Liquid crystalline order in polymers

CERN Document Server

Blumstein, Alexandre

1978-01-01

Liquid Crystalline Order in Polymers examines the topic of liquid crystalline order in systems containing rigid synthetic macromolecular chains. Each chapter of the book provides a review of one important area of the field. Chapter 1 discusses scattering in polymer systems with liquid crystalline order. It also introduces the field of liquid crystals. Chapter 2 treats the origin of liquid crystalline order in macromolecules by describing the in-depth study of conformation of such macromolecules in their unassociated state. The chapters that follow describe successively the liquid crystalli

Comparison of Cashew Nut Shell Liquid (CNS) Resin with Polyester ...

African Journals Online (AJOL)

Akorede

cobalt amine (accelerator), methyl ethyl ketone peroxide (catalyst) to develop two sets of ... shell liquid (CNSL) resin were comparable to those developed with polyester resin. ... permit diffusion of water, this function is often not adequately ... When designed ... blades in gas turbine engines, wing leading edges and flaps.

Liquid crystalline dihydroazulene photoswitches

DEFF Research Database (Denmark)

Petersen, Anne Ugleholdt; Jevric, Martyn; Mandle, Richard J.

2015-01-01

A large selection of photochromic dihydroazulene (DHA) molecules incorporating various substituents at position 2 of the DHA core was prepared and investigated for their ability to form liquid crystalline phases. Incorporation of an octyloxy-substituted biphenyl substituent resulted in nematic...... phase behavior and it was possible to convert one such compound partly into its vinylheptafulvene (VHF) isomer upon irradiation with light when in the liquid crystalline phase. This conversion resulted in an increase in the molecular alignment of the phase. In time, the meta-stable VHF returns...... to the DHA where the alignment is maintained. The systematic structural variation has revealed that a biaryl spacer between the DHA and the alkyl chain is needed for liquid crystallinity and that the one aromatic ring in the spacer cannot be substituted by a triazole. This work presents an important step...

Observation of hairpin defects in a nematic main-chain polyester

Science.gov (United States)

Li, M. H.; Brûlet, A.; Davidson, P.; Keller, P.; Cotton, J. P.

1993-04-01

The conformation of a main-chain liquid crystalline polyester in its oriented nematic phase has been determined by small-angle neutron scattering. The data are fitted by a model of rigid cylinder with orientational fluctuations. For a low degree of polymerization (~9) the chain is almost completely elongated in the direction of the nematic field. For a polymer 3 times longer, the existence of two hairpins is shown at high temperature; this number decreases with decreasing temperature.

Thermal Analysis, Mechanical and Rheological Behaviour of Melt Manufactured Polyethylene/Liquid Crystal Polymer Blends

Directory of Open Access Journals (Sweden)

Ilze ELKSNITE

2011-07-01

Full Text Available Modification of properties of conventional thermoplastics with thermotropic liquid crystal polymers, from one hand, allows decrease their viscosities, substantially facilitating processing conditions, and, from another hand, allows increase their exploitation properties. Orientation of the labile structure of liquid crystal polymer in extrusion or injection moulding causes specific reinforcement (so-called self-reinforcement to occur in the blends containing liquid crystal polymer. Up to now the effect of self-reinforcement is mostly investigated in the blends, containing considerable amount of liquid crystal polymer. In this research the effect of minor amounts of liquid crystalline co-polyester modifier on the properties of polyethylene is investigated. Various compositions of laboratory synthesized hydroxybenzoic acid /polyethylene terephtalate copolymer containing polyethylene composites have been manufactured by thermoplastic blending. It has been observed that 1 modulus of elasticity, yield strength and ultimate strength increase with raising the content of liquid crystalline modifier; 2 void content in the investigated polyethylene/liquid crystal copolymer composites is not greater that 1 %; 3 addition of liquid crystalline co-polyester modifier improves arrangement of PE crystalline phase.http://dx.doi.org/10.5755/j01.ms.17.2.483

Controlling the morphology of side chain liquid crystalline block copolymer thin films through variations in liquid crystalline content.

