polypropylene. The samples were molded by injection, irradiated and submitted to thermal and mechanical tests. The mechanical properties (hardness, impact strength and tensile strength), temperature of thermal distortion (HDT) and Vicat softening temperature of the non irradiated and irradiated composites were determined. The irradiation doses were of 30, 50 and 100kGy in a gamma cell. Regarding the thermal and mechanical properties of non-irradiated samples, the incorporation of coconut fibers to polypropylene resulted in a decrease of impact strength, tensile strength and Vicat softening temperature as well as in an increase in hardness and HDT. This result indicates that the coconut fibers do not act like a reinforcement agent but as biodegradable filler. In the irradiated samples, it was observed a decrease in the impact strength, tensile strength, HDT, and thermal distortion temperature and an increase in the hardness and tensile strength. The Vicat softening temperature shows no change. (author)

Effect of ionizing radiation on polypropylene composites reinforced with coconut fibers

International Nuclear Information System (INIS)

Miranda, Leila F.; Pereira, Nilson C.; Faldini, Sonia B.; Masson, Terezinha J.; Silveira, Luiz H.

2009-01-01

The use of the polymeric composite materials has been increasing but these materials have environmental problems related to the discard. To reduce the discard deleterious effect, coconuts, sisal, as well as sugar cane pulp natural based fiber have been studied to replace the synthetic ones. These fibers embedded in a polymeric matrix plays a similar role as the synthetic ones, in terms of mechanical and thermal properties. The natural fibers are environmentally friendly, easy to recycle and biodegradable. The aim of this work is the study of ionizing radiation effects on the properties of recycled polypropylene composites, reinforced with 10%, 15% and 20% of the coconut fibers, using as coupling agent a substance based on maleic anhydride (MAPP) graphitized polypropylene. The samples were molded by injection, irradiated and submitted to thermal and mechanical tests. The mechanical properties (hardness, impact strength and tensile strength), temperature of thermal distortion (HDT) and Vicat softening temperature of the non irradiated and irradiated composites were determined. The irradiation doses were of 30, 50 and 100kGy in a gamma cell. Regarding the thermal and mechanical properties of non-irradiated samples, the incorporation of coconut fibers to polypropylene resulted in a decrease of impact strength, tensile strength and Vicat softening temperature as well as in an increase in hardness and HDT. This result indicates that the coconut fibers do not act like a reinforcement agent but as biodegradable filler. In the irradiated samples, it was observed a decrease in the impact strength, tensile strength, HDT, and thermal distortion temperature and an increase in the hardness and tensile strength. The Vicat softening temperature shows no change. (author)

Investigating the influence of alkalization on the mechanical and water absorption properties of coconut and sponge fibers reinforced polypropylene composites

Directory of Open Access Journals (Sweden)

Okikiola Ganiu AGBABIAKA

2014-11-01

Full Text Available Natural fibers are products made from renewable agricultural and forestry feedstock, which can include wood, grasses, and crops, as well as wastes and residues. There are two primary ways these fibers are used: to create polymers or as reinforcement and filler. Thermoplastic polymer may be reinforced or filled using natural fibers such as coir, sponge, hemp, flax, or sisal. This paper focused on the influence of alkalization (NaOH treatment on the mechanical and water absorption properties of selected natural fibers (coconut and sponge fibers reinforced polypropylene composites. In this study, coconut and sponge fiber were extracted from its husk by soaking them in water and was dried before it was cut into 10mm length. Those fibers were chemically treated with sodium hydroxide (NaOH in a shaking water bath before it was used as reinforcement in polypropylene composite. The reinforced polypropylene composite was produced by dispersing the coconut fibers randomly in the polypropylene before it was fabricated in a compression molding machine where the composite was produced. The fiber content used were; 2%wt, 4%wt, 6%wt, 8%wt and 10%wt. Tensile and flexural properties was observed from universal testing machine while water absorption test was carried out on the samples for seven (7 days. It was observed that the influence of NaOH treatment highly enhanced the Flexural and water absorption properties of sponge fiber reinforced polypropylene composites than coconut fiber reinforced composite samples.

Comparison of chemical changes during photooxidation of polypropylene film and filament containing phthalocyanine pigment

International Nuclear Information System (INIS)

Ahmadi, Z.; Haghighat Kish, M.; Kotak, R.; Katbab, A. A.

2008-01-01

Photooxidation as an important process, which significantly affects the service life of the polypropylene products, has been the subject of much theoretical and experimental study. Pigments used often change the light stabilities of polypropylene. Out-door applications of pigmented polypropylene are now increasingly developed in products such as artificial grass. The aim of this work is to examine the effect of photo-oxidation on the structure of isotactic polypropylene (iPP) in film and filament forms, where phthalocyanine pigment is used. For production of films and filaments, iPP granules with MFI 25 g/10 min were used, with and without phthalocyanine pigment. Samples were exposed to xenon lamp for various time lengths. The extent of the changes in chemical and structural parameters was examined by differential scanning calorimetry, Fourier transform infrared spectroscopy and wide angle x-ray diffraction. The results show that carbonyl and hydroperoxide indices increase during the exposure to the radiation. The changes in melting points of the samples were not significant after irradiation process. The effects of phthalocyanine pigment in the photooxidation of film and filament were different. Crystalline fractions of the non-pigmented filament samples decreased during the irradiation time while increased in film samples. Build up of hydroperoxide and carbonyl group in filament was higher than in film samples; that could be due to the differences in structural parameters. Crystallinity variations during photooxidation are related to the nucleation effect of the pigment, chemical crystallization and phase transformation

Comparison of Chemical Changes During Photooxidation of Polypropylene Film and Filament Containing Phthalocyanine Pigment

Directory of Open Access Journals (Sweden)

Z. Ahmadi

2008-02-01

Full Text Available Photooxidation as an important process, which significantly affects the service life of the polypropylene products, has been the subject of much theoretical and experimental study. Pigments used often change the light stabilities of polypropylene. Out-door applications of pigmented polypr-opylene are now increasingly developed in products such as artificial grass. The aim of this work is to examine the effect of photo-oxidation on the structure of isotactic polypropylene (iPP in film and filament forms, where phthalocyanine pigment is used. For production of films and filaments, iPP granules with MFI 25 g/10min were used, with and without phthalocyanine pigment. Samples were exposed to xenon lamp for various time lengths. The extent of the changes in chemical and structural parameters was examined by differential scanning calorimetry, Fourier transform infrared spectroscopy and wide angle x-ray diffraction. The results show that carbonyl and hydroperoxide indices increase during the exposure to the radiation. The changes in melting points of the samples were not significant after irradiation process. The effects of phthalocyanine pigment in the photooxidation of filmand filament were different. Crystalline fractions of the non-pigmented filament samples decreased during the irradiation time while increased in film samples. Build up of hydroperoxide and carbonyl group in filament was higher than in film samples; that could be due to the differences in structural parameters. Crystallinity variations during photooxidation are related to the nucleation effect of the pigment, chemical crystallization and phase transformation.

PEG-template for surface modification of zeolite: A convenient material to the design of polypropylene based composite for packaging films

Directory of Open Access Journals (Sweden)

S. Toommee

2018-06-01

Full Text Available Zeolite was successfully modified by conventional synthetic route. Polyethylene glycol was employed for surface modification of zeolite. The surface of zeolite exhibited therefore hydrophobic properties. Less than 5 wt% of modified zeolites with uniform size and shape were integrated into polypropylene matrix. Mechanical properties of composite exhibited the similar trend compare to neat polypropylene. Oxygen transmission rate and water vapor transmission rate were evaluated and it exhibited the strong potential to be a good candidate material in active packaging. Keywords: Zeolite, Composite, Polypropylene, Packaging, PEG-template

Wear resistance of polypropylene-SiC composite

Science.gov (United States)

Abenojar, J.; Enciso, B.; Martínez, MA; Velasco, F.

2017-05-01

In this work, the wear resistance of thermoplastic composites with a high amount of ceramic is evaluated. Composites made of polypropylene (PP) and silicon carbide (SiC) powder at 50 wt% were used with the final objective of manufacturing ablative materials. This is the first part of a project studying the wear resistance and the mechanical properties of those composites, to be used in applications like habitat industry. In theory, the exposure to high temperature of ablative materials involves the elimination of thermal energy by the sacrifice of surface polymer. In our case, PP will act as a heat sink, up to the reaction temperature (melting or sublimation), where endothermic chemical decomposition into charred material and gaseous products occurs. As the surface is eroded, it is formed a SiC like-foam with improved insulation performance. Composites were produced by extrusion and hot compression. The wear characterization was performed by pin-on-disk test. Wear test was carried out under standard ASTM G99. The parameters were 120 rpm speed, 15 N load, a alumina ball with 6 mm as pin and 1000 m sliding distance. The tracks were also observed by opto-digital microscope.

Wear resistance of polypropylene-SiC composite

International Nuclear Information System (INIS)

Abenojar, J; Enciso, B; Martínez, MA; Velasco, F

2017-01-01

In this work, the wear resistance of thermoplastic composites with a high amount of ceramic is evaluated. Composites made of polypropylene (PP) and silicon carbide (SiC) powder at 50 wt% were used with the final objective of manufacturing ablative materials. This is the first part of a project studying the wear resistance and the mechanical properties of those composites, to be used in applications like habitat industry. In theory, the exposure to high temperature of ablative materials involves the elimination of thermal energy by the sacrifice of surface polymer. In our case, PP will act as a heat sink, up to the reaction temperature (melting or sublimation), where endothermic chemical decomposition into charred material and gaseous products occurs. As the surface is eroded, it is formed a SiC like-foam with improved insulation performance. Composites were produced by extrusion and hot compression. The wear characterization was performed by pin-on-disk test. Wear test was carried out under standard ASTM G99. The parameters were 120 rpm speed, 15 N load, a alumina ball with 6 mm as pin and 1000 m sliding distance. The tracks were also observed by opto-digital microscope. (paper)

Evaluation of the acquirement of nano composites of polypropylene and a bentonite organophilized by different methodologies

International Nuclear Information System (INIS)

Paiva, Lucilene B. de; Morales, Ana R.; Branciforti, Marcia C.; Bretas, Rosario E.S.

2009-01-01

This work describes the organophilization of an argentinean sodium bentonite with a quaternary ammo nium salt, by two methodologies: cation exchange in aqueous dispersion and intercalation in semi-solid medium. The modified samples were used in the preparation of nano composites, with polypropylene as a matrix and polypropylene-graft-maleic anhydride as a coupling agent, through melt intercalation by using a twin-screw micro extruder. The organophilic bentonites were characterized by the swelling capacity test in water and in xylene and by X-ray diffraction, and the nano composites were characterized by X-ray diffraction and transmission electronic microscopy. The results showed that were obtained nano composites with structures partially intercalated and exfoliated. (author)

Synthesis and characterization of polypropylene/jigsaw wood ash composite

International Nuclear Information System (INIS)

Sudirman; Karo Karo, Aloma; Gunawan, Indra; Handayani, Ari; Hertinvyana, Evi

2002-01-01

The composite of polypropylene (PP) polymer with jigsaw wood ash as filler is the alternative composite material. The dispersion of the filler in the composite is random with the jigsaw wood ash composition of 10,30, and 50% by volume. The characterization of composite are done to measure its mechanical properties, physical properties and microstructure by using XRD and SEM. From this research, it is concluded that increasing filler content of the composite will decrease its mechanical and physical properties. The comparation of different composites are found that tensile strength of PP MF 10 is higher 4.24% compared with PP MF 2 as a matrix. It is also found that melting temperature of PP MF 10 is higher 4.09% compared with PP MF 2 as a matrices and the decomposition temperature different is 0.17%. The degree of crystallinity of composite with PP MF 10 as a matrices is 2.55% higher compared with PP MF 2. The higher degree of crystallinity is increasing the tensile strength

Mechanical and thermal properties of polypropylene composites with curaua fibre irradiated with gamma radiation

International Nuclear Information System (INIS)

Egute, Nayara S.; Forster, Pedro L.; Parra, Duclerc F.; Fermino, Danilo M.; Santana, Sebastiao; Lugao, Ademar B.

2009-01-01

Thermal and mechanical behavior of polypropylene with curaua fibre composites were investigated. The treatment of the curaua fibres was processed in alkaline solution (10% wt NaOH). A coupling agent was used (maleic anhydride) to increase the adhesion of the fibre/matrix interface. This composite was irradiated with gamma source in the doses of 5, 15 and 30 kGy and the adhesion between the fibres and the polymeric matrix was monitored to observe probable changes. The thermal behavior was evaluated using differential scanning calorimetry (DSC) and Thermogravimetry (TGA). The mechanical behavior was evaluated using tensile strength in comparison with non-reinforced polypropylene resin. The morphology of the composite fracture surface was observed using scanning electron microscopy (SEM). There were no significant changes in the thermal properties neither in the adhesion of irradiated fibres at doses of 5, 15 and 30 kGy of gamma radiation. (author)

Mechanical performance of hemp fiber polypropylene composites at different operating temperatures

Science.gov (United States)

Mehdi Tajvidi; Nazanin Motie; Ghonche Rassam; Robert H. Falk; Colin Felton

2010-01-01

In order to quantify the effect of temperature on the mechanical properties of hemp fiber polypropylene composites, formulations containing 25% and 40% (by weight) hemp fiber were produced and tested at three representative temperatures of 256, 296, and 336 K. Flexural, tensile, and impact tests, as well as dynamic mechanical analysis, were performed and the reduction...

Effect of polypropylene maleic anhydride (PPMAH) on mechanical and morphological properties of polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr)/empty fruit bunch (EFB) composites

Science.gov (United States)

Othman, Nurul Syazwani; Santiagoo, Ragunathan; Abdillahi, Khalid Mohamed; Ismail, Hanafi

2017-07-01

The fabrication of polypropylene (PP)/ recycled acrylonitrile butadiene rubber (NBRr)/ empty fruit bunch (EFB) composites were investigated. The effects of polypropylene maleic anhydride (PPMAH) as a compatibilizer on the mechanical and morphological properties of PP/NBRr/EFB composites were studied. Composites were prepared through melt mixing using heated two roll mill at 180 °C for 9 minutes and rotor speed of 15 rpm. NBRr loading were varied from 0 to 60 phr and PPMAH was fixed for 5 phr. The composites were moulded into a 1 mm thin sheet using hot press machine and then cut into dumbbell shape. The mechanical and morphological properties of composites were examined using universal tensile machine (UTM) and scanning electron microscope (SEM), respectively. Tensile strength and Young's modulus of PP/NBRr/EFB composites decreased with increasing NBRr loading, whilst increasing the elongation at break. However, PPMAH compatibilized composites have resulted 27% to 40% and 25% to 42% higher tensile strength and Young's modulus, respectively, higher compared to uncompatibilized composites. This was due to the better adhesion between PP/NBRr matrices and EFB filler with the presence of maleic anhydride moieties. From the morphological study, the micrograph of PPMAH compatibilized composites has proved the well bonded and good attachments of EFB filler with PP/NBRr matrices which results better tensile strength to the PP/NBRr/EFB composites.

Flow-induced solidification of high-impact polypropylene copolymer compositions : morphological and mechanical effects

NARCIS (Netherlands)

Drongelen, van M.; Gahleitner, M.; Spoelstra, A.B.; Govaert, L.E.; Peters, G.W.M.

2015-01-01

Polypropylene-based impact copolymers are a complex composition of matrix material, a dispersed phase and many optional modifiers. The final heterophasic morphology of such systems is influenced significantly by the processing step, adding an additional level of complexity to understanding the

Impact of Surface Modification and Nanoparticle on Sisal Fiber Reinforced Polypropylene Nano composites

International Nuclear Information System (INIS)

Ibrahim, I. D.; Jamiru, T.; Sadiku, E. R.; Agwuncha, S. Ch.; Kupolati, W. K.

2016-01-01

The use of plant fibers, polymer, and nanoparticles for composite has gained global attention, especially in the packaging, automobile, aviation, building, and construction industries. Nano composites materials are currently in use as a replacement for traditional materials due to their superior properties, such as high strength-to-weight ratio, cost effectiveness, and environmental friendliness. Sisal fiber (SF) was treated with 5% NaOH for 2 hours at 70"°C. A mixed blend of sisal fiber and recycled polypropylene (rPP) was produced at four different fiber loadings: 10, 20, 30, and 40 wt.%, while nano clay was added at 1, 3, and 5 wt.%. Maleic anhydride grafted polypropylene (MAPP) was used as the compatibilizer for all composites prepared except the untreated sisal fibers. The characterization results showed that the fiber treatment, addition of MAPP, and nano clay improved the mechanical properties and thermal stability and reduced water absorption of the SF/rPP nano composites. The tensile strength, tensile modulus, and impact strength increased by 32.80, 37.62, and 5.48%, respectively, when compared to the untreated SF/rPP composites. Water absorption was reduced due to the treatment of fiber and the incorporation of MAPP and nano clay.

Evaluation of Mechanical Property of Carbon Fiber/Polypropylene Composite According to Carbon Fiber Surface Treatment

International Nuclear Information System (INIS)

Han, Song Hee; Oh, Hyun Ju; Kim, Seong Su

2013-01-01

In this study, the mechanical properties of a carbon fiber/polypropylene composite were evaluated according to the carbon fiber surface treatment. Carbon fiber surface treatments such as silane coupling agents and plasma treatment were performed to enhance the interfacial strength between carbon fibers and polypropylene. The treated carbon fiber surface was characterized by XP S, Sem, and single-filament tensile test. The interlaminar shear strength (Ilks) of the composite with respect to the surface treatment was determined by a short beam shear test. The test results showed that the Ilks of the plasma-treated specimen increased with the treatment time. The Ilks of the specimen treated with a silane coupling agent after plasma treatment increased by 48.7% compared to that of the untreated specimen

Mechanical Properties and Weathering Behavior of Polypropylene-Hemp Shives Composites

Directory of Open Access Journals (Sweden)

Marcel Ionel Popa

2013-01-01

Full Text Available This paper presents the obtaining and the characterization of composites with polypropylene matrix and hemp shives as filler in different ratios and containing poly(propylene-co maleic anhydride (MAH-PP 3% wt as compatibility agent. The weathering behavior of the composite enclosing 60% hemp shives, performed after the exposure to UV radiations at different exposure times, was evaluated. The changes in the chemical and morphological structures were investigated by FT-IR and RAMAN spectroscopies and AFM microscopy. The mechanical characteristics of the composites were determined before and after an artificial aging process, and they are within the limits of the values reported for polyolefin-based composites and materials with natural fillers. During the accelerated weathering process, the correlation between the chemical degradation of the main components of the composite and the modification of the mechanical properties after the process of aging has been observed.

Fatigue mechanisms in unidirectional glass-fibre-reinforced polypropylene

DEFF Research Database (Denmark)

Gamstedt, E.K.; Berglund, L.A.; Peijs, T.

1999-01-01

Polypropylene (PP) and polypropylene modified with maleic anhydride (MA-PP) reinforced by continuous longitudinal glass fibres have been investigated. The most prominent effect of the modification with maleic anhydride in the composite is a stronger fibre/matrix interface. The effects of interfac......Polypropylene (PP) and polypropylene modified with maleic anhydride (MA-PP) reinforced by continuous longitudinal glass fibres have been investigated. The most prominent effect of the modification with maleic anhydride in the composite is a stronger fibre/matrix interface. The effects...... of interfacial strength on fatigue performance and on the underlying micromechanisms have been studied for these composite systems. Tension-tension fatigue tests (R = 0.1) were carried out on 0 degrees glass-fibre/PP and glass-fibre/ MA-PP coupons. The macroscopic fatigue behaviour was characterized in terms...

Coir dust reinforced recycled polypropylene composites; Compositos de polipropileno reciclado e po de coco

Energy Technology Data Exchange (ETDEWEB)

Santos, Bianca B. dos; Costa, Marysilvia F. da; Thire, Rossana M. da S.M., E-mail: bianca@metalmat.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

2015-07-01

The environmental impacts caused by disposed plastics encourage the search for new alternatives. Recycling polymers leads to the degradation of their mechanical properties, which can be modified by the addition of fillers. In this paper, recycled polypropylene from plastic cups with 2%, 5% and 10% of coir dust were produced with and without the addition of additives. These composites were characterized by tensile tests, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy on the fracture surface. It was verified the effectiveness of the addition of coir dust in improving the elasticity modulus of recycled polypropylene besides the effectiveness of additives used in promoting the adhesion of the powder to the matrix. However, higher levels of coir dust caused the appearance of air bubbles inside the material, which contributed to its embrittlement. The addition of coir dust promoted a decrease in the degree of polypropylene crystallinity. (author)

Mechanical properties of unidirectional and randomly oriented kenaf bast fibre composites using polypropylene resin matrix

International Nuclear Information System (INIS)

Sharifah Hanisah Syed Abd Aziz; Khairul Zaman Mohd Dahlan

2004-01-01

Fibres are known to confer strength and rigidity to the weak and brittle matrix and currently, research in composite materials is being directed at using natural fibers instead of synthetic fibres. In this work long and random kenaf fibers were used in the as-received condition and alkalized with a 0.06M NaOH solution. They were combined with polypropylene thin sheets and hot-pressed to form natural fibre composites. The mechanical properties of the composites were investigated to observe the effect of fibre alignment, fibre treatment, and the method of moulding technique used. A general trend was observed whereby alkalized and long fibre composites give higher flexural modulus and flexural strength compared with random mat and untreated fibres. The long fibre composites also gave a higher work of fracture. However, the correlation between fibre surface treatment and the work of fracture was less clear. The method of moulding used also need to be improved to optimize the performance of the composites manufactured as the overall mechanical test result showed some irregularities. Pre-irradiation on the polypropylene pellets before the composite is manufactured will be considered as one of the mechanism in enhancing the mechanical performance of the composites in future work. (Author)

Mechanical, Thermal Degradation, and Flammability Studies on Surface Modified Sisal Fiber Reinforced Recycled Polypropylene Composites

Directory of Open Access Journals (Sweden)

Arun Kumar Gupta

2012-01-01

Full Text Available The effect of surface treated sisal fiber on the mechanical, thermal, flammability, and morphological properties of sisal fiber (SF reinforced recycled polypropylene (RPP composites was investigated. The surface of sisal fiber was modified with different chemical reagent such as silane, glycidyl methacrylate (GMA, and O-hydroxybenzene diazonium chloride (OBDC to improve the compatibility with the matrix polymer. The experimental results revealed an improvement in the tensile strength to 11%, 20%, and 31.36% and impact strength to 78.72%, 77%, and 81% for silane, GMA, and OBDC treated sisal fiber reinforced recycled Polypropylene (RPP/SF composites, respectively, as compared to RPP. The thermogravimetric analysis (TGA, differential scanning calorimeter (DSC, and heat deflection temperature (HDT results revealed improved thermal stability as compared with RPP. The flammability behaviour of silane, GMA, and OBDC treated SF/RPP composites was studied by the horizontal burning rate by UL-94. The morphological analysis through scanning electron micrograph (SEM supports improves surface interaction between fiber surface and polymer matrix.

Ag2S deposited on oxidized polypropylene as composite material for solar light absorption

NARCIS (Netherlands)

Krylovaa, V.; Milbrat, Alexander; Embrachts, A.; Baltrusaitis, Jonas

2014-01-01

Thin film metal chalcogenides are superior solar light absorbers and can be combined into a functional material when deposited on polymeric substrates. Ag2S composite materials were synthesized on oxidized polypropylene using chemical bath deposition method and their properties were explored using

Study of gel formation in polypropylene modified by gamma irradiation; Estudo da formacao de geis em polipropileno modificado por irradiacao gama

Energy Technology Data Exchange (ETDEWEB)

Oliani, W.L.; Parra, D.F.; Fermino, D.M.; Lima, L.F.C.P.; Lugao, A.B., E-mail: washoliani@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Riella, H.G. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

2010-07-01

The linearity of the chains of iPP (isotactic polypropylene) confers to this, low melt strength. This fact limits the use of iPP in processes that demand high stretching. The graft of branches confers improvements in its extensional viscosity, resulting in Polypropylene with High Melt Strength (HMS-PP). Preparation process of the HMS-PP, included iPP in pellets, conditioned in plastic container containing acetylene under pressure of 110 kPa and radiation with {gamma} source of {sup 60}Co in the doses of 5, 12.5 and 20 kGy. The gel fraction of the samples was determined by the extraction of soluble components in xylene under boiling for 12 hours at 138 deg C. The soluble part of the samples was decanted with the total volatilization of the xylene to the room temperature (25 deg C) and deposition in glass blades. These samples had been characterized by Optic Microscopy, Scanning Electron Microscopy and Infrared Spectroscopy. In this study of the morphology, we obtained the formation of gel and microgel of polypropylene with higher incidence in HMS-PP 20 kGy. (author)

Effect of gamma radiation on the performance of jute fabrics-reinforced polypropylene composites

Energy Technology Data Exchange (ETDEWEB)

Haydaruzzaman [Department of Physics, Jahangirnagar University, Savar, Dhaka (Bangladesh); Khan, Ruhul A. [Radiation and Polymer Chemistry Laboratory, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, G. P.O. Box 3787, Dhaka 1000 (Bangladesh); Khan, Mubarak A. [Radiation and Polymer Chemistry Laboratory, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, G. P.O. Box 3787, Dhaka 1000 (Bangladesh)], E-mail: makhan.inst@gmail.com; Khan, A.H.; Hossain, M.A. [Department of Physics, Jahangirnagar University, Savar, Dhaka (Bangladesh)

2009-11-15

Jute fabrics-reinforced polypropylene (PP) composites (50% fiber) were prepared by compression molding. Composites were fabricated with non-irradiated jute fabrics/non-irradiated PP (C-0), non-irradiated jute fabrics/irradiated PP (C-1), irradiated jute fabrics/non-irradiated PP (C-2) and irradiated jute fabrics/irradiated PP (C-3). It was found that C-3 composite performed the best mechanical properties over other composites. Total radiation dose varied from 250-1000 krad and composites made of using 500 krad showed the best results. The optimized values (C-3 composites) for tensile strength (TS), bending strength (BS) and impact strength (IS) were found to be 63 MPa, 73 MPa and 2.93 kJ/m{sup 2}, respectively.

Electron beam processing of rubber wood fibers - polypropylene composites. Effects of reactive additives on the physical and mechanical properties

International Nuclear Information System (INIS)

Nor Yuziah Mohd Yunus; Jalaluddin Harun; Khairul Zaman

2000-01-01

The purpose of this study is to determine the suitability of producing agro-fiber reinforced plastic composite (agro-FRPC) from rubber wood fiber blended in polypropylene matrix. The effects of varying fiber dimension and fiber content on the physical and mechanical properties of the composite were evaluated to provide an insight into the fiber matrix adhesion. The effects of reactive additives on the physical and mechanical properties of the composite were evaluated which provides the insight on the reinforcement of the composite. Rubber wood fiber used in this study is currently being used in the manufacturing of medium density fiber (MDF) board. Two sizes of rubber wood fiber were used i.e. 0.5-1.0 mm and 1.0-2.0 mm. Homopolymer polypropylene of MFI 14.0 was used as a matrix. The irradiation work was carried out using electron beam accelerator, 3.0 MeV, 3.0 mA. Various types of reactive additives (RA) with mono-functional, di-functional, tri-functional and oligomer were applied in the blend. For comparison, a conventional chemical cross-linking using two types of maleated polypropylene, MPA (Mw=9,000) and PMAP (Mw=220,000) were also performed. (author)

Electron beam processing of rubber wood fibers - polypropylene composites. Effects of reactive additives on the physical and mechanical properties

Energy Technology Data Exchange (ETDEWEB)

Nor Yuziah Mohd Yunus; Jalaluddin Harun [Universiti Putra Malaysia, Selangor Darul Ehsan (Malaysia); Khairul Zaman [Malaysian Institute for Nuclear Technology Research (MINT), Selangor Darul Ehsan (Malaysia)

2000-07-01

The purpose of this study is to determine the suitability of producing agro-fiber reinforced plastic composite (agro-FRPC) from rubber wood fiber blended in polypropylene matrix. The effects of varying fiber dimension and fiber content on the physical and mechanical properties of the composite were evaluated to provide an insight into the fiber matrix adhesion. The effects of reactive additives on the physical and mechanical properties of the composite were evaluated which provides the insight on the reinforcement of the composite. Rubber wood fiber used in this study is currently being used in the manufacturing of medium density fiber (MDF) board. Two sizes of rubber wood fiber were used i.e. 0.5-1.0 mm and 1.0-2.0 mm. Homopolymer polypropylene of MFI 14.0 was used as a matrix. The irradiation work was carried out using electron beam accelerator, 3.0 MeV, 3.0 mA. Various types of reactive additives (RA) with mono-functional, di-functional, tri-functional and oligomer were applied in the blend. For comparison, a conventional chemical cross-linking using two types of maleated polypropylene, MPA (Mw=9,000) and PMAP (Mw=220,000) were also performed. (author)

Some Exploitation Properties of Wood Plastic Hybrid Composites Based on Polypropylene and Plywood Production Waste

Science.gov (United States)

Kajaks, Janis; Kalnins, Karlis; Uzulis, Sandris; Matvejs, Juris

2015-12-01

During the last 20-30 years many researchers have paid attention to the studies of properties of thewood polymer composites (WPC). A lot of works are closely related to investigations of exploitation properties of wood fibres or wood flour containing polyolefine composites [1, 2]. The most useful from wide selection of polyolefines are polypropylenes, but timber industry waste materials comprising lignocellulose fibres are often used as reinforcement of WPC [3-12]. Plywood industry is not an exception - part of waste materials (by-products) are used for heat energy, i.e. burned. In this work we have approbated reinforcing of polypropylene (PP) with one of the plywood industry by-products, such as birch plywood sawdust (PSWD),which containswood fibre fractions with different length [13]. The main fraction (50%) includes fibres with length l = 0.5 - 1 mm. Our previous study [13] has confirmed that PSWD is a promising filler for PP reinforcing. Addition of PSWD up to 40-50 wt.% has increased WPC tensile and flexural modulus, but decreased deformation ability of PP matrix, impact strength, water resistance and fluidity of composite melts. It was shown [13] that modification of the composites with interfacial modifier - coupling agent maleated polypropylene (MAPP content up to 5-7 wt.%) considerably improved all the abovementioned properties. SEM investigations also confirmed positive action of coupling agent on strengthening of adhesion interaction between components wood and PP matrix. Another way how to make better properties of the WPC is to form hybridcomposites [1, 14-24]. Very popular WPC modifiers are nanoparticle additions like organonanoclays, which increase WPC physical-mechanical properties - microhardness, water resistance and diminish barrier properties and combustibility [1, 2, 14-17, 19, 20]. The goal of this study was to investigate organonanoclays influence on plywood production industry by-product birch plywood sawdust (PSWD) containing

Radiation resistant modified polypropylene

International Nuclear Information System (INIS)

Bojarski, J.; Zimek, Z.

1997-01-01

Radiation technology for production of radiation resistant polypropylene for medical use has been presented. The method consists in radiation induced copolymerization of polypropylene with ethylene and addition of small amount of copolymer of polyethylene and vinyl acetate. The material of proposed composition has a very good mechanical properties and elevated radiation resistivity decided on possibility of radiosterilization of products made of this material and designed for medical use. 3 figs, 3 tabs

Short Jute Fiber Reinforced Polypropylene Composites: Effect of Nonhalogenated Fire Retardants

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Sk. Sharfuddin Chestee

2017-01-01

Full Text Available Short jute fiber reinforced polypropylene (PP composites were prepared using a single screw extrusion moulding. Jute fiber content in the composites is optimized with the extent of mechanical properties, and composites with 20% jute show higher mechanical properties. Dissimilar concentrations of several fire retardants (FRs, such as magnesium oxide (MO, aluminum oxide (AO, and phosphoric acid (PA, were used in the composites. The addition of MO, AO, and PA improved the fire retardancy properties (ignition time, flame height, and total firing time of the composites. Ignition time for 30% MO, flame height for 30% PA, and total firing time for 20% MO content composites showed good results which were 8 sec, 1 inch, and 268 sec, respectively. Mechanical properties (tensile strength, tensile modulus, bending strength, bending modulus, and elongation at break, degradation properties (soil test, weathering test, and percentage of weight loss, and water uptake were studied.

Fabrication and characterization of jute fabrics reinforced polypropylene-based composites: effects of ionizing radiation and disaccharide (sucrose)

Science.gov (United States)

Sahadat Hossain, Md.; Uddin, Muhammad B.; Razzak, Md.; Sarwaruddin Chowdhury, A. M.; Khan, Ruhul A.

2017-12-01

Composites were prepared successfully by compression molding technique using jute fabrics (reinforcing agent) and polypropylene (matrix). Jute fabrics were treated with disaccharide (sucrose) solution and composites were fabricated with the treated fabric and polypropylene. The fiber content of the prepared composites was 40% by weight. It was found that the sucrose (2% solution) decreased the tensile strength (TS) and elongation at break about 6% and 37%, respectively, but tensile modulus and impact strength improved about 27% and 32%, respectively. When gamma radiation was applied through the untreated and treated composites the mechanical properties were improved much higher in non-treated Jute/PP-based composites than that of sucrose treated composites. For 5.0 kGy gamma dose the highest mechanical properties were observed for non-treated composites. At 5.0 kGy gamma dose the improvement of TS was 14% and 2% for non-treated and sucrose treated composites, respectively. The water uptake property of the sucrose treated composites was performed up to 10 days and composites absorbed 18% water. The functional groups of the both composites were analyzed by Fourier transform infrared spectroscopy machine. The scanning electron microscopic images of the both composites were taken for the surface and fiber adhesion analysis.

Study of the rice husk ash utilization as filler polypropylene matrix and ionization radiation effect on this composite

International Nuclear Information System (INIS)

Alfaro, Eduardo de Faria

2010-01-01

In the first step of this work, it was evaluated the possibility of using rice husk ash as a filler in polypropylene (PP) making a comparison with talc which is the most used mineral filler in polymers. This comparison was made by using polypropylene with 20% rice husk ash as well as polypropylene with 20% talc measuring their properties. Despite the properties of the PP with 20% rice husk ash decreased compared with the composite of polypropylene with 20% talc it can be said that the rice husk ash can be used as filler for or other utilization less noble of PP . This way it is being given a destination for this residue that it is disposable in the environment contributing to its preservation, moreover reducing the product cost. This work had also as an aim to study the ionizing radiation effect in the properties of these composites. It was used the coupling agent, maleic anhydride , to verify a best sample homogenization. According to the results it can be said that PP is a semicrystalline polymer, and so it has its morphology modified when exposed to the irradiation process. This fact is due to the scission mechanisms of the polymeric chains which it is in compliance to the literature. (author)

The influence of irradiated wood filler on some properties of polypropylene - wood composites

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Điporović-Momčilović Milanka

2007-01-01

Full Text Available The problem of compatibility between the wood filler and thermoplastic matrix is of essential importance in composite production. Numerous methods have been developed for increasing this compatibility, which is still representing a challenging objective of composite research throughout the world. The research into these methods is primarily directed towards their efficiency from the viewpoint of the composite performance and their economical acceptability. The latter is of particular importance for the composite production in the developing countries with respect to the shortage of the corresponding funds. With this respect, the utilization of ionizing radiation might have considerable advantages. In this research, the beech wood flour was irradiated by a dose of 10 kGy of 60Co gamma rays for purpose of provoking the changes by the ionizing effect. The effects of ionizing radiation upon the properties of wood particles have been examined by IR spectroscopy and by determination of contents of hydroxyl groups in wood by acetylating as an indirect method. All these methods have been expected to reveal the chemical effects of the applied radiation treatment. The irradiated and the control wood flour were used in order to produce the samples of composite with polypropylene. The polypropylene-wood flour (PP-WF composites were produced with 40% of wood particles having fraction size 0.3 mm. The melt-blended composites were modified with amido-acrylic acid (AMACA as a new coupling agent synthesized for this propose in amount of 6 wt.% (based on wood filler and successively with 0.05 wt.% (based on PP of organic peroxide during mixing step. The composites containing coupling agents showed superior mechanical properties, compared to the untreated one. The highest extent of improvement of tensile was achieved in PP-WFl composites modified with AMACA coupling agent.

Woodflour as Reinforcement of Polypropylene

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José Cláudio Caraschi

2002-10-01

Full Text Available The effect of the filler content and size, as well as accelerated aging on the mechanical properties of polypropylene composites reinforced with woodflour (WF/PP were evaluated. The composites were prepared by the extrusion of polypropylene with woodflour (Pinus elliotti based on following ratios: 15, 25 and 40 wt% with two different granulometries. The specimens were injection molded according to ASTM standards. The composite properties did not show significant differences as a function of the filler granulometry. We also observed that by increasing the filler content, both the mechanical properties and the melt flow index (MFI decreased, and the elasticity modulus, hardness and density increased. Concerning the accelerated aging, the composite presented a reduction in tensile properties. The results showed that the composite properties are extremely favorable when compared to other commercial systems reinforced by inorganic fillers.

Modelling of polypropylene fibre-matrix composites using finite element analysis

Directory of Open Access Journals (Sweden)

2009-01-01

Full Text Available Polypropylene (PP fibre-matrix composites previously prepared and studied experimentally were modelled using finite element analysis (FEA in this work. FEA confirmed that fibre content and composition controlled stress distribution in all-PP composites. The stress concentration at the fibre-matrix interface became greater with less fibre content. Variations in fibre composition were more significant in higher stress regions of the composites. When fibre modulus increased, the stress concentration at the fibres decreased and the shear stress at the fibre-matrix interface became more intense. The ratio between matrix modulus and fibre modulus was important, as was the interfacial stress in reducing premature interfacial failure and increasing mechanical properties. The model demonstrated that with low fibre concentration, there were insufficient fibres to distribute the applied stress. Under these conditions the matrix yielded when the applied stress reached the matrix yield stress, resulting in increased fibre axial stress. When the fibre content was high, there was matrix depletion and stress transfer was inefficient. The predictions of the FEA model were consistent with experimental and published data.

Effects of consolidation process on microstructure and mechanical properties of commingled glass/polypropylene composites

International Nuclear Information System (INIS)

Tufail, M.; Long, A.C.; Rudd, C.D.

2001-01-01

The thermal history of a thermoplastic composite material during forming and consolidation is critical to the quality of the component. Attempts to process outside the normal melt region will result in incomplete consolidation and voidage. Clearly then, the preheat phase plays a key role in successful processing. Too low a preheat temperature results in insufficient matrix flow while, if the temperature is increased too much, degradation of the matrix occurs, again resulting in poor quality of the composite. In particular polypropylene has poor chemical (oxidative) resistance, and oxidative degradation reduces the average molecular weight of the materials. If excessive, this can result in a dramatic reduction in mechanical properties. Flat plaques of braided, commingled glass/polypropylene yarn were produced to examine these effects using both isothermal and non-isothermal consolidation. Woven plaques were also produced from commingled yarn in a similar fashion as control samples in order to identify any effects specific to the braiding process. This paper describes the effect of heating and stamping cycles on the properties of these composites, concentrating on the effects of temperature, heating time and compaction rate. (author)

Study of the effect of ionizing radiation on composites of wood flour in polypropylene matrix using barium titanate as coupling agent

International Nuclear Information System (INIS)

Ulloa, Maritza Eliza Perez

2007-01-01

The purpose of this work was to study the effects of ionizing radiation on the properties of wood flour composites in polypropylene matrix, using barium titanate as a coupling agent and the reactive monomer tripropylene glycol diacrylate (TPDGA). An electron accelerator was used in the study as the radiation source. The physical properties of virgin compounds and of the polypropylene/wood flour composite, with and without barium titanate and TPDGA addition, were investigated. The composites were developed from the load treatment, which first consisted of incorporating additives to the wood flour reinforcement and after that, the fusion process of polypropylene and composite mixing in a 'calander'. Subsequently, the samples to be irradiated and submitted to thermal and mechanical assays were molded by injection. The mechanical properties (hardness, impact resistance and molten fluidity index (MFI)), as well as the thermal properties (HDT and Vicat) of the composites were determined. The investigated compositions consisted of polypropylene/wood flour, polypropylene/wood flour with barium titanate and polypropylene/wood flour with barium titanate and TPDGA, using different wood flour concentrations of 10 por cent, 15 por cent and 20 por cent in the polypropylene matrix. The samples were separated in groups and irradiated to doses of 10 kGy and 20 kGy in the samples of the essays of traction. Besides these doses, it was also used doses of 15 kGy and 25 kGy to be observed the behavior of the sample of the sample due to the increase of the radiation. These doses were chosen to show that with low doses the composite material presents reticulation, what represents a viable commercial option. There was a reduction of the flow rate for the composites containing wood flour, being this reduction more effective in the presence of TiBa. The superficial treatment using TPDGA monomer influence in the composite samples because it acted as a plastic additive becoming the sample

Rheological properties of polypropylene nanocomposites

International Nuclear Information System (INIS)

Oliveira, Camila F. de P.; Demarquette, Nicole R.

2009-01-01

In this work, composites of polypropylene with a master batch to obtain clay containing nano composites were obtained. The materials were characterized by X ray diffraction, small angle X-ray scattering and by rheological analysis. (author)

Electromagnetic interference shielding effectiveness of polypropylene/conducting fiber composites

International Nuclear Information System (INIS)

Lee, Pyoung-Chan; Kim, Bo-Ram; Jeoung, Sun Kyoung; Kim, Yeung Keun

2016-01-01

Electromagnetic released from the automotive electronic parts is harmful to human body. Electromagnetic interference (EMT) shielding refers to the reflection and/or adsorption of electromagnetic radiation by a material, which thereby acts as a shield against the penetration of the radiation through the shield. Polypropylene (PP)/conductive micro fiber composites containing various fiber contents and fiber length were injection-molded. The effect of fiber content and length on electrical properties of the composites was studied by electrical resistivity and EMT shielding measurements. The through-plane electrical conductivity and dielectric permittivity were obtained by measuring dielectric properties. The EMT shielding effectiveness (SE) was investigated by using S-parameter in the range of 100 ~ 1500 MHz. Reflection, absorption and multiple-reflection are the EMT attenuation mechanisms. From the measurement of S-Parameters, the absorption coefficient, reflection coefficient, and the shielding efficiency of the materials were calculated. The EMT SE of PP/conducing fiber composites is 40 dB over a wide frequency range up to 1.5 GHz, which is higher than that of PP/talc composite used automotive parts, viz. 0 dB.

Influence of Magnetite Nanoparticles on the Dielectric Properties of Metal Oxide/Polymer Nanocomposites Based on Polypropylene

Science.gov (United States)

Maharramov, A. A.; Ramazanov, M. A.; Di Palma, Luca; Shirinova, H. A.; Hajiyeva, F. V.

2018-01-01

Structure and dielectric properties of polymer nanocomposites based on isotactic polypropylene and iron oxide (Fe3O4) nanoparticles are studied. Distribution of magnetite nanoparticles in a polymer matrix was studied by scanning electron microscopy (SEM, Carl Zeiss). Dielectric properties of nanocomposites were examined by means of E7-21 impedance spectrometer in the frequency range of 102-106 Hz and temperature interval of 298-433 K. The frequency and temperature dependences of the dielectric permittivity ɛ, as well as the temperature dependence of log (ρ) were constructed. It is shown that introduction of the magnetite (Fe3O4) nanoparticles into a polypropylene matrix increases the dielectric permittivity of nanocomposites. An increase in the dielectric permittivity is explained by the increase in the polarization ability of nanocomposites. It is found that a decrease in the specific resistance with increasing temperature up to 318 K is associated with an increase in the ionic conductivity of nanocomposites. An increase in the resistance at temperatures higher than 358 K is due to the destruction of the crystalline phase of the polymer, as a result of which the distance between the Fe3O4 nanoparticles increases.

Removal of light petroleum hydrocarbons from water sources using polypropylene and titanium dioxide nano-composite

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H. Karyab

2016-08-01

Full Text Available Background: Petroleum hydrocarbons are the most important pollutants which threat human health and aquatics. Adsorbents are one of the common equipment in water pollution management; however, their applications have been associated with limitations. Objective: To evaluate the potential of polypropylene/titanium dioxide Nano-composite in adsorption of light petroleum hydrocarbons from water sources. Methods: This experimental study was conducted at school of health, Qazvin University of Medical Sciences in 2014-15. Activation of polypropylene fibers, with 1 cm length and 300 microns diameters, was achieved with wet heating. To synthesize of nano-composite the fibers were coated with nano-titanium dioxide with 20 nm diameter. The sonication was performed at 26 kHz and 100 W of power in 40ºc. The morphology of the fractured surfaces of impact specimens was examined by FESEM. The adsorption rate of petrol and gasoline, as surrogate of TPH, was evaluated in different retention time within polyamide mesh aperture diameter of 250 nm. Average of TPH adsorbing, per unit weight of adsorbent, were analyzed with analysis of variance and Scheffe post hoc tests. Findings: The FESEM micrographs showed that the dispersion of the nano-Tio2 particles was relatively good and only few aggregations exist. The maximum adsorption capacity of petrol and gasoline was obtained in 30 minute. The adsorption rate of gasoline was 6.49±0.10 g/g and oil was 7.01±0.13 g/g. Conclusion: According to the results and in comparison with commercial imported adsorbents, the synthesized Nano-composite had favorable performance. The results show that the polypropylene/Tio2 Nano-composite can be used effectively in light petroleum hydrocarbons removal from polluted water sources.

Polypropylene Nano composites Obtained by In Situ Polymerization Using Metallocenes Catalyst: Influence of the Nanoparticles on the Final Polymer Morphology

International Nuclear Information System (INIS)

Zapata, P.; Quijada, R.

2012-01-01

Polypropylene nano composites containing silica nanospheres based on the sol-gel methods were produced via in situ polymerization using a rac-Et(Ind) 2 ZrCl 2 /methylaluminoxane (MAO) system. Two different routes were used depending on the interaction between the silica nanoparticles with the catalytic system. In route 1 the nanoparticles were added together with the catalytic system (rac-Et(Ind) 2 ZrCl 2 )/(MAO) directly into the reactor, and in route 2 the metallocenes rac-Et(Ind) 2 ZrCl 2 was supported on silica nanospheres pretreated with (MAO). SEM images show that when the nanospheres were added by both routes, they were replicated in the final polymer particle morphology; this phenomenon was more pronounced for PP obtained by route 2. The polypropylene (PP) nano composites obtained by both routes had a slightly higher percent crystallinity and crystallinity temperatures than pure PP. Transmission electron microscopy (TEM) images show that the nanospheres were well dispersed into the polypropylene matrix, particularly in the nano composites obtained by the support system (route 2).

Studies on Poly(propylene fumarate-co-caprolactone diol Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices

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M. Jayabalan

2009-01-01

Full Text Available The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus.

Studies on Poly(propylene fumarate-co-caprolactone diol) Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices.

Science.gov (United States)

Jayabalan, M

2009-01-01

The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol) was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus.

Radiation-modified blends of the basis of polyethylene terephthalate and polypropylene

International Nuclear Information System (INIS)

Mery-Meri, R.; Revyakin, O.; Zicans, J.

2000-01-01

The binary composite systems on the basis of post-consumer poly-(ethylene terephthalate) and polypropylene have been investigated. Mechanical properties of the compositions were studied in detail in order to expand the application possibilities of tested binary composites. Structural changes of the poly (ethylene terephthalate) / polypropylene blends depending on the concentration of the components were investigated also. Additionally, the optimum processing conditions were established. Particular attention was paid to study the influence of the ionizing γ-radiation on the structural and mechanical properties of the composition systems tested. The magnitude of the adsorbed dose od γ-radiation was established to affect differently the structure of poly(ethylene terephalate) and polypropylene. At small absorbed doses (50 kGy) crosslinking of the polymer was observed for both poly(ethylene terephthalate) and polypropylene resulting in the increase of some mechanical properties of pure materials as well of their compositions, whereas the absorbed dose of 300 kGy caused the destruction of the tested materials. It is important to mention that the rate of radiation-chemical destruction of polypropylene is higher than poly(ethylene terephthalate) destruction rate. (author)

Transparent Low Electrostatic Charge Films Based on Carbon Nanotubes and Polypropylene. Homopolymer Cast Films

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Zoe Vineth Quiñones-Jurado

2018-01-01

Full Text Available Use of multi-wall carbon nanotubes (MWCNTs in external layers (A-layers of ABA-trilayer polypropylene films was investigated, with the purpose of determining intrinsic and extrinsic factors that could lead to antistatic behavior of transparent films. The incorporation of 0.01, 0.1, and 1 wt % of MWCTNs in the A-layers was done by dilution through the masterbatch method. Masterbatches were fabricated using isotactic polypropylene (iPP with different melt flow indexes 2.5, 34, and 1200 g/10 min, and using different ultrasound assist methods. It was found that films containing MWCNTs show surface electrical resistivity of 1012 and 1016 Ω/sq, regardless of the iPP melt flow index (MFI and masterbatch fabrication method. However, electrostatic charge was found to depend upon the iPP MFI, the ultrasound assist method and MWCNT concentration. A percolation electron transport mechanism was determined most likely responsible for this behavior. Optical properties for films containing MWCNTs do not show significant differences compared to the reference film at MWCNT concentrations below 0.1 wt %. However, an enhancement in brightness was observed, and it was attributed to ordered iPP molecules wrapping the MWCNTs. Bright transparent films with low electrostatic charge were obtained even for MWCNTs concentrations as low as 0.01 wt %.

Crystalline structure of polypropylene in blends with thermoplastic elastomers after electron beam irradiation

International Nuclear Information System (INIS)

Steller, Ryszard; Zuchowska, Danuta; Meissner, Wanda; Paukszta, Dominik; Garbarczyk, Jozef

2006-01-01

Isotactic polypropylene (PP) was blended in extruder with 0-50% addition of styrene-ethylene/butylene-styrene (SEBS) and styrene-butadiene-styrene (SBS) block copolymers. Granulated blends were irradiated with electron beam (60 kGy) and 1 week later processed with injection molding machine. Properties of samples molded from irradiated and non-irradiated granulates were investigated using DSC, WAXS, MFR, SEM and mechanical and solubility tests. It was found that the SEBS based systems are more resistant to irradiation in comparison to similar blends with SBS copolymer. Such behavior can be explained by the presence of double bonds in elastic SBS block. Irradiation of PP-SBS blends leads to considerable structure changes of crystalline and amorphous PP phases and elastic SBS phase. It indicates creation of new (inter)phase consisting of products of grafting and cross-linking reactions. Irradiated PP-SBS blends show significant improvement of impact strength at low temperatures

Pulse NMR-spectroscopy of structural changes of chemically modified polypropylene

International Nuclear Information System (INIS)

Gafarov, A.M.; Galibeev, S.S.; Kochnev, A.M.; Sukhanov, P.P.; Arkhireev, V.P.

2004-01-01

The structure of polypropylene compositions is studied by the method of pulse NMR-spectroscopy. The polypropylene compositions are derived by means of the modification by multicomponent systems. The analysis of relaxation times in a wide temperature range is carried out. Character of changes going on at a level of supermolecular structures is described. It is shown that the amplifications that manifest themselves under the polypropylene modification by the mixtures based on 2,4-tolyilendiisocyanate and e-caprolactam, are related to the change in the intermolecular interaction and formation of a more ordered polymer structure. (authors)

Synthesis And Thermal Characterization Of Polypropylene ...

African Journals Online (AJOL)

The present work investigates the heat transfer and specifically, thermal conductivity, diffusivity and specific heat in Aluminium composite materials. The composites were obtained by mixing polypropylene (PP) with oxidized Aluminium (Al) under various volume fractions. Two sizes of filler are used in the sample composite ...

Polypropylene /Aspen/ liquid polybutadienes composites: maximization of impact strength, tensile and modulus by statistical experimental design

Czech Academy of Sciences Publication Activity Database

Kokta, B. V.; Fortelný, Ivan; Kruliš, Zdeněk; Horák, Zdeněk; Michálková, Danuše

2005-01-01

Roč. 99, - (2005), s. 10-11 ISSN 0009-2770. [International Conference on Polymeric Materials in Automotive , Slovak Rubber Conference /17./. 10.5.2005-12.5.2005, Bratislava] Institutional research plan: CEZ:AV0Z40500505 Keywords : polypropylene * Aspen-PP composite Subject RIV: CD - Macromolecular Chemistry

Bio composites from polypropylene/ clay/eva polymers and kenaf natural fiber

International Nuclear Information System (INIS)

Siti Hasnah Kamarudin; Khalina Abdan; Bernard Maringgal; Wan Mohd Zin Wan Yunus

2009-01-01

Full text: There is an increasing need to investigate more environmental friendly, sustainable materials to replace existing materials as industry attempts to lessen dependence on petroleum based fuels and products. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. In this experiment, mixing process of polymer/nano clay composites from polypropylene, organo clay and ethylene vinyl acetate were prepared using a Brabender twin screw compounder. The composites sheets were then laminated with kenaf fibers and subjected to hot and cold press machine to form a bio composite. The mechanical properties such as flexural and impact strength are compare favourably between polymers reinforced kenaf fiber and polymers without kenaf fiber. In addition, various analysis techniques were used to characterize the dispersion and the properties of nano composites, using scanning electron micrograph (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). These results suggest that kenaf fibers are a viable alternative to inorganic mineral-based reinforcing fibers as long as the right processing conditions are used and they are used in applications where the higher water absorption is not critical. (author)

Characterization of Polypropylene Green Composites Reinforced by Cellulose Fibers Extracted from Rice Straw

Directory of Open Access Journals (Sweden)

Ngo Dinh Vu

2018-01-01

Full Text Available Polypropylene (PP based green composites containing 10, 20, 30, 40 and 50 wt% of cellulose fibers (CFs which were extracted from rice straw were successfully prepared by melt blend method. The CFs washed with H2O2 after alkaline extraction showed lower water absorption than that not washed with H2O2. The thermal, mechanical, and biodegradation properties of composites were also investigated. The 10% weight loss temperature of the composites was decreased with the increasing CFs content, but all the composites showed over 300°C. Young’s modulus and flexural properties of PP were improved by blending PP with CFs. The pure PP showed no degradability, but the PP/CFs composites degraded from about 3 to 23 wt%, depending on CFs content after being buried in soil for 50 days. These PP/CFs composites with high thermal, mechanical properties and biodegradability may be useful as green composite materials for various environmental fields.

Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering

DEFF Research Database (Denmark)

Stribeck, Norbert; Schneider, Konrad; Zeinolebadi, Ahmad

2014-01-01

The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline......-shaped phyllosilicate filler particles....

Effect of Isotacticity of Linear Poly(N-isopropylacrylamide) on its ...

Indian Academy of Sciences (India)

decreased with the increase in the isotacticity of the polymer. Gelation ... microscopy (SEM), differential scanning calorimetry ... The gap between two paral- ... sidering degree of polymerization, x = 6) with benzyl ..... Apart from the blue shift, the absorbance value grad- ..... for Bethe lattice, n should have the value equal to.

PEG-template for surface modification of zeolite: A convenient material to the design of polypropylene based composite for packaging films

Science.gov (United States)

Toommee, S.; Pratumpong, P.

2018-06-01

Zeolite was successfully modified by conventional synthetic route. Polyethylene glycol was employed for surface modification of zeolite. The surface of zeolite exhibited therefore hydrophobic properties. Less than 5 wt% of modified zeolites with uniform size and shape were integrated into polypropylene matrix. Mechanical properties of composite exhibited the similar trend compare to neat polypropylene. Oxygen transmission rate and water vapor transmission rate were evaluated and it exhibited the strong potential to be a good candidate material in active packaging.

The influence of filler surface modification on mechanical and material properties of layered double hydroxide -containing polypropylene composites

CSIR Research Space (South Africa)

Moyo, Lumbidzani

2017-03-01

Full Text Available The processing and properties of layered double hydroxides (LDHs)-containing polypropylene (PP) composites have been studied extensively. However, no detailed studies have reported on how stearic acid (SA)-intercalated and SA-coated LDHs influence...

Flammability of polypropylene/organoclay nanocomposites

International Nuclear Information System (INIS)

Alves, Tatianny Soares; Barbosa, Renata; Carvalho, Laura Hecker de; Canedo, Eduardo Luis

2014-01-01

The flammabilities of nanocomposites made with three polypropylene grades (homo and copolymers) with 5 wt % of organoclay (Cloisite 20A), 5 or 15 wt % of maleated polypropylene as compatibilizer, and 0, 0.5 or 1 wt % of cis-13-docosenamide (Erucamide) as co-intercalant, were studied using the horizontal burning test UL94HB. Masterbatches prepared in an internal mixer were diluted in the polypropylene matrix using a corotating twin-screw extruder, with different screw configurations and operating at 240 or 480 rpm. Results indicate that the high burning rate of the composites was not affected by the processing conditions. For all formulations was observed a significant reduction in smoke release, lack of dripping and the formation of a char surface layer, that protected the core of the samples. (author)

Influence of the chemical modification and content of the clay on the mechanical properties of polypropylene and national bentonite composites

International Nuclear Information System (INIS)

Libano, Elaine V.D.G.; Pacheco, Elen B.A.V.; Visconte, Leila L.Y.

2011-01-01

The polypropylene/national clay composite was prepared by melt intercalation in a counter-rotating twin screw extruder, using bentonite as filler either in the natural (BENT) form or modified with the ammonium salt, cetyltrimethylammonium chloride (BENT-org). The clay was used in 1, 3 and 5%w. The influence of the modification and content of clay on the mechanical properties of this system was analysed. The analyses of infrared spectroscopy (FTIR) and X-ray diffraction (XRD) showed that clay organophilization did occur. The tensile modulus and the tensile strength at the yield point were not affected by chemical modification (BENT and BENT-org) or clay content. On the other hand, it was evidenced that the elongation at the yield point decreased with the addition of BENT and BENT-org to polypropylene. According to the thermogravimetric results, it was evidenced that the incorporation of clay into polypropylene improved thermal stability of the polymer in the composites with 5%w of BENT and 3 and 5%w of BENT-org. (author)

Preparation of Polypropylene/Montmorillonite Nanocomposites Using Ionizing Radiation

International Nuclear Information System (INIS)

Güven, Olgun; Zengin, Fatma

2011-01-01

Polymer/clay nanocomposites are new generation materials that bring significant changes in mechanical, thermal and permeation properties of base polymers by low clay loading. In this study, polypropylene/montmorillonite nanocomposites were prepared by melt intercalation method by using batch type mixer. Two polypropylene samples with different melt flow indexes are used as the matrix, maleic anhydride grafted polypropylene (PP-g-MAH), and polypropylene granules oxidized by radiation/ozone are used as compatibilizer and unmodified clay (Na + montmorillonite, MMT) as the filler. Aim of this study is to examine the effect of different compatibilizers in the mechanical properties of polypropylene composite. Firstly, PP/clay samples were prepared and the effect of clay was examined, then 5, 10, 20kGy oxidized/degraded polypropylenes were used as compatibilizer and, 10 kGy was determined to be the most suitable irradiation dose for the best compatibilizing effect. Polypropylene granules were ozonated until they contained carbonyl groups equivalent to 10kGy oxidized PP, which was checked by FTIR-ATR spectroscopy. UV-visible reflectance measurements were also made on film samples and no significant changes were observed in visible region. Nano structures of some nanocomposites were characterized by PALS (Positron Annihilation Lifetime Spectroscopy) where it was observed that the addition of clay decreased the number of free volume holes and free volume hole radia. The dispersion state of MMT within polymer matrix was analyzed by XRD (X-ray diffraction). Tensile tests were made and the effect of the addition of clay and compatibilizers investigated. At low melt flow index PP, 1% MMT of PP/10kGyPP/MMT nanocomposite showed an increase in E-modulus 26% and in tensile strength 8% as compared to those of pristine PP. In conclusion radiation degraded (chain scissioned and oxidized) PP has been found to show very good compatibilizing effect for the natural montmorillonite/polypropylene

Preparation of Polypropylene/Montmorillonite Nanocomposites Using Ionizing Radiation

Energy Technology Data Exchange (ETDEWEB)

Güven, Olgun; Zengin, Fatma

2011-07-01

Polymer/clay nanocomposites are new generation materials that bring significant changes in mechanical, thermal and permeation properties of base polymers by low clay loading. In this study, polypropylene/montmorillonite nanocomposites were prepared by melt intercalation method by using batch type mixer. Two polypropylene samples with different melt flow indexes are used as the matrix, maleic anhydride grafted polypropylene (PP-g-MAH), and polypropylene granules oxidized by radiation/ozone are used as compatibilizer and unmodified clay (Na{sup +} montmorillonite, MMT) as the filler. Aim of this study is to examine the effect of different compatibilizers in the mechanical properties of polypropylene composite. Firstly, PP/clay samples were prepared and the effect of clay was examined, then 5, 10, 20kGy oxidized/degraded polypropylenes were used as compatibilizer and, 10 kGy was determined to be the most suitable irradiation dose for the best compatibilizing effect. Polypropylene granules were ozonated until they contained carbonyl groups equivalent to 10kGy oxidized PP, which was checked by FTIR-ATR spectroscopy. UV-visible reflectance measurements were also made on film samples and no significant changes were observed in visible region. Nano structures of some nanocomposites were characterized by PALS (Positron Annihilation Lifetime Spectroscopy) where it was observed that the addition of clay decreased the number of free volume holes and free volume hole radia. The dispersion state of MMT within polymer matrix was analyzed by XRD (X-ray diffraction). Tensile tests were made and the effect of the addition of clay and compatibilizers investigated. At low melt flow index PP, 1% MMT of PP/10kGyPP/MMT nanocomposite showed an increase in E-modulus 26% and in tensile strength 8% as compared to those of pristine PP. In conclusion radiation degraded (chain scissioned and oxidized) PP has been found to show very good compatibilizing effect for the natural montmorillonite/polypropylene

Evaluation of the environmental aging and mechanical properties of the polypropylene/sugarcane bagasse composites

International Nuclear Information System (INIS)

Paiva, Rayane Lima de Moura; Mulinari, Daniella Regina

2013-01-01

Polypropylene (PP) reinforced with fibers from sugarcane bagasse composites in different proportions were prepared. Also environmental aging was conducted for the composites and their mechanical properties determined. The results showed that chemical treatment caused changes in color and chemical composition of the fibers, removing impurities and amorphous constituents such as lignin and hemicellulose, techniques of FTIR, X-ray diffraction and scanning electron microscopy confirmed these data. Also, it was observed that addition of natural fiber in PP matrix provided an improvement in the mechanical properties materials. The weathering test revealed a slight mass gain after 75 days, but it was clear that the inclusion of fibers has a higher mass gain compared to pure PP. (author)

Pre-irradiation technique for processing of oil palm fruit bunch fibers - polypropylene composites

International Nuclear Information System (INIS)

Khairul Zaman Dahlan; Manarpaac, G.A.; Harun Jalaluddin

2002-01-01

Researches on oil palm empty fruit bunch (EFB) fibers and thermoplastic composites have been carried out by many workers in the last decade. The main focus was to enhance the properties of the resultant composites in view of the incompatibility of the two components. Thus, efforts have been made to enhance their properties by using coupling agents, treating the fibers and modifying the matrices. In this study, the effects of electron beam (EB) irradiation and some reactive additives (RAs) on the mechanical properties of EFB-PP (polypropylene) composites were evaluated. Different modes of irradiation were investigated. Mono, di and tri functional of monomers of RAs were used. irradiating PP alone, compared to irradiating the EFB fibers or irradiating both components, gave optimum properties for EFB-PP composites. Further, improvements of the properties of the composites were achieved with the addition of RAs with TMPTA (trymethylol propane triacrylate) giving the optimum results. (Author)

Enthalpy relaxation in the cooling/heating cycles of polypropylene/organosilica nanocomposites

International Nuclear Information System (INIS)

Privalko, V.P.; Dinzhos, R.V.; Privalko, E.G.

2005-01-01

Non-isothermally crystallized samples of the neat isotactic polypropylene homopolymer (PP-0) and of a series of nanocomposites (PNC) containing up to 4.68 vol.% of organosilica were characterized by wide-angle and small-angle X-ray diffraction and by the standard DSC, while their melting behavior was studied in the temperature-modulated DSC mode at three underlying heating rates and five modulation frequencies. It was established that the lamellar morphology of PP remained essentially unchanged, whatever the previous cooling rate and/or the organoclay content. The patterns of melting endotherms in both the neat PP sample and the PNC could be semi-quantitatively characterized by a simple Debye model with a single, temperature- and underlying heating rate-dependent characteristic time. The mechanisms of structural rearrangements in the melting intervals of the neat PP sample and the PNC were basically similar; however, the spatial scale of such rearrangements in the latter samples was significantly reduced due to severe steric constraints on the PP chain mobility in the melt state from the infinite cluster of nanoparticles

Mechanical Properties of Non-Woven Polyester Fibers and Polymer-Modified Bitumen Composites

Directory of Open Access Journals (Sweden)

V. Hadadi

2007-12-01

Full Text Available Blown bitumen (110/10 was mixed with heavy vacuum slops (H.V.S, 60/70 penetration grade bitumen and recycled isotactic polypropylene (iPP at different levels. The resulting resins were used to impregnate non-woven poly(ethylene terephthalate fibers to form composites. The modulus and penetration grade of the resulting bituminous resins were determined. It was found that these bituminous resins drastically affect the modulus of the composites formed by low-Young’s modulus fibers such as polyesters. Consequently, interactions between resin and fibers and the correlation length of asphalthenes (in absence of iPP and interdiffused coalescence and segregated network of asphalthenes (in presence of iPP result in a non-linear behavior of composite’s modulus. The behavior of the composites with or without iPP is controlled by resin toughness and resin interactions with the fiber through the viscosity. Comparison of the experimental composite modulus data with the theoretical modulus data revealed that the Takayanangi’s model best predicts the behavior of these composites. The adjustment factors of this model were reported and proposed as an indication of fiber-resin interaction. It was also found that the modulus of fibers is affected by toughness, viscosity and the iPP content of the bituminous resin.

Effects of Particle Size and Surface Chemistry on the Dispersion of Graphite Nanoplates in Polypropylene Composites

Directory of Open Access Journals (Sweden)

Raquel M. Santos

2018-02-01

Full Text Available Carbon nanoparticles tend to form agglomerates with considerable cohesive strength, depending on particle morphology and chemistry, thus presenting different dispersion challenges. The present work studies the dispersion of three types of graphite nanoplates (GnP with different flake sizes and bulk densities in a polypropylene melt, using a prototype extensional mixer under comparable hydrodynamic stresses. The nanoparticles were also chemically functionalized by covalent bonding polymer molecules to their surface, and the dispersion of the functionalized GnP was studied. The effects of stress relaxation on dispersion were also analyzed. Samples were removed along the mixer length, and characterized by microscopy and dielectric spectroscopy. A lower dispersion rate was observed for GnP with larger surface area and higher bulk density. Significant re-agglomeration was observed for all materials when the deformation rate was reduced. The polypropylene-functionalized GnP, characterized by increased compatibility with the polymer matrix, showed similar dispersion effects, albeit presenting slightly higher dispersion levels. All the composites exhibit dielectric behavior, however, the alternate current (AC conductivity is systematically higher for the composites with larger flake GnP.

Radioluminescence of aromatic molecule solutions in atactic and isotactic polystyrene

International Nuclear Information System (INIS)

Lisovskaya, I.A.; Alfimov, M.V.; Milinchuk, V.K.; Skvortsov, V.G.

1975-01-01

The generation of excited states of naphthalene-d 8 and carbazole molecules in polystyrene (PS) under X-ray illumination was investigated using luminescence method. A comparison of the concentration dependences of radioluminescence of the aromatic additives to solid PS and to toluene as well as the pattern of concentration versus photoluminescence of naphthalene-d 8 in PS demonstrates that unlike toluene there is no singlet-triplet conversion in PS owing to the formation of excimers. It is shown that the excited ststes of the aromatic additives in PS are populated under radiolysis via an energy transfer from singlet to triplet molecules of the matrix. Under the radiolysis the excited states of PS molecules may generate upon charge recombination. A comparison of radio luminescence spectra of the corresponding aromatic additives in two isomeric PS structures (atacting and isotactic) shows different processes with charge participation. The difference detected in the radioluminescence spectra of aromatic additives in the atactic and isotactic PS explained by the greater number of defects in atactic PS competing with the polymer molecule ion for charge capture

Effects of the cooling rate on the shear behavior of continuous glass fiber/impact polypropylene composites (GF-IPP)

KAUST Repository

Wafai, Husam

2016-09-20

Fiber-reinforced composites with improved dissipation of energy during impact loading have recently been developed based on a polypropylene copolymer commonly called impact polypropylene (IPP). Composites made of IPP reinforced with glass fibers (GF) are particularly attractive to the automotive industry due to their low cost and good impact resistance. In such composites, the cooling rate varies depending on processing techniques and manufacturing choices. Here, we study the effects of the cooling rate of GF-IPP composites on shear behavior, which is critical in impact applications, using [±45]s monotonic and cyclic (load/unload) tensile specimens. The specimens were manufactured under a wide range of cooling rates (3 °C/min, 22 °C/min, 500–1000 °C/min). Mainly dominated by the properties of the matrix, the global shear behavior of GF-IPP composites differed considerably with respect to the cooling rate. However, the performance of the fiber-matrix interface (chemically modified) appeared to be unaffected by the range of cooling rates used in this study. We found that the cooling rate has a minor effect on the rate of damage accumulation, while it strongly modifies the shear-activated rate-dependant viscoelastic behavior. © 2016 Elsevier Ltd

Melt rheological properties of natural fiber-reinforced polypropylene

Science.gov (United States)

Jarrod J. Schemenauer; Tim A. Osswald; Anand R. Sanadi; Daniel F. Caulfield

2000-01-01

The melt viscosities and mechanical properties of 3 different natural fiber-polypropylene composites were investigated. Coir (coconut), jute, and kenaf fibers were compounded with polypropylene at 30% by weight content. A capillary rheometer was used to evaluate melt viscosity. The power-law model parameters are reported over a shear rate range between 100 to 1000 s–1...

Flexure and impact properties of glass fiber reinforced nylon 6-polypropylene composites

Science.gov (United States)

Kusaseh, N. M.; Nuruzzaman, D. M.; Ismail, N. M.; Hamedon, Z.; Azhari, A.; Iqbal, A. K. M. A.

2018-03-01

In recent years, polymer composites are rapidly developing and replacing the metals or alloys in numerous engineering applications. These polymer composites are the topic of interests in industrial applications such as automotive and aerospace industries. In the present research study, glass fiber (GF) reinforced nylon 6 (PA6)-polypropylene (PP) composite specimens were prepared successfully using injection molding process. Test specimens of five different compositions such as, 70%PA6+30%PP, 65%PA6+30%PP+5%GF, 60%PA6+30%PP+10%GF, 55%PA6+30%PP+15%GF and 50%PA6+30%PP+20%GF were prepared. In the experiments, flexure and impact tests were carried out. The obtained results revealed that flexure and impact properties of the polymer composites were significantly influenced by the glass fiber content. Results showed that flexural strength is low for pure polymer blend and flexural strength of GF reinforced composite increases gradually with the increase in glass fiber content. Test results also revealed that the impact strength of 70%PA6+30%PP is the highest and 55%PA6+30%PP+15%GF composite shows moderate impact strength. On the other hand, 50%PA6+30%PP+20%GF composite shows low toughness or reduced impact strength.

Effect of compatibilizer, bamboo fiber size and content on the mechanical properties of PP-g-MA compatibilized polypropylene/bamboo fiber composites

International Nuclear Information System (INIS)

Caranti, Lilian R.A.; Bonse, Baltus C.; Costa, Ricardo A. da

2011-01-01

The contemporary need for ecological preservation is a challenge to the realms of science to develop environmentally sustainable materials and processes. Research on composites reinforced with natural cellulosic fibers seeks to meet that need. An investigation was performed on the mechanical and thermal behavior of a composite comprising a polypropylene thermoplastic matrix and bamboo fibers (Phyllostachys Edulis). Interfacial adhesion between the two materials was achieved by the addition of compatibilizer maleic anhydride grafted polypropylene PPg- MA. An investigation was carried out with 8 compositions by varying the average fiber size (lower level = 0.94 mm and upper level = 2.19 mm), fiber content (20 and 40 weight %) and compatibilizer PP-g-MA (1 and 4 weight %). The mechanical behavior of the composites was studied by carrying out tensile, flexural, impact and fatigue tests. Thermal behavior was investigated by heat deflection temperature tests. Crystallinity was measured by means of X Ray diffraction and fractured surfaces were observed and analyzed by scanning electron microscopy. (author)

Thermal Conductivity Performance of Polypropylene Composites Filled with Polydopamine-Functionalized Hexagonal Boron Nitride.

Science.gov (United States)

Chen, Lin; Xu, Hong-Fei; He, Shao-Jian; Du, Yi-Hang; Yu, Nan-Jie; Du, Xiao-Ze; Lin, Jun; Nazarenko, Sergei

2017-01-01

Mussel-inspired approach was attempted to non-covalently functionalize the surfaces of boron nitride (BN) with self-polymerized dopamine coatings in order to reduce the interfacial thermal barrier and enhance the thermal conductivity of BN-containing composites. Compared to the polypropylene (PP) composites filled with pristine BN at the same filler content, thermal conductivity was much higher for those filled with both functionalized BN (f-BN) and maleic anhydride grafted PP (PP-g-ma) due to the improved filler dispersion and better interfacial filler-matrix compatibility, which facilitated the development of more thermal paths. Theoretical models were also applied to predict the composite thermal conductivity in which the Nielsen model was found to fit well with the experimental results, and the estimated effective aspect ratio of fillers well corresponded to the degree of filler aggregation as observed in the morphological study.

Composite TiO2/hydrocarbon plasma polymer films prepared by magnetron sputtering of TiO2 and poly(propylene)

Czech Academy of Sciences Publication Activity Database

Drabik, M.; Hanuš, J.; Kousal, J.; Choukourov, A.; Biederman, H.; Slavínská, D.; Macková, Anna; Pešička, J.

2007-01-01

Roč. 4, č. 6 (2007), s. 654-663 ISSN 1612-8850 Institutional research plan: CEZ:AV0Z10480505 Keywords : composite thin films * magnetron * poly(propylene) (PP) Subject RIV: BE - Theoretical Physics Impact factor: 2.132, year: 2007

The effect of modified ijuk fibers to crystallinity of polypropylene composite

Science.gov (United States)

Prabowo, I.; Nur Pratama, J.; Chalid, M.

2017-07-01

Nowadays, plastics becomes concern associated with its degradation and environmental issues. It has led studies to develop an environmental-friendly material. To minimize the impact of those problems, recently the usage of natural fibers as a filler are introduced because of biodegradability and availability. The promising natural fiber is “ijuk” fiber from Arenga pinnata plant as a filler and polypropylene (PP) polymer as a matrix. Unfortunately, the natural fibers and polymers have the different properties on which polymers are polar while natural fibers are non-polar so that reducing the compatibility and resulting the poor crystallinity. To enhance the compatibility and crystallinity, ijuk fibers were prepared by multistage treatments including alkalinization with 5 and 10% sodium hydroxide (NaOH), oxidation with 3 and 6% sodium hypochlorite (NaClO) and hydrolysis with 20% sulphuric acid (H2SO4) in sequences. The purposes of multistage treatments are to remove the components such as lignin, wax, hemicellulose, to cause an oxidative fragmentation of remaining lignin and to annihilate the amorphous parts respectively. Fourier-Transform Infrared (FTIR) confirms the compatibility meanwhile Differential Scanning Calorimetry (DSC) reveals the crystallinity and Scanning Electron Microscope (SEM) displays surface morphology of polypropylene. The experiments were revealing that the effects of “ijuk” fibers by the multistage treatments of 5 and 10% NaOH resulting the crystallinity of polypropylene around 31.2 and 27.64% respectively compared to the crystallinity before adding the “ijuk” fibers for 16.8%. It indicates that the entire treatments increasing the compatibility and crystallinity of polypropylene. In addition, the use of 5% NaOH offers the better crystallinity than non-treated polypropylene. The experiments conclude that by adding alkalinized “ijuk” fibers of multistage treatments can increase the compatibility and crystallinity of polypropylene.

Effect of Nanosilica Filled Polyurethane Composite Coating on Polypropylene Substrate

Directory of Open Access Journals (Sweden)

Yern Chee Ching

2013-01-01

Full Text Available Acrylic based polyurethane (PU coatings with various amounts of nanosilica contents were prepared using solution casting method. The nanosilica (SiO2 particles used are around 16 nm in diameter. The friction and wear test was conducted using the reciprocating wear testing machine. The tests were performed at rotary speed of 100 rpm and 200 rpm with load of 0.1 kg to 0.4 kg under 1 N interval. The effect of the PU/nano-SiO2 composite coating on friction and wear behavior of polypropylene substrate was investigated and compared. The worn surface of coating film layer after testing was investigated by using an optical microscope. The introduction of PU/nanosilica composite coating containing 3 wt% of nano-SiO2 content gives the lowest friction coefficient and wear rate to PP substrate. Both the friction and wear rate of PP substrate coated with >3 wt% of nano-SiO2 filled PU coating would increase with the increasing of applied load and sliding time.

Effect of processing conditions on the mechanical properties of polypropylene/bentonite nano composites

International Nuclear Information System (INIS)

Alves, Tatianny S.; Cipriano, Pamela B.; Lira, Vanize F.; Canedo, Eduardo L.; Carvalho, Laura H. de

2009-01-01

This work dealt with the effect of processing conditions on the properties of polypropylene/bentonite compounds, using natural clay and an organoclay prepared with hexadecyl trimethyl ammonium bromide. Compounds with 1% clay were prepared by melt compounding in a single-screw extruder and in a counter-rotating twin-screw extruder, and characterized x-ray diffraction; tensile and impact mechanical tests. X ray diffraction results on clays and compounds show that the surfactant was incorporated within the clay galleries and that intercalated nano composites were obtained with the organoclay processed in either the single or the twin-screw extruder. The data also indicated that, without the addition of a compatibilizer, no significant variation of mechanical properties was observed for the composites processed in either extruder. (author)

Analysis physical properties of composites polymer from cocofiber and polypropylene plastic waste with maleic anhydrate as crosslinking agent

Science.gov (United States)

Pelita, E.; Hidayani, T. R.; Akbar, A.

2017-07-01

This research was conducted with the aim to produce composites polymer with polypropylene plastic waste materials and cocofiber which aims to produce wood replacement material in the home furnishings industry. This research was conducted with several stages. The first stage is the process of soaking coco fiber with detergent to remove oil and 2% NaOH. The second stage is to combine the polypropylene plastic waste with cocofiber is a chemical bond, modification by adding maleic anhydride as a crosslinking agent and benzoyl peroxide as an initiator each as much as 1%. Mixing materials done by reflux method using xylene solvent. In this study, carried out a wide range of weight variation of coco fiber are added to the 10, 20, 30, 40 and 50%. The third stage is a polymer composite molding process using hot press at a temperature of 158°C. The results of polymer composites Showed optimum condition on the addition of 40% cocofiber with supple tensile strength value of 90.800 kgf /cm2 and value of elongation break at 3.6726 x 104 (kgf/cm2), melting point at 160.02°C, burning point 463.43°C, residue of TGA is 19%, the density of 0.84 g/mL. From these data, conclude that the resulting polymer composites meet the SNI 03-2105-2006 about ordinary composite polymer and polymer composite structural type 8 regular types from 17.5 to 10.5.

Influence of Rubber Powders on Foaming Behavior and Mechanical Properties of Foamed Polypropylene Composites

Directory of Open Access Journals (Sweden)

HE Yue

2017-02-01

Full Text Available Polypropylene/rubber powders composites with different kinds of rubber powders were foamed by injection molding machine equipped with volume-adjustable cavity. The effect of dispersity of rubber powders and crystallization behavior of composites on the foaming behavior and mechanical properties was investigated. The results show that the addition of rubber powders can improve the cell structure of foamed PP with fine and uniform cell distribution. And cell density and size of PP/PP-MAH/NBR foams are 7.64×106cell/cm3 and 29.78μm respectively, which are the best among these foams. Combining cell structures with mechanical properties, notch impact strength of PP/PP-MAH/CNBR composites increases approximately by 2.2 times while tensile strength is reduced just by 26% compared with those of the pure PP. This indicates that PP/PP-MAH/CNBR composites are ideal foamed materials.

Effect of fibre treatment using fluorosilane on Sansevieria Trifasciata/Polypropylene composite

Science.gov (United States)

Aref, Yanzur Mohd; Baharum, Azizah

2018-04-01

Recently, there is an increasing interest in the development of wood-plastic composites (WPC) due to their advantages such as wide availability, low cost, environment friendliness and sustainability. However, some major factors limiting the large scales production of WPC including the tendency of natural fibres to absorb water and the poor compatibility between fibre and matrix. In this study, we investigated the effectiveness of natural fibre treatment using fluorosilane in imparting hydrophobicity to the polypropylene (PP) matrix composite reinforced with Sansevieria Trifasciata (ST) fibres. ST fibres are subjected to silane treatment with 1H,1H,2H,2H-perfluorooctyltriethoxsysilane (POTS) at 1, 3 and 5% for a period of 2 hours. Influence of POTS treatment on the physical and mechanical properties of composites was studied to determine the optimum condition of silane treatment. The water contact angle (WCA) of WPC increased after POTS treatment where the highest value of 115° was shown by 3% POTS treated ST/PP composite. Based on mechanical properties results, incorporation of POTS treated ST fibre improves the mechanical properties with the enhancement of flexural and impact strength. The treatment with 3% POTS revealed statistically higher flexural strength and modulus compared to 1 and 5%. The water absorption test of ST/PP composites also gives the best result for 3% POTS treatment with 20.90% water uptake.

The effect of alkaline treatment and fiber orientation on impact resistant of bio-composites Sansevieria trifasciata fiber/polypropylene as automotive components material

Science.gov (United States)

Shieddieque, Apang Djafar; Mardiyati, Suratman, Rochim; Widyanto, Bambang

2018-04-01

The increasing amount of car usage is causing an escalated amount of fuel consumption and CO2 emission. It implicates demand for the automotive industry to increase the efficiency of their products, One of the most effective ways to solve the issue is to find green weight light material for the interior automotive component. The Aim of this research was to investigate the effect of alkaline treatment and fiber orientation on the impact resistant of material bio- composite sansevieiria trifasciata fiber/Polypropylene. In this research, bio-composites sansevieria trifasciata fiber/Polypropylene was prepared with random fiber orientation and unidirectional orientation by using a hot press method with pressure 140 Bar and temperature 240°C. Fiber was taken from Sansevieria trifasciata by using mechanical retting. In this study, Sansevieria fiber was given alkaline treatment (mercerization) with NaOH 3% (w/w) solution at temperature 100°C for an hour. The fraction of fiber volume that were used in this experiment are 0%, 5%, 10%, and 15%. The impact test was conducted based on ASTM D 6110 - 04, and the fracture analysis was investigated by scanning electron microscope (SEM). The best result of impact toughness and fracture analysis were achieved by bio composite untreated and unidirectional sansevieria trifasciata fiber/Polypropylene with fiber volume fraction of 15%, which was 48.092kJ/m2 for impact resistant. As compared to the impact toughness standard, which needed for interior automotive component, the impact toughness of sansevieria trifasciata fiber/Polypropylene has fulfilled the standard of the interior material automotive industry. Therefore, this material can be potentially used as materials on the car exterior component.

Abdominal wall hernia repair with a composite ePTFE/polypropylene mesh: clinical outcome and quality of life in 152 patients

DEFF Research Database (Denmark)

Iversen, E; Lykke, Anna; Hensler, M

2010-01-01

No consensus has yet been reached regarding the optimal mesh for the repair of small ventral hernias. A composite polytetrafluoroethylene/polypropylene mesh (Ventralex(®)) is designed for this purpose, and this paper reports its use in a larger series of patients....

The Usage Of Nutshell In The Production of Polypropylene Based on Polymer Composite Panels

Directory of Open Access Journals (Sweden)

Selçuk Akbaş

2013-04-01

Full Text Available Natural fibers have been commonly utilized to reinforced materials for many years. Recently due to advantages of natural fibers such as low cost, high physical and mechanical resistance are produced plastic-composite materials by mixing various proportions. In addition, plastic composites are used natural fibers include agricultural wastes (wheat straw, rice straw, hemp fiber, shells of various dry fruits, etc.. In this study, polymer composites were manufactured using waste nutshell flour as filler and polypropylene (PP as polymer matrix. The nutshell-PP composites were manufactured via extrusion and compression methods. The final product tested to determine their tensile, flexural, impact strength properties as well as some physical features such as thickness swelling and water absorptions. The best results were obtained composites containing 30% nutshell flour. In addition, composites which were produced nutshell provided the values of ASTM D6662 standard. The data collected in our country which waste a large portion of nutshell allows for the evaluation of the production polymer composites. The incorporation of nutshell flour feasible to produce plastic composites when appropriate formulations were used. As a result hazelnut shell which was considered agricultural waste can be utilized in polymer composite production.

Radiation resistant modified polypropylene; Polipropylen modyfikowany odporny radiacyjnie

Energy Technology Data Exchange (ETDEWEB)

Bojarski, J; Zimek, Z [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

1997-10-01

Radiation technology for production of radiation resistant polypropylene for medical use has been presented. The method consists in radiation induced copolymerization of polypropylene with ethylene and addition of small amount of copolymer of polyethylene and vinyl acetate. The material of proposed composition has a very good mechanical properties and elevated radiation resistivity decided on possibility of radiosterilization of products made of this material and designed for medical use. 3 figs, 3 tabs.

Impact of chemical treatments on the mechanical and water absorption properties of coconut fibre (Cocos nucifera reinforced polypropylene composites

Directory of Open Access Journals (Sweden)

Isiaka O. OLADELE

2016-07-01

Full Text Available In this work, chemically treated coconut fibres were used to reinforce Homopolymer Polypropylene in order to ascertain the effect of the treatments on the mechanical and water absorption properties of the composites produced. Coconut fibre was first extracted from its husk by soaking it in water and was dried before it was cut into 10 mm lengths. It was then chemically treated in alkali solution of sodium hydroxide (NaOH and potassium hydroxide (KOH in a shaker water bath. The treated coconut fibres were used as reinforcements in polypropylene matrix to produce composites of varied fibre weight contents; 2, 4, 6, 8 and 10 wt.%. Tensile and flexural properties were investigated using universal testing machine while water absorption test was carried out on the samples for 7 days. It was observed from the results that, NaOH treated samples gave the best tensile properties while KOH treated samples gave the best flexural and water repellent properties.

Electrical resistivity and thermal properties of compatibilized multi-walled carbon nanotube/polypropylene composites

Directory of Open Access Journals (Sweden)

A. Szentes

2012-06-01

Full Text Available The electrical resistivity and thermal properties of multi-walled carbon nanotube/polypropylene (MWCNT/PP composites have been investigated in the presence of coupling agents applied for improving the compatibility between the nanotubes and the polymer. A novel olefin-maleic-anhydride copolymer and an olefin-maleic-anhydride copolymer based derivative have been used as compatibilizers to achieve better dispersion of MWCNTs in the polymer matrix. The composites have been produced by extrusion followed by injection moulding. They contained different amounts of MWCNTs (0.5, 2, 3 and 5 wt% and coupling agent to enhance the interactions between the carbon nanotubes and the polymer. The electrical resistivity of the composites has been investigated by impedance spectroscopy, whereas their thermal properties have been determined using a thermal analyzer operating on the basis of the periodic thermal perturbation method. Rheological properties, BET-area and adsorption-desorption isotherms have been determined. Dispersion of MWCNTs in the polymer has been studied by scanning electron microscopy (SEM.

Polypropylene compositional evolution under 3.5 MeV He+ ion irradiation

Science.gov (United States)

Abdesselam, M.; Muller, D.; Djebara, M.; Chami, A. C.; Montgomery, P.

2012-05-01

A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 μm in thickness. The fluence ranges from 2 × 1012 to 3.5 × 1015 cm-2. The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C(α, α)C) and hydrogen elastic recoil detection (H(α, H)α), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of ˜5 × 1013 He+ cm-2. The carbon depletion levels off at a fluence of ˜5 × 1014 He+ cm-2 approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 × 10-16 cm2, respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He+ beam is made.

Development of plasma-treated polypropylene nonwoven-based composites for high-performance lithium-ion battery separators

International Nuclear Information System (INIS)

Li, Xiaofei; He, Jinlin; Wu, Dazhao; Zhang, Mingzu; Meng, Juwen; Ni, Peihong

2015-01-01

Graphical abstract: A composite separator based on plasma-treated fluorinated polypropylene (PP) nonwoven, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and SiO 2 nanoparticles exhibiting enhanced thermal stability, ionic conductivity and electrochemical properties. Display Omitted -- Highlights: •Fluorinated segments are introduced on the surface of PP nonwoven through plasma treatment. •The obtained composite separators exhibit better physical and electrochemical properties. •The capacity of half-cell with composite separator keeps above 150 mA h g −1 after 100 charge–discharge cycles. -- Abstract: Separators have drawn substantial attention because of their important role in achieving the safety and good electrochemical performance of lithium-ion batteries. In this study, we report a new type of composite membrane prepared by a combination of fluorinated polypropylene (PP) nonwoven fabric, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and SiO 2 nanoparticles. 2, 2, 3, 3, 4, 4, 5, 5-Octafluoropentyl methacrylate (OFPMA) is first grafted on the surface of PP nonwoven by plasma treatment to improve the nonwoven’s adhesion with PVdF-HFP. Two kinds of composite separators have been prepared by using the different PP nonwovens together with PVdF-HFP and SiO 2 nanoparticles. They were separately designated as PHS for commercially raw PP nonwoven system and PHS-n for OFPMA-modified PP nonwoven systems (n means plasma treatment time). The morphology, electrolyte uptake, ionic conductivity and electrochemical properties of the composite separators have been analyzed by scanning electron microscope (SEM) analysis, impedance measurement, charge-discharge cycle and C-rate tests, respectively. The results indicate that PHS-10 composite separator using the modified PP nonwoven treated by plasma for 10 min exhibits much better properties than PHS separator, including an improved mechanical property, thermal stability, electrolyte uptake

Lignocellulose nanofibers prepared by ionic liquid pretreatment and subsequent mechanical nanofibrillation of bagasse powder: Application to esterified bagasse/polypropylene composites.

Science.gov (United States)

Ninomiya, Kazuaki; Abe, Megumi; Tsukegi, Takayuki; Kuroda, Kosuke; Tsuge, Yota; Ogino, Chiaki; Taki, Kentaro; Taima, Tetsuya; Saito, Joji; Kimizu, Mitsugu; Uzawa, Kiyoshi; Takahashi, Kenji

2018-02-15

In the present study, we examined the efficacy of choline acetate (ChOAc, a cholinium ionic liquid))-assisted pretreatment of bagasse powder for subsequent mechanical nanofibrillation to produce lignocellulose nanofibers. Bagasse sample with ChOAc pretreatment and subsequent nanofibrillation (ChOAc/NF-bagasse) was prepared and compared to untreated control bagasse sample (control bagasse), bagasse sample with nanofibrillation only (NF-bagasse) and with ChOAc pretreatment only (ChOAc-bagasse). The specific surface area was 0.83m 2 /g, 3.1m 2 /g, 6.3m 2 /g, and 32m 2 /g for the control bagasse, ChOAc-bagasse, NF-bagasse, and the ChOAc/NF-bagasse, respectively. Esterified bagasse/polypropylene composites were prepared using the bagasse samples. ChOAc/NF-bagasse exhibited the best dispersion in the composites. The tensile toughness of the composites was 0.52J/cm 3 , 0.73J/cm 3 , 0.92J/cm 3 , and 1.29J/cm 3 for the composites prepared using control bagasse, ChOAc-bagasse, NF-bagasse, and ChOAc/NF-bagasse, respectively. Therefore, ChOAc pretreatment and subsequent nanofibrillation of bagasse powder resulted in enhanced tensile toughness of esterified bagasse/polypropylene composites. Copyright © 2017 Elsevier Ltd. All rights reserved.

Supercritical CO2 foaming of radiation crosslinked polypropylene/high-density polyethylene blend: Cell structure and tensile property

Science.gov (United States)

Yang, Chenguang; Xing, Zhe; Zhang, Mingxing; Zhao, Quan; Wang, Mouhua; Wu, Guozhong

2017-12-01

A blend of isotactic polypropylene (PP) with high-density polyethylene (HDPE) in different PP/HDPE ratios was irradiated by γ-ray to induce cross-linking and then foamed using supercritical carbon dioxide (scCO2) as a blowing agent. Radiation effect on the melting point and crystallinity were analyzed in detail. The average cell diameter and cell density were compared for PP/HDPE foams prepared under different conditions. The optimum absorbed dose for the scCO2 foaming of PP/HDPE in terms of foaming ability and cell structure was 20 kGy. Tensile measurements showed that the elongation at break and tensile strength at break of the crosslinked PP/HDPE foams were higher than the non-crosslinked ones. Of particular interest was the increase in the foaming temperature window from 4 ℃ for pristine PP to 8-12 ℃ for the radiation crosslinked PP/HDPE blends. This implies much easier handling of scCO2 foaming of crosslinked PP with the addition of HDPE.

Mechanical and thermal properties of bio-composites based on polypropylene reinforced with Nut-shells of Argan particles

International Nuclear Information System (INIS)

Essabir, H.; Hilali, E.; Elgharad, A.; El Minor, H.; Imad, A.; Elamraoui, A.; Al Gaoudi, O.

2013-01-01

Highlights: ► Nuts-shells of Argan particles are used as reinforcement in thermoplastic matrix. ► Particles are homogeneously dispersed and distributed within PP matrix. ► Mechanical and thermal characterization of the composite are applied. ► Particles–matrix adhesion was assured by the use of a SBS compatibilizer. - Abstract: This study treats the combined effects of both particle sizes and particle loading on the mechanical and thermal properties of polypropylene (PP) composites reinforced with Nut-shells of Argan (NA) particles. Three range sizes of particles were used in the presence of a polypropylene matrix grafted with 8 wt.% of a linear block copolymer based on styrene and butadiene coupling agent, to improve adhesion between the particles and the matrix. The composites were prepared through melt-blending using an internal mixer and the tensile specimens were prepared using a hot press molding machine. Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and tensile tests were employed to characterize the composites at 10, 15, 20 and 25 wt.% particle contents. Results show a clear improvement in Young’s modulus from the use of particles when compared to the neat PP, a gain of 42.65%, 26.7% and 2.9% at 20 wt.% particle loading, for particle range 1, 2 and 3, respectively. In addition a notable increase in the Young’s modulus was observed when decrease the particle size. The thermal stability of composites exhibits a slight decrease (256–230 °C) with particles loading from 10 to 25 wt.%, against neat PP (258 °C)

Study on the Properties of Microcapsulated Chlorocyclophosphazene Polypropylene Composites%三聚氯化磷腈微胶囊阻燃剂/聚丙烯复合材料的性能研究

Institute of Scientific and Technical Information of China (English)

刘亚青; 赵贵哲

2007-01-01

Microcapsulated chlorocyclophosphazenes were synthesized, and then microcapsulated chlorocyclophosphazene/polypropylene(PP) composites were prepared.The results showed that microcapsulated chlorocyclophosphazene had good high thermal stability through thermogravimetric analysis (TGA).The flammability and mechanical properties of microcapsulated chlorocyclophosphazene/polypropylene composites were investigated by limiting oxygen index experiment, UL 94V flame retardancy test, cone calorimetry, tensile experiment, and impact test, respectively.It was shown that the microcapsulated chlorocyclophosphazene/PP composites had better tensile strength, impact strength, flame retardant properties and smoke suppress properties compared with chlorocyclophosphazene/PP composites.

Polypropylene compositional evolution under 3.5 MeV He+ ion irradiation

International Nuclear Information System (INIS)

Abdesselam, M.; Muller, D.; Djebara, M.; Chami, A.C.; Montgomery, P.

2012-01-01

A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 μm in thickness. The fluence ranges from 2 × 10 12 to 3.5 × 10 15 cm −2 . The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C(α, α)C) and hydrogen elastic recoil detection (H(α, H)α), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of ∼5 × 10 13 He + cm −2 . The carbon depletion levels off at a fluence of ∼5 × 10 14 He + cm −2 approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 × 10 −16 cm 2 , respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He + beam is made.

STRUCTURAL EVOLUTION AND COMPOSITION CHANGE IN THE SURFACE REGION OF POLYPROPYLENE/CLAY NANOCOMPOSITES ANNEALED AT HIGH TEMPERATURES

Institute of Scientific and Technical Information of China (English)

唐涛

2009-01-01

A model experiment was done to clear the formation mechanism of protective layers during combustion of polypropylene(PP)/organically modified montmorillonite(OMMT) nanocomposites.The investigation was focused on the effects of annealing temperature on the structural changes and protective layer formation.The decomposition of OMMT and degradation of PP/OMMT nanocomposites were characterized by means of thermogravimetric analysis(TGA).The structural evolution and composition change in the surface region of...

Structural interpretations of deformation and fracture behavior of polypropylene/multi-walled carbon nanotube composites

International Nuclear Information System (INIS)

Ganss, Martin; Satapathy, Bhabani K.; Thunga, Mahendra; Weidisch, Roland; Poetschke, Petra; Jehnichen, Dieter

2008-01-01

The deformation and crack resistance behavior of polypropylene (PP) multi-walled carbon nanotube (MWNT) composites have been studied and their interrelation to the structural attributes studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarization light microscopy has been discussed. The composites were produced from industrial available MWNT by extrusion melt-mixing and injection-molding. In stress-strain measurements a strong increase in the yield stress and the Young's modulus at low MWNT contents has been observed, which was attributed to an efficient load transfer between the carbon nanotubes and polypropylene matrix through a good polymer-nanotube adhesion as indicated by SEM. The extent of enhancement in mechanical properties above 1.5 wt.% of MWNT decreased due to an apparently increased tendency of clustering of carbon nanotubes. Several theoretical models have been taken into account to explain the mechanical properties and to demonstrate the applicability of such models to the system under investigation. The crack resistance behavior has been studied with the essential work of fracture (EWF) approach based on post-yield fracture mechanics (PYFM) concept. A maximum in the non-essential work of fracture was observed at 0.5 wt.% MWNT demonstrating enhanced toughness compared to pure PP, followed by a sharp decline as the MWNT content was increased to 1.5 wt.% reveals a ductile-to-semi-ductile transition. Studies on the kinetics of crack propagation aspects have revealed a qualitative picture of the nature of such a transition in the fracture modes

Isotactic polypropylene/carbon nanotube composites prepared by latex technology: Electrical conductivity study

NARCIS (Netherlands)

Grossiord, N.; Wouters, M.E.L.; Miltner, H.E.; Lu, K.; Loos, J.; Van Mele, B.; Koning, C.E.

2010-01-01

Several series of nanocomposites were prepared using a latex-based process, the main step of which consisted of mixing an aqueous suspension of exfoliated carbon nanotubes (CNTs) and a polymer latex. In the present work, a systematic study on the electrical properties of fully amorphous (polystyrene

Photo-oxidative degradation of TiO{sub 2}/polypropylene films

Energy Technology Data Exchange (ETDEWEB)

García-Montelongo, X.L. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Martínez-de la Cruz, A., E-mail: azael70@yahoo.com.mx [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Vázquez-Rodríguez, S. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Torres-Martínez, Leticia M. [Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico)

2014-03-01

Graphical abstract: - Highlights: • Photo-oxidative degradation of polypropylene is accelerated by TiO{sub 2} incorporation. • Weight loss, FTIR, SEM and GPC shown high degree of degradation of polypropylene. • A mechanism of the photo-degradation of polypropylene by TiO{sub 2} is proposed. - Abstract: Photo-oxidative degradation of polypropylene films with TiO{sub 2} nanoparticles incorporated was studied in a chamber of weathering with Xenon lamps as irradiation source. TiO{sub 2} powder with crystalline structure of anatase was synthesized by thermal treatments at 400 and 500 °C starting from a precursor material obtained by sol–gel method. Composites of TiO{sub 2}/polypropylene were prepared with 0.1, 0.5 and 1.0 wt% of TiO{sub 2}. The mixture of components was performed using a twin screw extruder, the resulting material was pelletized by mechanical fragmenting and then hot-pressed in order to form polypropylene films with TiO{sub 2} dispersed homogeneously. Photo-oxidative degradation process was followed by visual inspection, weight loss of films, scanning electron microscopy (SEM), infrared spectroscopy with Fourier transformed (FTIR), and gel permeation chromatography (GPC)

Chemical synthesis of perfectly isotactic and high melting bacterial poly(3-hydroxybutyrate) from bio-sourced racemic cyclic diolide.

Science.gov (United States)

Tang, Xiaoyan; Chen, Eugene Y-X

2018-06-11

Bacterial poly(3-hydroxybutyrate) (P3HB) is a perfectly isotactic, crystalline material possessing properties suitable for substituting petroleum plastics, but high costs and low volumes of its production are impractical for commodity applications. The chemical synthesis of P3HB via ring-opening polymerization (ROP) of racemic β-butyrolactone has attracted intensive efforts since the 1960s, but not yet produced P3HB with high isotacticity and molecular weight. Here, we report a route utilizing racemic cyclic diolide (rac-DL) derived from bio-sourced succinate. With stereoselective racemic catalysts, the ROP of rac-DL under ambient conditions produces rapidly P3HB with perfect isotacticity ([mm] > 99%), high melting temperature (T m  = 171 °C), and high molecular weight (M n  = 1.54 × 10 5  g mol -1 , Đ = 1.01). With enantiomeric catalysts, kinetic resolution polymerizations of rac-DL automatically stops at 50% conversion and yields enantiopure (R,R)-DL and (S,S)-DL with >99% e.e. and the corresponding poly[(S)-3HB] and poly[(R)-3HB] with high T m  = 175 °C.

A study on flexural and water absorption of surface modified rice husk flour/E-glass/polypropylene hybrid composite

Science.gov (United States)

Rassiah, K.; Sin, T. W.; Ismail, M. Z.

2016-10-01

This work is to study the effects of rice husk (RH)/E-Glass (EG)/polypropylene (PP) hybrid composites in terms of flexural and water absorption properties. The tests conducted are the flexural test and also the water absorption test using two types of water: distilled and sea water. The hybrid composites are prepared with various ratios of fibre weight fractions and the rice husk is treated using 2% Sodium Hydroxide (NaOH) to improve interaction and adhesion between the non-polar matrix and the polar lignocellulosic fibres. It was found that the content of rice husk/E-Glass fillers affected the structural integrity and flexural properties of hybrid composites. In addition, a higher ratio of rice husk contributes to higher water absorption in the hybrid composites.

Highly Conductive 3D Segregated Graphene Architecture in Polypropylene Composite with Efficient EMI Shielding

Directory of Open Access Journals (Sweden)

Fakhr E. Alam

2017-12-01

Full Text Available The extensive use of electronic equipment in modern life causes potential electromagnetic pollution harmful to human health. Therefore, it is of great significance to enhance the electrical conductivity of polymers, which are widely used in electronic components, to screen out electromagnetic waves. The fabrication of graphene/polymer composites has attracted much attention in recent years due to the excellent electrical properties of graphene. However, the uniform distribution of graphene nanoplatelets (GNPs in a non-polar polymer matrix like polypropylene (PP still remains a challenge, resulting in the limited improvement of electrical conductivity of PP-based composites achieved to date. Here, we propose a single-step approach to prepare GNPs/PP composites embedded with a segregated architecture of GNPs by coating PP particles with GNPs, followed by hot-pressing. As a result, the electrical conductivity of 10 wt % GNPs-loaded composites reaches 10.86 S·cm−1, which is ≈7 times higher than that of the composites made by the melt-blending process. Accordingly, a high electromagnetic interference shielding effectiveness (EMI SE of 19.3 dB can be achieved. Our method is green, low-cost, and scalable to develop 3D GNPs architecture in a polymer matrix, providing a versatile composite material suitable for use in electronics, aerospace, and automotive industries.

Influence of Interleaved Films on the Mechanical Properties of Carbon Fiber Fabric/Polypropylene Thermoplastic Composites

Directory of Open Access Journals (Sweden)

Jong Won Kim

2016-05-01

Full Text Available A laminated composite was produced using a thermoplastic prepreg by inserting an interleaved film with the same type of matrix as the prepreg during the lay-up process to improve the low interlaminar properties, which is a known weakness of laminated composites. Carbon fiber fabric (CFF and polypropylene (PP were used to manufacture the thermoplastic prepregs. Eight prepregs were used to produce the laminated composites. Interleaved films with different thicknesses were inserted into each prepreg. The physical properties of the composite, such as thickness, density, fiber volume fraction (Vf, and void content (Vc, were examined. The tensile strength, flexural strength, interlaminar shear strength (ILSS, impact property, and scanning electron microscopy (SEM were used to characterize the mechanical properties. Compared to the composite without any inserted interleaved film, as the thickness of the inserted interleaved resin film was increased, Vc decreased by 51.45%. At the same time, however, the tensile strength decreased by 8.75%. Flexural strength increased by 3.79% and flexural modulus decreased by 15.02%. Interlaminar shear strength increased by 11.05% and impact strength increased by 15.38%. Fracture toughness of the laminated composite was improved due to insertion of interleaved film.

Influence of Interleaved Films on the Mechanical Properties of Carbon Fiber Fabric/Polypropylene Thermoplastic Composites.

Science.gov (United States)

Kim, Jong Won; Lee, Joon Seok

2016-05-06

A laminated composite was produced using a thermoplastic prepreg by inserting an interleaved film with the same type of matrix as the prepreg during the lay-up process to improve the low interlaminar properties, which is a known weakness of laminated composites. Carbon fiber fabric (CFF) and polypropylene (PP) were used to manufacture the thermoplastic prepregs. Eight prepregs were used to produce the laminated composites. Interleaved films with different thicknesses were inserted into each prepreg. The physical properties of the composite, such as thickness, density, fiber volume fraction ( V f ), and void content ( V c ), were examined. The tensile strength, flexural strength, interlaminar shear strength (ILSS), impact property, and scanning electron microscopy (SEM) were used to characterize the mechanical properties. Compared to the composite without any inserted interleaved film, as the thickness of the inserted interleaved resin film was increased, V c decreased by 51.45%. At the same time, however, the tensile strength decreased by 8.75%. Flexural strength increased by 3.79% and flexural modulus decreased by 15.02%. Interlaminar shear strength increased by 11.05% and impact strength increased by 15.38%. Fracture toughness of the laminated composite was improved due to insertion of interleaved film.

Designing tough and fracture resistant polypropylene/multi wall carbon nanotubes nanocomposites by controlling stereo-complexity and dispersion morphology

International Nuclear Information System (INIS)

Das, Dibyendu; Satapathy, Bhabani K.

2014-01-01

Highlights: • New pathway to improve dispersion and toughness by tacticity modification. • >330% toughness enhancement in PP/MWCNT nanocomposites with stereo-complex PP. • Prominent dispersion and distribution morphology due to matrix stereocomplexity. • Tacticity induced “Semi-ductile-to-tough-to-quasi-brittle” transitions in the PP/MWCNT. • Two-fold reduced steady state CTOD rate in i-PP+s-PP/ MWCNT nanocomposites. - Abstract: A remarkable toughness enhancement (>330%) of multi wall carbon nanotubes (MWCNT) filled stereo-complex polypropylene (PP) matrix i.e. blend of isotactic-PP and syndiotactic-PP (70:30) with differences in stereo-regularity has been observed. The enhancement has been correlated to quantifiable morphological parameters such as free-space lengths concerning dispersion and relatively greater reduction in crystallite size/lamellar thickness. Systematic analysis of glass transition data and estimation of multi wall carbon nanotubes induced reduction in interfacial polymer chain immobilization reiterates susceptibility of polymer segments to ready-mobility. The extent of toughening has quantitatively been analyzed by fracture-energy partitioning, essential work of fracture (EWF), approach enabling the detection of a “semi-ductile-to-tough-to-quasi-brittle” transition in the MWCNT filled stereo-complex polypropylene. Real-time fracture kinetics analysis revealed toughening mechanism to be primarily blunting-assisted; an aspect also corroborated by extensive plastic flow without much energy dissipation in the inner fracture process zone. Thus the study establishes a new pathway of tacticity-defined matrix modification to toughen nanocomposites

Thermal and mechanical properties of polypropylene/titanium dioxide nanocomposite fibers

International Nuclear Information System (INIS)

Esthappan, Saisy Kudilil; Kuttappan, Suma Kumbamala; Joseph, Rani

2012-01-01

Highlights: ► Wet synthesis method was used for the synthesis of TiO 2 nano particles. ► Mechanical properties of polypropylene fibers were increased by the addition of TiO 2 nanoparticles. ► Thermal stability of polypropylene fiber was improved significantly by the addition of TiO 2 nano particles. ► TiO 2 nanoparticles dispersed well in polypropylene fibers. -- Abstract: Titanium dioxide nanoparticles were prepared by wet synthesis method and characterized by transmission electron microscopy and X-ray diffraction studies. The nanotitanium dioxide then used to prepare polypropylene/titanium dioxide composites by melt mixing method. It was then made into fibers by melt spinning and subsequent drawing. Mechanical properties of the fibers were studied using Favimat tensile testing machine with a load cell of 1200 cN capacity. Thermal behavior of the fibers was studied using differential scanning calorimetry and thermogravimetric analysis. Scanning electron microscope studies were used to investigate the titanium dioxide surface morphology and crosssection of the fiber. Mechanical properties of the polypropylene fiber was improved by the addition of titanium dioxide nanoparticles. Incorporation of nanoparticles improves the thermal stability of polypropylene. Differential scanning calorimetric studies revealed an improvement in crystallinity was observed by the addition of titanium dioxide nanoparticles.

Alumina/Phenolphthalein Polyetherketone Ceramic Composite Polypropylene Separator Film for Lithium Ion Power Batteries

International Nuclear Information System (INIS)

Wang, Jing; Hu, Zhiyu; Yin, Xiunan; Li, Yunchao; Huo, Hong; Zhou, Jianjun; Li, Lin

2015-01-01

Highlights: • PEK-C (T g : ∼230 °C) was used as binder to prepare ceramic coated composite PP separator. • The composite PP separator was stable and showed low thermal shrinkage in the electrolyte solvent. • The composite PP separator was helpful for high current density discharge. • The composite PP separator improved the safety performance of the coin cells. - Abstract: One way to obtain the lithium ion power battery with better safety performance was to increase the thermal shrinkage resistance of the separator at higher temperature. Phenolphthalein polyetherketone (PEK-C) is a polymer that can withstand high temperature to about 230 °C. Here, we developed a new Al 2 O 3 coated composite polypropylene (PP) separator with PEK-C as binder. The coating layer was formed on the surface of the PP separator and both ceramic particles and binder did not infiltrated into the separator along the thickness direction. The composite separator with 4 μm coating layer provided balanced permeability and thermal shrinkage properties. The composite separator was stable at the electrochemical window for lithium ion battery. The coin cells with composite separator showed better charge/discharge performance than that of the cells with the PP separator. It seemed that the composite separator was helpful for high current density discharge. Also, the battery safety performance test had verified that the Al 2 O 3 coated composite separator with PEK-C as binder had truly improved the safety performance of the coin cells. So, the newly developed Al 2 O 3 coated composite PP separator was a promising safety product for lithium ion power batteries with high energy density

Study of microcellular injection-molded polypropylene/waste ground rubber tire powder blend

International Nuclear Information System (INIS)

Xin, Zhen Xiang; Zhang, Zhen Xiu; Pal, Kaushik; Byeon, Jong Ung; Lee, Sung Hyo; Kim, Jin Kuk

2010-01-01

Microcellular polypropylene/waste ground rubber tire powder blend processing was performed on an injection-molding machine with a chemical foaming agent. The molded samples produced based on the design of experiments (DOE) matrices were subjected to tensile testing and scanning electron microscope (SEM) analyses. Molding conditions and waste ground rubber tire (WGRT) powder have been found to have profound effects on the cell structures and mechanical properties of polypropylene (PP) and waste ground rubber tire powder composite samples. The result shows that microcellular PP/WGRT blend samples exhibit smaller cell size and higher cell density compare with polypropylene resin. Among the molding parameters studied, chemical foaming agent weight percentage has the most significant effect on cell size, cell density, and tensile strength. The results also suggest that tensile strength of microcellular PP/WGRT composites is sensitive to weight reduction, and skin thickness.

Effects of gamma irradiation on polypropylene, polypropylene + high density polyethylene and polypropylene + high density polyethylene + wood flour

Energy Technology Data Exchange (ETDEWEB)

Reyes, J.; Albano, C.; Davidson, E.; Poleo, R. [Universidad Central de Venezuela, Caracas (Venezuela). Escuela de Quimica; Gonzalez, J.; Ichazo, M. [Universidad Simon Bolivar, Dept. de Mecanica, Caracas (Venezuela); Chipara, M. [Research Institute for Electrotechnics, Bucharest (Romania)

2001-04-01

The effect of the gamma-irradiation on the mechanical properties of the composites, Polypropylene (PP), PP+high density Polyethylene (HDPE), PP+ HDPE+wood flour, where HDPE is virgin and recycled, was studied. This paper discusses the behavior of the composites after exposure to various doses of gamma irradiation (1-7 MRads) in the presence of oxygen. The dependence of mechanical properties on the integral dose for a constant dose rate of 0.48 MRads/h confirms the influence of the irradiation. Strong effects on the elongation at break and break strength is noticed. The mathematical analysis suggests for the PP+r-HDPE a bimolecular process of the elongation at break. On the order hand, for the PP+HDPE a complex process is represented for a three exponential equation. (orig.)

Effects of gamma irradiation on polypropylene, polypropylene + high density polyethylene and polypropylene + high density polyethylene + wood flour

International Nuclear Information System (INIS)

Reyes, J.; Albano, C.; Davidson, E.; Poleo, R.; Chipara, M.

2001-01-01

The effect of the gamma-irradiation on the mechanical properties of the composites, Polypropylene (PP), PP+high density Polyethylene (HDPE), PP+ HDPE+wood flour, where HDPE is virgin and recycled, was studied. This paper discusses the behavior of the composites after exposure to various doses of gamma irradiation (1-7 MRads) in the presence of oxygen. The dependence of mechanical properties on the integral dose for a constant dose rate of 0.48 MRads/h confirms the influence of the irradiation. Strong effects on the elongation at break and break strength is noticed. The mathematical analysis suggests for the PP+r-HDPE a bimolecular process of the elongation at break. On the order hand, for the PP+HDPE a complex process is represented for a three exponential equation. (orig.)

Polypropylene compositional evolution under 3.5 MeV He{sup +} ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Abdesselam, M., E-mail: abdesselam_m@yahoo.fr [Faculte de Physique, USTHB, BP32, El Alia, 16111 BEZ (Algeria); Muller, D. [InESS, UMR7163, 23 rue du Loess, BP20, F-67037 Strasbourg Cedex 02 (France); Djebara, M.; Chami, A.C. [Faculte de Physique, USTHB, BP32, El Alia, 16111 BEZ (Algeria); Montgomery, P. [InESS, UMR7163, 23 rue du Loess, BP20, F-67037 Strasbourg Cedex 02 (France)

2012-05-01

A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 {mu}m in thickness. The fluence ranges from 2 Multiplication-Sign 10{sup 12} to 3.5 Multiplication-Sign 10{sup 15} cm{sup -2}. The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C({alpha}, {alpha})C) and hydrogen elastic recoil detection (H({alpha}, H){alpha}), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of {approx}5 Multiplication-Sign 10{sup 13} He{sup +} cm{sup -2}. The carbon depletion levels off at a fluence of {approx}5 Multiplication-Sign 10{sup 14} He{sup +} cm{sup -2} approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 Multiplication-Sign 10{sup -16} cm{sup 2}, respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He{sup +} beam is made.

Influence of nonmetals recycled from waste printed circuit boards on flexural properties and fracture behavior of polypropylene composites

International Nuclear Information System (INIS)

Zheng Yanhong; Shen Zhigang; Cai Chujiang; Ma Shulin; Xing Yushan

2009-01-01

Flexural strength and flexural modulus of the composites can be successfully improved by filling nonmetals recycled from waste printed circuit boards (PCBs) into polypropylene (PP). By using scanning electron microscopy (SEM), the influence of nonmetals on fracture behavior of PP composites is investigated by in situ flexural test. Observation results show that the particles can effectively lead to mass micro cracks instead of the breaking crack. The process of the crack initiation, propagation and fiber breakage dissipate a great amount of energy. As a result, the flexural properties of the composites can be reinforced significantly. Results of the in situ SEM observation and analysis to the dynamic flexural process supply effective test evidence for the reinforcing mechanism of the nonmetals/PP composites on the basis of the energy dissipation theory

Modification of polypropylene with radiation-treated wood fiber

International Nuclear Information System (INIS)

Czvikovszky, T.; Tapolcai, I.

1983-01-01

The dispersed wood material is used not only as filler for thermosetting polymers but also as a new type of fibrous additive for thermoplastics e.g. polypropylene. Benefit of this additive (filler or reinforcement) is determined by the coupling between the wood and the synthetic resin. Fibrous, dispersed wood material was preirradiated in air, treated with vinyl monomer containing polyester resin and then mixed in polypropylene. Processability of such thermoplastic blends as well as reactivity of the mixed components were followed by measuring energy, absorbed during the kneading of the melt. The vinylmonomer vinylmonomer - polyester additive, activated at higher temperature by the radiation-formed peroxy groups on the wood fiber, results in good processability of the thermoplastic blend, and gives interesting mechanical properties. Calandering, extrusion, pressmoulding and mechanical testing demonstrated good workability and practical value of the polypropylene composite material containing radiation-treated wood fiber. (author)

Influence of residual stress on the adhesion and surface morphology of PECVD-coated polypropylene

Science.gov (United States)

Jaritz, Montgomery; Hopmann, Christian; Behm, Henrik; Kirchheim, Dennis; Wilski, Stefan; Grochla, Dario; Banko, Lars; Ludwig, Alfred; Böke, Marc; Winter, Jörg; Bahre, Hendrik; Dahlmann, Rainer

2017-11-01

The properties of plasma-enhanced chemical vapour deposition (PECVD) coatings on polymer materials depend to some extent on the surface and material properties of the substrate. Here, isotactic polypropylene (PP) substrates are coated with silicon oxide (SiO x ) films. Plasmas for the deposition of SiO x are energetic and oxidative due to the high amount of oxygen in the gas mixture. Residual stress measurements using single Si cantilever stress sensors showed that these coatings contain high compressive stress. To investigate the influence of the plasma and the coatings, residual stress, silicon organic (SiOCH) coatings with different thicknesses between the PP and the SiO x coating are used as a means to protect the substrate from the oxidative SiO x coating process. Pull-off tests are performed to analyse differences in the adhesion of these coating systems. It could be shown that the adhesion of the PECVD coatings on PP depends on the coatings’ residual stress. In a PP/SiOCH/SiO x -multilayer system the residual stress can be significantly reduced by increasing the thickness of the SiOCH coating, resulting in enhanced adhesion.

Antimicrobial Carvacrol-Containing Polypropylene Films: Composition, Structure and Function

Directory of Open Access Journals (Sweden)

Max Krepker

2018-01-01

Full Text Available Significant research has been directed toward the incorporation of bioactive plant extracts or essential oils (EOs into polymers to endow the latter with antimicrobial functionality. EOs offer a unique combination of having broad antimicrobial activity from a natural source, generally recognized as safe (GRAS recognition in the US, and a volatile nature. However, their volatility also presents a major challenge in their incorporation into polymers by conventional high-temperature-processing techniques. Herein, antimicrobial polypropylene (PP cast films were produced by incorporating carvacrol (a model EO or carvacrol, loaded into halloysite nanotubes (HNTs, via melt compounding. We studied the composition-structure-property relationships in these systems, focusing on the effect of carvacrol on the composition of the films, the PP crystalline phase and its morphology and the films’ mechanical and antimicrobial properties. For the first time, molecular dynamics simulations were applied to reveal the complex interactions between the components of these carvacrol-containing systems. We show that strong molecular interactions between PP and carvacrol minimize the loss of this highly-volatile EO during high-temperature polymer processing, enabling semi-industrial scale production. The resulting films exhibit outstanding antimicrobial properties against model microorganisms (Escherichia coli and Alternaria alternata. The PP/(HNTs-carvacrol nanocomposite films, containing the carvacrol-loaded HNTs, display a higher level of crystalline order, superior mechanical properties and prolonged release of carvacrol, in comparison to PP/carvacrol blends. These properties are ascribed to the role of HNTs in these nanocomposites and their effect on the PP matrix and retained carvacrol content.

Comparison of the mechanical properties between carbon nanotube and nanocrystalline cellulose polypropylene based nano-composites

International Nuclear Information System (INIS)

Huang, Jun; Rodrigue, Denis

2015-01-01

Highlights: • SWCNT and NCC can effectively improve the mechanical properties of nano-composites. • SWCNT is more effective than NCC to increase modulus and strength. • Longer NCC is more effective to improve the mechanical properties of nano-composites. • It is more economic to use NCC than SWCNT to improve mechanical properties. - Abstract: Using beam and tetrahedron elements to simulate nanocrystalline cellulose (NCC), single wall carbon nanotube (SWCNT) and polypropylene (PP), finite element method (FEM) is used to predict the mechanical properties of nano-composites. The bending, shear and torsion behaviors of nano-composites are especially investigated due to the limited amount of information in the present literature. First, mixed method (MM) and FEM are used to compare the bending stiffness of NCC/PP and SWCNT/PP composites. Second, based on mechanics of materials, the shear moduli of both types of nano-composites are obtained. Finally, fixing the number of fibers and for different volume contents, four NCC lengths are used to determine the mechanical properties of the composites. The bending and shearing performances are also compared between NCC and SWCNT based composites. In all cases, the elastic–plastic analyses are carried out and the stress or strain distributions for specific regions are also investigated. From all the results obtained, an economic analysis shows that NCC is more interesting than SWCNT to reinforce PP

Deformation and failure kinetics of iPP polymorphs

NARCIS (Netherlands)

Caelers, H.J.M.; Parodi, E.; Cavallo, D.; Peters, G.W.M.; Govaert, L.E.

2017-01-01

In this study, the mechanical performance of thedifferent polymorphs of isotactic polypropylene, typically pre-sent in iPP crystallized under industrial processing conditions,is assessed. Different preparation strategies were used toobtain samples consisting of almost solely alpha, beta, or gamma

Using rheometry for determining nucleation density in colored system containing a nucleation agent

NARCIS (Netherlands)

Ma, Z.; Steenbakkers, R.J.A.; Giboz, J.; Peters, G.W.M.

2011-01-01

A new suspension-based rheological method was applied to study experimentally the crystallization of a nucleating agent (NA) filled isotactic polypropylene. This method allows for determination of point-nucleation densities where other methods fail. For example, optical microscopy can fail because

The influences of the physical-chemical factors on the free-volume relations in polymers

International Nuclear Information System (INIS)

Bartos, J.; Kristiak, J.; Kristiakova, K.; Sausa, O.; Bandzuch, P.

1995-01-01

The positron annihilation spectroscopy was used to the study of different physical-chemical factors on the free-volume microstructure of the model polymeric systems [amorphous 1,4-cis-poly(butadiene), amorphous a-tactic and semi-crystal iso-tactic poly(propylene), polycarbonate

Evaluation of elevated temperature influence on mechanical properties of a commercial unrefined bagasse fiber-polypropylene composite

Directory of Open Access Journals (Sweden)

Foroogh Dastoorian

2014-11-01

Full Text Available An experimental investigation was conducted to evaluate the effect of elevated temperatures, ranging from room temperature to 80oC, on mechanical characteristics of a commercial bagasse fiber/polypropylene composite. The test results were used to determine the temperature dependencies of the mechanical properties of the studied composite material at temperatures up to 80°C in order to develop temperature adjustment factors for the use in structural applications. The results have shown that as temperature increases, the material become more ductile due to increased plastic deformation gets lower stiffness and fails at higher strains. The resulted adjustment factors were different for each loading mode and the results also have indicated that the influence of elevated temperatures on values of modulus was higher than that on strengths.

A Combined Self-Consistent Method to Estimate the Effective Properties of Polypropylene/Calcium Carbonate Composites

Directory of Open Access Journals (Sweden)

Zhongqiang Xiong

2018-01-01

Full Text Available In this work, trying to avoid difficulty of application due to the irregular filler shapes in experiments, self-consistent and differential self-consistent methods were combined to obtain a decoupled equation. The combined method suggests a tenor γ independent of filler-contents being an important connection between high and low filler-contents. On one hand, the constant parameter can be calculated by Eshelby’s inclusion theory or the Mori–Tanaka method to predict effective properties of composites coinciding with its hypothesis. On the other hand, the parameter can be calculated with several experimental results to estimate the effective properties of prepared composites of other different contents. In addition, an evaluation index σ f ′ of the interactional strength between matrix and fillers is proposed based on experiments. In experiments, a hyper-dispersant was synthesized to prepare polypropylene/calcium carbonate (PP/CaCO3 composites up to 70 wt % of filler-content with dispersion, whose dosage was only 5 wt % of the CaCO3 contents. Based on several verifications, it is hoped that the combined self-consistent method is valid for other two-phase composites in experiments with the same application progress as in this work.

Ecotoxicity and fungal deterioration of recycled polypropylene/wood composites: effect of wood content and coupling.

Science.gov (United States)

Sudár, András; López, María J; Keledi, Gergely; Vargas-García, M Carmen; Suárez-Estrella, Francisca; Moreno, Joaquín; Burgstaller, Christoph; Pukánszky, Béla

2013-09-01

Recycled polypropylene (rPP) was recovered from an industrial shredder and composites were prepared with a relatively wide range of wood content and with two coupling agents, a maleated PP (MAPP) and a maleated ethylene-propylene-diene elastomer (MAEPDM). The mechanical properties of the composites showed that the coupling agents change structure only slightly, but interfacial adhesion quite drastically. The durability of the materials was determined by exposing them to a range of fungi and, ecotoxicity was studied on the aquatic organism Vibrio fischeri. The composites generally exhibit low acute toxicity, with values below the levels considered to have direct ecotoxic effect on aquatic ecosystems (deterioration proved that wood facilitates fungal colonization. Fungi caused slight mass loss (below 3%) but it was not correlated with substantial deterioration in material properties. MAPP seems to be beneficial in the retention of mechanical properties during fungal attack. rPP/wood composites can be considered non-ecotoxic and quite durable, but the influence of wood content on resistance to fungal attack must be taken into account for materials intended for applications requiring long-term outdoor exposure. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparative studies of Titanium Dioxide and Zinc Oxide as a potential filler in Polypropylene reinforced rice husk composite

Science.gov (United States)

Awang, M.; Mohd, W. R. Wan

2018-04-01

Arising global environmental issues have triggered the search of new products and processes that are compatible with the environment while maintaining novel properties of materials. In this work, green composites containing rice husk (RH), polypropylene (PP), and incorporated with two different fillers namely titanium dioxide (TiO2) and zinc oxide (ZnO) were prepared using an internal mixer and were injected into desired specimen by using an injection molding method. Mechanical properties of the composite were studied using Instron universal testing machine with load cell of 30kN capacity. Morphological of tensile fractured surface of composites was observed using scanning electron microscopy (SEM). The results show that the composites with the addition of TiO2 gave an excellent mechanical properties than the composites filled with ZnO. Furthermore, morphological image of PP/RH/TiO2 also shows a good interaction occurred between polymer matrix and RH particles as compared to that of PP/RH/ZnO.

EFFECT OF SEA WATER ON THE STRENGTH OF POROUS CONCRETE CONTAINING PORTLAND COMPOSITE CEMENT AND MICROFILAMENT POLYPROPYLENE FIBER

OpenAIRE

TJARONGE, M.W

2011-01-01

The aim of this research is to study the influence of sea water on the strength of porous concrete containing Portland Composite cement and micro monofilament polypropylene fibre. The specimens of porous concrete were immersed in the sea water up to 28 days. The compressive strength test and flexural strength test were carried out at 3, 7 and 28 days in order to investigate the strength development. The test result indicated that the strength of porous concrete can develop in t...

Genome Regions Associated with Functional Performance of Soybean Stem Fibers in Polypropylene Thermoplastic Composites.

Directory of Open Access Journals (Sweden)

Yarmilla Reinprecht

Full Text Available Plant fibers can be used to produce composite materials for automobile parts, thus reducing plastic used in their manufacture, overall vehicle weight and fuel consumption when they replace mineral fillers and glass fibers. Soybean stem residues are, potentially, significant sources of inexpensive, renewable and biodegradable natural fibers, but are not curretly used for biocomposite production due to the functional properties of their fibers in composites being unknown. The current study was initiated to investigate the effects of plant genotype on the performance characteristics of soybean stem fibers when incorporated into a polypropylene (PP matrix using a selective phenotyping approach. Fibers from 50 lines of a recombinant inbred line population (169 RILs grown in different environments were incorporated into PP at 20% (wt/wt by extrusion. Test samples were injection molded and characterized for their mechanical properties. The performance of stem fibers in the composites was significantly affected by genotype and environment. Fibers from different genotypes had significantly different chemical compositions, thus composites prepared with these fibers displayed different physical properties. This study demonstrates that thermoplastic composites with soybean stem-derived fibers have mechanical properties that are equivalent or better than wheat straw fiber composites currently being used for manufacturing interior automotive parts. The addition of soybean stem residues improved flexural, tensile and impact properties of the composites. Furthermore, by linkage and in silico mapping we identified genomic regions to which quantitative trait loci (QTL for compositional and functional properties of soybean stem fibers in thermoplastic composites, as well as genes for cell wall synthesis, were co-localized. These results may lead to the development of high value uses for soybean stem residue.

Contact mechanics of polyolefins: effect of pre-stretch on the frictional response and the onset of wear

NARCIS (Netherlands)

Looijmans, S.F.S.P.; Anderson, P.D.; van Breemen, L.C.A.; Crosby, A.J.; Govaert, L.E.

2018-01-01

As a result of processing history, polymer products are, more often than not, anisotropic. In this work, single-asperity sliding friction experiments are used to characterize the tribology of semi-crystalline polymer films. We show the improved scratch resistance of oriented isotactic polypropylene

Full characterization of multiphase, multimorphological kinetics in flow-induced crystallization of IPP at elevated pressure

NARCIS (Netherlands)

Troisi, E.M.; Caelers, H.J.M.; Peters, G.W.M.

2017-01-01

Understanding the complex crystallization behavior of isotactic polypropylene (iPP) in conditions comparable to those found in polymer processing, where the polymer melt experiences a combination of high shear rates and elevated pressures, is key for modeling and therefore predicting the final

Effect of surface modified kaolin on properties of polypropylene grafted maleic anhydride

Science.gov (United States)

Yang, Ni; Zhang, Zuo-Cai; Ma, Ning; Liu, Huan-Li; Zhan, Xue-Qing; Li, Bing; Gao, Wei; Tsai, Fang-Chang; Jiang, Tao; Chang, Chang-Jung; Chiang, Tai-Chin; Shi, Dean

To achieve reinforcement of mechanical and thermal performances of polypropylene (PP) product, this work aimed at fabrication of surface modified kaolin (M-kaolin) filled polypropylene grafted maleic anhydride (PP-g-MAH) composites with varying contents of fillers and investigation of their mechanical and thermal properties. And the prepared PP-g-MAH/M-kaolin composites were characterized by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Fracture analysis by SEM showed M-kaolin particles were well dispersed in the PP-g-MAH matrix. Mechanical behaviors were determined by tensile strength, tensile strain at break and impact strength analysis. Impact strength of PP-g-MAH/2 wt% M-kaolin composites was improved up to 30% comparing with unfilled composites. Thermostability had been found enhanced when M-kaolin added. The results revealed PP-g-MAH/M-kaolin composites showed the optimal thermal and mechanical properties when 2 wt% of M-kaolin was added.

Mechanical and thermal properties of polypropylene (PP) composites filled with modified shell waste

Energy Technology Data Exchange (ETDEWEB)

Yao, Z.T., E-mail: sxyzt@126.com [College of Materials Science and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Chen, T. [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Li, H.Y. [Zhoushan Ocean Research Institute, Zhejiang University, Zhoushan 316021 (China); Xia, M.S., E-mail: msxia@zju.edu.cn [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Ye, Y.; Zheng, H. [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China)

2013-11-15

Highlights: • Adding modified shell powder could significantly increase the properties of PP. • The modified shell powder could act as a nucleating agent in PP matrix. • The modified shell powder has a potential to be used as a bio-filler. -- Abstract: Shell waste, with its high content of calcium carbonate (CaCO{sub 3}) plus organic matrix, has a potential to be used as a bio-filler. In this work, shell waste was modified by furfural and then incorporated to reinforce polypropylene (PP). The shell waste and modified powder were characterized by means of X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), X-ray photoelectronic spectroscopy (XPS), and Fourier transformed infrared spectroscopy (FTIR). The mechanical and thermal properties of neat PP and PP composites were investigated as well. Thermal gravimetric (TG) analyses confirmed the reinforcing role of modified powder in PP composites. The mechanical properties studied showed that adding modified powder could significantly increase the impact strength, elongation at break point and flexural modulus of composites. The maximum incorporation content could reach 15 wt.% with a good balance between toughness and stiffness of PP composites. Differential scanning calorimetry (DSC) results showed that the modified powder could act as a nucleating agent and thus increase the crystallization temperature of PP. Polarized optical microscopy (POM) observation also indicated that the introduction of modified powder could promote the heterogeneous nucleation of PP matrix.

Resonance – Journal of Science Education | Indian Academy of ...

Indian Academy of Sciences (India)

The story of how Natta discoveredpolypropylene is an engrossing one – one of stiff competitionamongst contemporaries, Natta's intimate relationship withthe Italian industries, and his unique scientific background.Natta's identification of isotactic polypropylene as a righthandedthree fold 'single helix' in March 1954, in quick ...

Melamine-formaldehyde microcapsules filled sappan dye modified polypropylene composites: encapsulation and thermal properties

Science.gov (United States)

Phanyawong, Suphitcha; Siengchin, Suchart; Parameswaranpillai, Jyotishkumar; Asawapirom, Udom; Polpanich, Duangporn

2018-01-01

Sappan dye, a natural dye extracted from sappan wood is widely used in cosmetics, textile dyeing and as food additives. However, it was recognized that natural dyes cannot withstand high temperature. In this study, a protective coating of melamine-formaldehyde shell material was applied over the sappan dye to improve its thermal stability. The percentage of sappan dye used in the microencapsulation was 30, 40, 50, 60 and 70 wt%. The color, shape, size, and thermal stability of sappan dye microcapsules were investigated. It was found that increasing amount of sappan dye content in the microcapsules decreased the particle size. Thermal analysis reveals that the melamine-formaldehyde resin served as an efficient protective shell for sappan dye. Besides, 30 wt% sappan dye microcapsules with different weight percent (1, 3 and 5 wt%) of sappan dye was used as modifier for polypropylene (PP). All the prepared composites are red in color which supports the thermal stability of the microcapsules. The changes in crystallinity and melting behavior of PP by the addition of microcapsules were studied in detail by differential scanning calorimetry. Thermogravimetric studies showed that the thermal stability of PP composites increased by the addition of microcapsules.

Effect of combined extrusion parameters on mechanical properties of basalt fiber-reinforced plastics based on polypropylene

Science.gov (United States)

Bashtannik, P. I.; Ovcharenko, V. G.; Boot, Yu. A.

1997-11-01

Basalt fibers are efficient reinforcing fillers for polypropylene because they increase both the mechanical and the tribotechnical properties of composites. Basalt fibers can compete with traditional fillers (glass and asbestos fibers) of polypropylene with respect to technological, economic, and toxic properties. The effect of technological parameters of producing polypropylene-based basalt fiber-reinforced plastics (BFRPs) by combined extrusion on their mechanical properties has been investigated. The extrusion temperature was found to be the main parameter determining the mechanical properties of the BFRPs. With temperature growth from 180 to 240°C, the residual length of the basalt fibers in the composite, as well as the adhesive strength of the polymer-fiber system, increased, while the composite defectiveness decreased. The tensile strength and elastic modulus increased from 35 to 42 MPa and 3.2 to 4.2 GPa, respectively. At the same time, the growth in composite solidity led to its higher brittleness. Thus, a higher temperature of extrusion allows us to produce materials which can be subjected to tensile and bending loads, while the materials produced at a lower temperature of extrusion are impact stable. The effect of the gap size between the extruder body and moving disks on the mechanical properties of the BFRPs is less significant than that of temperature. An increase of the gap size from 2 to 8 mm improves the impregnation quality of the fibers, but the extruder productivity diminishes. The possibility of controling the properties of reinforced polypropylene by varying the technological parameters of combined extrusion is shown. The polypropylene-based BFRPs produced by the proposed method surpass the properties of glass and asbestos fiber-reinforced plastics.

The method of polymer compositions manufacturing on the base of polypropylene[Radiation processing]; Sposob wytwarzania kompozycji polimerow na bazie polipropylenu

Energy Technology Data Exchange (ETDEWEB)

Zimek, Z; Bulhak, Z; Bojarski, J; Stachowicz, W [Warsaw (Poland); Mirkowski, K [Legionowo (Poland)

1966-06-28

The method of manufacturing of radiation resistant polymer composition of medical quality have been proposed. The raw material consisted of polypropylene homopolymer with propylene-ethylene copolymer, ethylene-vinyl acetate copolymer and polystyrene suspension have been mixed and extruded during heating at 190-270{sup o}C. Then obtained mixture have been granulated. The material structure with microagglomerates is responsible for elevated radiation resistance of material being destinated for medical devices production and radiosterilization.

Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

Energy Technology Data Exchange (ETDEWEB)

Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B. [Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario, Canada M5S 3G8 (Canada); Pötschke, P. [Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Strasse 6, D-01069 Dresden (Germany)

2015-05-22

A combination of high dielectric permittivity (ε′) and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ε′ and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ε′ and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube’s arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ε′=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ε′=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

[Quantification of Wood Flour and Polypropylene in Chinese Fir/Polypropylene Composites by FTIR].

Science.gov (United States)

Lao, Wan-li; Li, Gai-yun; Zhou, Qun; Qin, Te-fu

2015-06-01

The ratio of wood and plastic in Wood Plastic Composites (WPCss) influences quality and price, but traditional thermochemical methods cannot rapidly and accurately quantify the ratio of wood/PP in WPCss. This paper was addressed to investigate the feasibility of quantifying the wood flour content and plastic content in WPCss by Fourier Transform Infrared (FTIR) spectroscopy. With Chinese fir, polypropylene (PP) and other additives as raw materials, 13 WPCs samples with different wood flour contents, ranging from 9.8% to 61.5%, were prepared by modifying wood flour, mixing materials and extrusion pelletizing. The samples were analyzed by FTIR with the KBr pellets technique. The absorption peaks of WPCss at 1059, 1 033 and 1 740 cm(-1) are considered as characteristic of Chinese fir, and the absorption peaks at 1 377, 2 839 and 841 cm(-1) are typical of PP by comparing the spectra of WPCss with that of Chinese fir, PP and other additives. The relationship between the wood flour content, PP content in WPCss and their characteristic IR peaks height ratio was established. The results show that there is a strong linear correlation between the wood flour content in WPCss and I1 059/l 1 377/I1 033, /I1377, R2 are 0.992 and 0.993 respectively; there is a high linear correlation between the PP content in WPCss and I1 377/I1 740, I2 839 /I1 740 R2 are 0.985 and 0.981, respectively. Quantitative methods of the wood flour content and PP content in WPCss by FTIR were developed, the predictive equations of the wood flour content in WPCss are y = 53.297x-9. 107 and y = 55.922x-10.238, the predictive equations of the PP content in WPCss are y = 6.828 5x+5.403 6 and y = 8.719 7x+3.295 8. The results of the accuracy test and precision test show that the method has strong repeatability and high accuracy. The average prediction relative deviations of the wood flour content and PP content in WPCss are about 5%. The prediction accuracy has been improved remarkably, compared to

Biodegradation of Polypropylene Nonwovens

Science.gov (United States)

Keene, Brandi Nechelle

The primary aim of the current research is to document the biodegradation of polypropylene nonwovens and filament under composting environments. To accelerate the biodegradat ion, pre-treatments and additives were incorporated into polypropylene filaments and nonwovens. The initial phase (Chapter 2) of the project studied the biodegradation of untreated polypropylene with/without pro-oxidants in two types of composting systems. Normal composting, which involved incubation of samples in food waste, had little effect on the mechanical properties of additive-free spunbond nonwovens in to comparison prooxidant containing spunbond nonwovens which were affected significantly. Modified composting which includes the burial of samples with food and compressed air, the polypropylene spunbond nonwovens with/without pro-oxidants displayed an extreme loss in mechanical properties and cracking on the surface cracking. Because the untreated spunbond nonwovens did not completely decompose, the next phase of the project examined the pre-treatment of gamma-irradiation or thermal aging prior to composting. After exposure to gamma-irradiation and thermal aging, polypropylene is subjected to oxidative degradation in the presence of air and during storage after irradiat ion. Similar to photo-oxidation, the mechanism of gamma radiation and thermal oxidative degradation is fundamentally free radical in nature. In Chapter 3, the compostability of thermal aged spunbond polypropylene nonwovens with/without pro-oxidant additives. The FTIR spectrum confirmed oxidat ion of the polypropylene nonwovens with/without additives. Cracking on both the pro-oxidant and control spunbond nonwovens was showed by SEM imaging. Spunbond polypropylene nonwovens with/without pro-oxidants were also preirradiated by gamma rays followed by composting. Nonwovens with/without pro-oxidants were severely degraded by gamma-irradiation after up to 20 kGy exposure as explained in Chapter 4. Furthermore (Chapter 5), gamma

Assessment of extrusion-sonication process on flame retardant polypropylene by rheological characterization

Directory of Open Access Journals (Sweden)

Guadalupe Sanchez-Olivares

2016-05-01

Full Text Available In this work, the rheological behavior of flame retardant polypropylene composites produced by two methods: 1 twin-screw extrusion and 2 ultrasound application combined with a static mixer die single-screw extrusion is analyzed in detail; results are related to the morphology of the composites. The flame retardant polymer composites are composed of a polypropylene matrix, an intumescent flame retardant system and functionalized clay. Scanning electron microscopy revealed that the combination of the static mixer die and on-line sonication reduced particle size and improved the dispersion and distribution of the intumescent additives in the polypropylene matrix at the micrometric level. From linear viscoelastic properties, the Han, Cole-Cole and van Gurp-Palmen diagrams characterized the improved particle dispersion of the flame retardant additives. Two well-defined rheological behaviors were observed in these diagrams. These behaviors are independent on clay presence and concentration. In fact, the ultrasound device generates a 3D highly interconnected structure similar to a co-continuous pattern observed in polymer blends as evidenced by rheological measurements. This improvement in the dispersion and distribution of the additives is attributed to the combined effect of the static mixer die and on-line sonication that allowed reducing the additive content while achieving the optimum classification UL94-V0.

Engineering new polypropylene copolymer for asphalt modification. Progettazione di un polimero a base polipropilenica adatto per la modifica dei bitumi

Energy Technology Data Exchange (ETDEWEB)

Giavarini, C.; Santarelli, M.L. (Rome Univ. (Italy). Dipt. di Ingegneria Chimica); Braga, V. (Himont Centro Ricerche ' G. Natta' , Ferrara (Italy))

1993-04-01

Polypropylene polymers: isotactic PP, random, heterophasic copolymer, ethylene-propylene rubber, are suitable as modifiers for road bitumens. Among the advantages of PP polymers, such as heterophasic polymers, prepared via synthesis, are good thermal and ageing resistance, and the fact that they can be easily tailored to the specific application. Various types of PP and EPR polymers, possibly blended, prepared or modified for this purpose, were mixed with bitumens to study the dispersion of the polymer, segregation characteristics, ageing and viscoelastic properties. The experimental results gave indications on the characteristics of a polyolefinic copolymer for bitumen modification. The PP based products applicable as bitumen modifiers are the heterophasic copolymers containing a substantial amounts of EPR, possibly modified to increase branching. For road bitumens with a penetration between 100 and 200 dmm, the average molecular weight of the polymer should be arranged to reach an intrinsic viscosity between about 1.5 and 2.0 dl/g. Partial branching (or partial crosslinking) of the chains in the PP-phase is helpful when not followed by EPR-phase crosslinking.

Mechanical and thermal properties of polymer composite based on natural fibers: Moroccan hemp fibers/polypropylene

International Nuclear Information System (INIS)

Elkhaoulani, A.; Arrakhiz, F.Z.; Benmoussa, K.; Bouhfid, R.; Qaiss, A.

2013-01-01

Highlights: ► Moroccan hemp fibers are used as reinforcement in thermoplastic matrix. ► Moroccan hemp fiber was alkali treated to remove waxes and noncellulosic component. ► Fiber–matrix adhesion was assured by the use of a SEBS-g-MA as a compatibilizer. - Abstract: Moroccan hemp is a cellulosic fiber obtained from the north of Morocco. Their use as reinforcement in thermoplastic matrix composite requires a knowledge of their morphology and structure. In this paper the Moroccan hemp fiber was alkali treated to remove waxes and noncellulosic surface components. Fiber/matrix adhesion was assured by the use of a styrene-(ethylene-butene)-styrene three-block copolymer grafted with maleic anhydride (SEBS-g-MA) as a compatibilizer. Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), tensile and torsional tests were carried out for hemp fibers polypropylene composite and the compatibilized composite at different fiber content. Thus, the binary composite PP/hemp fibers (Alk) and ternary system with maleic anhydride indicate clearly an improved adhesion of the fiber to the matrix as results of the good interaction at the interface. A gain of 50% on the Young’s modulus of PP/hemp 25 wt.% without coupling agent and 74% on the PP/hemp 20 wt.% composite with the coupling agent were found. Tensile strength curve shows a remarkable stabilization when the coupling agent was used

Poly(lauryl acrylate) and poly(stearyl acrylate) grafted multiwalled carbon nanotubes for polypropylene composites

DEFF Research Database (Denmark)

Daugaard, Anders Egede; Jankova Atanasova, Katja; Hvilsted, Søren

2014-01-01

Two new polymer grafts on an industrial grade multiwalled carbon nanotube (MWCNT) were prepared through a non-oxidative pathway employing controlled free radical polymerization for surface initiated polymer grafting. After photochemical introduction of an ATRP initiator onto the MWCNT......, polymerizations of lauryl or stearyl acrylate were performed, resulting in two novel polymer modifications on the MWCNT (poly(lauryl acrylate) or poly(stearyl acrylate)). The method was found to give time dependent loading of polymers as a function of time (up to 38 wt% for both acrylates), and showed a plateau...... in loading after 12 h of polymerization. The modified nanomaterials were melt mixed into polypropylene composites with very low filler loading (0.3 wt%), whereafter both the thermal and electrical properties were investigated by DSC and dielectric resonance spectroscopy. The electrical properties were found...

Effects of electron beam radiation dose on the compatibilization behaviour in recycled polypropylene/microcrystalline cellulose composites

Science.gov (United States)

Samat, N.; Motsidi, S. N. R.; Lazim, N. H. M.

2018-01-01

The purpose of this research was to evaluate the influence of dose level of electron beam on the compatibilization behavior of recycled polypropylene (rPP) in rPP/microcrystalline cellulose (MCC) composites. Initially, the rPP was irradiated with various dose of electron beam (5 kGy up to 250 kGy) which then mixed with unirradiated rPP (u-rPP) at a ratio of 30:70 respectively. The composites were prepared by incorporating a series wt% of MCC fibers into rPP (u-rPP : i-rPP) using extruder and finally moulded with an injection moulding machine. The compatibility behavior of irradiated rPP (i-rPP) were analysed with mechanical tensile and thermal methods. The results of mechanical analysis showed great improvement in tensile modulus but an increase in radiation dosage gradually decreased this property. Nevertheless, the tensile strength exhibited a minor effect. The thermal stability of composites is lowered with increase in the absorbed dose, more significantly at higher content of MCC. Fracture surface observations reveal adhesion between the cellulose and rPP matrix.

Bond Characteristics of Macro Polypropylene Fiber in Cementitious Composites Containing Nanosilica and Styrene Butadiene Latex Polymer

Directory of Open Access Journals (Sweden)

Jae-Woong Han

2015-01-01

Full Text Available This study evaluated the bond properties of polypropylene (PP fiber in plain cementitious composites (PCCs and styrene butadiene latex polymer cementitious composites (LCCs at different nanosilica contents. The bond tests were evaluated according to JCI SF-8, in which the contents of nanosilica in the cement were 0, 2, 4, 6, 8, and 10 wt%, based on cement weight. The addition of nanosilica significantly affected the bond properties between macro PP fiber and cementitious composites. For PCCs, the addition of 0–2 wt% nanosilica enhanced bond strength and interface toughness, whereas the addition of 4 wt% or more reduced bond strength and interface toughness. The bond strength and interfacial toughness of LCCs also increased with the addition of up to 6% nanosilica. The analysis of the relative bond strength showed that the addition of nanosilica affects the bond properties of both PCC and LCC. This result was confirmed via microstructural analysis of the macro PP fiber surface after the bond tests, which revealed an increase in scratches due to frictional forces and fiber tearing.

Rheological and mechanical properties of polypropylene prepared with multi-walled carbon nanotube masterbatch.

Science.gov (United States)

Shim, Young-Sun; Park, Soo-Jin

2012-07-01

In this study, the effects of polypropylene-grafted maleic-anhydride-treated multi-walled carbon nanotubes (PP-MWNTs) on the viscoelastic behaviors and mechanical properties of a polypropylene-(PP)-based composite system were examined. The PP-MWNT/PP composites were prepared via melt mixing with a 3:1 ratio of PP-g-MA and acid-treated MWNTs at 220 degrees C. The surface characteristics of the PP-MWNTs were confirmed via Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The viscoelastic behavior and mechanical properties of the PP-MWNT/PP composites were confirmed using a rheometer and an ultimate testing machine (UTM). The storage and loss moduli increased with increasing PP-MWNT content. The critical intensity stress factor (K(IC)) of the PP-MWNT/PP composites at high filler loading was also higher than that of the MWNT/PP composites. In conclusion, the viscoelastic behavior and mechanical properties of MWNT/PP can be improved by grafting MWNTs to PP-g-MA.

Modelling of Creep and Stress Relaxation Test of a Polypropylene Microfibre by Using Fraction-Exponential Kernel

Directory of Open Access Journals (Sweden)

Andrea Sorzia

2016-01-01

Full Text Available A tensile test until breakage and a creep and relaxation test on a polypropylene fibre are carried out and the resulting creep and stress relaxation curves are fit by a model adopting a fraction-exponential kernel in the viscoelastic operator. The models using fraction-exponential functions are simpler than the complex ones obtained from combination of dashpots and springs and, furthermore, are suitable for fitting experimental data with good approximation allowing, at the same time, obtaining inverse Laplace transform in closed form. Therefore, the viscoelastic response of polypropylene fibres can be modelled straightforwardly through analytical methods. Addition of polypropylene fibres greatly improves the tensile strength of composite materials with concrete matrix. The proposed analytical model can be employed for simulating the mechanical behaviour of composite materials with embedded viscoelastic fibres.

Effect of porous zeolite on temperature-dependent physical properties of polypropylene/octadecane (PP/OD composite films

Directory of Open Access Journals (Sweden)

D. Kim

2018-07-01

Full Text Available Polymeric materials with temperature-dependent gas permeabilities using a phase change material are designed and their applicability as a packaging system investigated. Polypropylene/octadecane/zeolite (PP/OD/ZL composite films were prepared via extrusion process. ZL was used as a filler to enhance the dispersion and interfacial interaction between the OD and the PP originating from different flowabilities during the extrusion process. (FTIR and (WAXD analyses showed that the incorporation of ZL increased the interfacial interaction between PP and OD, resultantly enhancing the thermal stability, mechanical properties, and the oxygen transmittance rate and mechanical properties after contact with food simulants and thermal treatment. When the temperature was elevated from 10 to 30 °C, oxygen and water vapor transmittance rate of the composite films increased sharply because of the influence of the OD content. It was surmised that temperaturedependent permeation jump caused by increasing of segmental mobility of OD phase and converting the crystalline structure to an amorphous one of OD phase in the composite films. However, the permeation jump in the composite films was weakened as the ZL content increased. These results are related to changes in the interfacial interaction and crystallinity in the composite films due to the addition of ZL.

Smart Natural Fiber Reinforced Plastic (NFRP) Composites Based On Recycled Polypropylene in The Presence Kaolin

Science.gov (United States)

Suharty, N. S.; Ismail, H.; Diharjo, K.; Handayani, D. S.; Lestari, W. A.

2017-07-01

Composites contain double filler material which act as reinforcement and flame retardants of recycled polypropylene (rPP)/kaolin(Kao)/palm oil empty bunch fiber (PEBF) have been succesfully prepared. The composites were synthesized through reactively solution method, using coupling agent PP-g-AA and compatibilizer DVB. The effect of double filler [Kao/PEBF] were investigated flexural strength (FS), inflammability, and morphology. Mechanical testing result in accordance to ASTM D790, the FS of rPP/DVB/PP-g-AA/Kao+ZB/PEBF composite was 48% higher than that of rPP matrix. Moreover, flexural modulus (FM) was significantly improved by 56% as compared to that of rPP matrix. The scanning electron images (SEM) shown good dispersion of [Ka/PEBF] and good filler-matrix interaction. The inflammability testing result which is tested using ASTM D635, showed that the flame resistance of rPP/DVB/PP-g-AA/Kao+ZB/PEBF composite was improve by increasing of time to ignition (TTI) about 857% and burning rate (BR) decreasing to 66% compared to the raw material rPP matrix. In the same time, the addition of 20% (w/w) PEBF as a second filler to form rPP/DVB/PP-g-AA/Kao+ZB/PEBF composites (F5) is able to increase: the FS by 17.5%, the FM by 19%, the TTI by 7.6% and the BR by 3.7% compared to the composite without PEBF (F2).

Tuning the nano/micro-structure and properties of melt-processed ternary composites of polypropylene/ethylene vinyl acetate blend and nanoclay: The influence of kinetic and thermodynamic parameters

CSIR Research Space (South Africa)

Mofokeng, Tladi G

2017-09-01

Full Text Available The present study reports the dependence of the nano/micro-structure and properties of polypropylene (PP)/ethylene vinyl acetate (EVA)/nanoclay ternary composites on the kinetics and thermodynamics of the melt-mixing process. The size of dispersed...

From atactic to isotactic CO/p-methylstyrene copolymer by proper modification of Pd(II) catalysts bearing achiral alpha-diimines.

Science.gov (United States)

Binotti, Barbara; Carfagna, Carla; Zuccaccia, Cristiano; Macchioni, Alceo

2005-01-07

Cationic Pd(II) complexes modified with achiral C(2v)-symmetric alpha-diimine ligands allow preparation of atactic or isotactic stereoblock CO/p-methylstyrene copolymers; both catalyst activity and polyketone microstructure depend on the choice of alpha-diimine substituents and counterion.

Flammability of polypropylene/organoclay nanocomposites; Inflamabilidade de nanocompositos de polipropileno/argila organofilica

Energy Technology Data Exchange (ETDEWEB)

Alves, Tatianny Soares; Barbosa, Renata [Universidade Federal do Piaui (UFPI), Teresina (Brazil); Carvalho, Laura Hecker de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Canedo, Eduardo Luis [Instituto de Tecnologia de Pernambuco, Recife (Brazil)

2014-11-01

The flammabilities of nanocomposites made with three polypropylene grades (homo and copolymers) with 5 wt % of organoclay (Cloisite 20A), 5 or 15 wt % of maleated polypropylene as compatibilizer, and 0, 0.5 or 1 wt % of cis-13-docosenamide (Erucamide) as co-intercalant, were studied using the horizontal burning test UL94HB. Masterbatches prepared in an internal mixer were diluted in the polypropylene matrix using a corotating twin-screw extruder, with different screw configurations and operating at 240 or 480 rpm. Results indicate that the high burning rate of the composites was not affected by the processing conditions. For all formulations was observed a significant reduction in smoke release, lack of dripping and the formation of a char surface layer, that protected the core of the samples. (author)

Jute fiber reinforced polypropylene produced by continuous extrusion compounding. Part 1. Processing and ageing properties

NARCIS (Netherlands)

Oever, van den M.J.A.; Snijder, M.H.B.

2008-01-01

This article addresses the processing and ageing properties of jute fiber reinforced polypropylene (PP) composites. The composite has been manufactured by a continuous extrusion process and results in free flowing composite granules, comprising up to 50 weight percent (wt %) jute fiber in PP. These

Modification of bentonite clay and application on polypropylene nano composites

International Nuclear Information System (INIS)

Oliveira, Akidauana D.B.; Rodrigues, Andre W.B.; Agrawal, Pankaj; Araujo, Edcleide M.; Melo, Tomas J.A.

2009-01-01

This work consisted on the modification of Brasgel PA clay with ionic surfactant Praepagen WB and its incorporation into polypropylene. The results of infrared and DR-X was showed that the intercalation of surfactant in the clay and the incorporation of organoclay in PP matrix resulted in the formation of an intercalated structure. The impact strength of PP increased with the incorporation of organoclay. (author)

Role of carbon nanotubes (CNTs) in improving wear properties of polypropylene (PP) in dry sliding condition

International Nuclear Information System (INIS)

Ashok Gandhi, R.; Palanikumar, K.; Ragunath, B.K.; Paulo Davim, J.

2013-01-01

Highlights: ► Role of carbon nanotubes (CNTs) on wear behaviour of polypropylene (PP) is evaluated. ► Effect of applied pressure and composition against a steel counter face is investigated. ► Microstructure and worn surfaces of samples are observed by scanning electron microscope. ► The wear phenomenon has been discussed based on wear losses and worn surfaces. ► The coefficient of friction (μ) and sliding time for PP and PP/CNT blend is investigated. - Abstract: Polymers are widely used for sliding couples against metals and other materials. Polypropylene is a polymer used in variety of applications includes packaging, laboratory equipments, automotive components, etc. Polypropylene is often desirable automotive material due to its low cost, colorability, chemical resistance and UV stability. In addition the range of potential polypropylene uses is nearly unlimited through the use of modifiers, additives and fillers. In the present work, the sliding wear of polypropylene (PP) and carbon nanotube (CNT) blends are evaluated as a function of applied load and composition against a steel counter face in dry condition. The addition of CNT in PP in wear performance is investigated and presented in detail. Microstructure and worn surfaces of samples were observed by scanning electron microscope. The wear phenomenon has been discussed based on wear losses and worn surfaces

Recycling effects on the rheological and thermomechanical properties of polypropylene-based composites

International Nuclear Information System (INIS)

Bahlouli, Nadia; Pessey, Daniel; Raveyre, Claude; Guillet, Jacques; Ahzi, Said; Dahoun, Abdessalam; Hiver, Jean Marie

2012-01-01

Highlights: → Recycling effect on high impact PP with or without talc for automotive industries. → Rheological/mechanical tests, effect of molecular weight, deformation and damage. → Embrittlement of the amorphous matrix by chain scissions and growth of cavitation. → Better stability for talc filled HiPP, but decreased failure stress. → Interfaces talc/PP matrix and EPDM droplets/PP matrix are degraded. -- Abstract: As recycled materials are increasingly used in design of structural components, it is necessary to understand the effect of recycling on the properties and durability of these materials. In this work, the recycling effects on two high impact polypropylenes (HiPP) are studied. The recycling process was simulated by performing several extrusion runs with the same material in order to get a better understanding of the multi recycling effects. These effects were identified not only on the molecular weight and the rheological properties but also on the mechanical properties and the deformation mechanisms. The volume strain has been also measured as a damage indicator in the studied polymers. For both materials, the analysis of the different results showed that the rheological and the mechanical properties were affected by the thermomechanical recycling process. In particular, this process led to the decrease of the molecular weight, the decrease of the failure stress and the decrease of the impact energy. Moreover, Scanning Electronic Micoscopy (SEM) pictures showed a modification of the deformation process due to the embrittlement of the amorphous matrix by the chain scission and by cavitation. Moreover, a better stability for talc filled HiPP was observed but a decrease of the failure stress was obtained because the interfaces talc/polypropylene (PP) matrix and ethylene propylene diene monomer (EPDM) droplets/PP matrix were degraded. Indeed, the knowledge of the molecular characteristics as well as the rheological and mechanical properties of

The radiation chemistry of macromolecules

CERN Document Server

1973-01-01

The Radiation Chemistry of Macromolecules, Volume II is a collection of papers that discusses radiation chemistry of specific systems. Part 1 deals with radiation chemistry of substituted vinyl polymers, particularly polypropylene (PP) as its structure is intermediate between polyethylene and polyisobutylene. This part also discusses polypropylene oxide (PPOx) for it can be prepared in the atactic, isotactic, and optically active forms. One paper focuses on the fundamental chemical processes and the changes in physical properties that give rise to many different applications of polystyrene. An

Role of PET in improving wear properties of PP in dry sliding condition

Indian Academy of Sciences (India)

Unknown

... blends were studied using scanning elec- tron microscopy. Sliding wear properties of these blends have been determined and studied for various blend com- positions. 2. Materials and methods. 2.1 Materials. Isotactic polypropylene PP (density 0⋅91 g/cc, grade SRM. 100 N) was obtained from M/s Indian Petrochemicals.

Effect of Nano-clay on Rheological and Extrusion Foaming Process of a Block-Copolymerized Polypropylene

Directory of Open Access Journals (Sweden)

Wang Mingyi

2016-01-01

Full Text Available The effects of nano-clay and the corresponding coupling agent maleic anhydride grafted polypropylene (PP-g-MAH on thermal properties, rheological properties and extrusion foaming process of a block-copolymerized polypropylene (B-PP were studied. Supercritical CO2 (SC CO2 was used as the foaming agent with a concentration of 5wt%. Each step of foamed B-PP/ PP-g-MAH/ nano-clay composites processing is addressed, including mixing of the composites, manufacture of the composites, foaming process of the composites and characterization of the cell structure. The results showed that incorporation of nano-clay and PP-g-MAH caused reduced melt strength and complex viscosity of B-PP. However, the heterogeneous nucleation induced by nano-clay and PP-g-MAH improved the maximum foaming expansion ratio and cell-population density of B-PP foam.

Structural characterization and mechanical properties of polypropylene reinforced natural fibers

Science.gov (United States)

Karim, M. A. A.; Zaman, I.; Rozlan, S. A. M.; Berhanuddin, N. I. C.; Manshoor, B.; Mustapha, M. S.; Khalid, A.; Chan, S. W.

2017-10-01

Recently the development of natural fiber composite instead of synthetics fiber has lead to eco-friendly product manufacturing to meet various applications in the field of automotive, construction and manufacturing. The use of natural fibers offer an alternative to the reinforcing fibers because of their good mechanical properties, low density, renewability, and biodegradability. In this present research, the effects of maleic anhydride polypropylene (MAPP) on the mechanical properties and material characterization behaviour of kenaf fiber and coir fiber reinforced polypropylene were investigated. Different fractions of composites with 10wt%, 20wt% and 30wt% fiber content were prepared by using brabender mixer at 190°C. The 3wt% MAPP was added during the mixing. The composites were subsequently molded with injection molding to prepare the test specimens. The mechanical properties of the samples were investigated according to ISO 527 to determine the tensile strength and modulus. These results were also confirmed by the SEM machine observations of fracture surface of composites and FTIR analysis of the chemical structure. As the results, the presence of MAPP helps increasing the mechanical properties of both fibers and 30wt% kenaf fiber with 3wt% MAPP gives the best result compare to others.

Mechanical properties of thermoplastic composites reinforced with Entada Mannii fibre

Directory of Open Access Journals (Sweden)

Oluwayomi BALOGUN

2017-06-01

Full Text Available The mechanical properties and fracture mechanisms of thermoplastic composites reinforced with Entada mannii fibres was investigated. Polypropylene reinforced with 1, 3, 5, and 7 wt% KOH treated and untreated Entada mannii fibres were processed using a compression moulding machine. The tensile properties, impact strength, and flexural properties of the composites were evaluated while the tensile fracture surface morphology was examined using scanning electron microscopy. The results show that reinforcing polypropylene with Entada mannii fibres resulted in improvement of the tensile strength and elastic modulus. This improvement is remarkable for 5 wt% KOH treated Entada mannii fibre reinforced composites by 28 % increase as compared with the unreinforced polypropylene. The composites reinforced with Entada mannii fibres also had impact strength values of 70 % higher than the unreinforced polypropylene. However, the polypropylene reinforced with 5 and 7wt% KOH treated fibres exhibited significantly higher flexural strength and Young’s modulus by 53% and 52% increase as compared with the unreinforced polypropylene. The fracture surface of the polypropylene composites reinforced with untreated Entada mannii fibres were characterized by fibre debonding, fibre pull-out and matrix yielding while less voids and fibre pull-outs are observed in the composites reinforced with KOH treated Entada mannii fibres. v

Synthesis and characterization of polypropylene/graphite nano composite preparation for in situ polymerization

International Nuclear Information System (INIS)

Montagna, L.S.; Fim, F. de C.; Galland, G.B.

2010-01-01

This paper presents the synthesis of polypropylene/graphite nanocomposites through in situ polymerization, using the metallocene catalyst C 20 H 16 Cl 2 Zr (dichloro(rac-ethylenebis(indenyl))zircon(IV)). The graphite nanosheets in nano dimensions were added to the polymer matrix in percentages of 0.6;1.0;4.2;4.8 and 6.0% (w/w). The TEM images indicated that the thickness of graphite nanosheets ranged from 4 to 60 nm and by means of XRD analysis it was observed that the physical and chemical treatment did not destroyed the graphite layers. The presence of nanosheets did not decrease the catalytic activity of the nanocomposites. TEM images and XRD analysis of nanocomposites showed a good dispersion of the graphite nanosheets in the polypropylene matrix. (author)

Fire retardancy assessment of polypropylene composite filed with nano clay prepared from Iraqi bentonite

Science.gov (United States)

Kareem Salih, Watheq

2018-05-01

Fire retardants have an extraordinary importance because of their role in saving the people, property and reducing the damages and minimizing the dangers resulting from fires and burning of polymeric composites which are used in different civil and industrial fields. The work in this paper can be divided into two main stages. In first one nano-clay was manufactured from Iraqi bentonite and it was characterized using AFM, XRD, XRF, SEM, and BET. The AFM test showed the particle size of prepared nano clay was about 99.25 nm. In the second stage, polypropylene/nano clay composites at three low loading percents (0%,2%,4%,6%) were formulated via twin screw extruder. The fire retardancy tests included burning rate according to ASTM:D-635 and maximum flame height of flame according to ASTM:D-3014. Besides, the mechanical tests and thermal behavior of prepared samples were investigated. The results showed that (4%) of nano-clay had the maximum fire retardancy and while at (2%) loading, the maximum value of tensile strength and Yong modulus were obtained. The maximum heat of fusion was recorded for 6% nano clay sample. The final results assessment confirmed on the possibility of using low loadings of prepared nano clay to improve the fire retardancy, mechanical and thermal properties successfully.

Effect of Pin Geometry on the Mechanical Strength of Friction-Stir-Welded Polypropylene Composite Plates

Science.gov (United States)

Kordestani, F.; Ashenai Ghasemi, F.; Arab, N. B. M.

2017-09-01

Friction stir welding (FSW) is a solid-state welding process, which has successfully been applied in aerospace and automotive industries for joining materials. The friction stir tool is the key element in the FSW process. In this study, the effect of four different tool pin geometries on the mechanical properties of two types of polypropylene composite plates, with 30% glass and carbon fiber, respectively, were investigated. For this purpose, four pins of different geometry, namely, a threaded-tapered pin, square pin, four-flute threaded pin, and threaded-tapered pin with a chamfer were made and used to carry out the butt welding of 5-mm-thick plates. The standard tensile and Izod impact tests were performed to evaluate the tensile strength and impact toughness of welded specimens. The results indicated that the threaded-tapered pin with a chamfer produced welds with a better surface appearance and higher tensile and impact strengths. The tests also showed that, with the threaded-tapered pin with a chamfer, the impact strength of the glass- and carbon-fiber composite welds were about 40 and 50%, respectively, of that of the base materials.

Study of the effect of ionizing radiation on composites of wood flour in polypropylene matrix using barium titanate as coupling agent; Estudo do efeito da radiacao ionizante em compositos de polipropileno/po de madeira usando titanato de bario como agente de acoplagem

Energy Technology Data Exchange (ETDEWEB)

Ulloa, Maritza Eliza Perez

2007-07-01

The purpose of this work was to study the effects of ionizing radiation on the properties of wood flour composites in polypropylene matrix, using barium titanate as a coupling agent and the reactive monomer tripropylene glycol diacrylate (TPDGA). An electron accelerator was used in the study as the radiation source. The physical properties of virgin compounds and of the polypropylene/wood flour composite, with and without barium titanate and TPDGA addition, were investigated. The composites were developed from the load treatment, which first consisted of incorporating additives to the wood flour reinforcement and after that, the fusion process of polypropylene and composite mixing in a 'calander'. Subsequently, the samples to be irradiated and submitted to thermal and mechanical assays were molded by injection. The mechanical properties (hardness, impact resistance and molten fluidity index (MFI)), as well as the thermal properties (HDT and Vicat) of the composites were determined. The investigated compositions consisted of polypropylene/wood flour, polypropylene/wood flour with barium titanate and polypropylene/wood flour with barium titanate and TPDGA, using different wood flour concentrations of 10 por cent, 15 por cent and 20 por cent in the polypropylene matrix. The samples were separated in groups and irradiated to doses of 10 kGy and 20 kGy in the samples of the essays of traction. Besides these doses, it was also used doses of 15 kGy and 25 kGy to be observed the behavior of the sample of the sample due to the increase of the radiation. These doses were chosen to show that with low doses the composite material presents reticulation, what represents a viable commercial option. There was a reduction of the flow rate for the composites containing wood flour, being this reduction more effective in the presence of TiBa. The superficial treatment using TPDGA monomer influence in the composite samples because it acted as a plastic additive becoming the

Rheological properties of molten flax- and Tencel"®-polypropylene composites: Influence of fiber morphology and concentration

International Nuclear Information System (INIS)

Abdennadher, Ahmed; Vincent, Michel; Budtova, Tatiana

2016-01-01

The rheological properties of short fiber reinforced polypropylene were investigated. Flax and Tencel"® are two cellulose based fibers used in this study. Flax fibers are extracted from the bast of plants. They are composed of thin elementary fibers and rigid thick bundles made of elementary fibers “glued” together. Tencel"® is a man-made cellulosic fiber spun from cellulose solution, with a uniform diameter, thin, and flexible. First, fiber dimensions before and after compounding were analyzed. Both types of fibers were broken during compounding. Flax shows larger length and diameter than Tencel"®, but aspect ratio of flax is smaller. The reason is that after compounding flax remained in bundles. Dynamic viscosity, elastic and viscous moduli were studied as a function of fiber type, concentration (from 0 to 30 wt. %), and composite temperature (from 180 to 200 °C). All Tencel"®-based composites showed higher apparent yield stress, viscosity, and moduli compared to flax-based composites at the same fiber concentrations. The results are analyzed in terms of the influence of fiber type, aspect ratio, and flexibility. The importance of considering fiber morphology is demonstrated as far as it controls fiber flexibility and fiber-fiber interactions

Spinning, drawing and physical properties of polypropylene nanocomposite fibers with fumed nanosilica

Czech Academy of Sciences Publication Activity Database

Dabrowska, I.; Fambri, L.; Pegoretti, A.; Šlouf, Miroslav; Vacková, Taťana; Kolarik, J.

2015-01-01

Roč. 9, č. 3 (2015), s. 277-290 ISSN 1788-618X R&D Projects: GA ČR(CZ) GA14-17921S Institutional support: RVO:61389013 Keywords : polypropylene * fibers * nanocomposites Subject RIV: JI - Composite Materials Impact factor: 2.965, year: 2015

OPTIMIZATION OF PROCESS PARAMETERS FOR ENHANCED MECHANICAL PROPERTIES OF POLYPROPYLENE TERNARY NANOCOMPOSITES

Directory of Open Access Journals (Sweden)

Oladipupo Olaosebikan Ogunleye

2015-02-01

Full Text Available Preparation of Polypropylene ternary nanocomposites (PPTN was accomplished by blending multiwall carbon nanotube (MWCNT in polypropylene/clay binary system using a melt intercalation method. The effects of MWCNT loadings (A, melting temperature (B and mixing speed (C were investigated and optimized using central composite design. The analysis of the fitted cubic model clearly indicated that A and B were the main factors influencing the tensile properties at a fixed value of C. However, the analysis of variance showed that the interactions between the process parameters, such as; AB, AC, AB2, A2B and ABC, were highly significant on both tensile strength and Young’s modulus enhancement, while no interaction is significant in all models considered for elongation. The established optimal conditions gave 0.17%, 165 °C, and 120 rpm for A, B and C, respectively. These conditions yielded a percentage increase of 57 and 63% for tensile strength and Young’s modulus respectively compared to the virgin Polypropylene used.

The Effect of Size and Crumb Rubber Composition as a Filler with Compatibilizer Pp-G-Ma in Polypropylene Blends and Sir-20 Compound on Mechanical and Thermal Properties

Directory of Open Access Journals (Sweden)

Erna Frida

2013-04-01

Full Text Available Having been researched the development of thermoplastic elastomer material of polypropylene and natural rubber SIR-20 compound with Crumb Rubber as the filler. Reinforced polypropylene with size 60 mesh with 1 mm, and the composition of the Crumb rubber (30, 40, and 50 wt%. Observed mechanical properties are tensile strength, fracture elongation, Young's modulus, tear strength and impact strength. Thermal properties are analyzed by DSC and DTA/TGA. It is acquired that for the size of 60 mesh crumb rubber tensile strength, fracture elongation, Young’s modulus, tear strength and impact strength are bigger than 1mm size. The addition of 60 mesh crumb rubber increases but it decreases by adding of 50 weight%. While for crumb rubber 1 mm tensile strength, fracture elongation, tear strength and impact strength decreas. Based on analysis of DSC that the addition of crumb rubber does not make a difference boiling point significantly between samples containing crumb rubber and polypropylene Analysis TGA/DTA to an increase in enthalpy and decomposition temperature with the addition of crumb rubber used and thermal stability.

Environmental Particle Emissions due to Automated Drilling of Polypropylene Composites and Nanocomposites Reinforced with Talc, Montmorillonite and Wollastonite

Science.gov (United States)

Starost, K.; Frijns, E.; Laer, J. V.; Faisal, N.; Egizabal, A.; Elizextea, C.; Nelissen, I.; Blazquez, M.; Njuguna, J.

2017-05-01

In this study, the effect on nanoparticle emissions due to drilling on Polypropylene (PP) reinforced with 20% talc, 5% montmorillonite (MMT) and 5% Wollastonite (WO) is investigated. The study is the first to explore the nanoparticle release from WO and talc reinforced composites and compares the results to previously researched MMT. With 5% WO, equivalent tensile properties with a 10 % weight reduction were obtained relative to the reference 20% talc sample. The materials were fabricated through injection moulding. The nanorelease studies were undertaken using the controlled drilling methodology for nanoparticle exposure assessment developed within the European Commission funded SIRENA Life 11 ENV/ES/506 project. Measurements were taken using CPC and DMS50 equipment for real-time characterization and measurements. The particle number concentration (of particles <1000nm) and particle size distribution (4.87nm - 562.34nm) of the particles emitted during drilling were evaluated to investigate the effect of the silicate fillers on the particles released. The nano-filled samples exhibited a 33% decrease (MMT sample) or a 30% increase (WO sample) on the average particle number concentration released in comparison to the neat polypropylene sample. The size distribution data displayed a substantial percentage of the particles released from the PP, PP/WO and PP/MMT samples to be between 5-20nm, whereas the PP/talc sample emitted larger particle diameters.

Nuclear magnetic resonance study of the effect of the addition of clay on polypropylene

International Nuclear Information System (INIS)

Nogueira, Regina F.; San Gil, Rosane A.S.; Tavares, Maria Ines B.

2001-01-01

Polypropylene (PP) samples and polypropylene (PP)/clay (M) composite prepared by melting mixing have been characterized by solution and solid state nuclear magnetic resonance spectroscopy (NMR). The monomer sequences distribution and the influence of time and temperature of mechanical mix on the modifications in the PP structure were investigated by 13 C solution NMR. The solid state NMR investigation showed that the 13 C routine spectra such as MAS and CPMAS allowed obtaining information on the molecular domains of chains, and also permits to evaluate the domains mobility. 29 Si and 27 Al solid state NMR were used to characterize the clay and the PP/M composite samples. The results showed that the heating and friction in the range of temperature and time used in the sample preparation did not affect the distribution of configurational sequence in the PP chains. The effect of clay in the PP/M composite structure could be detected, using both 13 C solution and in 29 Si solid state NMR spectra. (author)

Effect of the interfacial adhesion on the tensile and impact properties of carbon fiber reinforced polypropylene matrices

Directory of Open Access Journals (Sweden)

Clara Leal Nogueira

2005-03-01

Full Text Available Thermoplastic composites have been applied in a wide variety of industrial products, showing recently a great potential to be used in aeronautical field. The objectives of this work were to evaluate the fiber/matrix interface of carbon fiber reinforced polypropylene-based matrices after tensile and impact tests and also to compare the mechanical test results of the manufactured laminates. The laminates were prepared by stacking carbon fiber fabric style Plain Weave (CF and films of four different polypropylene matrices, described as (a polypropylene-PP, (b polypropylene-polyethylene copolymer-PP-PE, (c PP-PE with an interfacial compatibilizer-AM1 and (d PP-PE containing an elastomeric modifier-AM2. The composites were processed using hot compression molding. The mechanical testing results showed that the CF-AM1 laminate family presented the lowest impact strength and the highest tensile strength values when compared to the other laminates. SEM analysis observations of both tensile and impact fractured specimens of the CF-PP/PE-AM1 specimens revealed a stronger fiber/matrix interface. The CF-PP/PE-AM2 laminate showed a lower tensile strength and higher impact strength values when compared to the CF-PP/PE-AM1 one. PP-PE and PP laminates presented the lowest impact strength values.

Styrene-butadiene-styrene copolymer compatibilized carbon black/polypropylene/polystyrene composites with tunable morphology, electrical conduction and rheological stabilities.

Science.gov (United States)

Song, Yihu; Xu, Chunfeng; Zheng, Qiang

2014-04-21

We report a facile kinetic strategy in combination with styrene-butadiene-styrene (SBS) copolymer compatibilizers for preparing carbon black (CB) filled immiscible polypropylene (PP)/polystyrene (PS) (1/1) blends with finely tuned morphologies and show the important role of location and migration of CB nanoparticles in determining the electrical conductivity and rheological behaviour of the composites. A novel method of mixing a SBS/CB (5/3) masterbatch with the polymers allowed producing composites with CB aggregates dispersed partially in the unfavorable PP phase and partially in the PP side of the interface to exhibit diverse phase connectivity and electrical conductivity depending on the compounding sequences. A cocontinuous morphology with CB enrichment along the interface was formed in the composite prepared by mixing the SBS/CB masterbatch with the premixed PP/PS blend, giving rise to a highest electrical conductivity and dynamic moduli at low frequencies. On the other hand, mixing the masterbatch with one and then with another polymer yielded droplet (PS)-in-matrix (filled PP) composites. The composites underwent phase coalescence and CB redistribution accompanied by marked dynamic electrical conduction and modulus percolations as a function of time during thermal annealing at 180 °C. The composites with the initial droplet-in-matrix morphology progressed anomalously into the cocontinuous morphology, reflecting a common mechanism being fairly nonspecific for understanding the processing of filled multicomponent composites with tailored performances of general concern.

Electrical conductivity and physical changes of functionalized carbon nanotube/graphite/stainless steel (SS316L/polypropylene composites immersed in an acidic solution

Directory of Open Access Journals (Sweden)

Hendra Suherman

2018-02-01

Full Text Available Chemical functionalization of carbon nanotubes (CNTs and graphite (G was performed to improve their adhesion to a metal powder (SS316L and a polypropylene (PP matrix. A conductive pathway was thus formed to utilize the high electrical conductivity of the SS316L for conductive polymer composites (CPCs applications. The rheological properties of the feedstock mixture were measured, and samples were formed by injection molding. Fourier transform infrared spectroscopy indicated the existence of functional groups generated by chemical wet oxidation. Only feedstock mixtures containing more than 28 vol% of the PP composite showed a shear rate (102 s -1 to 105 s -1 , shear viscosity (10 Pa·s to 103 Pa·s, and flow behavior index (n<1 suitable for injection molding. The functionalized composites exhibited improved electrical and mechanical properties over the as-produced composites. The functionalized composites containing 28 vol% PP obtained an electrical conductivity of 6 S/m, compared to 0.5 S/m for the as-produced composites.

Radiation crosslinking of polypropylene

International Nuclear Information System (INIS)

Nojiri, A.; Sawasaki, T.

1984-01-01

The radiation crosslinking of polypropylene with several kinds of polyfunctional monomers has been examined, and it has been clarified that the enhanced crosslinking may be classified into two types. In particular, the irradiation crosslinking process of polypropylene containing a polyfunctional monomer having an acryloyloxy group giving a specific gel - dose curve has been studied by infrared absorption spectrum and oxygen absorptivity measurement in comparison with the non-enhanced system. (author)

The radiation degradation of polypropylene

International Nuclear Information System (INIS)

De Hollain, G.

1977-04-01

Polypropylene is used extensively in the manufacture of disposable medical devices because of its superior properties. Unfortunately this polymer does not lend itself well to radiation sterilization, undergoing serious degradation which affects the mechanical properties of the polymer. In this paper the effects of radiation on the mechanical and physical properties of polypropylene are discussed. A programme of research to minimize the radiation degradation of this polymer through the addition of crosslinking agents to counteract the radiation degradation is proposed. It is furthermore proposed that a process of annealing of the irradiated polymer be investigated in order to minimize the post-irradiation degradation of the polypropylene [af

Influência da estrutura do catalisador a base de Zirconoceno na estereorregularidade e propriedades do polipropileno formado Influence of Zirconocene structure on polypropylene stereorregularity and properties

Directory of Open Access Journals (Sweden)

Mário R. Meneghetti

1997-03-01

Full Text Available RESUMO: Catalisadores de metalocenos com diferentes simetrias, cocatalisados por metilaluminoxanas (MAO, foram avaliados em diferentes temperaturas de polimerização do propileno. Os metalocenos com ponte interanelar, ou seja, o dicloreto de rac-etileno bis(h5-1-indenil zircônio, com simetria C2, e o dicloreto de isopropilideno(h5-ciclopentadienil(h5-9-fluorenil zircônio, com simetria Cs, produziram, respectivamente, polipropileno isotático e sindiotático. O grau de taticidade desses polímeros diminui com o aumento da temperatura de polimerização. Os metalocenos sem ponte, dicloreto de bis(h5-ciclopentadienilzircônio e bis(h5-indenilzircônio, em qualquer uma das temperaturas investigadas, produziram, somente, polipropileno atático. A estereorregularidade dos polímeros foram determinadas por Ressonância Magnética Nuclear de 13C.ABSTRACT: Metallocenes with different symmetries in combination with methylaluminoxane (MAO, have been investigated at different propylene polymerization temperatures. The metallocenes rac-ethylene bis(h5-1-indenyl zirconium dichloride, with C2 symmetry and isopropylidene (h5cyclopentadienyl(h5-9-fluorenyl zirconium dichloride, with Cs symmetry, produce isotactic and syndiotactic polypropylene respectively. The degree of tacticity of these polymers decreases with the increase of polymerization temperature. Only atactic polypropylene was formed with the unbridged zirconocenes bis(h5-cyclopentadienyl zirconium dichloride and bis(h5-indenyl zirconium dichloride at any temperature investigated. The polymer microtacticity was analysed by 13C NMR.

Synergistic reinforcement of highly oriented poly(propylene) tapes by sepiolite nanoclay

NARCIS (Netherlands)

Bilotti, E.; Deng, H.; Zhang, R.; Lu, D.; Bras, W.; Fischer, H.R.; Peijs, T.

2010-01-01

This paper reports the properties of highly oriented nanocomposite tapes based on isotactic PP and needle-like sepiolite nanoclay, obtained by a solid state drawing process. The intrinsic 1D character of sepiolite allows its exploitation in 1D objects, such as oriented polymer fibres and tapes,

Study on the formation of the nanogel and microgels polypropylene modified by gamma radiation and incorporation of silver nanoparticles to biocides activity

International Nuclear Information System (INIS)

Oliani, Washington Luiz

2013-01-01

The study consists of the synthesis of HMSPP (polypropylene with high melt strength), also called polypropylene modified by gamma irradiation from iPP (isotactic polypropylene) in presence of acetylene at 110 kPa pressure and irradiated with γ of 60 Co source at doses of 5, 12.5 and 20 kGy. The gel fraction of the samples was determined by extracting in xylene. The soluble portion of the samples was decanted to deposition on glass substrate until complete volatilization of xylene at room temperature of 25 °C. On the soluble portion of 12.5 kGy irradiated sample were added silver nanoparticles (AgNPs) in proportions of 0.25, 0.5, 1.0, 2.0 and 4.0 wt%. These gel samples were characterized by: scanning electron microscopy/energy dispersive spectroscopy (SEM / EDS), infrared spectroscopy (FTIR), scanning electron microscopy with field emission (FE-SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), reduction of colony forming unit (CFU) (%) and cytotoxicity assay. In this study of the morphology, it has been observed the formation of microgels in polypropylene increasing with the dose PP 5 kGy < PP 12.5 kGy < 20 kGy. Nanoscale structures of gels polypropylene (nanogels and nanofibers) were found in samples of PP 12.5 kGy and 20 kGy. The nanogels are formation of crosslinking, branching and entanglement that are nucleated in regions of high energy concentration (spurs) of one irradiated sample. Efficiency in tests of bactericide activity of the gels with AgNPs was observed versus E. coli and S. aureus from 1% AgNPs and non cytotoxicity were characterized in those samples for mammalian cells. In a second stage of this work films of the blend of PP and modified PP (50/50) were produced in a twin screw extruder. AgNPs were added to the extrusion processing in proportions of 0.1; 0.25; 0.5; 1.0; 1.0 PVP; 2.0 and 4.0 wt%. The films obtained were characterized by differential scanning calorimetry (DSC), thermogravimetry

Influence of polymer swelling and dissolution into food simulants on the release of graphene nanoplates and carbon nanotubes from poly(lactic) acid and polypropylene composite films

OpenAIRE

Velichkova, Hristiana; Petrova, Ivanka; Kotsilkov, Stanislav; Ivanov, Evgeni; Vitanov, Nikolay K.; Kotsilkova, Rumiana

2017-01-01

The study compared the effects of swelling and dissolution of a matrix polymer by food simulants on the release of graphene nanoplates (GNPs) and multiwall carbon nanotubes (MWCNTs) from poly(lactic) acid (PLA) and polypropylene (PP) composite films. The total migration was determined gravimetrically in the ethanol and acetic acid food simulants at different time and temperature conditions, while migrants were detected by laser diffraction analysis and transmission electron microscopy. Swelli...

Permeation Tests on Polypropylene Fiber Materials

Science.gov (United States)

2018-03-16

Permeation Tests on Polypropylene Fiber Materials Brandy J. White Martin H. Moore Brian J. Melde Laboratory for the Study of Molecular Interfacial...ABSTRACT Permeation Tests on Polypropylene Fiber Materials Brandy J. White, Martin H. Moore, Brian J. Melde Center for Bio/Molecular Science

Green aqueous surface modification of polypropylene for novel polymer nanocomposites.

Science.gov (United States)

Thakur, Vijay Kumar; Vennerberg, Danny; Kessler, Michael R

2014-06-25

Polypropylene is one of the most widely used commercial commodity polymers; among many other applications, it is used for electronic and structural applications. Despite its commercial importance, the hydrophobic nature of polypropylene limits its successful application in some fields, in particular for the preparation of polymer nanocomposites. Here, a facile, plasma-assisted, biomimetic, environmentally friendly method was developed to enhance the interfacial interactions in polymer nanocomposites by modifying the surface of polypropylene. Plasma treated polypropylene was surface-modified with polydopamine (PDA) in an aqueous medium without employing other chemicals. The surface modification strategy used here was based on the easy self-polymerization and strong adhesion characteristics of dopamine (DA) under ambient laboratory conditions. The changes in surface characteristics of polypropylene were investigated using FTIR, TGA, and Raman spectroscopy. Subsequently, the surface modified polypropylene was used as the matrix to prepare SiO2-reinforced polymer nanocomposites. These nanocomposites demonstrated superior properties compared to nanocomposites prepared using pristine polypropylene. This simple, environmentally friendly, green method of modifying polypropylene indicated that polydopamine-functionalized polypropylene is a promising material for various high-performance applications.

Antifriction basalt-plastics based on polypropylene

Science.gov (United States)

Bashtannik, P. I.; Ovcharenko, V. G.

1997-05-01

A study is made of the dependence of the mechanical and friction-engineering properties of polypropylene reinforced with basalt fibers on the viscosity of the polymer matrix. It is established that the main factors that determine the mechanical properties of the plastics are the quality of impregnation of the fibers by the binder and the residual length of the reinforcing filler in the composite after extrusion and injection molding. The material that was developed has a low friction coefficient and low rate of wear within a relatively brood range of friction conditions. The basalt-plastics can be used in the rubbing parts of machines and mechanisms subjected to dry friction.

Study of the rice husk ash utilization as filler polypropylene matrix and ionization radiation effect on this composite; Estudos da utilizacao da cinza de casca de arroz como carga em matriz de polipropileno e do efeito da radiacao ionizante sobre este composito

Energy Technology Data Exchange (ETDEWEB)

Alfaro, Eduardo de Faria

2010-07-01

In the first step of this work, it was evaluated the possibility of using rice husk ash as a filler in polypropylene (PP) making a comparison with talc which is the most used mineral filler in polymers. This comparison was made by using polypropylene with 20% rice husk ash as well as polypropylene with 20% talc measuring their properties. Despite the properties of the PP with 20% rice husk ash decreased compared with the composite of polypropylene with 20% talc it can be said that the rice husk ash can be used as filler for or other utilization less noble of PP . This way it is being given a destination for this residue that it is disposable in the environment contributing to its preservation, moreover reducing the product cost. This work had also as an aim to study the ionizing radiation effect in the properties of these composites. It was used the coupling agent, maleic anhydride , to verify a best sample homogenization. According to the results it can be said that PP is a semicrystalline polymer, and so it has its morphology modified when exposed to the irradiation process. This fact is due to the scission mechanisms of the polymeric chains which it is in compliance to the literature. (author)

Controlled drug release from a novel injectable biodegradable microsphere/scaffold composite based on poly(propylene fumarate).

Science.gov (United States)

Kempen, Diederik H R; Lu, Lichun; Kim, Choll; Zhu, Xun; Dhert, Wouter J A; Currier, Bradford L; Yaszemski, Michael J

2006-04-01

The ideal biomaterial for the repair of bone defects is expected to have good mechanical properties, be fabricated easily into a desired shape, support cell attachment, allow controlled release of bioactive factors to induce bone formation, and biodegrade into nontoxic products to permit natural bone formation and remodeling. The synthetic polymer poly(propylene fumarate) (PPF) holds great promise as such a biomaterial. In previous work we developed poly(DL-lactic-co-glycolic acid) (PLGA) and PPF microspheres for the controlled delivery of bioactive molecules. This study presents an approach to incorporate these microspheres into an injectable, porous PPF scaffold. Model drug Texas red dextran (TRD) was encapsulated into biodegradable PLGA and PPF microspheres at 2 microg/mg microsphere. Five porous composite formulations were fabricated via a gas foaming technique by combining the injectable PPF paste with the PLGA or PPF microspheres at 100 or 250 mg microsphere per composite formulation, or a control aqueous TRD solution (200 microg per composite). All scaffolds had an interconnected pore network with an average porosity of 64.8 +/- 3.6%. The presence of microspheres in the composite scaffolds was confirmed by scanning electron microscopy and confocal microscopy. The composite scaffolds exhibited a sustained release of the model drug for at least 28 days and had minimal burst release during the initial phase of release, as compared to drug release from microspheres alone. The compressive moduli of the scaffolds were between 2.4 and 26.2 MPa after fabrication, and between 14.9 and 62.8 MPa after 28 days in PBS. The scaffolds containing PPF microspheres exhibited a significantly higher initial compressive modulus than those containing PLGA microspheres. Increasing the amount of microspheres in the composites was found to significantly decrease the initial compressive modulus. The novel injectable PPF-based microsphere/scaffold composites developed in this study

Thermal Properties, Structure and Morphology of Graphene Reinforced Polyethylene Terephthalate/ Polypropylene Nano composites

International Nuclear Information System (INIS)

Inuwa, I.M.; Hassan, A.; Shamsudin, S.A.

2014-01-01

In this work the thermal properties, structure and morphology of a blend of polyethylene terephthalate (PET) and polypropylene (PP) reinforced with graphene nano platelets (GNP) were investigated. A blend of PET/ PP (70/ 30 weight percent) compatibilized with styrene-ethylene-butylene-styrene grafted maleic anhydride triblock copolymer (10 phr) were fabricated by melt extrusion process in a twin screw extruder. The effective thermal conductivity of the nano composites increased as a function of the GNP concentration. More than 80 % increase in effective thermal conductivity was observed for the 7 phr reinforced sample compared to the neat blend. This observation was attributed to the development interconnected GNP sheets which formed heat conductive bridges that are suitable for maximum heat transfer. However, in the case of thermal stability which is a function of dispersibility of GNP in polymer matrix, the maximum increase was observed at 3 phr GNP loading which could be attributed to the uniform dispersion of GNPs in the matrix. It is explained that the GNP nano fillers migrated to the surface of matrix forming an effective oxygen barrier due to char formation. Morphological studies revealed uniform dispersion graphene in the polymer matrix at 3 phr GNP loading along with isolated instances of exfoliation of the graphene layers. (author)

Nanocomposites of polypropylene and organophilic clay: X ray diffraction, absorption infrared spectroscopy with fourier transform and water vapor permeation

International Nuclear Information System (INIS)

Morelli, Fernanda C.; Ruvolo Filho, Adhemar

2010-01-01

In this work nano composites were prepared from polypropylene, graft polypropylene with maleic anhydride as compatibilizer and organophilic montmorillonite Cloisite 20A with concentrations of 1.5, 2.5, 5.0 and 7.5% clay. The mixture was made in the melt state using a twin screw extruder. The materials were characterized by X ray diffraction, infrared spectroscopy with Fourier transform and analysis of water vapor permeation. The results of X ray diffraction and absorption infrared spectroscopy indicates the formation of nano composites with structures probably exfoliate and or intercalated for concentrations of 1.5 and 2.5% clay, and provided a marked decrease in the water permeability, corroborating with other analyses. (author)

Influence of alkaline treatment and fiber loading on the physical and mechanical properties of kenaf/polypropylene composites for variety of applications☆

Institute of Scientific and Technical Information of China (English)

Majid Niaz Akhtar; Abu Bakar Sulong; M.K. Fadzly Radzi; N.F. Ismail; M.R. Raza; Norhamidi Muhamad; Muhammad Azhar Khan

2017-01-01

Due to current trend and increasing interest towards natural based fiber products, Kenaf (Hibiscus cannabinus) fibers have been used for the developments of many products. Therefore, Kenaf fiber-reinforced composites have been widely used in engineering and industrial applications. The present work deals with the fabricating and characterization of untreated and treated kenaf/polypropylene (PP)-reinforced composites. Composites of PP reinforced with treated and untreated kenaf fibers were fabricated using the injection molding technique. Different fiber loadings of 10, 20, 30, 40, 50 wt%treated and untreated kenaf composites were also prepared. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis (TGA) were performed on the treated, untreated kenaf fibers and kenaf/PP composites. Moreover, the alkaline-treated kenaf composites exhibit better physical, morphological, and mechanical properties because of the compatibility of kenaf with PP. However, variations in tensile and flexural properties depend on treatment and kenaf fiber contents. The percentage increase in the mechanical properties of the treated kenaf/PP composites relative to that of PP was also measured. In addition, 40 wt%kenaf fiber loading resulted in higher mechanical properties. By contrast, kenaf/PP composite with 50%fiber loading was not successfully prepared because of improper mixing and the burning of kenaf fibers in the PP matrix. To conclude, 40%kenaf/PP composites with superior physical and mechanical properties may be used in variety of applications such as automotive, sports, construction, animal bedding, and mass production industries.

Effect of Multiwalled Carbon Nanotubes on the Mechanical Properties of Carbon Fiber-Reinforced Polyamide-6/Polypropylene Composites for Lightweight Automotive Parts

Directory of Open Access Journals (Sweden)

Huu-Duc Nguyen-Tran

2018-03-01

Full Text Available The development of lightweight automotive parts is an important issue for improving the efficiency of vehicles. Polymer composites have been widely applied to reduce weight and improve mechanical properties by mixing polymers with carbon fibers, glass fibers, and carbon nanotubes. Polypropylene (PP has been added to carbon fiber-reinforced nylon-6 (CF/PA6 composite to achieve further weight reduction and water resistance. However, the mechanical properties were reduced by the addition of PP. In this research, multiwalled carbon nanotubes (CNTs were added to compensate for the reduced mechanical properties experienced when adding PP. Tensile testing and bending tests were carried out to evaluate the mechanical properties. A small amount of CNTs improved the mechanical properties of carbon fiber-reinforced PA6/PP composites. For example, the density of CF/PA6 was reduced from 1.214 to 1.131 g/cm3 (6.8% by adding 30 wt % PP, and the tensile strength of 30 wt % PP composite was improved from 168 to 173 MPa (3.0% by adding 0.5 wt % CNTs with small increase of density (1.135 g/cm3. The developed composite will be widely used for lightweight automotive parts with improved mechanical properties.

Effects of Polypropylene Orientation on Mechanical and Heat Seal Properties of Polymer-Aluminum-Polymer Composite Films for Pouch Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Fangxinyu Zeng

2018-01-01

Full Text Available In this study, polyamide-aluminum foil-polypropylene (PA-Al-PP composite films with different orientation status of the PP layer were prepared, and their morphology, tensile, peeling and heat seal behavior were studied. The comparative study of tensile and fracture behaviors of single-layer film of PA, Al and PP, as well as the composite films of PA-Al, PP-Al and PA-Al-PP revealed that in PA-Al-PP composite film, the PA layer with the highest tensile strength can share the tensile stress from the Al layer during stretching, while the PP layer with the lowest tensile strength can prevent further development of the small cracks on boundary of the Al layer during stretching. Moreover, the study of heat seal behavior suggested that both the orientation status and the heat seal conditions were important factors in determining the heat seal strength (HSS and failure behavior of the sample. Four failure types were observed, and a clear correspondence between HSS and failure types was found. The results also elucidated that for the composite film, only in the cases where the tensile stress was efficiently released by each layer during HSS measurement could the composite film exhibit desired high HSS that was even higher than its tensile strength.

Metamaterial Behavior of Polymer Nanocomposites Based on Polypropylene/Multi-Walled Carbon Nanotubes Fabricated by Means of Ultrasound-Assisted Extrusion

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Juan C. Pérez-Medina

2016-11-01

Full Text Available Metamaterial behavior of polymer nanocomposites (NCs based on isotactic polypropylene (iPP and multi-walled carbon nanotubes (MWCNTs was investigated based on the observation of a negative dielectric constant (ε′. It is demonstrated that as the dielectric constant switches from negative to positive, the plasma frequency (ωp depends strongly on the ultrasound-assisted fabrication method, as well as on the melt flow index of the iPP. NCs were fabricated using ultrasound-assisted extrusion methods with 10 wt % loadings of MWCNTs in iPPs with different melt flow indices (MFI. AC electrical conductivity (σ(AC as a function of frequency was determined to complement the electrical classification of the NCs, which were previously designated as insulating (I, static-dissipative (SD, and conductive (C materials. It was found that the SD and C materials can also be classified as metamaterials (M. This type of behavior emerges from the negative dielectric constant observed at low frequencies although, at certain frequencies, the dielectric constant becomes positive. Our method of fabrication allows for the preparation of metamaterials with tunable ωp. iPP pure samples show only positive dielectric constants. Electrical conductivity increases in all cases with the addition of MWCNTs with the largest increases observed for samples with the highest MFI. A relationship between MFI and the fabrication method, with respect to electrical properties, is reported.

Metamaterial Behavior of Polymer Nanocomposites Based on Polypropylene/Multi-Walled Carbon Nanotubes Fabricated by Means of Ultrasound-Assisted Extrusion

Science.gov (United States)

Pérez-Medina, Juan C.; Waldo-Mendoza, Miguel A.; Cruz-Delgado, Víctor J.; Quiñones-Jurado, Zoe V.; González-Morones, Pablo; Ziolo, Ronald F.; Martínez-Colunga, Juan G.; Soriano-Corral, Florentino; Avila-Orta, Carlos A.

2016-01-01

Metamaterial behavior of polymer nanocomposites (NCs) based on isotactic polypropylene (iPP) and multi-walled carbon nanotubes (MWCNTs) was investigated based on the observation of a negative dielectric constant (ε′). It is demonstrated that as the dielectric constant switches from negative to positive, the plasma frequency (ωp) depends strongly on the ultrasound-assisted fabrication method, as well as on the melt flow index of the iPP. NCs were fabricated using ultrasound-assisted extrusion methods with 10 wt % loadings of MWCNTs in iPPs with different melt flow indices (MFI). AC electrical conductivity (σ(AC)) as a function of frequency was determined to complement the electrical classification of the NCs, which were previously designated as insulating (I), static-dissipative (SD), and conductive (C) materials. It was found that the SD and C materials can also be classified as metamaterials (M). This type of behavior emerges from the negative dielectric constant observed at low frequencies although, at certain frequencies, the dielectric constant becomes positive. Our method of fabrication allows for the preparation of metamaterials with tunable ωp. iPP pure samples show only positive dielectric constants. Electrical conductivity increases in all cases with the addition of MWCNTs with the largest increases observed for samples with the highest MFI. A relationship between MFI and the fabrication method, with respect to electrical properties, is reported. PMID:28774042

Selective laser vaporization of polypropylene sutures and mesh

Science.gov (United States)

Burks, David; Rosenbury, Sarah B.; Kennelly, Michael J.; Fried, Nathaniel M.

2012-02-01

Complications from polypropylene mesh after surgery for female stress urinary incontinence (SUI) may require tedious surgical revision and removal of mesh materials with risk of damage to healthy adjacent tissue. This study explores selective laser vaporization of polypropylene suture/mesh materials commonly used in SUI. A compact, 7 Watt, 647-nm, red diode laser was operated with a radiant exposure of 81 J/cm2, pulse duration of 100 ms, and 1.0-mm-diameter laser spot. The 647-nm wavelength was selected because its absorption by water, hemoglobin, and other major tissue chromophores is low, while polypropylene absorption is high. Laser vaporization of ~200-μm-diameter polypropylene suture/mesh strands, in contact with fresh urinary tissue samples, ex vivo, was performed. Non-contact temperature mapping of the suture/mesh samples with a thermal camera was also conducted. Photoselective vaporization of polypropylene suture and mesh using a single laser pulse was achieved with peak temperatures of 180 and 232 °C, respectively. In control (safety) studies, direct laser irradiation of tissue alone resulted in only a 1 °C temperature increase. Selective laser vaporization of polypropylene suture/mesh materials is feasible without significant thermal damage to tissue. This technique may be useful for SUI procedures requiring surgical revision.

Polypropylene fumarate/phloroglucinol triglycidyl methacrylate blend for use as partially biodegradable orthopaedic cement.

Science.gov (United States)

Jayabalan, M; Thomas, V; Rajesh, P N

2001-10-01

Polypropylene fumarate/phloroglucinol triglycidyl methacrylate oligomeric blend-based bone cement was studied. Higher the percentage of phloroglucinol triglycidyl methacrylate, lesser the setting time. An optimum setting time could be arrived with 50:50 blend composition of the two oligomers. Composite cement of 50:50 blend prepared with hydroxyapatite granules of particle size 125 microm binds bovine rib bones. The tensile strength of this adhesive bond was found to be 1.11 kPa. The thermal studies suggest the onset of cross-linking reaction in the cured blend if the blend is heated. The absence of softening endotherm in the cured blend shows the thermosetting-like amorphous nature of blend system, which may restrict the changes in creep properties. The in vitro biodegradation studies reveal possible association of calcium ions with negatively charged units of degrading polymer chain resulting in slow down of degradation. Relatively slow degradation was observed in Ringer's solution. The study reveals the potential use of polypropylene fumarate/phloroglucinol triglycidyl methacrylate as partially degradable polymeric cement for orthopaedic applications.

Mechanical properties, morphology and thermal degradation of a biocomposite of polypropylene and curaua fibers: coupling agent effect

Directory of Open Access Journals (Sweden)

Barbara Mano

2013-01-01

Full Text Available Biocomposites of polymers with vegetal fibers have a broad spectrum of applications due to their high specific properties in comparison to their counterparts made with fiberglass. Polypropylene, PP, composites with curaua fiber compatibilized with different concentrations of maleic anhydride grafted polypropylene, PP-g-MA, were characterized according to their mechanical properties, morphologies and thermal stabilities in oxidative and inert atmospheres. The composites were prepared by single screw extrusion and injection molded specimens were used for testing. The composite with 20 wt % of curaua fiber with and without compatibilizer presented improved mechanical properties compared to pure PP. The use of PP-g-MA as a compatibilizer significantly increased fiber/matrix adhesion, however, the mechanical properties were only slightly improved in comparison with composites without compatibilizer. We observed an improvement in thermal stability of the composites, compared to that expected from the weighted average of the individual components, both under inert and oxidative atmospheres. Furthermore, the thermal stability improved under inert atmosphere as a function of the concentration of compatibilizer. In this situation, indeed, there was a different shift of the weight loss processes owing to the presence of the compatibilizer.

Extraction of Micro- and Nano-Fibrils from Nylon 6/Polypropylene Grafted with Maleic Anhydride/Polypropylene Blended Films

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E. Bagheban Kochak

2013-01-01

Full Text Available Atechnical feasibility study has been conducted on production of nano- and micro-fibrils from nylon 6/polypropylene grafted with maleic anhydride/polypropylene blended films. Fibrils are prepared in four consecutive steps.In the first step the polymers melt blended in an extruder with and without compatibilizers to produce chips; in the second step films are extruded from polymer blends chips, in the third step films are cold drawn with different draw ratios at room temperature and in the forth step fibrils are extracted by Soxhlet extraction with formic acid as solvent for nylon 6.  The films and fibrils were examined by scanning electron microscope and FTIR spectroscopy. It is found that the polypropylene dispersed phase deforms and coalesces into elongated fibrils during drawing  operation. The  fibrils’ diameters in the blends containing compatibilizer are more uniform and are smaller than those from films without compatibilizers. The thinnest polypropylene fibril observed has a diameter around 300 nm with the aspect ratio above 150. The stress-elongation curves show three distinctive regions, elastic, yield and hardening-leading to breakage. The elastic region is short and follows by necking and yield, i.e., elongation without increase in load. The hardening region is accompanied by the increase in the slope. The deformations of the polypropylene particles are noticed during the last regions of the extension; the fibril deformations seem to be more severe during breakage.

Montmorillonite clay/polypropylene (HMSPP) nanocomposites: evaluation of thermal and mechanical properties

International Nuclear Information System (INIS)

Komatsu, L.G.H.; Oliani, W.L.; Lugao, A.B.; Parra, D.F.

2014-01-01

The evaluation of HMSPP (high melt strength polypropylene) properties in nanocomposites was done in composites of 0.1; 1; 3; 5; 10 wt% of Cloisite 20A clay. The PP-g-MA (polypropylene graft maleic anhydride) was the compatibilizer agent in the process of extrusion in twin-screw. Mechanical tests performed in the nanocomposites with higher clay content showed higher values of rupture in 5 and 10 wt% of Cloisite. The thermal properties were evaluate utilizing Calorimetry Differential Exploratory (DSC) and in the sample of 10 wt% of Cloisite were observed increase of the melting temperature and increase of crystallinity. The morphology was investigated by the Scanning Electron Microscopy (SEM) and Fourier Transformed Infrared (FTIR), in which the sample with lower clay amount, 1 wt% of Cloisite showed better dispersion of the clay. X-Ray Diffraction reported the clay intercalation in the sample with 5 wt% of clay. (author)

Development of polypropylene (PP)/bentonite organoclay nanocomposites; Desenvolvimento de nanocompositos de polipropileno/argila bentonitica organofilica

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Carlos Ivan Ribeiro de; Rocha, Marisa Cristina Guimaraes; Verly, Jessica, E-mail: carlosivanr@gmail.com [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico; Silva, Ana Lucia Nazareth da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Macromoleculas Professora Eloisa Mano; Bertolino, Luiz Carlos [Centro de Tecnologia Mineral (CETEM), Rio de Janeiro, RJ (Brazil)

2016-07-01

In recent years, a significant number of studies on polymer/clay nanocomposites has been developed due to the improved properties these materials have compared to those of the conventional composites. Among the various clays used for preparing nanocomposites, the bentonite clays have been the most widely used. In this context, the aim of this work is to develop polypropylene/organoclay nanocomposites based on deposits of bentonite clays recently discovered in Cubati, PB. The composites were prepared in a twin screw extruder. The structural characterization of the produced materials indicated a possible intercalation of the polymer chains between the layers of the organoclay. The results of impact strength showed that the addition of clay as well as the initial addition of clay and compatibilizer decreased the impact strength of polypropylene. The Young's modulus and tensile strength of the polymer were not significantly affected by the filler addition. However, an increase of the elongation at break was observed. (author)

Influence of alkaline treatment and fiber loading on the physical and mechanical properties of kenaf/polypropylene composites for variety of applications

Institute of Scientific and Technical Information of China (English)

Majid Niaz Akhtar; Abu Bakar Sulong; M.K.Fadzly Radzi; N.F.Ismail; M.R.Raza; Norhamidi Muhamad; Muhammad Azhar Khan

2016-01-01

Due to current trend and increasing interest towards natural based fiber products,Kenaf (Hibiscus cannabinus) fibers have been used for the developments of many products.Therefore,Kenaf fiber-reinforced composites have been widely used in engineering and industrial applications.The present work deals with the fabricating and characterization of untreated and treated kenaf/polypropylene (PP)-reinforced composites.Composites of PP reinforced with treated and untreated kenaf fibers were fabricated using the injection molding technique.Different fiber loadings of 10,20,30,40,50 wt％ treated and untreated kenaf composites were also prepared.Xray diffraction (XRD),scanning electron microscopy (SEM),Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis (TGA) were performed on the treated,untreated kenaf fibers and kenaf/PP composites.Moreover,the alkaline-treated kenaf composites exhibit better physical,morphological,and mechanical properties because of the compatibility of kenaf with PP.However,variations in tensile and flexural properties depend on treatment and kenaf fiber contents.The percentage increase in the mechanical properties of the treated kenaf/PP composites relative to that of PP was also measured.In addition,40 wt％kenaf fiber loading resulted in higher mechanical properties.By contrast,kenaf/PP composite with 50％ fiber loading was not successfully prepared because of improper mixing and the burning of kenaf fibers in the PP matrix.To conclude,40％ kenaf/PP composites with superior physical and mechanical properties may be used in variety of applications such as automotive,sports,construction,animal bedding,and mass production industries.

Influence of alkaline treatment and fiber loading on the physical and mechanical properties of kenaf/polypropylene composites for variety of applications

Directory of Open Access Journals (Sweden)

Majid Niaz Akhtar

2016-12-01

Full Text Available Due to current trend and increasing interest towards natural based fiber products, Kenaf (Hibiscus cannabinus fibers have been used for the developments of many products. Therefore, Kenaf fiber-reinforced composites have been widely used in engineering and industrial applications. The present work deals with the fabricating and characterization of untreated and treated kenaf/polypropylene (PP-reinforced composites. Composites of PP reinforced with treated and untreated kenaf fibers were fabricated using the injection molding technique. Different fiber loadings of 10, 20, 30, 40, 50 wt% treated and untreated kenaf composites were also prepared. X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared (FTIR spectroscopy and thermo gravimetric analysis (TGA were performed on the treated, untreated kenaf fibers and kenaf/PP composites. Moreover, the alkaline-treated kenaf composites exhibit better physical, morphological, and mechanical properties because of the compatibility of kenaf with PP. However, variations in tensile and flexural properties depend on treatment and kenaf fiber contents. The percentage increase in the mechanical properties of the treated kenaf/PP composites relative to that of PP was also measured. In addition, 40 wt% kenaf fiber loading resulted in higher mechanical properties. By contrast, kenaf/PP composite with 50% fiber loading was not successfully prepared because of improper mixing and the burning of kenaf fibers in the PP matrix. To conclude, 40% kenaf/PP composites with superior physical and mechanical properties may be used in variety of applications such as automotive, sports, construction, animal bedding, and mass production industries.

Effect of Mesoporous Silica and Hydroxyapatite Nanoparticles on the Tensile and Dynamic Mechanical Thermal Properties of Polypropylene and Polypropylene Foam

Directory of Open Access Journals (Sweden)

Alireza Albooyeh

2014-12-01

Full Text Available The main purpose of this paper is the experimental study on the tensile and dynamic - mechanical thermal properties of polypropylene (PP and polypropylene foam reinforced with mesoporous silica (MCM-41, hydroxyapatite (HA and the composite of mesoporous silica and hydroxyapatite (MCM41-HA nanoparticles. Nanocomposites and nanocomposite foams containing PP, maleic anhydride grafted polypropylene, different nanoparticles and chemical blowing agent (for foam samples are mixed using the melt-compounding technique in a twin-screw extruder. The results of the tests show that at the same nanoparticles content, all the nanofillers cause better mechanical properties than neat PP and PP foam. Also, due to the porous structure of the foam samples, these samples have the higher damping characteristics and lower tensile properties than the solid samples. Because of higher rigidity and higher strength of HA nanoparticles, the greatest increase in modulus and tensile strength occurs by adding these nanoparticles to neat PP and PP foam. The highest damping factor is obtained by adding MCM-41-HA nanoparticles to PP and PP foam, because of the porous nature of the MCM-41 particles which were reinforced by HA particles. The results of differential scanning calorimetry show that the addition of different nanoparticles does not have any significant effect on crystallinity and melting behavior of PP. Scanning electron microscopy images show that the nanomaterials were fine and uniformly dispersed within the polymer matrix. Furthermore, the addition of different nanoparticles to PP foam causes to increase the cell density, to reduce the cell sizes and to improve the cell sizes distribution. In this respect, the lowest cell sizes and the highest cell density are created by adding HA and MCM41-HA  nanopaticles to PP foams.

Preparation, characterization and properties of nano-hydroxyapatite/polypropylene carbonate biocomposite

Energy Technology Data Exchange (ETDEWEB)

Liao, Jianguo, E-mail: liaojianguo10@hpu.edu.cn [School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000 (China); Li, Yanqun [School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000 (China); Zou, Qin [Analytical & Testing Center, Sichuan University, Chengdu 610064 (China); Duan, Xingze; Yang, Zhengpeng; Xie, Yufen [School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000 (China); Liu, Haohuai [School of Chemistry and Chemical Engineering, Analytical and Testing Center, Guangzhou University, Guangzhou 510006 (China)

2016-06-01

The combination of nano-hydroxyapatite (n-HA) and polypropylene carbonate (PPC) was used to make a composite materials by a coprecipitation method. The physical and chemical properties of the composite were tested. Scanning electron microscope (SEM) observation indicated that the biomimetic n-HA crystals were uniformly distributed in the polymer matrix. As the n-HA content increased in the composite, the fracture mechanism of the composites changes from gliding fracture to gliding and brittle fracture. Furthermore, the chemical interaction between inorganic n-HA and polypropylene carbonate was also investigated and discussed in detail. The hydrogen bonds might be formed between –OH/CO{sub 3}{sup 2−} of n-HA crystal and the ester group (–COO–) of PPC. The tensile strength of n-HA/PPC (40/60) was similar to that of the cancellous bone, and reached ca 58 MPa. The osteoblasts were cultured for up to 7 days, and then the adhesion and proliferation of osteoblasts were measured by Methyl thiazolyl tetrazolium (MTT) colorimetry assay and SEM. The cells proliferated, grew normally in fusiform shape and well attached. The in vitro test confirmed that the n-HA/PPC composites were biocompatible and showed undetectable negative effect on osteoblasts. In vivo implantation of the composite in New Zealand white rabbits was performed. It can stimulate the growth of a new bone, and at the same time the material begins to degrade. These results suggested that the composite may be suitable for the reparation or replacement of bone defects and possessed the potential for clinical applications. - Graphical abstract: SEM micrographs of the induced osteoblasts cultured on the n-HA/PC (40/60) composite. After 2 day cell culture (a), after 4 days (b) hematoxylin/eosin-stained sections of n-HA/PPC (40/60) composite materials. In the photos, M denotes n-HA/PPC (40/60) composite materials, B denotes bone, while NB denotes newly formed bone tissue. - Highlights: • A novel method, co

Development of bio/blood compatible polypropylene through low pressure nitrogen plasma surface modification

International Nuclear Information System (INIS)

Gomathi, N.; Rajasekar, R.; Babu, R. Rajesh; Mishra, Debasish; Neogi, S.

2012-01-01

Surface modification of polypropylene by nitrogen containing plasma was performed in this work in order to improve the wettability which resulted in enhanced biocompatibility and blood compatibility. Various nitrogen containing functional groups as well as oxygen containing functional groups were found to be incorporated to the polymer surface during plasma treatment and post plasma reaction respectively. Wettability of the polymers was evaluated by static contact angle measurement to show the improvement in hydrophilicity of plasma treated polypropylene. Cross linking and surface modification were reported to be dominating in the case of nitrogen plasma treatment compared to degradation. The effect of various process variables namely power, pressure, flow rate and treatment time on surface energy and weight loss was studied at various levels according to the central composite design of response surface methodology (RSM). Except pressure the other variables resulted in increased weight loss due to etching whereas with increasing pressure weight loss was found to increase and then decrease. The effect of process variables on surface morphology of polymers was evaluated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Well spread fibroblast cells on nitrogen plasma treated polypropylene due to the presence of CO, NH 2+ and NH + was observed. Reduced platelet adhesion and increased partial thromboplastin time evidenced the increased blood compatibility. - Highlights: ► Improved biocompatibility and blood compatibility of polypropylene. ► Nitrogen plasma surface modification. ► Maintaining a balance between polar group incorporation and weight loss due to etching. ► Optimization of process conditions by response surface methodology.

Enhancement of mechanical properties and interfacial adhesion by chemical odification of natural fibre reinforced polypropylene composites

CSIR Research Space (South Africa)

Erasmus, E

2008-11-01

Full Text Available with the polymer matrix. Therefore, the constituents need to be chemically modified to enhancing adhesion between fibre and polymer matrix. The aim of this work is to improve the interfacial adhesion between the polypropylene matrix and the natural fibre...

Shear effects on crystallization behaviors and structure transitions of isotactic poly-1-butene

DEFF Research Database (Denmark)

Li, Jingqing; Guan, Peipei; Zhang, Yao

2014-01-01

Different melt pre-shear conditions were applied to isotactic poly-1-butene (iP-1-B) and the effect on the crystallization behaviors and the crystalline structure transitions of iP-1-B were investigated. The polarized optical microscope observations during isothermal crystallization process...... revealed that the applied melt pre-shear within the experimental range could enhance the nucleation of crystal II and accelerate the diameter growth of the formed spherulites. If the applied melt pre-shear rate was large enough, Shish-Kebabs structure could be formed. After the isothermal crystallization...... was formed in the melt pre-sheared iP-1-B samples. Further investigations were applied with synchrotron radiation instruments. Wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS) after the crystal transition showed that the applied melt pre-shear could result in orientated fine...

New fillers in the synthesis of polypropylene nano composites with Ziegler-Natta catalysts

International Nuclear Information System (INIS)

Rosa, Jeferson L.S.; Silva, Marcelo C.V.; Marques, Maria F.V.

2011-01-01

In this study, Ziegler-Natta catalysts bi-supported on MgCl 2 and natural clays were prepared in order to synthesize polypropylene nanocomposites. The employed clays were bentonite, as reference, as well as halloysite, vermiculite and mica. Propylene polymerizations were carried out using those catalysts and the properties of the obtained materials were analyzed using techniques of thermogravimetric analysis X-ray diffraction, dynamic mechanical thermal analysis e scanning electronic microscopy. Results showed the production of nanocomposites with higher thermal degradation temperature. (author)

Synthesis and characterization of CNTs using polypropylene waste as precursor

Energy Technology Data Exchange (ETDEWEB)

Bajad, Ganesh S. [Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur 440010 (India); Tiwari, Saurabh K. [Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Vijayakumar, R.P., E-mail: vijayakumarrp@che.vnit.ac.in [Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur 440010 (India)

2015-04-15

Graphical abstract: - Highlights: • A facile method for producing CNTs from polypropylene waste is proposed. • Optimization of Ni/Mo mole ratio using RSM suggests the adequacy of cubic model. • Process parameters were optimized by RSM using Box–Behnken four factorial design. • Maximum desirability of one suggested that 514% of CNTs would yield over Ni{sub 4}Mo{sub 0.2}MgO{sub 1}. • Increase in Ni/Mo ratio from 0.5 to 20, inner diameter of CNTs decreases from 25 to 2 nm. - Abstract: We study the synthesis of MWCNTs using polypropylene waste as a precursor and Ni/Mo/MgO as a catalyst by the combustion technique. Molar ratios of Ni, Mo and MgO in the Ni/Mo/MgO catalyst were optimized using response surface methodology (RSM) to obtain the maximum yield of CNTs. The mole ratio 4/0.2/1 was found to yield more carbon product. Further, process parameters such as combustion temperature, combustion time, polymer and catalyst weight were optimized by RSM using Box–Behnken three-level and four-factorial design. The best possible combination of process parameters (combustion time of 10 min, combustion temperature of 800 °C, polymer weight of 5 g and catalyst weight of 150 mg) for maximum yield of CNTs was obtained. HRTEM indicates that the diameter of CNTs depends on the catalyst composition used for the synthesis of CNTs. The results of the study indicate a facile method for producing CNTs from polypropylene waste.

Synthesis and characterization of CNTs using polypropylene waste as precursor

International Nuclear Information System (INIS)

Bajad, Ganesh S.; Tiwari, Saurabh K.; Vijayakumar, R.P.

2015-01-01

Graphical abstract: - Highlights: • A facile method for producing CNTs from polypropylene waste is proposed. • Optimization of Ni/Mo mole ratio using RSM suggests the adequacy of cubic model. • Process parameters were optimized by RSM using Box–Behnken four factorial design. • Maximum desirability of one suggested that 514% of CNTs would yield over Ni 4 Mo 0.2 MgO 1 . • Increase in Ni/Mo ratio from 0.5 to 20, inner diameter of CNTs decreases from 25 to 2 nm. - Abstract: We study the synthesis of MWCNTs using polypropylene waste as a precursor and Ni/Mo/MgO as a catalyst by the combustion technique. Molar ratios of Ni, Mo and MgO in the Ni/Mo/MgO catalyst were optimized using response surface methodology (RSM) to obtain the maximum yield of CNTs. The mole ratio 4/0.2/1 was found to yield more carbon product. Further, process parameters such as combustion temperature, combustion time, polymer and catalyst weight were optimized by RSM using Box–Behnken three-level and four-factorial design. The best possible combination of process parameters (combustion time of 10 min, combustion temperature of 800 °C, polymer weight of 5 g and catalyst weight of 150 mg) for maximum yield of CNTs was obtained. HRTEM indicates that the diameter of CNTs depends on the catalyst composition used for the synthesis of CNTs. The results of the study indicate a facile method for producing CNTs from polypropylene waste

Research on mechanical properties of carbon fiber /polyamide reinforced PP composites

Science.gov (United States)

Chen, Xinghui; Yu, Qiang; Liu, Lixia; Ji, Wenhua; Yang, Li; Fan, Dongli

2017-10-01

The polyamide composites reinforced by carbon fiber/polypropylene are produced by injection molding processing. The flow abilities and mechanical properties of the CF/PA/PP composite materials are studied by the fusion index instrument and the universal testing machine. The results show that with the content of carbon fiber/polyamide increase, the impact breaking strength and the tensile property of the composite materials increase, which is instructive to the actual injection production of polypropylene products.

Formation of CuxS Layers on Polypropylene Sulfurized by Molten Sulfur

Directory of Open Access Journals (Sweden)

Rasa ALABURDAITĖ

2011-11-01

Full Text Available The processes of formation of electrically conductive layers of copper sulfides CuxS by the sorption-diffusion method on polypropylene (PP using molten sulfur as sulfurizing agent was investigated. The amount of sorbed sulfur increased with the increase of the duration of treatment. Copper sulfide layers were formed on the surface of polypropylene after the treatment of sulfurized polymer with Cu(II/I salt solution. The amount of copper sulfide in layer increased with the increase of treatment duration in copper salt solution. XRD spectra of PP films treated for 3 min with molten sulfur and then with Cu(II/I salt solution for the different time showed that the copper sulfide phases, mostly digenite, Cu2-xS and a-chalcocite, Cu2S were formed in the layers. Electromotive force measurement results confirmed the composition of formed CuxS layers on PP. The phase composition of layers also changed after the annealing. The value of electrical resistance of copper sulfide layers on PP varied from 20 W/cm2 to 80 W/cm2 and after annealing at 80 °C - in the interval of 10 W/cm2 - 60 W/cm2.http://dx.doi.org/10.5755/j01.ms.17.4.776

Evaluation of the environmental aging and mechanical properties of the polypropylene/sugarcane bagasse composites; Avaliacao do envelhecimento ambiental e das propriedades mecanicas dos compositos de polipropileno/bagaco de cana-de-acucar

Energy Technology Data Exchange (ETDEWEB)

Paiva, Rayane Lima de Moura; Mulinari, Daniella Regina [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil)

2013-06-15

Polypropylene (PP) reinforced with fibers from sugarcane bagasse composites in different proportions were prepared. Also environmental aging was conducted for the composites and their mechanical properties determined. The results showed that chemical treatment caused changes in color and chemical composition of the fibers, removing impurities and amorphous constituents such as lignin and hemicellulose, techniques of FTIR, X-ray diffraction and scanning electron microscopy confirmed these data. Also, it was observed that addition of natural fiber in PP matrix provided an improvement in the mechanical properties materials. The weathering test revealed a slight mass gain after 75 days, but it was clear that the inclusion of fibers has a higher mass gain compared to pure PP. (author)

Abaca fibre reinforced PP composites and comparison with jute and flax fibre PP composites

Directory of Open Access Journals (Sweden)

2007-11-01

Full Text Available Abaca fibre reinforced PP composites were fabricated with different fibre loadings (20, 30, 40, 50wt% and in some cases 35 and 45 wt%. Flax and jute fibre reinforced PP composites were also fabricated with 30 wt% fibre loading. The mechanical properties, odour emission and structure properties were investigated for those composites. Tensile, flexural and Charpy impact strengths were found to increase for fibre loadings up to 40 wt% and then decreased. Falling weight impact tests were also carried out and the same tendency was observed. Owing to the addition of coupling agent (maleated polypropylene -MAH-PP, the tensile, flexural and falling weight impact properties were found to increase in between 30 to 80% for different fibre loadings. When comparing jute and flax fibre composites with abaca fibre composites, jute fibre composites provided best tensile properties but abaca fibre polypropylene composites were shown to provide best notch Charpy and falling weight impact properties. Odours released by flax fibre composites were smaller than jute and abaca fibre composites.

Autoclaved Sand-Lime Products with a Polypropylene Mesh

Science.gov (United States)

Kostrzewa, Paulina; Stępień, Anna

2017-10-01

The paper presents the results of the research on modifications of silicate bricks with a polypropylene mesh and their influence on physical, mechanical and microstructural properties of such bricks. The main goal of the paper was to determine effects of the polypropylene mesh on sand-lime product parameters. The analysis has focused on compressive strength, water absorption, bulk density and structural features of the material. The obtained product is characterized by improved basic performance characteristics compared to traditional silicate products. Using the polypropylene mesh increased compressive strength by 25% while decreasing the product density. The modified products retain their form and do not disintegrate after losing their bearing capacity.

Microstructural evolution during tensile deformation of polypropylenes

International Nuclear Information System (INIS)

Dasari, A.; Rohrmann, J.; Misra, R.D.K.

2003-01-01

Tensile deformation processes occurring at varying strain rates in high and low crystallinity polypropylenes and ethylene-propylene di-block copolymers have been investigated by scanning electron microscopy. This is examined for both long and short chain polymeric materials. The deformation processes in different polymeric materials show striking dissimilarities in spite of the common propylene matrix. Additionally, the deformation behavior of long and their respective short chain polymers was different. Deformation mechanisms include crazing/tearing, wedging, ductile ploughing, fibrillation, and brittle fracture. The different modes of deformation are depicted in the form of strain rate-strain diagrams. At a constant strain rate, the strain to fracture follows the sequence: high crystallinity polypropylenes< low crystallinity polypropylenes< ethylene-propylene di-block copolymers, indicative of the trend in resistance to plastic deformation

Effect of ultraviolet radiation (300-400 nanometers) on polypropylene

International Nuclear Information System (INIS)

Lerman, S.

1983-01-01

Polypropylene discs and shavings were exposed to simulated ambient ultraviolet (UV) radiation (lambda 300-400 nm) for a period equivalent to at least two years of wear within the eye, assuming the eye to be exposed to ambient UV radiation for four hours per day at 1 mW/cm2. The polypropylene and the incubation media were measured by several forms of optical spectroscopy, and there was no photochemical change in either. Where polypropylene discs were exposed to a very high level of UV radiation (greater than 500 W/cm2), they became brittle and discolored within five to ten days. This level of exposure, however, was equivalent to a total of over 20 million joules/cm2, which is at least one million times levels for expected ambient UV exposure to polypropylene within the eye

Thermal properties of light-weight concrete with waste polypropylene aggregate

Science.gov (United States)

Záleská, Martina; Pokorný, Jaroslav; Pavlíková, Milena; Pavlík, Zbyšek

2017-07-01

Thermal properties of a sustainable light-weight concrete incorporating high volume of waste polypropylene as partial substitution of natural aggregate were studied in the paper. Glass fiber reinforced polypropylene (GFPP), a by-product of PP tubes production, partially substituted fine natural silica aggregate in 10, 20, 30, 40, and 50 mass%. In order to quantify the effect of GFPP use on concrete properties, a reference concrete mix without plastic waste was studied as well. For the applied GFPP, bulk density, matrix density, and particle size distribution were measured. Specific attention was paid to thermal transport and storage properties of GFPP that were examined in dependence on compaction time. For the developed light-weight concrete, thermal properties were accessed using transient impulse technique, whereas the measurement was done in dependence on moisture content, from the dry state to fully water saturated state. Additionally, the investigated thermal properties were plotted as function of porosity. The tested light-weight concrete was found to be prospective construction material possessing improved thermal insulation function. Moreover, the reuse of waste plastics in concrete composition was beneficial both from the environmental and financial point of view considering plastics low biodegradability and safe disposal.

Graft copolimerization of hydrophilic monomers onto irradiated polypropylene fibers

International Nuclear Information System (INIS)

Sundardi, F.

1978-01-01

A method of graft copolymerization of hydrophilic monomers, such as 1-vinyl-2-pyrrolidone, acrylonitrile, acrylic acid, and acrylamide, onto irradiated polypropylene fibers has been studied. γ ray as well as electron beam were employed for the irradiation processes. Graft-copolymerization kinetics and the properties of grafted fibers have been investigated. Moisture regain, dyes absorption, and melting point of the grafted fibers were found to increase with the increasing of the degree of grafting. Polypropylene for 1-vinyl-2-pyrrolidone grafted fibers showed excellent dye absorption for almost all kinds of dyes such as direct, basic, acid, reactive, disper, and naphthol dyes. However, for polypropylene acrylic acid grafted fibers, the colorfastness to washing was found to be unsatisfactory. The colorfastness to washing for polypropylene 1-vinyl-2-pyrrolidone grafted fibers was found to be fairly good for certain types of dyes such as vat and naphthol dyes. (author)

The effects of normal paraffins mobilizers on irradiated polypropylene

International Nuclear Information System (INIS)

Chen Wenxiu; Gao Ling

1995-01-01

The n-paraffins blended with polypropylene (PP) as mobilizer had been investigated. The effectiveness of mobilizer (n-paraffins) on irradiated polypropylene is dependent on the molecular weight of mobilizer and its content on polypropylene. The n-docosame (n-C 22 ) possesses the best effectiveness of radiation tolerance on PP among the mobilizer paraffins: n-decane (n-C 10 ), n-hexadecane (n-C 16 ), n-docosane (n-C 22 ) and n-hexatriacontane (n-C 36 ). The 2% (w/w) content of a given mobilizer is the most effective at reducing the embrittlement of irradiated PP as evidenced by the elongation at break. The physical properties of polypropylene with mobilizers such as density, Young's modulus, the Fraction of free volume and the weight swelling ratio in p-xylene at room temperature were measured. Above phenomena are related with the constructive of blended PP and demonstrated by its physical properties

Studies of Electrical and Thermal Conductivities of Sheared Multi-Walled Carbon Nanotube with Isotactic Polypropylene Polymer Composites

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Parvathalu Kalakonda

2015-01-01

at higher temperature due to isotropic electrical and thermal contact in both directions. Oriented MWCNT/iPP nanocomposites exhibit higher electrical and thermal conductivities, attributed primarily by orientation of nanotubes due to the shearing fabrication process.

Effect of modified polypropylene on the interfacial bonding of polymer–aluminum laminated films

International Nuclear Information System (INIS)

Liang, Chang-Sheng; Lv, Zhong-Fei; Bo, Yang; Cui, Jia-Yang; Xu, Shi-Ai

2015-01-01

Highlights: • Aluminium-polymer composite packing material with high T-peel strength was prepared. • Polypropylene was grafted by acrylic acid, glycidyl methacrylate, maleic anhydride. • Grafted polypropylene greatly improved the T-peel strength. • Chemical bonding plays an important role in improving the adhesion strength. - Abstract: The interfacial bonding between functionalized polymers and chromate–phosphate treated aluminum (Al) foil were investigated in this study. Glycidyl methacrylate (GMA), acrylic acid (AA) and maleic anhydride (MAH) were grafted onto polypropylene (PP) to improve its adhesion strength with the treated Al foil. The interfacial peel strength was evaluated by the T-peel test, and the results showed that modification of PP resulted in a significant improvement in the interfacial peel strength from 1 N/15 mm for pure PP to 10–14 N/15 mm for the modified PP. The surface chemistry, topography and surface energy of the modified PP and Al foil after peeling were characterized by time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and contact angle measurement. The treated Al foil could react with the functional groups of PP, resulting in the formation of new carboxylates. The new chemical bonding rather than the mechanical interlocking contributed to the improvement of adhesion strength

Strength of biodegradable polypropylene tapes filled with a modified starch

Science.gov (United States)

Vinidiktova, N. S.; Ermolovich, O. A.; Goldade, V. A.; Pinchuk, L. S.

2006-05-01

The possibility of creating composite materials with high deformation and strength characteristics based on polypropylene (PP) and a natural polysaccharide in the form of a modified starch (MS) has been studied. The modified starch is shown to interact chemically with functional groups of PP, thereby positively affecting the physicomechanical properties, structure, and water absorption properties of films and oriented flat fibers based on starch-filled PP. The strength characteristics of both oriented and unoriented composites are 1.5-2.0 times as high as those of the initial PP. The water absorption ability of the materials varies symbatically with content of MS, which points to the dominant contribution of interactions at the PP-MS interface. The introduction of MS into synthetic polymers offers a possibility of producing new ecologically safe materials with high strength characteristics.

Polypropylene and polycarbonate radiosterilization: effects on the stress resistance

International Nuclear Information System (INIS)

Musico Filho, W.; Terence, M.C.; Guedes, S.M.L.; Araujo, E.S. de

1994-01-01

The gamma radiation effect on polymer sterilization used in the fabrication of medical supplies, national polycarbonate and polypropylene, was studied in function of the tensile strength. During the polycarbonate irradiation occur the scission of polymer chain and the crosslinking/scission of the polypropylene, but in the sterilization dose, 25 kGy, does not occur expressive changes in the tensile strength. After the polypropylene sterilization the tensile strength continues increasing as consequence of the crosslinking. Since the sixth day the oxidation reaction predominates as consequence of the radical migration to the amorphous region. (author). 7 refs, 6 figs

A Comprehensive Study of the Polypropylene Fiber Reinforced Fly Ash Based Geopolymer

DEFF Research Database (Denmark)

Ranjbar, Navid; Mehrali, Mehdi; Behnia, Arash

2016-01-01

and long term impacts of different volume percentages of polypropylene fiber (PPF) reinforcement on fly ash based geopolymer composites. Different characteristics of the composite were compared at fresh state by flow measurement and hardened state by variation of shrinkage over time to assess the response...... of composites under flexural and compressive load conditions. The fiber-matrix interface, fiber surface and toughening mechanisms were assessed using field emission scan electron microscopy (FESEM) and atomic force microscopy (AFM). The results show that incorporation of PPF up to 3 wt % into the geopolymer......As a cementitious material, geopolymers show a high quasi-brittle behavior and a relatively low fracture energy. To overcome such a weakness, incorporation of fibers to a brittle matrix is a well-known technique to enhance the flexural properties. This study comprehensively evaluates the short...

The effect of halloysite modification combined with in situ matrix modifications on the structure and properties of polypropylene/halloysite nanocomposites

Czech Academy of Sciences Publication Activity Database

Khunova, V.; Kristóf, J.; Kelnar, Ivan; Dybal, Jiří

2013-01-01

Roč. 7, č. 5 (2013), s. 471-479 ISSN 1788-618X R&D Projects: GA AV ČR IAA200500904 Institutional support: RVO:61389013 Keywords : nanocomposites * polypropylene * halloysite Subject RIV: JI - Composite Materials Impact factor: 2.953, year: 2013

Polypropylene/graphite nanocomposites by in situ polymerization

International Nuclear Information System (INIS)

Milani, Marceo A.; Galland, Giselda B.; Quijada, Raul

2011-01-01

This work presents the synthesis of nanocomposites of polypropylene/graphite by in situ polymerization using metallocene catalyst and graphene nanosheets. Initially was analyzed which of the metallocene catalysts rac-Et(Ind) 2 ZrCl 2 or rac-Me 2 Si(Ind) 2 ZrCl 2 produces polypropylene with mechanical properties more relevant. Then it were performed the in situ polymerization reactions to obtain the nanocomposites. The polymeric materials were characterized by XRD, DSC, GPC and DMTA. (author)

Propylene

Directory of Open Access Journals (Sweden)

M. Emami

2007-08-01

Full Text Available This is a report on the study of high melt flow, highly isotactic polypropylene homopolymer synthesized in liquid monomer using a fifth generation Ziegler-Natta catalytic system. At highest catalyst productivity, the response of thecatalyst to hydrogen as chain transfer is studied. Melt flow rate is controlled by hydrogen as chain transfer from 0.4 to 300 g/10min with changing the amount of hydrogen from 0 to 1400 ppm. Results show that the melt flow rate of homopolymer is increased linearly with increasing the amount of hydrogen in polymerization. The effect of external electron donor on catalyst productivity and stereoregularity of the final product has been studied. The external electron donor on the catalyst caused an increase in polymer isotacticity, but led to decrease in catalyst productivity andits response to hydrogen (i.e., requiring relatively more hydrogen for molecular weight control. This new generation of Z-N catalyst system containing 1,3-diether as internal electron donor has the ability to produce very high MFR polymers (for thin wall parts in combination with narrow molecular weight distribution. These reactor grades of polypropylene have many advantages compared to visbroken (controlled rheology grades such as lower cost and better processability. These resins can be used as homopolymer matrix in sequential polymerization to obtain impactcopolymers (heterophasic copolymers.

Thermal aging and accelerated weathering of HMSPP: structural and morphological studies

International Nuclear Information System (INIS)

Oliani, Washington L.; Komatsu, Luiz G.H.; Parra, Duclerc F.

2015-01-01

This work focuses of the influence of weathering factors - UV radiation, humidity, and temperature on the structure and morphology polypropylene with high melt strength (HMSPP), also called polypropylene modified by irradiation. The HMSPP was prepared from iPP (isotactic polypropylene) in presence of acetylene at 110 kPa pressure and irradiated with γ of "6"0Co at doses of 5, 12.5 and 20 kGy. It has been observed that HMSPP deteriorates the weathering resistance, the thermal behavior and the long-term stability of HMSPP, beyond substantial color changes. The samples aged were characterized by infrared spectroscopy (FTIR), optical microscopy (OM) and differential scanning calorimetry (DSC). The optical microscopy images on the surface show that thermal aging and artificial weathering proceed by different mechanisms. The effects of elevated temperature aging were evaluated in HMSPPs exposed surface according to the order: HMSPP 20 >12.5 > kGy >iPP, showing intense crack formation in surface exposed due to thermo oxidative degradation. (author)

Comparative Effects of MMT Clay Modified with Two Different Cationic Surfactants on the Thermal and Rheological Properties of Polypropylene Nanocomposites

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Meshal Al-Samhan

2017-01-01

Full Text Available Polypropylene montmorillonite (MMT nanocomposites were prepared by melt blending using two different organoclays modified with imidazolium and alkylammonium surfactants. The imidazolium and ammonium modified organoclays were characterized by the FTIR and SEM analysis. The effect of organic clay (MMT on the physical properties of polypropylene was evaluated, thermal and rheological properties with different filler weight percentage. Differential scanning calorimetric results showed that imidazolium modified clay (IMMT exhibits low melting temperature compared to the ammonium modified clay (AMMT. The crystallinity analysis showed that crystallization improved in all nanocomposites irrespective of surface modification; the thermogravimetric analysis showed that the imidazolium modified polymer composites are more thermally stable than conventional ammonium modified composites. The Transmission Electron Microscopy (TEM analyses indicated that the PP-IMMT composites displayed exfoliated morphologies compared with the intercalated structure in PP-AMMT, and the rheological analysis at 180°C showed an enhancement in the viscoelastic properties as the clay concentration increases. The melt viscosity, crossover modulus, and relaxation times were comparable for both the surface modified composites with two different cations. The imidazolium based surfactant was found to be an effective organic modification for MMT to prepare thermally stable PP/MMT nanocomposites.

Structure of single-chain single crystals of isotactic polystyrene and their radiation resistance

International Nuclear Information System (INIS)

Bu Haishan; Cao Jie; Xu Shengyong; Zhang Ze

1997-01-01

The structure of the single-chain single crystals of isotactic polystyrene (i-PS) was investigated by electron diffraction (ED) and high resolution electron microscopy (HREM). The nano-scale single-chain single crystals were found to be very stable to electron irradiation. According to the unit cell of i-PS crystals, the reflection rings in ED pattern and the lattice fringes in HREM images could be indexed, but the lower-index diffractions were not found. It is proposed that the single-chain single crystals are very small, thus secondary electrons may be allowed to escape and radiation damage is highly reduced, and that there are less lower-index lattice planes in the single-chain single crystals to provide sufficient diffraction intensity for recording. HREM images can be achieved at room temperature in the case of single-chain single crystals because of its stability to electron irradiation, therefore, this might be a novel experimental approach to the study of crystal structure of macromolecules

Functionalization of Silica Nanoparticles for Polypropylene Nanocomposite Applications

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Diego Bracho

2012-01-01

Full Text Available Synthetic silica nanospheres of 20 and 100 nm diameter were produced via the sol-gel method to be used as filler in polypropylene (PP composites. Modification of the silica surface was further performed by reaction with organic chlorosilanes in order to improve the particles interaction with the hydrophobic polyolefin matrix. These nanoparticles were characterized using transmission electronic microscopy (TEM, elemental analysis, thermogravimetric analysis (TGA, and solid-state nuclear magnetic resonance (NMR spectroscopy. For unmodified silica, it was found that the 20 nm particles have a greater effect on both mechanical and barrier properties of the polymeric composite. In particular, at 30 wt%, Young's modulus increases by 70%, whereas water vapor permeability (WVP increases by a factor of 6. Surface modification of the 100 nm particles doubles the value of the composite breaking strain compared to unmodified particles without affecting Young's modulus, while 20 nm modified particles presented a slight increase on both Young's modulus and breaking strain. Modified 100 nm particles showed a higher WVP compared to the unmodified particles, probably due to interparticle condensation during the modification step. Our results show that the addition of nanoparticles on the composite properties depends on both particle size and surface modifications.

2-hydroxyethyl methacrylate composite - polypropylene mesh for preventing peritoneal adhesions in female dogs Compósito 2-hidroxietil dimetacrilato-tela de polipropileno para prevenção de aderências peritoneais em cadelas

Directory of Open Access Journals (Sweden)

Marcelo Seixo de Brito e Silva

2010-08-01

Full Text Available PURPOSE: To evaluate whether the lining facing the visceral side of polypropylene mesh made with 2-hydroxyethyl methacrylate (p(HEMA hydrogel could avoid peritoneal adhesion in female dogs. METHODS: Eight animals (group PP had a polypropylene mesh implanted to correct a defect in the rectal abdominal muscle, whereas in the other group (group PH the polypropylene mesh was coated with p(HEMA composite on the surface facing the peritoneal area. RESULTS: Adhesions were observed on the mesh in 62.5% of the PP group. In the PH group adhesions were present only on the suture lines. CONCLUSION: p(HEMA hydrogel was well tolerated and effective in avoiding visceral and omental adhesions on the surface of the polypropylene mesh.OBJETIVO: Avaliar se o revestimento da face visceral de uma tela de polipropileno com 2-hidroxietil dimetacrilato (p(HEMA poderia evitar aderências peritoniais em cadelas. MÉTODOS: Em oito animais (Grupo PP foram implantadas telas de polipropileno para correção de um defeito do músculo reto abdominal, enquanto em outro grupo (Grupo PH fez-se a implantação de uma tela de polipropileno cuja face peritonial foi revestida por 2-hidroxietil dimetacrilato (p(HEMA. RESULTADOS: Foram observados 62,5% de aderências peritoniais sobre a tela nos animais do Grupo PP, enquanto que no Grupo PH estas não ocorreram, exceto sobre a linha se sutura. CONCLUSÃO: O hidrogel de p(HEMA foi bem tolerado pelos animais e mostrou-se efetivo na prevenção das aderências viscerais e omentais sobre a tela de polipropileno.

Comparison of polypropylene and silicone Ahmed Glaucoma Valves.

Science.gov (United States)

Ishida, Kyoko; Netland, Peter A; Costa, Vital P; Shiroma, Lineu; Khan, Baseer; Ahmed, Iqbal Ike K

2006-08-01

To evaluate and compare the clinical outcomes after implantation of the silicone plate and the polypropylene plate Ahmed Glaucoma Valves. Prospective, multicenter, comparative series. A total of 132 patients with uncontrolled glaucoma were treated with either the silicone or polypropylene Ahmed Glaucoma Valve implant. Success was defined according to 2 criteria: (1) intraocular pressure (IOP) of 6 mmHg or more or 21 mmHg or less, and (2) IOP reduction of at least 30% relative to preoperative values. Eyes requiring further glaucoma surgery, including cyclophotocoagulation, or showing loss of light perception were classified as failures. Average follow-up was 12.8 months (range, 6-30 months) for the silicone plate group and 14.5 months (range, 6-30 months) for the polypropylene plate group (P = 0.063). At the last follow-up examination, the mean IOP was 13.8+/-3.9 mmHg and 17.3+/-6.5 mmHg (PAhmed Glaucoma Valve (model FP7) showed improved IOP reduction compared with the polypropylene (model S2) implant. Differences observed in mean IOP, success rate, and complications suggest that plate material may influence clinical outcome.

Additive manufacturing with polypropylene microfibers.

Science.gov (United States)

Haigh, Jodie N; Dargaville, Tim R; Dalton, Paul D

2017-08-01

The additive manufacturing of small diameter polypropylene microfibers is described, achieved using a technique termed melt electrospinning writing. Sequential fiber layering, which is important for accurate three-dimensional fabrication, was achieved with the smallest fiber diameter of 16.4±0.2μm obtained. The collector speed, temperature and melt flow rate to the nozzle were optimized for quality and minimal fiber pulsing. Of particular importance to the success of this method is appropriate heating of the collector plate, so that the electrostatically drawn filament adheres during the direct-writing process. By demonstrating the direct-writing of polypropylene, new applications exploiting the favorable mechanical, stability and biocompatible properties of this polymer are envisaged. Copyright © 2017. Published by Elsevier B.V.

Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

Science.gov (United States)

Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

2016-06-01

Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

Effect of nanosilica particles on polypropylene polymer modified asphalt mixture performance

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Nura Bala

2018-06-01

Full Text Available The current study was conducted to investigate the effect of nanosilica particles on the performance characteristics of polymer modified asphalt binders. In this study, control 80/100 binder were modified with polypropylene polymer and nanosilica particles at concentration of 0%–4%. Both nanosilica particles and polypropylene polymer were added by weight of total bitumen content. The asphalt performance tests flexural four point beam fatigue test, indirect tensile strength, indirect tensile stiffness modulus and draindown tests are conducted to evaluate the effect of nanosilica particles. The results of the study shows that nanosilica particles improves the fatigue properties of polypropylene polymer modified binder. This indicates that nanosilica particles have significant effect on improving the performance properties of polymer modified binders. Also, the result reveals that thermoplastic polymer polypropylene with nanosilica particles when used as bitumen modifiers improve the performance and durability of asphalt mixtures. Keywords: Polypropylene, Fatigue cracking, Stiffness modulus, Modified asphalt, Draindown

Polypropylene Track Membranes for Mikro and Ultrafiltration of Chemically Aggressive Agents

CERN Document Server

Kravets, L I; Apel, P Yu

2000-01-01

A production process for track membranes on the basis of chemically resistant polymer polypropylene has been developed. Research in all stages of the formation of the polypropylene track membranes has been conducted: the main principles of the process of chemical etching of polypropylene irradiated with accelerated ions have been investigated, the most effective structure of the etchant for a selective etching of the heavy ion tracks has been selected, the parameters of etching have been optimized. A method for sensibilization of latent tracks in polypropylene by effect of solvents has been developed. It helps to reach a significant increase in etching selectivity. A method for destruction of an absorbed chromocontaining layer on the surface of polypropylene track membranes formed during etching has been elaborated. Experimental samples of the membranes for micro and ultrafiltration have been obtained and their properties have been studied in course of their exploitation in chemically aggressive agents. For t...

The influence of glass fibers on the morphology of β-nucleated isotactic polypropylene evaluated by differential scanning calorimetry

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Janevski Aco

2015-01-01

Full Text Available The presence of fillers/fibers can significantly affect the polymorphic behavior of semi-crystalline polymers. The influence of glass fibers on morphology of β-nucleated iPP during isothermal and nonisothermal crystallization was analyzed in detail by DSC, and the kinetics and thermodynamic parameters were determined for the systems containing 10-60 % glass fibers. The presence of glass fibers in model composites with β-iPP has insignificant effect on the morphology of the polymer. Thermodynamic and kinetics parameters of crystallization of iPP in model composites are close to those obtained for the nucleated polymer. The relative content of β-crystalline phase is slightly affected by increasing glass fiber’s content from 10 % mas to 60 % mas, due to appearance of α-crystallites. However, the stability of β-crystalline phase is decreased by the increasing glass fibers content and there appeared certain amount of β1 and β2 phases which are known as disposed to recrystallization.

Synergistic effects of iron powder on intumescent flame retardant polypropylene system

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2009-06-01

Full Text Available The effects of iron powder as a synergistic agent on the flame retardancy of intumescent flame retardant polypropylene composites (IFR-PP were studied. The thermogravimetric analysis (TGA and cone calorimeter (CONE were used to evaluate the synergistic effects of iron powder (Fe. The TGA data showed that Fe could enhance the thermal stability of the IFR-PP systems at high temperature and effectively increase the char residue formation. The CONE results revealed that Fe and IFR could clearly change the decomposition behavior of PP and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate (HRR, mass loss (ML, Mass loss rate (MLR, total heat release (THR, carbon monoxide and so on. Thus, a suitable amount of Fe plays a synergistic effect in the flame retardancy of IFR composites.

STRUCTURAL EVOLUTION AND COMPOSITION CHANGE IN THE SURFACE REGION OF POLYPROPYLENE/CLAY NANOCOMPOSITES ANNEALED AT HIGH TEMPERATURES

Institute of Scientific and Technical Information of China (English)

Zhe Wang; Rong-jun Song; Xiao-hua Du; Xiao-yu Meng; Zhi-wei Jiang; Tao Tang

2009-01-01

A model experiment was done to clear the formation mechanism of protective layers during combustion of polypropylene (PP)/organically modified montmorillonite (OMMT) nanocomposites. The investigation was focused on the effects of annealing temperature on the structural changes and protective layer formation. The decomposition of OMMT and degradation of PP/OMMT nanocomposites were characterized by means of thermogravimetric analysis (TGA). The structural evolution and composition change in the surface region of PP/OMMT nanocomposites during heating were monitored by means of X-ray photoelectron spectroscopy (XPS), ATR-FTIR and field emission scanning electron microscopy (FESEM). The results showed that the formation of the carbonaceous silicate barrier in the surface region of PP/OMMT nanocomposites resulted from the following three processes: (1) The formation of strong acid sites on the MMT sheets, which could promote the degradation of PP and the carbonization of its degradation products; (2) The gases and gas bubbles formed by decomposition of the surfactant and degradation of PP, which pushed the molten sample to the surface; (3) The degradation of PP and the carbonization of the degradation products, which led to accumulation of MMT sheets tightly linked by the char in the surface region.

Physical and dielectric properties of irradiated polypropylene and poly(ethylene terephthalate)

International Nuclear Information System (INIS)

Kita, H.; Okamoto, K.

1986-01-01

The effect of high-energy electron irradiation in air and in nitrogen on the physical and dielectric properties of polypropylene and poly(ethylene terephthalate) has been studied by measurements of electric strength, dielectric constant, dissipation factor, tensile strength, gel fraction and molecular weight distribution. Electric strength of polypropylene was improved by irradiation, while dielectric properties of poly(ethylene terephthalate) were virtually unaffected by irradiation of 1.0-20 Mrad. Possible mechanisms for increasing electric strength are discussed from the point of view of degradation and oxidation taking place simultaneously with crosslinking of polypropylene. The maximum dose level to improve the electric strength of polypropylene is determined to be about 5 Mrad. (author)

Co-60 gamma radiation assisted diffusion of iodine in polypropylene

Energy Technology Data Exchange (ETDEWEB)

Mathakari, N.L.; Bhoraskar, V.N. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune, Maharashtra 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ernet.i [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune, Maharashtra 411007 (India)

2010-09-15

Thin films of polypropylene having dimensions 50 mm x 15 mm x 350 {mu}m were immersed in 1 N iodine solution and then irradiated with Co-60 gamma radiation for the periods of 48, 96 and 144 h at the doses varying from 14.4 to 43.2 kGy. The films were also kept immersed in iodine solution for similar periods but without irradiation. Furthermore, the films were also directly-irradiated with Co-60 gamma radiation for similar periods and doses. The radiation-iodinated, plain-iodinated and directly-irradiated samples were characterized by using various techniques such as weight gain EDS, SEM, FTIR, UV-visible spectroscopy, contact angle and XRD. Weight gain, EDS and SEM collectively reveal that gamma irradiation enhances iodine intake in polypropylene. FTIR, EDS and contact angle measurements indicate that presence of iodine during irradiation resists radiation induced carbonylation of polypropylene. FTIR also shows presence of HOI (Hypoiodous acid) species instead of expected C-I bonds. UV-visible analysis unambiguously shows that presence of iodine enhances radiation induced band gap reduction process of polypropylene. XRD indicates that iodine decreases the crystallinity of polypropylene.

A new constitutive model for prediction of impact rates response of polypropylene

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Buckley C.P.

2012-08-01

Full Text Available This paper proposes a new constitutive model for predicting the impact rates response of polypropylene. Impact rates, as used here, refer to strain rates greater than 1000 1/s. The model is a physically based, three-dimensional constitutive model which incorporates the contributions of the amorphous, crystalline, pseudo-amorphous and entanglement networks to the constitutive response of polypropylene. The model mathematics is based on the well-known Glass-Rubber model originally developed for glassy polymers but the arguments have herein been extended to semi-crystalline polymers. In order to predict the impact rates behaviour of polypropylene, the model exploits the well-known framework of multiple processes yielding of polymers. This work argues that two dominant viscoelastic relaxation processes – the alpha- and beta-processes – can be associated with the yield responses of polypropylene observed at low-rate-dominant and impact-rates dominant loading regimes. Compression test data on polypropylene have been used to validate the model. The study has found that the model predicts quite well the experimentally observed nonlinear rate-dependent impact response of polypropylene.

Interfacial Effects on the Spherulitic Morphology of Isotactic Polystyrene Thin Films on Liquid Substrates

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Takashi Sasaki

2016-01-01

Full Text Available The influence of interfaces on the morphology of flat spherulites of isotactic polystyrene (iPS grown in thin films on liquid substrates was investigated. Amorphous iPS thin films spin-cast from a solution were annealed for cold crystallization on glycerol and silicone oil (nonsolvents for iPS. The number density of grown spherulites was revealed to be higher on the glycerol substrate than on the silicone oil substrate. This implies that the primary nucleation rate of crystallization is greater at the iPS/glycerol interface than at the iPS/silicone oil interface. The results may be consistent with the previous findings that concern the molecular interaction between atactic polystyrene and nonsolvents at the interface. In some cases, holes were formed in the thin films during the cold crystallization due to dewetting, which also significantly affect the spherulite morphology via, for example, transcrystallization.

Nucleation of polypropylene crystallization with gold nanoparticles. Part 2: relation between particle morphology and nucleation activity

Czech Academy of Sciences Publication Activity Database

Šlouf, Miroslav; Vacková, Taťana; Zhigunov, Alexander; Sikora, Antonín; Piorkowska, E.

2016-01-01

Roč. 55, č. 4 (2016), s. 393-410 ISSN 0022-2348 R&D Projects: GA ČR GAP205/10/0348; GA ČR(CZ) GA14-17921S Institutional support: RVO:61389013 Keywords : crystallization * gold nanoparticles * isotactic polyproplylene Subject RIV: JJ - Other Materials Impact factor: 0.828, year: 2016

Thermal degradation kinetics and estimation of lifetime of radiation grafted polypropylene films

International Nuclear Information System (INIS)

Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Bhalla, Vinod Kumar

2017-01-01

In this research work, thermal stability and degradation behavior of acrylic acid grafted polypropylene (PP-g-PAAc) films were investigated by using thermogravimetric (TGA) analysis at four different heating rates 5, 10, 15 and 20 °C/min over a temperature range of 40–550 °C in nitrogen atmosphere. The kinetic parameters namely activation energy (E a ), reaction order (n) and frequency factor (Z) were calculated by three multiple heating rate methods. The thermal stability of PP-g-PAAc films is found to decrease with increase in degree of grafting. The TGA data and thermal kinetic parameters were also used to predict the lifetime of grafted PP films. The estimated lifetime of neat PP as well as grafted PP decreased with increase in temperature by all the three methods. Studies also indicated that E a and lifetime of PP-g-PAAc films decreased with increase in degree of grafting, which may also be helpful in biodegradation of grafted PP films. - Highlights: • Thermal stability of grafted polypropylene films have been observed lower than for neat polypropylene film. • Multiple heating rate methods have been used for determination of activation energy. • Activation energies of grafted polypropylene films were lower than polypropylene film. • The lifetimes of grafted polypropylene films were shorter than for neat polypropylene film.

Determination of Partition Coefficients of Selected Model Migrants between Polyethylene and Polypropylene and Nanocomposite Polypropylene

Directory of Open Access Journals (Sweden)

Pablo Otero-Pazos

2016-01-01

Full Text Available Studies on nanoparticles have focused the attention of the researchers because they can produce nanocomposites that exhibit unexpected hybrid properties. Polymeric materials are commonly used in food packaging, but from the standpoint of food safety, one of the main concerns on the use of these materials is the potential migration of low molecular substances from the packaging into the food. The key parameters of this phenomenon are the diffusion and partition coefficients. Studies on migration from food packaging with nanomaterials are very scarce. This study is focused on the determination of partition coefficients of different model migrants between the low-density polyethylene (LDPE and polypropylene (PP and between LDPE and nanocomposite polypropylene (naPP. The results show that the incorporation of nanoparticles in polypropylene increases the mass transport of model migrants from LDPE to naPP. This quantity of migrants absorbed into PP and naPP depends partially on the nature of the polymer and slightly on the chemical features of the migrant. Relation (RPP/naPP between partition coefficient KLDPE/PP and partition coefficient KLDPE/naPP at 60°C and 80°C shows that only BHT at 60°C has a RPP/naPP less than 1. On the other hand, bisphenol A has the highest RPP/naPP with approximately 50 times more.

Influence of clay type on the performance of Ziegler-Natta catalyst for the synthesis of nanocomposites of PE and PP

International Nuclear Information System (INIS)

Almeida, Lidiane A.; Marques, Maria F.V.; Oliveira, Jaqueline S.

2011-01-01

Polymer nanocomposites present highly improved general properties in comparison with original polymer and their conventional composites. The mayor disadvantage in preparing these materials is the difficulty in the dispersion of the nanofillers in the polymer matrix. In the present work, the synthesis of bisupported (MgCl 2 /clay) catalyst was performed for obtaining polyethylene and polypropylene nanocomposites by in situ polymerization with the aim to achieve higher dispersion of the nanofillers in the polyolefin matrix. Moreover, the influence of ammonium salt (employed in the organophilization of the clay) on the fixation of the catalyst components and therefore, on the catalyst activity was evaluated. The catalysts were characterized by TGA, SEM, EDX, and XRD. Polymers were characterized by DSC, isotactic index through heptane extractables (HS), TGA, EDX, XRD, and optical microscopy (OM). The results showed that the type of clay modifier has a great influence on the catalyst performance. (author)

Novel polypropylene biocomposites reinforced with carbon nanotubes and hydroxyapatite nanorods for bone replacements

Energy Technology Data Exchange (ETDEWEB)

Liao, Cheng Zhu; Li, Kai [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Wong, Hoi Man; Tong, Wing Yin; Yeung, Kelvin Wai Kwok [Department of Orthopedics and Traumatology, The University of Hong Kong (Hong Kong); Tjong, Sie Chin, E-mail: aptjong@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2013-04-01

Multi-walled carbon nanotubes (MWNTs) of 0.1 and 0.3 wt.% and hydoxyapatite nanorods (nHAs) of 8–20 wt.% were incorporated into polypropylene (PP) to form biocomposites using melt-compounding and injection molding techniques. The structural, mechanical, thermal and in vitro cell responses of the PP/MWNT–nHA hybrids were investigated. Tensile and impact tests demonstrated that the MWNT additions are beneficial in enhancing the stiffness, tensile strength and impact toughness of the PP/nHA nanocomposites. According to thermal analysis, the nHA and MWNT fillers were found to be very effective to improve dimensional and thermal stability of PP. The results of osteoblast cell cultivation and dimethyl thiazolyl diphenyl tetrazolium (MTT) tests showed that the PP/MWNT–nHA nanocomposites are biocompatible. Such novel PP/MWNT–nHA hybrids are considered to be potential biomaterials for making orthopedic bone implants. - Highlights: ► Multiwalled carbon nanotubes (MWNTs) and hydroxyapatite nanorods (nHA) are used as hybrid fillers to reinforce polypropylene. ► MWNT additions are beneficial in enhancing tensile strength and stiffness of PP/nHA composites. ► Hybridizing MWNT with nHA fillers enhance thermal and dimensional stability of PP significantly. ► Hybridizing MWNT with nHA greatly enhance osteoblast adhesion and proliferation. ► PP/MWNT–nHA composites show attractive applications as load-bearing materials in orthopedics.

Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

Science.gov (United States)

Ávila-Orta, Carlos A.; Quiñones-Jurado, Zoe V.; Waldo-Mendoza, Miguel A.; Rivera-Paz, Erika A.; Cruz-Delgado, Víctor J.; Mata-Padilla, José M.; González-Morones, Pablo; Ziolo, Ronald F.

2015-01-01

Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. PMID:28793686

Development of more friendly food packaging materials base on polypropylene through blending with polylacticacid

Science.gov (United States)

Setiawan, Achmad Hanafi; Aulia, Fauzan

2017-01-01

The commonly food packaging materials today is used a thin layer plastic or film, which is made of a synthetic polymer, such as polypropylene (PP). However, the use of these polymers has a negative impact on the environment, because the synthetic polymer is difficult to degrade naturally by the biotic components such as micro-organisms decomposers and abiotic components such as the sunshine. The use of the biodegradable polymeric material will reduce the use of synthetic polymer products, thereby reducing plastic waste pollution at relatively low cost, it is expected to produce positive effects both for the environment and in terms of economy. PLA is a biodegradable polymer that can be substituted totally or partially to synthetic polymers as far as could fulfill the main function of packaging in the protection and preservation of food. Increasing PLA content in polypropylene blend will affect to the increasing in its water absorption and also its biodegradable. 20% PLA may the optimum composition of poly-blend for food packaging.

A Comprehensive Study of the Polypropylene Fiber Reinforced Fly Ash Based Geopolymer.

Directory of Open Access Journals (Sweden)

Navid Ranjbar

Full Text Available As a cementitious material, geopolymers show a high quasi-brittle behavior and a relatively low fracture energy. To overcome such a weakness, incorporation of fibers to a brittle matrix is a well-known technique to enhance the flexural properties. This study comprehensively evaluates the short and long term impacts of different volume percentages of polypropylene fiber (PPF reinforcement on fly ash based geopolymer composites. Different characteristics of the composite were compared at fresh state by flow measurement and hardened state by variation of shrinkage over time to assess the response of composites under flexural and compressive load conditions. The fiber-matrix interface, fiber surface and toughening mechanisms were assessed using field emission scan electron microscopy (FESEM and atomic force microscopy (AFM. The results show that incorporation of PPF up to 3 wt % into the geopolymer paste reduces the shrinkage and enhances the energy absorption of the composites. While, it might reduce the ultimate flexural and compressive strength of the material depending on fiber content.

THE FTIR STUDIES OF PHOTO-OXIDATIVE DEGRADATION OF POLYPROPYLENE

Institute of Scientific and Technical Information of China (English)

WEN Zaiqing; HU Xingzhou; SHEN Deyan

1988-01-01

The photo-oxidative degradation process of polypropylene film containing iron ions was investigated via FTIR and absorbance substraction technique. It is shown that the iron ions play an important role in the decomposition of hydroperoxide and the increase of the degradation rate of polypropylene film. Theamorphous region of PP film undergoes degradation prior to the crystalline one.

Processing of Polypropylene-Organic Montmorillonite Nanocomposite by Equal Channel Multiangular Extrusion

Directory of Open Access Journals (Sweden)

V. A. Beloshenko

2016-01-01

Full Text Available By the example of polypropylene-organic montmorillonite composite (PP-OMMT, the abilities of the method of equal channel multiangular extrusion have been studied with respect to the modification of the structure and the properties of polymeric nanocomposites. With using X-ray structure analysis, TEM, DSC, and dilatometry, it has been demonstrated that this kind of processing provides an additional intercalation of the polymer into OMMT tactoids with the succeeding exfoliation and facilitates an increase in the aspect ratio, the degree of platelet orientation, the crystalline lamellar thickness, and a decrease in the dispersion of the crystallite thickness, as well as the formation of biaxial orientation of the OMMT and PP crystals. The observed structure rearrangements determine enhanced microhardness, ductility, and the heat distortion temperature of the PP-OMMT composite.

Application to refrigerator plastics by mechanical recycling from polypropylene in waste-appliances

International Nuclear Information System (INIS)

Ha, Kyung Ho; Kim, Moon Saeng

2012-01-01

Highlights: → Polypropylene is mechanically recycled from waste-appliances. → Recycled polypropylene (RPP) is impact enhanced polypropylene with ethylene-propylene rubber (EPR). → Performance evaluation shows that RPP is applicable to refrigerator plastics. -- Abstract: For the application to refrigerator plastics by mechanical recycling from polypropylene (PP) in waste-appliances, it needs to identify the degradation and heterogeneity of recycled polypropylene (RPP). It is applicable the thermal analysis such as differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), spectroscopic analysis such as Fourier Transform Infrared (FTIR) and morphological analysis such as scanning electronic microscope (SEM). The analysis results show that RPP from waste-appliances is the polyethylene (PE) and polypropylene (PP) copolymer enhanced impact property (Impact-PP) and it is possible to apply refrigerator plastics with good impact property at low temperature. Finally, the performance evaluation of RPP is estimated by Gel Permeation Chromatography (GPC) analysis and is performed by the various mechanical and physical testing methods. It shows that RPP has relatively high molecular weight and balanced properties with strength and toughness. It is expected that RPP by the mechanical recycling from waste-appliances will have about 50% cost-merit.

A study on the trans-crystallisation behaviour of flax fibre reinforced polypropylene composites and effect on mechanical properties

NARCIS (Netherlands)

George, J.; Garkhail, S.K.; Wieland, B.; Peijs, A.A.J.M.; Mattoso, L.H.C.

2000-01-01

The effect of flax fiber reinforcement on crystn. behavior of polypropylene (PP) was investigated using a hot-stage optical microscope. To follow the crystn. kinetics, cooling rate and crystn. temps. were varied. Flax fibers with different processing history e.g. green flax, Duralin flax, alkali and

Flame Retardancy and Mechanical Properties of Kenaf Filled Polypropylene (PP) Containing Ammonium Polyphosphate (APP)

International Nuclear Information System (INIS)

Atikah Ismail; Azman Hassan; Aznizam Abu Bakar; Jawaid, M.

2013-01-01

The effects of ammonium polyphosphate (APP) as flame retardant and kenaf as fillers on flammability, thermal and mechanical properties of polypropylene (PP) composites were determined. Test specimens were prepared by using a co-rotating twin screw extruder for the compounding process followed by injection molding. The flame retardancy of the composites was determined by using limiting oxygen index (LOI) test. Addition of flame retardant into kenaf-PP composites significantly increased the LOI values that indicated the improvement of flame retardancy. Thermogravimetric analysis was done to examine the thermal stability of the composites. The addition of kenaf fiber in PP composites decreased the thermal stability significantly but the influence of APP on thermal properties of the kenaf-filled PP composites was not significant. The flexural strength and modulus of composites increased with the addition of APP into kenaf filled PP composite. The addition of APP into kenaf filled PP causes increase in the impact strength while increasing the APP content in the kenaf filled PP composite show decrease in impact strength. (author)

Application of Glass Fiber Waste Polypropylene Aggregate in Lightweight Concrete – thermal properties

Science.gov (United States)

Citek, D.; Rehacek, S.; Pavlik, Z.; Kolisko, J.; Dobias, D.; Pavlikova, M.

2018-03-01

Actual paper focus on thermal properties of a sustainable lightweight concrete incorporating high volume of waste polypropylene aggregate as partial substitution of natural aggregate. In presented experiments a glass fiber reinforced polypropylene (GFPP) which is a by-product of PP tubes production, partially substituted fine natural silica aggregate in 10, 20, 30, 40 and 50 mass %. Results were compared with a reference concrete mix without plastic waste in order to quantify the effect of GFPP use on concrete properties. Main material physical parameters were studied (bulk density, matrix density without air content, and particle size distribution). Especially a thermal transport and storage properties of GFPP were examined in dependence on compaction time. For the developed lightweight concrete, thermal properties were accessed using transient impulse technique, where the measurement was done in dependence on moisture content (from the fully water saturated state to dry state). It was found that the tested lightweight concrete should be prospective construction material possessing improved thermal insulation function and the reuse of waste plastics in concrete composition was beneficial both from the environmental and financial point of view.

Study of modified polypropylene nanocomposites by gamma irradiation with addition of cloisite clay

International Nuclear Information System (INIS)

Komatsu, Luiz G.H.; Oliani, Washington L.; Parra, Duclerc F.; Lugao, Ademar B.

2011-01-01

Nanomaterials, and, in particular, nanoreinforcements for polymer composites have been the subject of intense research, development and commercialization. Clay-containing polymeric nanocomposites (CPNCs) are used as either functional or structural materials, large-volume CPNCs with a commodity or engineering polymer as the matrix, where the mechanical behavior is the main concern (followed by gas-vapor barrier properties, flammability, etc.). This work concerns to the study of the mechanical, thermal and morphological behavior nanocomposite, (HMSPP) Polypropylene High Melt Strength (obtained at dose of 12.5 kGy) and addition of 5 and 10 wt% of organoclay with Cloisite 20A nanocomposite. Agent compatibilizer polypropylene-graft, (PP-g-AM) was added at 3% concentration and the clay was dispersed through melt intercalation technique using a twin-screw extruder). We observed an increase in traction rupture. The mechanical behavior was evaluated by strength, the thermal behavior were evaluated by the technique of differential scanning calorimetry, the morphology of the nanocomposites was studied by scanning electron microscopy, melt flow index and Fourier transformed infrared spectroscopy in nanocomposites Cloisite 20 A at 10% wt. (author)

The Effectiveness of Polydimethylsiloxane (PDMS) and Hexamethyldisiloxane (HMDSO) As Compatibilizer on the Preparation of Betel Nut Fiber (BNF) and Polypropylene (PP) /Polystyrene (PS) Wood Composites

International Nuclear Information System (INIS)

Nurul Izzaty Khalid; Azizah Baharum; Siti Sarah Ramli; Siti Norhana Mohd Nor

2014-01-01

This research was carried out to investigate the effectiveness of polydimethylsiloxane (PDMS) and hexamethyldisiloxane (HMDSO) as compatibilizing agent in producing wood composites of betel nut fiber/ polypropylene (BNF/ PP) and betel nut fiber/ polystyrene (BNF/ PS). Wood composite was prepared by blending 40 % of matrix polymer and 60 % of treated and untreated BNF using internal mixer Brabender Plasticoder at 170 degree Celsius with 50 rpm rotor speed for 13 minutes. The treatment was done prior to blending the materials by immersing the BNF in PDMS and HMDSO solutions with 1 %, 3 % and 5 % of concentrations for 24 hours. The effects of 1 % HMDSO treatment on BNF/ PP composite contributed to high flexure strength and impact strength which are 19.2 MPa and 7.9 kJ/M2 respectively while the percentage of water absorption showed the minimum value of 6.7%. The impact strength of BNF/ PS composite treated with 3% HMDSO showed maximum value that is 4.7 kJ/ M 2 and minimum percentage of water absorption, 6.8 %. However, the flexure strength of untreated BNF/ PS composite is higher than treated BNF/ PS composite with value of 4.7 MPa. The morphology of treated BNF/ PP composites from SEM micrographs showed better interface interaction between fibers and matrices. FTIR spectra showed the presence of siloxane groups such as Si-O, Si-CH 3 , Si-(CH 3 ) and Si(CH 3 ) as a result of HMDSO and PDMS treatment. Based on the characterization analysis, HMDSO treated composite of BNF/ PP showed more effective interfacial interaction between BNF and matrices. (author)

Improvement of radiation resistance of polypropylene by blending with polyethylene and polystyrene

International Nuclear Information System (INIS)

Al Aji, Z.

2001-01-01

The use of polypropylene in production of medical component and packaging materials makes it an interesting material for applied research. Since the use of ethylene oxide for sterilization of medical components will be forbidden in the next future because of its carcinogens effect. Therefore, another alternative sterilization methods are required. The use of Gamma radiation is already established for sterilization of some medical components, this technique causes change in the physical mechanical properties of polypropylene, which makes the addition of stabilizers necessary. In this work, blends of domestically used polymers, polypropylene, linear low-density polyethylene, and polystyrene/butadiene were prepared in order to improve the radiation resistance of polypropylene; naphthalene was also used as an additive

Tribological performance of paddy straw reinforced polypropylene (PSRP and unidirectional glass-pultruded-kenaf (UGPK composites

Directory of Open Access Journals (Sweden)

R.M. Nasir

2014-06-01

Full Text Available In standard preparation and fabrication of natural-fibre embedded composites, 5 wt. % of natural fibre is enough to strengthen and homogenized in parental matrix as the mechanical strength was observed to increase by more than 25% of pure matrix. Hence, paddy straw and kenaf has been a potential candidate in northern region of Malaysia due to its abundance and easily replenished. A unidirectional glass-pultruded-kenaf (UGPK and paddy straws reinforced polypropylene (PSRP was studied focusing on its tribological performance. Meanwhile, friction and wear properties were examined using pin-on-disc machine under ambient temperature with dry contact condition. The tests were conducted at various sliding velocities (1.178-2.749m/s and applied normal loads (9.82-19.64N. The results showed that specific wear rate and friction coefficient decreased with increasing applied normal load and sliding velocity, but the applied normal load was more influential. The coefficient of friction ranges from 0.5 to 4 and wear rate varies from 0.5 to 4 x 10-5 mm3/Nm for PSRP. The friction coefficient of UGPK is within a range of 2.76 to 4.54 at the given test parameters while its wear rate ranging from 0.8 to 1.79 x 10-5mm3/Nm. The failure mode observed during the test was micro-buckling and followed by splitting while fiber-matrix interfacial failure occurred.

Reinforced poly(propylene oxide)- a very soft and extensible dielectric electroactive polymer

DEFF Research Database (Denmark)

Goswami, Kaustav; Galantini, F.; Mazurek, Piotr Stanislaw

2013-01-01

Poly(propylene oxide) (PPO), a novel soft elastomeric material, and its composites were investigated as a new dielectric electroactive polymer (EAP). The PPO networks were obtained from thiol-ene chemistry by photochemical crosslinking of ,!-diallyl PPO with a tetra-functional thiol. The elastomer...... was reinforced with hexamethylenedisilazane treated fumed silica to improve the mechanical properties of PPO. The mechanical properties of PPO and composites thereof were investigated by shear rheology and stress–strain measurements. It was found that incorporation of silica particles improved the stability...... of the otherwise mechanically weak pure PPO network. Dielectric spectroscopy revealed high relative dielectric permittivity of PPO at 103 Hz of 5.6. The relative permittivity was decreased slightly upon addition of fillers, but remained higher than the commonly used acrylic EAP material VHB4910...

Effect of coupling agent on durian skin fibre nanocomposite reinforced polypropylene

Science.gov (United States)

Siti Nur E'zzati, M. A.; Anuar, H.; Siti Munirah Salimah, A. R.

2018-01-01

This paper reports on the development of a composite-based natural fiber to reduce the reliance on petroleum-based product in order to amplify environmental awareness. The production of Durian Skin Nanofiber (DSNF) was conducted using biological fermentation method via rhizopus oryzae in order to obtain the nano dimension of the particle size. Polypropylene (PP) and DSNF were produced using Haake internal mixer via melt blending technique. The significant effect of maleic anhydride grafted polypropylene (MAPP) on the properties of PP/DSNF nanocomposite was investigated to study its mechanical properties which are tensile strength and thermal stability using thermogravimetric (TGA) and differential scanning analysis (DSC). The tensile property of PP nanocomposites increased from 33 MPa to 38 MPa with the presence of MAPP. The addition of MAPP also increased the thermal stability of PP/DSNF nanocomposite where the char residue increased by 52%. Besides that, the thermal degradation of PP/DSNF and PP/DSNF-MAPP were higher than PP where they exerted higher amount of weight loss at an elevated temperature. The percentage of crystallinity, %Xc, of PP nanocomposites improved with the addition of MAPP by 35% based on the differential scanning calorimetry (DSC) result. The SEM analysis showed that the PP/DSNF-MAPP exerts ductile fracture while PP/DSNF exerts brittle fracture.

Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Creusa Iara; Oliveira, Ricardo Vinicius Bof de; Mauler, Raquel Santos, E-mail: raquel.mauler@ufrgs.br [Universidade Federal do Rio Grande do Sul (PGCIMAT/IQ/UFRGS), Porto Alegre, RS (Brazil); Bianchi, Otavio [Universidade de Caxias do Sul (PGMAT/CCET/UCS), RS (Brazil); Oviedo, Mauro Alfredo Soto [Braskem S/A, Rio de Janeiro, RJ (Brazil)

2013-07-01

The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage) and G' (loss) moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength. (author)

Compositional analysis of nitrile terminated poly(propylene imine) dendrimers by high-performance liquid chromatography combined with electrospray mass spectrometry

NARCIS (Netherlands)

van der Wal, S; Mengerink, Y; Brackman, JC; de Brabander, EMM; Jeronimus-Stratingh, CM; Bruins, AP

1998-01-01

Separation methods for nitrile terminated poly(propylene imine) dendrimers were developed to monitor and optimize their large scale production. Detailed analyses of defects within a dendrimer generation were performed by HPLC at alkaline pH (sodium hydroxide) on a polymer-based column or at neutral

High strain rate behaviour of polypropylene microfoams

Science.gov (United States)

Gómez-del Río, T.; Garrido, M. A.; Rodríguez, J.; Arencón, D.; Martínez, A. B.

2012-08-01

Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc.) or personal safety (helmets, knee-pads, etc.). In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry) is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s-1) in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB). Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

Antioxidant action in irradiated polypropylene studied by ultraviolet spectroscopy

International Nuclear Information System (INIS)

Milosavljevic, B.H.; Novakovic, Lj.

1999-01-01

Ultraviolet spectrum of 0.2 mm thick film of polypropylene containing 0.5% ORGANOX 1010 showed that in the sample prepared by slow cooling about 15% of the antioxidant reacted during the preparation process. The difference in turbidity between the samples obtained in the slow and the fast cooling process is attributed to the degree of crystallinity, which is in agreement with the DSC data. Very pronounced effects of the oxygen concentration and the degree of crystallinity on antioxidant uptake in irradiated polypropylene films were observed and discussed. It was also shown that a Febetron 707 pulsed electron accelerator is capable of producing both the single pulse dose (50 kGy) and the dose rate (2.5 TGy/s) large enough to enable a comparison of dose rate effects and LET effects in the study of the antioxidant reactions in polypropylene

Reinforced poly(propylene oxide): a very soft and extensible dielectric electroactive polymer

International Nuclear Information System (INIS)

Goswami, K; Mazurek, P; Daugaard, A E; Skov, A L; Galantini, F; Gallone, G

2013-01-01

Poly(propylene oxide) (PPO), a novel soft elastomeric material, and its composites were investigated as a new dielectric electroactive polymer (EAP). The PPO networks were obtained from thiol-ene chemistry by photochemical crosslinking of α,ω-diallyl PPO with a tetra-functional thiol. The elastomer was reinforced with hexamethylenedisilazane treated fumed silica to improve the mechanical properties of PPO. The mechanical properties of PPO and composites thereof were investigated by shear rheology and stress–strain measurements. It was found that incorporation of silica particles improved the stability of the otherwise mechanically weak pure PPO network. Dielectric spectroscopy revealed high relative dielectric permittivity of PPO at 10 3 Hz of 5.6. The relative permittivity was decreased slightly upon addition of fillers, but remained higher than the commonly used acrylic EAP material VHB4910. The electromechanical actuation performance of both PPO and its composites showed properties as good as VHB4910 and a lower viscous loss. (paper)

Production of the oxidation-resistant polypropylene track membranes

International Nuclear Information System (INIS)

Kravets, L.I.; Dmitriev, S.N.; Apel, P.Y.

1999-01-01

This paper describes results of the method of manufacturing the polypropylene track membranes produced by physicochemical treatment under irradiation of accelerated heavy ions of polymer films. The developed method allows to produce membranes 0.1 - 0.2 μm in diameter and more with an improved structural and physicochemical properties. Poly-propylene track membranes of a novel sample are characterized by high homogeneity of pore sizes in magnitude, considerable mechanical strength, advanced thermal stability and resistance to oxidation in aggressive media. It opens new fields for their usage

Hofmeister effect of salt mixtures on thermo-responsive poly(propylene oxide)

DEFF Research Database (Denmark)

Moghaddam, Saeed Zajforoushan; Thormann, Esben

2015-01-01

of aqueous solutions of poly(propylene oxide) is affected by mixtures of ions with different location in the Hofmeister series. Our results show that the Hofmeister effects of pure salt species are not always linearly additive and that the relative effect of some ions can be reversed depending...... on the composition of the salt mixture as well as by the absolute and relative concentration of the different species. We suggest that these results can lead to a better understanding of the potential role of the Hofmeister effect in regulation of biological processes, which does always take place in salt mixtures...... rather than solutions containing just single salt species....

Characterization and Some Properties of Functionalized Graft Copolymer

International Nuclear Information System (INIS)

Hegazy El-Sayed, A.; Kamal, H.; Mahmoud, Gh.A.; Khalifa, N.A.

2000-01-01

The study involved the investigation and characterization of membranes prepared by graft copolymerization of acrylonitrile (AN) and vinyl acetate (VAc) binary monomers onto low density polyethylene (LDPE) and isotactic polypropylene (IPP). The mutual gamma-irradiation method was used as a grafting technique. The effects of grafting and chemical treatments on the thermal properties and crystallinity of prepared graft copolymer have been investigated using DSC, TGA and XRD. IR spectra recorded before and after grafting and also for the chemically treated membranes to elucidate the structural changes occurred due to grafting and chemical treatments

Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Carlos A. Ávila-Orta

2015-11-01

Full Text Available Isotactic polypropylenes (iPP with different melt flow indexes (MFI were used to fabricate nanocomposites (NCs with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM, Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.

Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

Directory of Open Access Journals (Sweden)

Creusa Iara Ferreira

2013-01-01

Full Text Available The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage and G'' (loss moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength.

Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Creusa Iara; Oliveira, Ricardo Vinicius Bof de; Mauler, Raquel Santos, E-mail: raquel.mauler@ufrgs.br [Universidade Federal do Rio Grande do Sul (PGCIMAT/IQ/UFRGS), Porto Alegre, RS (Brazil); Bianchi, Otavio [Universidade de Caxias do Sul (PGMAT/CCET/UCS), RS (Brazil); Oviedo, Mauro Alfredo Soto [Braskem S/A, Rio de Janeiro, RJ (Brazil)

2013-07-01

The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage) and G' (loss) moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength. (author)

Synthesis and characterization of kaolin with polystyrene via in-situ polymerization and their application on polypropylene

International Nuclear Information System (INIS)

Zhao, Songfang; Qiu, Shangchang; Zheng, Yuying; Cheng, Lei; Guo, Yong

2011-01-01

To improve both the mechanical and thermal properties of kaolin/polypropylene (PP) composites, kaolin was modified by using 3-(trimethoxysilyl) propylmethacrylate (YDH-570) as a coupling agent to form polymerizable particle. Styrene was radically polymerized through the immobilized vinyl using benzoyl peroxide (BPO) as an initiator. Fourier transform-infrared (FTIR) spectroscopy, particle size distribution, X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA) well demonstrated that the kaolin-polystyrene particles were successfully synthesized via in-situ polymerization. While the modified kaolin and raw kaolin were introduced into the PP matrix, it could be concluded that modified kaolin/PP composites have better mechanical and thermal properties than raw kaolin/PP composites, and these improvements were attributed to the desirable dispersion of kaolin in PP matrix.

High-voltage pulsed life of multistressed polypropylene capacitor dielectric

International Nuclear Information System (INIS)

Laghari, J.R.

1992-01-01

High-voltage polypropylene capacitors were aged under singular as well as simultaneous multiple stresses (electrical, thermal, and radiation) at the University of Buffalo's 2 MW thermal nuclear reactor. These stresses were combined neutron-gamma radiation with a total dose of 1.6 x 10 6 rad, electrical stress at 40 V rms /μm, and thermal stress at 90 degrees C. After exposure, the polypropylene dielectric was tested for life (number of pulses to fail) under high-voltage high-repetition-rate (100 pps) pulses. Pulsed life data were also compared with ac life data. Results show that radiation stress causes the most degradation in life, either acting alone or in combination with other stresses. The largest reduction in life occurs when polypropylene is aged under simultaneous multiple stresses (electrical, thermal, and radiation). In this paper, it is shown that pulsed life can be equivalently compared with ac life

PLASTIC SHRINKAGE CONTROLLING EFFECT BY POLYPROPYLENE SHORT FIBER WITH HYDROPHILY

Science.gov (United States)

Hosoda, Akira; Sadatsuki, Yoshitomo; Oshima, Akihiro; Ishii, Akina; Tsubaki, Tatsuya

The aim of this research is to clarify the mechanism of controlling plastic shrinkage crack by adding small amout of synthetic short fiber, and to propose optimum polypropylene short fiber to control plastic shrinkage crack. In this research, the effect of the hydrophily of polypropylene fiber was investigated in the amount of plastic shrinkage of mortar, total area of plastic shrinkage crack, and bond properties between fiber and mortar. The plastic shrinkage test of morar was conducted under high temperature, low relative humidity, and constant wind velocity. When polypropylene fiber had hydrophily, the amount of plastic shrinkage of mortar was restrained, which was because cement paste in morar was captured by hydrophilic fiber and then bleeding of mortar was restrained. With hydrophily, plastic shrinkage of mortar was restrained and bridging effect was improved due to better bond, which led to remarkable reduction of plastic shrinkage crack. Based on experimental results, the way of developing optimum polypropylene short fiber for actual construction was proposed. The fiber should have large hydrophily and small diameter, and should be used in as small amount as possible in order not to disturb workability of concrete.

Sensitivity of the polypropylene to the strain rate: experiments and modeling

International Nuclear Information System (INIS)

Abdul-Latif, A.; Aboura, Z.; Mosleh, L.

2002-01-01

, i.e. to describe the elastic-viscoplastic behavior of the polypropylene for other loading paths which did not use during the identification process. Finally, the obtained model being devoted to describe the stress-strain behavior of the polypropylene, is able to fairly well reproduce the strain rate dependent deformation of such a material under several loading conditions (uniaxial tensile load at different strain rates, strain rate jumping and relaxation phenomenon). It is important to keep in mind that the final objective will be to model the damaged behavior of women fibbers glass composite materials with thermoplastic matrix

High strain rate behaviour of polypropylene microfoams

Directory of Open Access Journals (Sweden)

Martínez A.B.

2012-08-01

Full Text Available Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc. or personal safety (helmets, knee-pads, etc.. In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s−1 in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB. Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

Polypropylene reinforced with organophilic clay and brazilian nut fibers

International Nuclear Information System (INIS)

Rocha-Gomes, L.V.; Mondelo-Garcia, F.J.; Vaccioli, K.; Valera, S.T.; Silva-Valenzuela, M.G.; Valenzuela-Diaz, F.R.

2014-01-01

Polymer nanocomposites have been shown to possess better properties when compared with traditional composites. This study aims to investigate the effects of the addition of organophilic clay and Brazilian nut fiber on the polypropylene (PP). First, 5%, 10% and 20% PP/compatibilizer maleic anhydride (PP-g-MA) by weight was added to Pure PP, respectively. From the results, 5% PP-g-MA was defined for preparing the nanocomposites. Samples were prepared containing 5% PP / PP-g-MA reinforced with 5% organophilic Brazilian smectite clay and 5%, 10% and 15% Brazilian nut fiber. Specimens were tested for tensile strength and impact. The materials were characterized by laser diffraction particle size and X-ray diffraction, and the nanocomposites, by mechanical strength and impact. The best result was obtained by inserting 15% fiber. (author)

Highest recorded electrical conductivity and microstructure in polypropylene-carbon nanotubes composites and the effect of carbon nanofibers addition

Science.gov (United States)

Ramírez-Herrera, C. A.; Pérez-González, J.; Solorza-Feria, O.; Romero-Partida, N.; Flores-Vela, A.; Cabañas-Moreno, J. G.

2018-04-01

In the last decade, numerous investigations have been devoted to the preparation of polypropylene-multiwalled carbon nanotubes (PP/MWCNT) nanocomposites having enhanced properties, and in particular, high electrical conductivities (> 1 S cm-1). The present work establishes that the highest electrical conductivity in PP/MWCNT nanocomposites is limited by the amount of nanofiller content which can be incorporated in the polymer matrix, namely, about 20 wt%. This concentration of MWCNT in PP leads to a maximum electrical conductivity slightly lower than 8 S cm-1, but only by assuring an adequate combination of dispersion and spatial distribution of the carbon nanotubes. The realization of such an optimal microstructure depends on the characteristics of the production process of the PP/MWCNT nanocomposites; in our experiments, involving composite fabrication by melt mixing and hot pressing, a second re-processing cycle is shown to increase the electrical conductivity values by up to two orders of magnitude, depending on the MWCNT content of the nanocomposite. A modest increase of the highest electrical conductivity obtained in nanocomposites with 21.5 wt% MWCNT content has been produced by the combined use of carbon nanofibers (CNF) and MWCNT, so that the total nanofiller content was increased to 30 wt% in the nanocomposite with PP—15 wt% MWCNT—15 wt%CNF.

Effect of atmospheric pressure plasma treatment condition on adhesion of ramie fibers to polypropylene for composite

Energy Technology Data Exchange (ETDEWEB)

Li, Ying [College of Material and Textile Engineering, Jiaxing University, Jiaxing 314033 (China); Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); School of Human Ecology, University of Wisconsin-Madison, Madison, WI 53706 (United States); Manolache, Sorin [Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); US Forest Products Laboratory, Madison, WI 53726 (United States); Qiu, Yiping, E-mail: ypqiu@dhu.edu.cn [College of Textiles, Donghua University, Shanghai 201620 (China); Sarmadi, Majid, E-mail: majidsar@wisc.edu [Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); School of Human Ecology, University of Wisconsin-Madison, Madison, WI 53706 (United States); Materials Science Program, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2016-02-28

Graphical abstract: - Highlights: • The continuous ethanol flow technique can successfully modify ramie fiber surface with an increase in IFSS value up to 50%. • Response surface methodology was applied to design the plasma treatment parameters for ramie fiber modification. • The ethanol flow rate was the most influential treatment parameter in plasma modification process. - Abstract: In order to improve the interfacial adhesion between hydrophilic ramie fibers and hydrophobic polypropylene (PP) matrices, ramie fibers are modified by atmospheric pressure dielectric barrier discharge (DBD) plasma with our continuous ethanol flow technique in helium environment. A central composite design of experiments with different plasma processing parameter combinations (treatment current, treatment time and ethanol flow rate) is applied to find the most influential parameter and to obtain the best modification effect. Field emission scanning electron microscope (SEM) shows the roughened surfaces of ramie fibers from the treated groups due to plasma etching effect. Dynamic contact angle analysis (DCAA) demonstrates that the wettability of the treated fibers drastically decreases. Microbond pullout test shows that the interfacial shear strength (IFSS) between treated ramie fibers and PP matrices increases significantly. Residual gas analysis (RGA) confirms the creation of ethyl groups during plasma treatment. This study shows that our continuous ethanol flow technique is effective in the plasma modification process, during which the ethanol flow rate is the most influential parameter but all parameters have simultaneous influence on plasma modification effect of ramie fibers.

Stabilization of polypropylene, polypropylene blends with poly (styrene-b-(ethylene-co-butylene)-b-styrene) under irradiation: A comparative investigation

International Nuclear Information System (INIS)

Luan Shifang; Yang Huawei; Shi Hengchong; Zhao Jie; Wang Jianwei; Yin Jinghua

2011-01-01

The aim of this paper is to investigate the stabilization of polypropylene in the poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)/polypropylene (PP) blends under irradiation with respect to PP. The PP films, SEBS/PP films were subjected to electron beam irradiation and characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and dynamic mechanical thermal analysis (DMTA). It demonstrated that upon irradiation, the molecular weight of PP had a pronounced decrease due to the major chain scission, and the minor chain cross-linking or chain branching occurred at the higher irradiation dose. Stabilization of PP was improved in the presence of SEBS, exhibiting an enhanced irradiation resistance.

Stabilization of polypropylene, polypropylene blends with poly (styrene-b-(ethylene-co-butylene)-b-styrene) under irradiation: A comparative investigation

Energy Technology Data Exchange (ETDEWEB)

Luan Shifang; Yang Huawei; Shi Hengchong; Zhao Jie [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wang Jianwei [Shandong Weigao Group Medical Polymer Company Limited, Weihai 264209 (China); Yin Jinghua, E-mail: yinjh@ciac.jl.c [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2011-01-15

The aim of this paper is to investigate the stabilization of polypropylene in the poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)/polypropylene (PP) blends under irradiation with respect to PP. The PP films, SEBS/PP films were subjected to electron beam irradiation and characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and dynamic mechanical thermal analysis (DMTA). It demonstrated that upon irradiation, the molecular weight of PP had a pronounced decrease due to the major chain scission, and the minor chain cross-linking or chain branching occurred at the higher irradiation dose. Stabilization of PP was improved in the presence of SEBS, exhibiting an enhanced irradiation resistance.

Influence of injection temperatures and fiberglass compositions on mechanical properties of polypropylene

Science.gov (United States)

Keey, Tony Tiew Chun; Azuddin, M.

2017-06-01

Injection molding process appears to be one of the most suitable mass and cost efficiency manufacturing processes for polymeric parts nowadays due to its high efficiency of large scale production. When down-scaling the products and components, the limits of conventional injection molding process are reached. These constraints had initiated the development of conventional injection molding process into a new era of micro injection molding technology. In this study, fiberglass reinforced polypropylenes (PP) with various glass fiber percentage materials were used. The study start with fabrication of micro tensile specimens at three different injection temperature, 260°C, 270°C and 280°C for different percentage by weight of fiberglass reinforced PP. Then evaluate the effects of various injection temperatures on the tensile properties of micro tensile specimens. Different percentage by weight of fiberglass reinforced PP were tested as well and it was found that 20% fiberglass reinforced PP possessed the greatest percentage increase of tensile strength with increasing temperatures.

Application of gas chromatography to the investigations on polypropylene radiolysis

International Nuclear Information System (INIS)

Zagorski, Z.P.; Gluszewski, W.

2006-01-01

Refinement of the gas chromatography (GC) instrumental approach permitted not only improvement of investigation in basic research, but also development of a new kind of polypropylene blends, more suitable for the production of medical devices and radiation sterilization. It has been shown, that using the GC method not only methane and carbon dioxide can be measured, but also the consumption of oxygen which reacts with free radicals on the polypropylene chain

Effect of polybutenes on mechanical and physical properties of polypropylene

International Nuclear Information System (INIS)

Nascimento, Uedson A. do; Timoteo, Gustavo Arante V.; Rabello, Marcelo S.

2009-01-01

This study investigated the effect of polybutene (PIB) of molecular weights ranging from 480 the 1.600 g/mol in polypropylene homopolymer. Compositions with 0, 3, 5 and 7% of PIB were prepared in internal mixer and compression moulded. The properties evaluated were: tensile strength, scanning electron microscopy (SEM), FTIR, X-ray diffraction (XRD) and melt flow index (IF). The results of mechanical tests showed that the presence of the plasticizer reduced the tensile strength, elastic modulus and hardness. The analysis of XRD showed a drop in the degree of crystallinity of PP/PIB blends. The micrographs obtained by SEM did not reveal the occurrence of the phase separation. The IF analysis confirm the effect of PIB as internal lubricant's, by increasing the rate of flow. (author)

High impact strength polymers having novel nano-structures produced via reactive extrusion

Science.gov (United States)

Tortorella, Nathan Fraser

A major focus of scientists and engineers over the last century has been to increase the impact strength and therefore reduce the brittleness of materials. By altering and adding energy absorption mechanisms, brittle failure can be averted. Isotactic polypropylene (PP) is the focus of this dissertation because it is an extremely low cost, high volume, versatile plastic but behaves in a brittle manner at or below room temperature or in a notched state. Early work on impact modification of polypropylene focused on blending energy-absorbing low density elastomers and rubbers. These binary blends all had a common problem---an increase in impact strength was paralleled by a significant decrease in both elastic modulus and yield stress. Reactive extrusion processing has allowed the in-situ compatibilization of isotactic polypropylene and metallocene-catalyzed ethylene-octene copolymers (EOCs). This process involves combining both the comonomer and vector fluid approaches to grafting polyolefins. Styrene monomer and a multifunctional acrylate monomer undergo peroxide-induced copolymerization and grafting in the presence of both PP and EOC. This results in a phase separated alloy with an impact strength over 13 times that of pure polypropylene and double that of the physical blend. There is also a significant improvement in stress-strain performance when comparing the alloys to physical blend counterparts. Many researchers have categorized the necessary components to toughening polypropylene as pertaining to the amorphous phase. The alloys described in this dissertation meet the criteria put forth by these researchers, namely low density, crystallinity, and modulus of the elastomer phase, sub-micron particle diameter, close inter-particle distance, and a high degree of entanglements of both the PP matrix phase and EOC minor phase. But many people neglect to study the crystalline state of impact modified PP in conjunction with the amorphous phase. This work shows that the

Study of mechanical, rheological and thermal properties of nanocomposite HMSPP (high melt strength polypropylene) with Brazilian bentonite

International Nuclear Information System (INIS)

Fermino, Danilo Marin

2011-01-01

This work concerns to the study of the mechanical, thermal and rheological behavior of the nano composite HMSPP - Polypropylene High Melt Strength (obtained at a dose of 12.5 kGy) and a bentonite clay Brazilian Paraiba, known as 'Chocolate' in concentrations of 5 and 10% by weight, comparison of to one American Clay, Cloisite 20A nanocomposite was done. Agent compatibilizer polypropylene-graft, known as maleic anhydride (PP-g-AM) was addict 3% concentration thought technique melt intercalation using a twin-screw extruder and the specimens were prepared by injection process. The mechanical behavior was evaluated by strength, flexural strength and impact tests. The thermal behavior was evaluated by the techniques of differential scanning calorimetry (DSC) and thermogravimetry (TGM). The rheological behavior was evaluated in rheometer. The morphology of the nanocomposites was studied by the technique of scanning electron microscopy (SEM). The organophilic bentonite and the nanocomposites were characterized by X-ray diffraction (XRD) and infrared (FTIR). (author)

Anomalous behavior of secondary dielectric relaxation in polypropylene glycols

Energy Technology Data Exchange (ETDEWEB)

Grzybowska, K; Grzybowski, A; Ziolo, J; Rzoska, S J; Paluch, M [Institute of Physics, Silesian University, Uniwersytecka 4, 40-007 Katowice (Poland)

2007-09-19

A surprising slow down in the dielectric secondary {gamma}-relaxation with temperature increasing near the glass transition is confirmed for several polypropylene glycols. The peculiar behavior diminishes as the molecular weight grows. The minimal model (Dyre and Olsen 2003 Phys. Rev. Lett. 91 155703) is applied successfully to describe the temperature dependences of the {gamma}-relaxation times. The minimal model parameters are analyzed for different molecular weights. A molecular explanation of the {gamma}-process anomaly for polypropylene glycols is proposed on the basis of the minimal model prediction.

Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site catalysts.

Science.gov (United States)

Makio, Haruyuki; Prasad, Aitha Vishwa; Terao, Hiroshi; Saito, Junji; Fujita, Terunori

2013-07-07

Bis(phenoxy-imine) Zr and Hf complexes were activated with (i)Bu3Al or (i)Bu2AlH in conjunction with Ph3CB(C6F5)4 and tested as catalysts for propylene polymerization with emphasis on the enantioselectivity of the isospecific species and the single site polymerization characteristics. The isoselective species was identified as the in situ generated bis(phenoxy-amine) complex whose isoselectivity was sensitive to subtle changes in ligand structure. By employing specific substituents at certain key positions the isotacticity reached an extremely high level comparable to high-end commercial isotactic polypropylenes (Tm > 160 °C). Single site polymerization characteristics depended upon the efficiency and selectivity of the in situ imine reduction which is sensitive to the substituent on the imine nitrogen and the reaction conditions. By using (i)Bu2AlH as a reducing agent, quantitative imine reduction can be achieved with a stoichiometric amount of the reducing agent. This lower alkylaluminum loading is beneficial for the catalyst and significantly enhances the polymerization activity and the molecular weight of the resultant polymer.

Influence of MCM-41 particle on mechanical and morphological behavior of polypropylene

International Nuclear Information System (INIS)

Wang Na; Shao Yawei; Shi Zhaoxin; Zhang Jing; Li Hongwei

2008-01-01

This study investigates the effects of different types of nanoparticles and amount of nanoparticles on morphology and mechanical performance of polypropylene (PP) composites. Three different types of nanoparticles, namely mesoporous MCM-41 (without template), mesoporous MCM-41 (with template), and mesoporous MCM-41, whose pore channels were filled with different flexible polymer inside the pore channels with the aid of supercritical CO 2 are considered. PP composites containing (0.5-5 wt.%) mesoporous MCM-41 were prepared by compounding. The tensile properties of the composites determined as a function of the filler loading and the different types of nanoparticles are found to vary with the different interface between different fillers and the matrix. The results of tensile tests showed that different flexible polymer filled mesoporous MCM-41 nanoparticles could simultaneously provide PP with strengthening and toughening effects at rather low filler content (0.5 wt.%). Scanning electron microscopy studies revealed a good dispersion of the MCM-41-S-PMMA and MCM-41-S-PS particles in the PP matrix and the enhancement of the interface between PP and MCM-41 are obtained

Mechanism of isotactic styrene polymerization with a C 6F 5-substituted bis(phenoxyimine) titanium system

KAUST Repository

Caporaso, Lucia; Loria, Marianna; Mazzeo, Mina; Michiue, Kenji; Nakano, Takashi; Fujita, Terunori; Cavallo, Luigi

2012-01-01

We report a combined, experimental and theoretical, study of styrene polymerization to clarify the regio- and stereocontrol mechanism operating with a C 6F 5-substituted bis(phenoxyimine) titanium dichloride complex. Styrene homopolymerization, styrene-propene and styrene-ethene-propene copolymerizations have been carried out to this aim. A combination of 13C NMR analysis of the chain-end groups and of the microstructure of the homopolymers and copolymers reveals that styrene polymerization is highly regioselective and occurs prevalently through 2,1-monomer insertion. DFT calculations evidenced that steric interaction between the growing chain and the monomer in the transition state insertion stage is at the origin of this selectivity. The formation of isotactic polystyrene with a chain-end like microstructure is rationalized on the base of a mechanism similar to that proposed for the syndiospecific propene polymerization catalyzed by bis(phenoxyimine) titanium dichloride complexes. Finally, a general stereocontrol mechanism operative in olefin polymerization with this class of complexes is proposed. © 2012 American Chemical Society.

Mechanism of isotactic styrene polymerization with a C 6F 5-substituted bis(phenoxyimine) titanium system

KAUST Repository

Caporaso, Lucia

2012-11-13

We report a combined, experimental and theoretical, study of styrene polymerization to clarify the regio- and stereocontrol mechanism operating with a C 6F 5-substituted bis(phenoxyimine) titanium dichloride complex. Styrene homopolymerization, styrene-propene and styrene-ethene-propene copolymerizations have been carried out to this aim. A combination of 13C NMR analysis of the chain-end groups and of the microstructure of the homopolymers and copolymers reveals that styrene polymerization is highly regioselective and occurs prevalently through 2,1-monomer insertion. DFT calculations evidenced that steric interaction between the growing chain and the monomer in the transition state insertion stage is at the origin of this selectivity. The formation of isotactic polystyrene with a chain-end like microstructure is rationalized on the base of a mechanism similar to that proposed for the syndiospecific propene polymerization catalyzed by bis(phenoxyimine) titanium dichloride complexes. Finally, a general stereocontrol mechanism operative in olefin polymerization with this class of complexes is proposed. © 2012 American Chemical Society.

Quality evaluation of polypropylene packaged corn yogurt during storage

Science.gov (United States)

Aini, Nur; Prihananto, V.; Sustriawan, B.; Astuti, Y.; Maulina, M. R.

2018-01-01

Packaging is an important factor to control the process of quality decrease of any food product, including to determine the shelf life. The objective of this study was to determine changes quality of corn yogurt packaged using polypropylene. The method were using was package yogurt polypropylene, then it was stored in a refrigerator at 5, 10, or 15°C during 21 days. The yogurt was analysed every 7 days over a 21-day period. The results indicate that protein content decreased during storage, while the lactic acid bacteria, total acid, pH, viscosity, and total solids were increased. At the end of storage, the amount of lactic acid bacteria still fulfil the minimum requirements of a probiotic food, with a count of 6.407 log CFU/g. Overal scoring by panelist (scores ranged from 0 to 5) have a 4.78 at the beginning of storage. By the 21st day of storage, yogurt was packaging using transparent polypropylene having a score of 3.85, and that stored in opaque white packaging having a value of 3.95.

Degradation of Polypropylene Membranes Applied in Membrane Distillation Crystallizer

Directory of Open Access Journals (Sweden)

Marek Gryta

2016-03-01

Full Text Available The studies on the resistance to degradation of capillary polypropylene membranes assembled in a membrane crystallizer were performed. The supersaturation state of salt was achieved by evaporation of water from the NaCl saturated solutions using membrane distillation process. A high feed temperature (363 K was used in order to enhance the degradation effects and to shorten the test times. Salt crystallization was carried out by the application of batch or fluidized bed crystallizer. A significant membrane scaling was observed regardless of the method of realized crystallization. The SEM-EDS, DSC, and FTIR methods were used for investigations of polypropylene degradation. The salt crystallization onto the membrane surface accelerated polypropylene degradation. Due to a polymer degradation, the presence of carbonyl groups on the membranes’ surface was identified. Besides the changes in the chemical structure a significant mechanical damage of the membranes, mainly caused by the internal scaling, was also found. As a result, the membranes were severely damaged after 150 h of process operation. A high level of salt rejection was maintained despite damage to the external membrane surface.

Study on the formation of the nanogel and microgels polypropylene modified by gamma radiation and incorporation of silver nanoparticles to biocides activity; Estudo da formacao de nanogeis e microgeis de polipropileno modificado por radiacao gama e incorporacao de nanoparticulas de prata visando a acao biocida

Energy Technology Data Exchange (ETDEWEB)

Oliani, Washington Luiz

2013-07-01

The study consists of the synthesis of HMSPP (polypropylene with high melt strength), also called polypropylene modified by gamma irradiation from iPP (isotactic polypropylene) in presence of acetylene at 110 kPa pressure and irradiated with γ of {sup 60}Co source at doses of 5, 12.5 and 20 kGy. The gel fraction of the samples was determined by extracting in xylene. The soluble portion of the samples was decanted to deposition on glass substrate until complete volatilization of xylene at room temperature of 25 °C. On the soluble portion of 12.5 kGy irradiated sample were added silver nanoparticles (AgNPs) in proportions of 0.25, 0.5, 1.0, 2.0 and 4.0 wt%. These gel samples were characterized by: scanning electron microscopy/energy dispersive spectroscopy (SEM / EDS), infrared spectroscopy (FTIR), scanning electron microscopy with field emission (FE-SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), reduction of colony forming unit (CFU) (%) and cytotoxicity assay. In this study of the morphology, it has been observed the formation of microgels in polypropylene increasing with the dose PP 5 kGy < PP 12.5 kGy < 20 kGy. Nanoscale structures of gels polypropylene (nanogels and nanofibers) were found in samples of PP 12.5 kGy and 20 kGy. The nanogels are formation of crosslinking, branching and entanglement that are nucleated in regions of high energy concentration (spurs) of one irradiated sample. Efficiency in tests of bactericide activity of the gels with AgNPs was observed versus E. coli and S. aureus from 1% AgNPs and non cytotoxicity were characterized in those samples for mammalian cells. In a second stage of this work films of the blend of PP and modified PP (50/50) were produced in a twin screw extruder. AgNPs were added to the extrusion processing in proportions of 0.1; 0.25; 0.5; 1.0; 1.0 PVP; 2.0 and 4.0 wt%. The films obtained were characterized by differential scanning calorimetry (DSC

Resterilized Polypropylene Mesh for Inguinal Hernia Repair

African Journals Online (AJOL)

2018-04-19

Apr 19, 2018 ... Conclusion: The use of sterilized polypropylene mesh for the repair of inguinal ... and nonabsorbable materials to reduce the tissue–mesh. INTRODUCTION ... which we have been practicing in our center since we introduced ...

Surface treated polypropylene (PP) fibres for reinforced concrete

Energy Technology Data Exchange (ETDEWEB)

López-Buendía, Angel M., E-mail: buendia@uv.es [AIDICO Technological Institute of Construction, Benjamin Franklin 17, 46380 Paterna, Valencia (Spain); Romero-Sánchez, María Dolores [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain); Climent, Verónica [Lafarge Cementos, Polígono Sepes, Isaac Newton s/n, 46500 Sagunto, Valencia (Spain); Guillem, Celia [AIDICO Technological Institute of Construction, Marble Technical Unit, Camí de Castella 4, 03660 Novelda. Alicante (Spain)

2013-12-15

Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

Mechanical properties of polypropylene/calcium carbonate nanocomposites

Directory of Open Access Journals (Sweden)

Daniel Eiras

2009-01-01

Full Text Available The aim of this work was to study the influence of calcium carbonate nanoparticles in both tensile and impact mechanical properties of a polypropylene homopolymer. Four compositions of PP/CaCO3 nanocomposites were prepared in a co-rotational twin screw extruder machine with calcium carbonate content of 3, 5, 7 and 10 wt. (% The tests included SEM analyzes together with EDS analyzer and FTIR spectroscopy for calcium carbonate, tensile and impact tests for PP and the nanocomposites. The results showed an increase in PP elastic modulus and a little increase in yield stress. Brittle-to-ductile transition temperature was reduced and the impact resistance increased with the addition of nanoparticles. From the stress-strain curves we determined the occurrence of debonding process before yielding leading to stress softening. Debonding stress was determined from stress-strain curves corresponding to stress in 1% strain. We concluded that the tensile properties depend on the surface contact area of nanoparticles and on their dispersion. Finally we believe that the toughening was due to the formation of diffuse shear because of debonding process.

The research on the interfacial compatibility of polypropylene composite filled with surface treated carbon fiber

International Nuclear Information System (INIS)

Li, J.

2009-01-01

Dielectric barrier discharges (DBD) in ambient air are used on carbon fiber to improve the fiber surface activity. Carbon fibers with length of 75 μm are placed into the plasma configuration. The interaction between modified carbon fibers and polypropylene (PP) was studied by three-point bending (TPB) test. The chemical changes induced by the treatments on carbon fiber surface are examined using X-ray photoelectron spectroscopy (XPS). XPS results reveal that the carbon fiber modified with the DBD at atmospheric pressure show a significant increase in oxygen and nitrogen concentration. These results demonstrate that the surface of the carbon fiber is more active and hydrophilic after plasma treatments using a DBD operating in ambient air.

The effects of gamma radiation and electron beam on the mechanical properties of polypropylene dominant natural rubber blend

International Nuclear Information System (INIS)

Mar Mar Oo; Khairul Zaman; Tin Hlaing

2001-01-01

The effects of irradiation, with dose ranging from 20 to 100 kGy on the mechanical properties of polypropylene and natural rubber blends (PP/NR blends) were investigated. Crosslinking of the PP/NR blends proved to play a major role in the improvement of the mechanical properties of the blend. The results also revealed that the blend composition the enhancement in properties depend on the irradiation dose and on the concentration of the crosslinking agent. (author)

Carbon ion irradiation induced surface modification of polypropylene

International Nuclear Information System (INIS)

Saha, A.; Chakraborty, V.; Dutta, R.K.; Chintalapudi, S.N.

2001-01-01

Polypropylene was irradiated with 12 C ions of 3.6 and 5.4 MeV energies in the fluence range of 5x10 13 -5x10 14 ions/cm 2 using 3 MV tandem accelerator. Ion penetration was limited to a few microns and surface modifications were investigated by scanning electron microscopy. At the lowest ion fluence only blister formation of various sizes (1-6 μm) were observed, but at higher fluence (1x10 14 ions/cm 2 ) a three-dimensional network structure was found to form. A gradual degradation in the network structure was observed with further increase in the ion fluence. The dose dependence of the changes on surface morphology of polypropylene is discussed

Carbon ion irradiation induced surface modification of polypropylene

Energy Technology Data Exchange (ETDEWEB)

Saha, A. E-mail: abhijit@alpha.iuc.res.in; Chakraborty, V.; Dutta, R.K.; Chintalapudi, S.N

2001-12-01

Polypropylene was irradiated with {sup 12}C ions of 3.6 and 5.4 MeV energies in the fluence range of 5x10{sup 13}-5x10{sup 14} ions/cm{sup 2} using 3 MV tandem accelerator. Ion penetration was limited to a few microns and surface modifications were investigated by scanning electron microscopy. At the lowest ion fluence only blister formation of various sizes (1-6 {mu}m) were observed, but at higher fluence (1x10{sup 14} ions/cm{sup 2}) a three-dimensional network structure was found to form. A gradual degradation in the network structure was observed with further increase in the ion fluence. The dose dependence of the changes on surface morphology of polypropylene is discussed.

Modification of low density polyethylene, isostatic polypropylene and their blends by gamma radiation

International Nuclear Information System (INIS)

Santos Rosa, D. dos

1991-01-01

The effects of the gamma radiation (of a 60 Co source), over low density polyethylene, isostatic polypropylene and their blends of low density polyethylene / polypropylene were studied. The structures modifications were attended by infrared spectrometry (IV), differential scanning calorimeter (DSC), strain-strain measurement, density measurement and scanning electron microscope (SEM). (author)

Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites

International Nuclear Information System (INIS)

Xie Lei; Ziegmann, Gerhard

2011-01-01

is increased to 30%, the E modulus and tensile strength of micro weld line were increased again compared with the low loading level. → Finally, an empirical prediction equation for micro injection molded weld line strength of nano PP composites was proposed for higher nano filler loading fraction than 10 wt%. - Abstract: The nano filled functional polymer materials have been widely processed with micro injection molding technology for micro electromechanical systems (MEMS) fabrication. As the unfavorable defect in micro injection molding parts, weld line brings reduced mechanical and physical properties, especially for nano filled composites. In this study, polypropylene (PP) was compounded respectively with carbon nano fibers (CNFs) and TiO 2 nano particles at various weight fractions (10, 20, 30, 35 wt%) through co-screws internal mixing. The morphological, thermal and rheological properties of nano composites were characterized by wider angle X-ray diffraction (WXRD), different scanning calorimeter (DSC) and high pressure capillary rheometer. Additionally, under the constant setting of injection molding process parameters in injection molding machine, micro tensile samples with weld lines for each nano filled PP composite were produced. The tensile tests were served as the characterizing method for weld line mechanical properties. The results show that when the CNFs is filled higher than 10 wt%, the tensile strength of samples with weld lines made of nano composites become lower than neat PP. While the raising CNFs content contributes to the improved E modulus of micro injection molded weld lines. Additionally, with the increasing fraction of CNFs in PP, the weld line area's elongation percent is decreased. Whereas for case of TiO 2 , the 10 wt% is the threshold for micro injection molded weld line tensile strength turning from decrease trend to increase. The same as CNFs, elongation of micro weld line samples were in general lower than neat PP as well, due to

Effect of Mixing Process on Polypropylene Modified Bituminous Concrete Mix Properties

OpenAIRE

Noor Zainab Habib; Ibrahim Kamaruddin; Madzalan Napiah; Isa Mohd Tan

2011-01-01

This paper presents a research conducted to investigate the effect of mixing process on polypropylene (PP) modified bitumen mixed with well graded aggregate to form modified bituminous concrete mix. Two mode of mixing, namely dry and wet with different concentration of polymer polypropylene was used with 80/100 pen bitumen, to evaluate the bituminous concrete mix properties. Three percentages of polymer varying from 1-3% by the weight of bitumen was used in this study. Three mixes namely cont...

Influence of electron beam Irradiation on PP/Piassava fiber composite prepared by melt extrusion process

International Nuclear Information System (INIS)

Gomes, Michelle G.; Ferreira, Maiara S.; Oliveira, Rene R.; Silva, Valquiria A.; Teixeira, Jaciele G.; Moura, Esperidiana A.B.

2013-01-01

In the latest years, the interest for the use of natural fibers in materials composites polymeric has increased significantly due to their environmental and technological advantages. Piassava fibers (Attalea funifera) have been used as reinforcement in the matrix of thermoplastic and thermoset polymers. In the present work (20%, in mass), piassava fibers with particle sizes equal or smaller than 250 μm were incorporated in the polypropylene matrix (PP) no irradiated and polypropylene matrix containing 10 % and 30 % of polypropylene treated by electron-beam radiation at 40 kGy (PP/PPi/Piassava). The composites PP/Piassava and PP/PPi/Piassava were prepared by using a twin screw extruder, followed by injection molding. The composite material samples obtained were treated by electron-beam radiation at 40 kGy, using a 1.5 MeV electron beam accelerator, at room temperature, in presence of air. After irradiation treatment, the irradiated and non-irradiated specimens tests samples were submitted to thermo-mechanical tests, melt flow index (MFI), sol-gel analysis, X-Ray diffraction (XRD) and scanning electron microscopy (SEM). (author)

Mechanical and rheological response of polypropylene/boehmite nanocomposites

CSIR Research Space (South Africa)

Pedrazzoli, D

2014-01-01

Full Text Available In this work the influence of synthetic boehmite alumina (BA) nanoparticles with various surface treatments on the morphology, crystallization behavior and mechanical properties of polypropylene copolymer (PP) nanocomposites was studied...

Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Furlan, L G [Federal Institute of Rio Grande do Sul, IFRS, Campus Restinga, Estrada Joao Antonio da Silveira, 351, Porto Alegre 91790-400 (Brazil); Ferreira, C I; Dal Castel, C; Santos, K S; Mello, A C.E. [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil); Liberman, S A; Oviedo, M A.S. [Braskem S.A., III Polo Petroquimico, Via Oeste, Lote 5, Triunfo 95853-000 (Brazil); Mauler, R.S., E-mail: mauler@iq.ufrgs.br [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil)

2011-08-25

Highlights: {yields} Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. {yields} Polypropylene Nanocomposites with higher increase on impact resistance. {yields} Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

International Nuclear Information System (INIS)

Furlan, L.G.; Ferreira, C.I.; Dal Castel, C.; Santos, K.S.; Mello, A.C.E.; Liberman, S.A.; Oviedo, M.A.S.; Mauler, R.S.

2011-01-01

Highlights: → Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. → Polypropylene Nanocomposites with higher increase on impact resistance. → Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

Short-term flow induced crystallization in isotactic polypropylene : how short is short?

NARCIS (Netherlands)

Ma, Z.; Balzano, L.; Portale, G.; Peters, G.W.M.

2013-01-01

The so-called "short-term flow" protocol is widely applied in experimental flow-induced crystallization studies on polymers in order to separate the nucleation and subsequent growth processes [Liedauer et al. Int. Polym. Proc. 1993, 8, 236–244]. The basis of this protocol is the assumption that

Functionalization of silica nanoparticles for polypropylene nanocomposites applications

International Nuclear Information System (INIS)

Bracho, Diego; Palza, Humberto; Quijada, Raul; Dougnac, Vivianne

2011-01-01

Synthetic silica nanospheres of different diameters produced via the sol-gel method were used in order to enhance the barrier properties of the polypropylene-silica nanocomposites. Modification of the silica surface by reaction with organic chlorosilanes was performed in order to improve the particles interaction with the polypropylene matrix and its dispersion. Unmodified and modified silica nanoparticles were characterized using electronic microscopy (TEM), elemental analysis, thermo gravimetric analysis (TGA), and solid state nuclear magnetic resonance (NMR) spectroscopy. Preliminary permeability tests of the polymer-silica nanocomposite films showed no significant change at low particles load (3 wt%) regardless its size or surface functionality, mainly because of the low aspect ratio of the silica nanospheres. However, it is expected that at a higher concentration of silica particles differences will be observed. (author)

Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

Energy Technology Data Exchange (ETDEWEB)

Abednejad, Atiye Sadat, E-mail: atiyeabednejad@gmail.com [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Amoabediny, Ghasem [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Research Center for New Technologies in Life Science Engineering, University of Tehran, P.O. Box 63894-14179, Tehran (Iran, Islamic Republic of); Ghaee, Azadeh [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of)

2014-09-01

Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H{sub 2} and O{sub 2} plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37 °C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. - Highlights: • H{sub 2} and O{sub 2} plasma graft polymerization of PEG on polypropylene membrane was carried out. • Changes in surface properties were investigated by FTIR, XPS, SEM, and AFM. • Surface wettability enhanced as a result of poly ethylene glycol grafting. • PEG grafting degree increase causes reduction of fouling and adhesion.

Storing of Extracts in Polypropylene Microcentrifuge Tubes Yields Contaminant Peak During Ultra-flow Liquid Chromatographic Analysis

OpenAIRE

Kshirsagar, Parthraj R.; Hegde, Harsha; Pai, Sandeep R.

2016-01-01

Background and Aim: This study was designed to understand the effect of storage in polypropylene microcentrifuge tubes and glass vials during ultra-flow liquid chromatographic (UFLC) analysis. Materials and Methods: One ml of methanol was placed in polypropylene microcentrifuge tubes (PP material, Autoclavable) and glass vials (Borosilicate) separately for 1, 2, 4, 8, 10, 20, 40, and 80 days intervals stored at ?4?C. Results: Contaminant peak was detected in methanol stored in polypropylene m...

An in-depth analysis of the physico-mechanical properties imparted by agricultural fibers and food processing residues in polypropylene biocomposites

Science.gov (United States)

Murdy, Rachel Campbell; Mak, Michelle; Misra, Manjusri; Mohanty, Amar K.

2015-05-01

The use of agricultural and food processing residues as potential reinforcements in plastics has been extensively studied. However, there is a large variation in the mechanical performance of agricultural fiber-based biocomposites due to different processing materials and parameters. An in-depth comparison of the resulting effect of the agricultural filler on the matrix is often not possible given the discrepancy in processing conditions. This study seeks to determine the intrinsic properties of agricultural fibers and food processing residues for their use in polypropylene biocomposites based on a standardization of experimental design. The effect of 25wt% loading of miscanthus, fall-and spring-harvest switchgrass, wheat straw, oat hull, soy hull, soy stalk, hemp and flax on the physico-mechanical properties of polypropylene biocomposites was investigated. The addition of fiber led to an improvement in flexural strength, flexural modulus, and tensile modulus, and a general decrease in tensile strength at yield, elongation at break and Izod impact strength. Scanning electron microscopy highlighted the interfacial adhesion, orientation and distribution of the fibers within the matrix, confirming that fiber length and dispersion within the matrix are positively correlated with mechanical properties. The crystallization of the polypropylene phase and a compositional analysis of the agricultural fibers and processing residues were also compared to offer insight into the effect of the filler's intrinsic properties on the resulting material performance.

An in-depth analysis of the physico-mechanical properties imparted by agricultural fibers and food processing residues in polypropylene biocomposites

International Nuclear Information System (INIS)

Murdy, Rachel Campbell; Mak, Michelle; Misra, Manjusri; Mohanty, Amar K.

2015-01-01

The use of agricultural and food processing residues as potential reinforcements in plastics has been extensively studied. However, there is a large variation in the mechanical performance of agricultural fiber-based biocomposites due to different processing materials and parameters. An in-depth comparison of the resulting effect of the agricultural filler on the matrix is often not possible given the discrepancy in processing conditions. This study seeks to determine the intrinsic properties of agricultural fibers and food processing residues for their use in polypropylene biocomposites based on a standardization of experimental design. The effect of 25wt% loading of miscanthus, fall-and spring-harvest switchgrass, wheat straw, oat hull, soy hull, soy stalk, hemp and flax on the physico-mechanical properties of polypropylene biocomposites was investigated. The addition of fiber led to an improvement in flexural strength, flexural modulus, and tensile modulus, and a general decrease in tensile strength at yield, elongation at break and Izod impact strength. Scanning electron microscopy highlighted the interfacial adhesion, orientation and distribution of the fibers within the matrix, confirming that fiber length and dispersion within the matrix are positively correlated with mechanical properties. The crystallization of the polypropylene phase and a compositional analysis of the agricultural fibers and processing residues were also compared to offer insight into the effect of the filler’s intrinsic properties on the resulting material performance

An in-depth analysis of the physico-mechanical properties imparted by agricultural fibers and food processing residues in polypropylene biocomposites

Energy Technology Data Exchange (ETDEWEB)

Murdy, Rachel Campbell; Mak, Michelle [Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); Misra, Manjusri; Mohanty, Amar K. [Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON N1G 2W1 (Canada); School of Engineering, Thornbrough Building, University of Guelph, ON N1G 2W1 (Canada)

2015-05-22

The use of agricultural and food processing residues as potential reinforcements in plastics has been extensively studied. However, there is a large variation in the mechanical performance of agricultural fiber-based biocomposites due to different processing materials and parameters. An in-depth comparison of the resulting effect of the agricultural filler on the matrix is often not possible given the discrepancy in processing conditions. This study seeks to determine the intrinsic properties of agricultural fibers and food processing residues for their use in polypropylene biocomposites based on a standardization of experimental design. The effect of 25wt% loading of miscanthus, fall-and spring-harvest switchgrass, wheat straw, oat hull, soy hull, soy stalk, hemp and flax on the physico-mechanical properties of polypropylene biocomposites was investigated. The addition of fiber led to an improvement in flexural strength, flexural modulus, and tensile modulus, and a general decrease in tensile strength at yield, elongation at break and Izod impact strength. Scanning electron microscopy highlighted the interfacial adhesion, orientation and distribution of the fibers within the matrix, confirming that fiber length and dispersion within the matrix are positively correlated with mechanical properties. The crystallization of the polypropylene phase and a compositional analysis of the agricultural fibers and processing residues were also compared to offer insight into the effect of the filler’s intrinsic properties on the resulting material performance.

Effect of water absorption on mechanical properties of hemp fibre/polyolefin’s composites

CSIR Research Space (South Africa)

Guduri, BBR

2007-12-01

Full Text Available malamaleated polypropylene and polyethylene were used. The tensile, flexural and impact properties of hemp fibre/polyolefin’s (PP & HDPE) composite specimens were found to increased with compatibilizer. The dry and water immersion specimens of the PP composites...

Catalytic copyrolysis of particle board and polypropylene over Al-MCM-48

Energy Technology Data Exchange (ETDEWEB)

Kim, Hannah; Choi, Suek Ju [School of Environmental Engineering, University of Seoul, Seoul 02504 (Korea, Republic of); Kim, Ji Man [Department of Chemistry, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Jeon, Jong-Ki [Department of Chemical Engineering, Kongju National University, Cheonan 31080 (Korea, Republic of); Park, Sung Hoon; Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, Suncheon 57922 (Korea, Republic of); Kim, Sang Chai [Department of Environmental Education, Mokpo National University, Muan 58554 (Korea, Republic of); Park, Young-Kwon, E-mail: catalica@uos.ac.kr [School of Environmental Engineering, University of Seoul, Seoul 02504 (Korea, Republic of)

2016-10-15

Highlights: • Al-MCM-48 was used for catalytic copyrolysis of particle board and polypropylene. • Catalytic produced mainly hydrocarbons. • The hydrocarbons produced were mainly in the diesel range. - Abstract: Particle board and polypropylene (PP) at a mixing ratio of 1:1 were copyrolyzed over two Al-MCM-48 catalysts with Si/Al ratios of 20 and 80. The catalyst characteristics were examined by measuring the Brunauer-Emmett-Teller surface area, temperature programmed desorption of ammonia, and X-ray diffraction. The main pyrolysis products of particle board were oxygenates, acids, and phenolics, whereas a large quantity of hydrocarbons within the diesel fuel range was produced from copyrolysis with polypropylene. The catalytic copyrolysis of particle board and PP over the Al-MCM-48 catalysts produced bio-oil with a much larger hydrocarbon content than that from the catalytic pyrolysis of particle board only. The hydrocarbons produced were mainly in the diesel range, highlighting the potential for the production of high-quality fuel.

Study on Welding Mechanism Based on Modification of Polypropylene for Improving the Laser Transmission Weldability to PA66

Science.gov (United States)

Liu, Huixia; Jiang, Hairong; Guo, Dehui; Chen, Guochun; Yan, Zhang; Li, Pin; Zhu, Hejun; Chen, Jun; Wang, Xiao

2015-01-01

Polypropylene and PA66 are widely used in our daily life, but they cannot be welded by laser transmission welding (LTW) because of polar differences and poor compatibility. In this paper, grafting modification technology is used to improve the welding performance between polypropylene and PA66. Firstly, the strong reactive and polar maleic-anhydride (MAH) is grafted to polypropylene and infrared spectrometer is used to prove that MAH has been grafted to polypropylene. At the same time, the mechanical and thermal properties of the graft modified polypropylene (TGMPP) are tested. The results prove that the grafting modification has little influence on them. Also, the optical properties of TGMPP are measured. Then, the high welding strength between TGMPP and PA66 is found and the mechanism of the weldability is researched, which shows that there are two reasons for the high welding strength. By observing the micro morphology of the welding zone, one reason found is that the modification of polypropylene can improve the compatibility between polypropylene and PA66 and make them easy to diffuse mutually, which causes many locking structures formed in the welding region. The other reason is that there are chemical reactions between TGMPP and PA66 proved by the X-ray photoelectron spectrometer. PMID:28793484

Polypropylene-modified kaolinite composites: Effect of chemical ...

African Journals Online (AJOL)

PP/kaolinite compounds were prepared by the melt intercalation method. The effects of modified clay on properties of the prepared composites were studied. The XRD results showed that the treatment with the ammonium salt caused the return to the initial state of the clay. The thermogravimetric analysis thermograms (TGA) ...

Texturing of polypropylene (PP) with nanosecond lasers

Science.gov (United States)

Riveiro, A.; Soto, R.; del Val, J.; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J.

2016-06-01

Polypropylene (PP) is a biocompatible and biostable polymer, showing good mechanical properties that has been recently introduced in the biomedical field for bone repairing applications; however, its poor surface properties due to its low surface energy limit their use in biomedical applications. In this work, we have studied the topographical modification of polypropylene (PP) laser textured with Nd:YVO4 nanosecond lasers emitting at λ = 1064 nm, 532 nm, and 355 nm. First, optical response of this material under these laser wavelengths was determined. The application of an absorbing coating was also studied. The influence of the laser processing parameters on the surface modification of PP was investigated by means of statistically designed experiments. Processing maps to tailor the roughness, and wettability, the main parameters affecting cell adhesion characteristics of implants, were also determined. Microhardness measurements were performed to discern the impact of laser treatment on the final mechanical properties of PP.

Development of hemp fibre reinforced polypropylene composite - Journal Article

CSIR Research Space (South Africa)

Hargitai, H

2005-06-01

Full Text Available strong decrease in three point bending properties was noticed after immersing the composite samples in the distilled water for 19 days, while the impact strength increased. Double carding of raw materials resulted into decreased anisotropy in composite...

Influence of procedure variables in formation and properties of polypropylene/bentonite nanocomposites

International Nuclear Information System (INIS)

Andrade, Daniela de Lourdes Anjos Coutinho Simoes

2009-01-01

The purpose of this work is to prepare nanocomposites of polypropylene/compatibilizer/bentonite, by melting intercalation, with a commercial sodium clay - Argel - as filler. This clay was organically purified and modified by different methods, with a quaternary ammonium salt. The clays were characterized by X-Ray diffraction (XRD), infrared spectroscopy (FTIR) and thermogravimetric analyses (TG) to determine the most efficient preparation method. Before that, in the second stage of this study, the influence of the type and contend of organoclay in the properties of the polypropylene films was measured; the same was done for the compatibilizer. The preliminary results indicate that the nanocomposites film with 1% of organoclay and 15% of polypropylene grafted with maleic anhydride show promise as packing materials and may be used, in the near future, as a new product by the national industry. (author)

Effects of gamma irradiation on food contact polyethylene, polypropylene and polystyrene. Volatiles

International Nuclear Information System (INIS)

Kawamura, Yoko; Sayama, Kayo; Yamada, Takashi

2000-01-01

The effects of gamma irradiation on the generation of volatiles from food contact polyethylene and polypropylene were investigated using head space (HS)/GC/MS. All samples generated volatiles such as acetic acid, propionic acid, butanoic acid, 2,2-dimethylpropionic acid, acetone, 2-butanone, 2-propanol, 2-methyl-2-propanol, hydrocarbons, etc., due to the gamma irradiation. Especially, acetic acid and acetone were formed in greatest amounts. Since these volatiles did not exist before irradiation and their amounts increased with increasing irradiation dose, they should be degradation products from the polymer or additives by irradiation. Polypropylene generated more kinds and larger amounts of volatiles than polyethylene, which showed that polypropylene is more sensitive to irradiation. Polystyrene contained styrene and ethylbenzene as monomers before irradiation and their amounts decreased after irradiation. Polystyrene generated few degradation products during the irradiation. (author)

Development of a Halogen Free Flame Retardant Masterbatch for Polypropylene Fibers

Directory of Open Access Journals (Sweden)

François Rault

2015-02-01

Full Text Available The efficiency of new phosphinates, in combination with melamine cyanurate, was studied using different polypropylene textile structures. The influence of different ratios up to a total amount of 6 wt% in the polypropylene fiber was investigated using the limiting oxygen index (LOI and cone calorimeter method for research purposes, while the performances were correlated to the standards FMVSS 302 (Federal Motor Vehicle Safety Standards and DIN 4102-l (Deutsches Institut für Normung used more specifically for automotive and building sector.

Conifer fibers as reinforcing materials for polypropylene-based composites

DEFF Research Database (Denmark)

Plackett, David; Chengzhi, Chuai; Almdal, Kristoffer

2001-01-01

in improved processing, as well as improvements in the thermal and mechanical properties of the resultant composites compared with the composites filled with untreated conifer fibers. Moreover, MAPP grafting and MAPP treating displayed more obvious benefits than EPDM treating in terms of thermal properties...

Evaluation of Electroless-Nickel Plated Polypropylene under Thermal Cycling and Mechanical Tests

Directory of Open Access Journals (Sweden)

O.O. Ajibola

2016-09-01

Full Text Available The electroless-nickel composite (ENC consisting of bright metallic electroless-nickel (EN and dull electroless-nickel-phosphorus (EN-P were deposited on the polypropylene (PP substrate from the sodium hypophosphite baths. The ENC plated specimens were subjected to abrasive wear-adhesion test of 1750, 3500, 7000 and 14000 cycles; thermal cycle-adhesion tests, and tensile strength and creep tests. The deposition of ENC influenced the strength and creep strain properties of the PP. The maximum stress σ of 118 (MPa was obtained from EN-PP specimen at strain  of 0.1 mm/mm as compared with the PP having stress σ of 36 (MPa at strain  of 0.07 mm/mm before failure The surface appearances and microstructures of ENC film on PP substrates were examined under the higher resolution metallurgical microscope with digital camera and microscopic camera. The composition of ENC film was characterized using Scanning Electron Microscopy and Energy Dispersive X-Ray analyses (Jeol JSM-7600F Field Emission SEM/EDX, The micrographs and spectra lines data generated were used to interpret the results.

Low-Frequency Noise Reduction by Earmuffs with Flax Fibre-Reinforced Polypropylene Ear Cups

Directory of Open Access Journals (Sweden)

Linus Yinn Leng Ang

2018-01-01

Full Text Available Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz cabin noise in military vehicles. Despite the use of commercial hearing protection devices, the risk of auditory damage is still imminent because the devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP as an alternative to the material selection for the ear cups of commercial earmuffs, which are typically made of acrylonitrile butadiene styrene (ABS. Different weaving configurations (woven and nonwoven and various noise environments (pink noise, cabin booming noise, and firing noise were considered to investigate the feasibility of the proposed composite earmuffs for low-frequency noise reduction. The remaining assembly components of the earmuff were kept consistent with those of a commercial earmuff, which served as a benchmark for results comparison. In contrast to the commercial earmuff, the composite earmuffs were shown to be better in mitigating low-frequency noise by up to 16.6 dB, while compromising midfrequency acoustical performance. Consequently, the proposed composite earmuffs may be an alternative for low-frequency noise reduction in vehicle cabins, at airports, and at construction sites involving heavy machineries.

Physical and mechanical properties of unidirectional plant fibre composites

DEFF Research Database (Denmark)

Madsen, B.; Lilholt, H.

2003-01-01

Unidirectional composites were made from filament wound non-treated flax yarns and polypropylene foils. With increasing composite fibre weight fractions from 0.56 to 0.72, porosity fractions increased from 0.04 to 0.08; a theoretical model was fitted to the data in order to describe the composite...... version of the "rule-of-mixtures", supplemented with parameters of composite porosity content and anisotropy of fibre properties, were developed to improve the prediction of composite tensile properties. (C) 2003 Elsevier Science Ltd. All rights reserved....

Laparoscopic Pelvic Floor Repair Using Polypropylene Mesh

Directory of Open Access Journals (Sweden)

Shih-Shien Weng

2008-09-01

Conclusion: Laparoscopic pelvic floor repair using a single piece of polypropylene mesh combined with uterosacral ligament suspension appears to be a feasible procedure for the treatment of advanced vaginal vault prolapse and enterocele. Fewer mesh erosions and postoperative pain syndromes were seen in patients who had no previous pelvic floor reconstructive surgery.

Short- and long-term results of chordal reconstruction using artificial suture material (polytetrafluoroethylene and polypropylene in the dog

Directory of Open Access Journals (Sweden)

Isamu Kanemoto

2017-04-01

Full Text Available No previous reports have compared the suitability of expanded polytetrafluoroethylene (ePTFE and polypropylene as artificial suture materials for chordal reconstruction in mitral valve plasty (MVP in the dog. Twelve normal dogs were subjected to MVP using surfaceinduced deep hypothermia. In the short-term group (1.5-4 months after surgery, all ePTFE sutures were covered by a tissue sheath including the paired suture arms, which gave the appearance of native chordae from 2 months after surgery. In contrast, all polypropylene sutures were not covered by tissue, and appeared the same as the paired polypropylene suture arms at the operation. In the long-term group (12 months after surgery, all ePTFE sutures were covered by a tissue sheath, which appeared the same as that in the short-term group, and had flexibility without increased thickness with time. In contrast, although the polypropylene suture was covered completely by a tissue sheath in 1 dog, all the other polypropylene sutures were exposed except for both ends of the suture. ePTFE may be superior to polypropylene as an artificial suture material for chordal reconstruction in MVP.

Flexural strength of self compacting fiber reinforced concrete beams using polypropylene fiber: An experimental study

Science.gov (United States)

Lisantono, Ade; Praja, Baskoro Abdi; Hermawan, Billy Nouwen

2017-11-01

One of the methods to increase the tensile strength of concrete is adding a fiber material into the concrete. While to reduce a noise in a construction project, a self compacting concrete was a good choices in the project. This paper presents an experimental study of flexural behavior and strength of self compacting fiber reinforced concrete (RC) beams using polypropylene fiber. The micro monofilament polypropylene fibers with the proportion 0.9 kg/m3 of concrete weight were used in this study. Four beam specimens were cast and tested in this study. Two beams were cast of self compacting reinforced concrete without fiber, and two beams were cast of self compacting fiber reinforced concrete using polypropylene. The beams specimen had the section of (180×260) mm and the length was 2000 mm. The beams had simple supported with the span of 1800 mm. The longitudinal reinforcements were using diameter of 10 mm. Two reinforcements of Ø10 mm were put for compressive reinforcement and three reinforcements of Ø10 mm were put for tensile reinforcement. The shear reinforcement was using diameter of 8 mm. The shear reinforcements with spacing of 100 mm were put in the one fourth near to the support and the spacing of 150 mm were put in the middle span. Two points loading were used in the testing. The result shows that the load-carrying capacity of the self compacting reinforced concrete beam using polypropylene was a little bit higher than the self compacting reinforced concrete beam without polypropylene. The increment of load-carrying capacity of self compacting polypropylene fiber reinforced concrete was not so significant because the increment was only 2.80 % compare to self compacting non fiber reinforced concrete. And from the load-carrying capacity-deflection relationship curves show that both the self compacting polypropylene fiber reinforced concrete beam and the self compacting non fiber reinforced concrete beam were ductile beams.

Plasma surface modification of polypropylene track-etched membrane to improve its performance properties

Science.gov (United States)

Kravets, L. I.; Elinson, V. M.; Ibragimov, R. G.; Mitu, B.; Dinescu, G.

2018-02-01

The surface and electrochemical properties of polypropylene track-etched membrane treated by plasma of nitrogen, air and oxygen are studied. The effect of the plasma-forming gas composition on the surface morphology is considered. It has been found that the micro-relief of the membrane surface formed under the gas-discharge etching, changes. Moreover, the effect of the non-polymerizing gas plasma leads to formation of oxygen-containing functional groups, mostly carbonyl and carboxyl. It is shown that due to the formation of polar groups on the surface and its higher roughness, the wettability of the plasma-modified membranes improves. In addition, the presence of polar groups on the membrane surface layer modifies its electrochemical properties so that conductivity of plasma-treated membranes increase.

Synthesis and characterization of polypropylene/graphite nano composite preparation for in situ polymerization; Sintese e caracterizacao de nanocompositos polipropileno/grafite obtidos pela polimerizacao in situ

Energy Technology Data Exchange (ETDEWEB)

Montagna, L.S.; Fim, F. de C.; Galland, G.B. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica; Basso, N.R.S., E-mail: nrbass@pucrs.b [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil)

2010-07-01

This paper presents the synthesis of polypropylene/graphite nanocomposites through in situ polymerization, using the metallocene catalyst C{sub 20}H{sub 16}Cl{sub 2}Zr (dichloro(rac-ethylenebis(indenyl))zircon(IV)). The graphite nanosheets in nano dimensions were added to the polymer matrix in percentages of 0.6;1.0;4.2;4.8 and 6.0% (w/w). The TEM images indicated that the thickness of graphite nanosheets ranged from 4 to 60 nm and by means of XRD analysis it was observed that the physical and chemical treatment did not destroyed the graphite layers. The presence of nanosheets did not decrease the catalytic activity of the nanocomposites. TEM images and XRD analysis of nanocomposites showed a good dispersion of the graphite nanosheets in the polypropylene matrix. (author)

Polypropylene/organoclay/SEBS nanocomposites with toughness-stiffness properties

DEFF Research Database (Denmark)

Sanporean (nee Potarniche), Catalina-Gabriela; Vuluga, Zina; Radovici, Constantin

2014-01-01

Polypropylene nanocomposites with a different amount of styrene-ethylene-butylene-styrene block copolymer (SEBS)/clay were prepared via a melt mixing technique. To improve the dispersion of commercial organoclay (denoted as OMMT), various amounts of SEBS were incorporated. At a fixed content of O...

Reel-to-Reel Atmospheric Pressure Dielectric Barrier Discharge (DBD Plasma Treatment of Polypropylene Films

Directory of Open Access Journals (Sweden)

Lukas JW Seidelmann

2017-03-01

Full Text Available Atmospheric pressure plasma treatment of the surface of a polypropylene film can significantly increase its surface energy and, thereby improve the printability of the film. A laboratory-scale dielectric barrier discharge (DBD system has therefore been developed, which simulates the electrode configuration and reel-to-reel web transport mechanism used in a typical industrial-scale system. By treating the polypropylene in a nitrogen discharge, we have shown that the water contact angle could be reduced by as much as 40° compared to the untreated film, corresponding to an increase in surface energy of 14 mNm−1. Ink pull-off tests showed that the DBD plasma treatment resulted in excellent adhesion of solvent-based inks to the polypropylene film.

Low Cost Processing of Commingled Thermoplastic Composites

Science.gov (United States)

Chiasson, Matthew Lee

A low cost vacuum consolidation process has been investigated for use with commingled thermoplastic matrix composites. In particular, the vacuum consolidation behaviour of commingled polypropylene/glass fibre and commingled nylon/carbon fibre precursors were studied. Laminates were consolidated in a convection oven under vacuum pressure. During processing, the consolidation of the laminate packs was measured by use of non-contact eddy current sensors. The consolidation curves are then used to tune an empirical consolidation model. The overall quality of the resulting laminates is also discussed. Dynamic mechanical analysis, differential scanning calorimetry and mechanical tensile testing were also performed in order to determine the effects of varying processing parameters on the physical and mechanical properties of the laminates. Through this analysis, it was determined that the nylon/carbon fibre blend was not suitable for vacuum consolidation, while the polypropylene/glass fibre blend is a viable option for vacuum consolidation. The ultimate goal of this work is to provide a foundation from which low cost unmanned aerial vehicle (UAV) components can be designed and manufactured from thermoplastic matrix composites using a low cost processing technique as an alternative to traditional thermoset composite materials.

Colorimetry analysis of polypropylene-polyethylene base copoliners

International Nuclear Information System (INIS)

Sunol, J. J.; Saurina, J.; Carrasco, F.; Pages, P.

1998-01-01

In this paper, crystallisation process study has been performed, from the molten material, in polypropylene-polyethylene (PP-PE) copolymers rich in PP (∼ 95 wgh.%), using different additives. Some samples have been artificially aged. Calorimetric analysis has been performed by different scanning calorimetry (DSC), from which crystallisation kinetics has been studied under dynamic conditions. (Author) 22 refs

Influence of chemical treatment of clay to obtain polypropylene nanocomposites

International Nuclear Information System (INIS)

Rosa, Jeferson L.S.; Marques, Maria F.V.

2009-01-01

Commercial clay was chemically treated to prepare a Ziegler-Natta catalyst containing MgCl 2 and clay for the synthesis of polypropylene nanocomposites by in situ polymerization. The performance of this catalyst and materials obtained in propylene polymerization was compared with a reference catalyst (without clay) and with another, whose composition presents the same clay but without prior chemical treatment. Techniques like differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and melt flow index (MFI) measurements were performed. There was a marked reduction in catalytic activity of clay catalysts in comparison with the reference one, and a slight reduction in melting temperature of the polymers produced from first ones. The melt flow index of polymers obtained with treated clay were notably higher than those synthesized with the untreated clay, so the treated clay caused treated the production of PP's with lower molar mass. The clays showed an increase of spacing and irregular stacking of the lamellas, especially if chemically treated. (author)

Extrudable polymer-polymer composites based on ultra-high molecular weight polyethylene

Science.gov (United States)

Panin, S. V.; Kornienko, L. A.; Alexenko, V. O.; Buslovich, D. G.; Dontsov, Yu. V.

2017-12-01

Mechanical and tribotechnical characteristics of polymer-polymeric composites of UHMWPE are studied with the aim of developing extrudable, wear-resistant, self-lubricant polymer mixtures for Additive Manufacturing (AM). The motivation of the study is their further application as feedstocks for 3D printing. Blends of UHMWPE with graft- and block copolymers of low-density polyethylene (HDPE-g-VTMS, HDPE-g-SMA, HDPE-b-EVA), polypropylene (PP), block copolymers of polypropylene and polyamide with linear low density polyethylene (PP-b-LLDPE, PA-b-LLDPE), as well as cross-linked polyethylene (PEX-b), are examined. The choice of compatible polymer components for an ultra- high molecular weight matrix for increasing processability (extrudability) is motivated by the search for commercially available and efficient additives aimed at developing wear-resistant extrudable polymer composites for additive manufacturing. The extrudability, mechanical properties and wear resistance of UHMWPE-based polymer-polymeric composites under sliding friction with different velocities and loads are studied.

The effect of impact modifier and of nucleating agent on the radiation tolerance of polypropylene

Energy Technology Data Exchange (ETDEWEB)

Liu Dongyuan (Beijing Normal Univ., BJ (China)); Czvikovszky, T.; Dobo, J.; Somogyi, A. (Research Inst. for the Plastics Industry, Budapest (Hungary))

1990-01-01

The effect of two types of additives was investigated with respect to the oxidative post-irradiation stability of polypropylene: SBS thermoplastic rubbers as impact modifiers and benzoic acid as nucleating agent. Testing was performed by ultimate deformation on bending. The thermoplastic rubber additive increased the post-irradiation stability of polypropylene substantially. (author).

The effect of impact modifier and of nucleating agent on the radiation tolerance of polypropylene

International Nuclear Information System (INIS)

Liu Dongyuan; Czvikovszky, T.; Dobo, J.; Somogyi, A.

1990-01-01

The effect of two types of additives was investigated with respect to the oxidative post-irradiation stability of polypropylene: SBS thermoplastic rubbers as impact modifiers and benzoic acid as nucleating agent. Testing was performed by ultimate deformation on bending. The thermoplastic rubber additive increased the post-irradiation stability of polypropylene substantially. (author)

Environmental and Cost Assessment of a Polypropylene Nanocomposite

NARCIS (Netherlands)

Roes, A.L.|info:eu-repo/dai/nl/303022388; Marsili, E.; Nieuwlaar, E.|info:eu-repo/dai/nl/073931373; Patel, M.K.|info:eu-repo/dai/nl/18988097X

2007-01-01

This paper describes a study on the use of a polypropylene (PP)/layered silicate nanocomposite as packaging film, agricultural film, and automotive panels. The study’s main question was “Are the environmental impacts and costs throughout the life cycle of nanocomposite products lower than those of

Development of hemp fibre - PP nonwoven composites - Conference Paper

CSIR Research Space (South Africa)

Hargitai, H

2005-09-01

Full Text Available Non-woven mats from hemp and polypropylene fibres in various proportions were produced and hot pressed to make composite material. The effect of hemp fibre content and anisotropy in non-woven mats resulting from the carding technology were examined...

Functional behaviour of polypropylene/ZnO-soluble starch nanocomposites

International Nuclear Information System (INIS)

Chandramouleeswaran, Subramani; Mhaske, S T; Kathe, A A; Varadarajan, P V; Prasad, Virendra; Vigneshwaran, Nadanathangam

2007-01-01

ZnO-polypropylene nanocomposites (nano-PP) were prepared using nanoparticles of ZnO stabilized by soluble starch (nano-ZnO) as filler in PP by the melt mixing process. X-ray diffraction (XRD) and other spectroscopic analysis-ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and photoluminescence-revealed the presence and characteristics of nano-ZnO in the composites. The presence of ZnO imparts whiteness, while starch increased the yellowing of polymers. The nanocomposites were analyzed for changes in optical, mechanical, electrical and rheological properties, as influenced by the increasing concentration of nano-ZnO. The mechanical properties were marginally increased and the dielectric strength of the nano-PP increased to a notable level. By monitoring the evolution of the carbonyl absorption bands from FTIR analysis, the efficacy of nano-ZnO in the reduction of photo-degradation due to UV irradiation was demonstrated. The excellent antibacterial activity exhibited by nano-ZnO impregnated PP against two human pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumoniae, makes it a suitable candidate for food packaging applications

Functional behaviour of polypropylene/ZnO soluble starch nanocomposites

Science.gov (United States)

Chandramouleeswaran, Subramani; Mhaske, S. T.; Kathe, A. A.; Varadarajan, P. V.; Prasad, Virendra; Vigneshwaran, Nadanathangam

2007-09-01

ZnO-polypropylene nanocomposites (nano-PP) were prepared using nanoparticles of ZnO stabilized by soluble starch (nano-ZnO) as filler in PP by the melt mixing process. X-ray diffraction (XRD) and other spectroscopic analysis—ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and photoluminescence—revealed the presence and characteristics of nano-ZnO in the composites. The presence of ZnO imparts whiteness, while starch increased the yellowing of polymers. The nanocomposites were analyzed for changes in optical, mechanical, electrical and rheological properties, as influenced by the increasing concentration of nano-ZnO. The mechanical properties were marginally increased and the dielectric strength of the nano-PP increased to a notable level. By monitoring the evolution of the carbonyl absorption bands from FTIR analysis, the efficacy of nano-ZnO in the reduction of photo-degradation due to UV irradiation was demonstrated. The excellent antibacterial activity exhibited by nano-ZnO impregnated PP against two human pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumoniae, makes it a suitable candidate for food packaging applications.

Vibration behaviour of foamed concrete floor with polypropylene and rise husk ash fibre

Science.gov (United States)

Azaman, N. A. Mohd; Ghafar, N. H. Abd; Ayub, N.; Ibrahim, M. Z.

2017-11-01

In the history of the construction industry, lightweight concrete or foamed concrete is a special concrete which can very useful in the construction sector because it is very lightweight and it can compact by itself at each angle of foamwork. Foamed concrete is one of lightweight concrete which widely used for floor construction due to its light weight and economic. The significant challenges in the floor design process are considering the vibration that needs improvements for the poor dynamic behaviour insulation. An alternative material to replace sand with certain amount of rice husk ash (RHA) and polypropylene was introduced. Research was determine the dynamic behavior of foam-polypropylene and foam-RHA concrete by using impact hammer test. The natural frequency for normal foamed concrete, 0.5 % of Polypropylene and 15% of RHA is 29.8 Hz, 29.3 Hz and 29.5 Hz respectively.

Polypropylene film with silver nanoparticles and nanoclay aiming to action biocidal

International Nuclear Information System (INIS)

Oliani, W.L.; Lima, L.F.C.P.; Lugao, A.B.; Parra, D.F.; Fermino, D.M.; Diaz, F.R.V.

2014-01-01

This paper presents an initial study of films made of polypropylene nanoclay and silver nanoparticles. The nanocomposite of polypropylene (iPP), commercial organoclay - montmorillonite (MMT), Cloisite 20A at concentrations of 1.0% and silver nanoparticles (AgNPs) at a concentration of 0.1% were prepared in a twin-screw-extruder, using polypropylene with maleic anhydride (PP-g-MA) as coupling agent. The properties of nanocomposites of PP/MMT/AgNPs are closely related to the dispersion of silver particles and the distribution of sheets of MMT in the polymer matrix, which define its efficiency in the case of the particles and their interaction clay/polymer matrix. However, this combination of MMT and AgNPs that are polar, with the polymer matrix nonpolar in the molten state, presents a challenge. The characterization of the film was performed by analysis of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and reduction of colony forming unit (CFU %). The results indicate the formation of predominantly exfoliated microstructures and agglomeration of silver nanoparticles in the film. The effect of silver nanoparticles was evaluated against bacteria E.coli and S.aureus. (author)

Ziegler-Natta catalyst for polypropylene and polyethylene nanocomposites preparation

International Nuclear Information System (INIS)

Silvino, Alexandre C.; Dias, Marcos L.; Bezerra, Ana Beatriz F.

2009-01-01

Polypropylene and polyethylene nanocomposites are well known for their improved properties when compared with the neat polymers. In this work we report the preparation, characterization and the activity studies of a fourth generation Ziegler-Natta catalyst for the preparation of polyolefin/clay nanocomposites. The catalyst was prepared treating an organo-modified silicate with magnesium and titanium compounds. The content of titanium and that of the magnesium of the catalyst were determined by UV-vis spectroscopy and atomic absorption respectively. The first results show that the catalyst is active for propylene polymerization being suitable for polypropylene/clay nanocomposite preparation. The catalyst activity for ethylene polymerization was also investigated. The X-ray diffraction patterns of the polyethylene samples suggest the clay exfoliation occurs in the in situ polymerization, even with high clay loading (about 9 %) indicating that a nanocomposite was formed. (author)

Electrochemical Impedance Study of Zinc Yellow Polypropylene-Coated Aluminum Alloy

Directory of Open Access Journals (Sweden)

Zhi-hua Sun

2010-01-01

Full Text Available Performance of zinc yellow polypropylene-coated aluminum alloy 7B04 during accelerated degradation test is studied using electrochemical impedance spectroscopy (EIS. It has been found that the zinc yellow polypropylene paint has few flaw and acts as a pure capacitance before accelerated test. After 336-hour exposure to the test, the impedance spectroscopy shows two time constants, and water has reached to the aluminum alloy/paint interface and forms corrosive microcell. For the scratched samples, the reaction of metal corrosion and the hydrolysis of zinc yellow ion can occur simultaneously. The impedance spectroscopy indicates inductance after 1008-hour exposure to the test, but the inductance disappears after 1344-hour exposure and the passivation film has pitting corrosion.

Improvement of the T-peel Strength of Polypropylene Adhesion Joints by Surface Photografting Pre-Treatment with Methyl Methacrylate

Science.gov (United States)

Balart, R.; Sánchez-Nácher, L.; Balart, J.; Fombuena, V.; España, J. M.

2010-06-01

Although polypropylene is one of the most used polymers at industrial level due to good balanced properties, it presents some restrictions in applications that require good adhesion properties as well as coating and painting. These restrictions are related to its non polar nature which leads to low wetting properties. So that, in most cases, it is necessary a previous surface pre-treatment in order to improve adhesion properties. These surface treatments could be physical or chemical. Among the wide variety of physical processes, plasma technologies are useful from both technical and environmental points of view. If we take into account economic considerations, chemical processes are interesting due to low cost equipment and procedures. In particular, we have used photografting of methyl methacrylate (MMA) monomer on polypropylene substrates with UV radiation and initiators. This process is useful to promote chemical modification of polypropylene surface by grafting MMA monomers into polypropylene polymer chains. Due to polarity of some groups in MMA monomers, it is possible to increase surface wettability thus promoting a remarkable increase in adhesion properties of polypropylene. In this work, changes in wettability of polypropylene surfaces in terms of the exposure time to UV radiation in presence of MMA monomers and initiators has been investigated. Furthermore, chemical changes have been characterized by FTIR analysis and mechanical performance of adhesion joints has been evaluated by T-peel tests.

Rheology of High-Melt-Strength Polypropylene for Additive Manufacturing

DEFF Research Database (Denmark)

Hofstätter, Thomas; Kamleitner, Florian; Jagenteufel, Ralf

Acrylonitrile butadiene styrene (ABS) is a widely used material for additive manufacturing (AM) fused deposition modeling (FDM). The rheological properties of high-melt-strength polypropylene (HMS-PP) were compared to commercially available ABS 250 filament to study the possibility of using...

Fracture behavior of polypropylene/clay nanocomposites.

Science.gov (United States)

Chen, Ling; Wang, Ke; Kotaki, Masaya; Hu, Charmaine; He, Chaobin

2006-12-01

Polypropylene (PP)/clay nanocomposites have been prepared via a reactive compounding approach with an epoxy based masterbatch. Compared with PP and common PP/organoclay nanocomposites, the PP/clay nanocomposites based on epoxy/clay masterbatch have higher impact strength. The phenomenon can be attributed to the epoxy phase dispersed uniformly in the PP matrix, which may act as impact energy absorber and helps to form a large damage zone, thus a higher impact strength value is achieved.

Mechanisms of Contact Electrification at Aluminum-Polytetrafluoroethylene and Polypropylene-Water

KAUST Repository

Nauruzbayeva, Jamilya

2017-01-01

of electrons, but a comprehensive understanding of contact electrification at interfaces of electrical insulators, such as air, water, polytetrafluoroethylene (PTFE), polypropylene remains incomplete. In fact, a variety of mechanisms responsible for transfer

Caracterização mecânica e morfológica de compósitos de polipropileno e fibras de coco verde: influência do teor de fibra e das condições de mistura Mechanical and morphological characterization of polypropylene and green coconut fiber composites: influence of fiber content and mixture conditions

Directory of Open Access Journals (Sweden)

Marina H. Ishizaki

2006-01-01

Full Text Available Compósitos de polipropileno com 10, 20 e 30% em volume de fibra de coco verde foram obtidos em câmara de mistura Haake, tendo como variáveis a temperatura de processamento e a velocidade de cisalhamento. O módulo de flexão e as características morfológicas dos diferentes compósitos obtidos foram avaliados e comparados com o polipropileno puro. Foi observado que a temperatura de 170 °C, a velocidade do rotor de 60rpm e o teor de fibra de coco verde de 30% forneceram o melhor desempenho quanto à flexão. Essas observações foram comprovadas pela análise da morfologia.Polypropylene composites containing 10, 20 and 30% in volume of green coconut fiber were prepared in a Haake chamber at various processing temperatures and shear rates. The flexural modulus and morphological characteristics of the composites were evaluated and compared with pure polypropylene. Optimization experiments indicated that a temperature of 170 °C, shear rate of 60rpm and green coconut fiber content of 30% showed the best properties by flexural modulus. These observations were confirmed by a morphology analysis.

Laparoscopic sacrocolpopexy for recurrent pelvic organ prolapse after failed transvaginal polypropylene mesh surgery.

Science.gov (United States)

Schmid, Corina; O'Rourke, Peter; Maher, Christopher

2013-05-01

A prospective case series to assess the safety and efficacy of laparoscopic sacrocolpopexy for the surgical management of recurrent pelvic organ prolapse (POP) after transvaginal polypropylene mesh prolapse surgery. Between January and December 2010, women with post-hysterectomy recurrent prolapse (≥ stage 2 POP-Q) after transvaginal polypropylene mesh prolapse surgery were included. Perioperative morbidity and short-term complications were recorded and evaluated. Surgical outcomes were objectively assessed utilising the Pelvic Organ Prolapse Quantification system (POP-Q), the validated, condition-specific Australian Pelvic Floor Questionnaire (APFQ) and the Patient Global Impression of Improvement (PGI-I) at 12 months. All 16 women in this study had undergone surgery with trocar-guided transvaginal polypropylene mesh kits. In 75% the recurrent prolapse affected the compartment of prior mesh surgery with the anterior (81%) and apical (75%) compartment prolapse predominating. At a mean follow-up of 12 months, all women had resolution of awareness of prolapse, had transvaginal mesh surgery is feasible and safe. Further widespread evaluation is required.

Elastomer modified polypropylene–polyethylene blends as matrices for wood flour–plastic composites

Science.gov (United States)

Craig Clemons

2010-01-01

Blends of polyethylene (PE) and polypropylene (PP) could potentially be used as matrices for wood–plastic composites (WPCs). The mechanical performance and morphology of both the unfilled blends and wood-filled composites with various elastomers and coupling agents were investigated. Blending of the plastics resulted in either small domains of the minor phase in a...

Dynamics of fibrillar precursors of shishes as a function of stress

Energy Technology Data Exchange (ETDEWEB)

Balzano, Luigi; Cavallo, Dario; Van Erp, Tim B; Ma Zhe; Housmans, Jan-Willem; Fernandez-Ballester, Lucia; Peters, Gerrit W M, E-mail: G.W.M.Peters@tue.n

2010-11-15

Shishes are fibrillar crystallites that can be created by deforming a polymer melt. The formation of shishes takes place when flow is strong enough to stretch molecules. In the early stages, bundles of stretched molecules with pre-crystalline order form metastable precursors whose stability depends on their size and, hence, on the stress level. We find that for a specific isotactic polypropylene, close to the nominal melting point, a stress larger than 0.10 MPa leads to stable fibrillar precursors that are partially crystalline immediately after flow. On the other hand, below 0.10 MPa, the aspect ratio of precursors tends to unity and the lack of crystallinity makes these structures prone to dissolution.

Enhancing the Dyeability of Polypropylene Fibers by Melt Blending with Polyethylene Terephthalate

Directory of Open Access Journals (Sweden)

Fereshteh Mirjalili

2013-01-01

Full Text Available Attempts were made to modify polypropylene fibers by melt blending with polyethylene terephthalate in order to enhance the dyeability of the resultant fiber. Five blends of polypropylene/polyethylene terephthalate/compatibilizer were prepared and subsequently spun into fibers. Three disperse dyes were used to dye such modified fibers at boiling and 130°C. The dyeing performance of the blend fibers, as well as the morphological, chemical, thermal, and mechanical properties, of the corresponding blends was characterized by means of spectrophotometry, polarized optical microscopy, scanning electron microscopy (SEM, FT-IR spectroscopy, differential scanning calorimetry (DSC, and tensile testing.

Properties of Recycled Aggregate Concrete Reinforced with Polypropylene Fibre

Directory of Open Access Journals (Sweden)

Wan Mohammad Wan Nur Syazwani

2016-01-01

Full Text Available This research work is aimed to investigate how the addition of various proportion of polypropylene fibre affects the mechanical strength and permeability characteristics of recycled aggregate concrete (RAC which has been produced with treated coarse recycled concrete aggregate (RCA. Further research on RAC properties and their applications is of great importance as the scarcity of virgin aggregate sources in close proximity to major urban centers is becoming a worldwide problem. In this study, the hardened RAC properties at the curing age of 7 and 28 days such as compressive strength, flexural strength, ultrasonic pulse velocity (UPV, water absorption and total porosity were evaluated and compare with control specimens. Experimental result indicates that although the inclusion of the treated coarse RCA can enhance the mechanical strength and permeability properties of RAC, Further modification by addition of polypropylene fibre can optimize the results.

Laser-induced selective metallization of polypropylene doped with multiwall carbon nanotubes