Science.gov (United States)

Verploegen, Eric; Zhang, Tejia; Jung, Yeon Sik; Ross, Caroline; Hammond, Paula T

2008-10-01

In this paper, we describe methods for manipulating the morphology of side-chain liquid crystalline block copolymers through variations in the liquid crystalline content. By systematically controlling the covalent attachment of side chain liquid crystals to a block copolymer (BCP) backbone, the morphology of both the liquid crystalline (LC) mesophase and the phase-segregated BCP microstructures can be precisely manipulated. Increases in LC functionalization lead to stronger preferences for the anchoring of the LC mesophase relative to the substrate and the intermaterial dividing surface. By manipulating the strength of these interactions, the arrangement and ordering of the ultrathin film block copolymer nanostructures can be controlled, yielding a range of morphologies that includes perpendicular and parallel cylinders, as well as both perpendicular and parallel lamellae. Additionally, we demonstrate the utilization of selective etching to create a nanoporous liquid crystalline polymer thin film. The unique control over the orientation and order of the self-assembled morphologies with respect to the substrate will allow for the custom design of thin films for specific nanopatterning applications without manipulation of the surface chemistry or the application of external fields.

An analysis of the anisotropic and topographic gratings in a side-chain liquid crystalline azobenzene polyester

DEFF Research Database (Denmark)

Holme, N.C.R.; Nikolova, L.; Ramanujam, P.S.

1997-01-01

We have examined in detail the formation of surface relief structures in azobenzene polyesters formed by polarization holography with orthogonally circularly polarized laser beams, We show that it is possible to separate the contribution to the diffraction efficiency into an anisotropic part...

Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

Directory of Open Access Journals (Sweden)

2011-07-01

Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

Solution processed nanogap organic diodes based on liquid crystalline materials

Science.gov (United States)

Wang, Yi-Fei; Iino, Hiroaki; Hanna, Jun-ichi

2017-09-01

Co-planar nanogap organic diodes were fabricated with smectic liquid crystalline materials of the benzothienobenzothiophene (BTBT) derivative by a spin-coating technique. A high rectification ratio of the order of 106 at ±3 V was achieved when a liquid crystalline material of 2,7-didecyl benzothieno[3,2-b][1]benzothiophene (10-BTBT-10) was used in a device configuration of Al/10-BTBT-10/pentafluorobenzenethiol-treated Au on a glass substrate, which was 4 orders higher than that of the device based on non-liquid crystalline materials of 2,7-dibutyl benzothieno[3,2-b][1]benzothiophene (4-BTBT-4) and BTBT. Similar results were also observed when another liquid crystalline material of ω, ω'-dioctylterthiophene (8-TTP-8) and a non-liquid crystalline material of terthiophene (TTP) were used. These improved rectifications can be ascribed to the self-assembly properties and controllable molecular orientation of liquid crystalline materials, which made uniform perpendicular oriented polycrystalline films favorable for superior charge transport in nano-channels.

A metastable liquid melted from a crystalline solid under decompression

Science.gov (United States)

Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Kono, Yoshio; Park, Changyong; Kenney-Benson, Curtis; Shen, Guoyin

2017-01-01

A metastable liquid may exist under supercooling, sustaining the liquid below the melting point such as supercooled water and silicon. It may also exist as a transient state in solid-solid transitions, as demonstrated in recent studies of colloidal particles and glass-forming metallic systems. One important question is whether a crystalline solid may directly melt into a sustainable metastable liquid. By thermal heating, a crystalline solid will always melt into a liquid above the melting point. Here we report that a high-pressure crystalline phase of bismuth can melt into a metastable liquid below the melting line through a decompression process. The decompression-induced metastable liquid can be maintained for hours in static conditions, and transform to crystalline phases when external perturbations, such as heating and cooling, are applied. It occurs in the pressure-temperature region similar to where the supercooled liquid Bi is observed. Akin to supercooled liquid, the pressure-induced metastable liquid may be more ubiquitous than we thought.

Biphotonic holographic gratings in azobenzene polyesters: Surface relief phenomena and polarization effects

DEFF Research Database (Denmark)

Sánchez, C.; Alcalá, R.; Hvilsted, Søren

2000-01-01

Biphotonic holographic gratings have been recorded in a side-chain azobenzene liquid crystalline polyester using a blue incoherent source and a He-Ne laser. Intensity gratings and the appearance of surface relief have been observed when two linearly polarized beams from a He-Ne laser are made...... to interfere on a film illuminated with blue light. Polarized holographic gratings are also created with two orthogonally circularly polarized He-Ne beams. All these gratings are stable in darkness but can be erased with blue light. (C) 2000 American Institute of Physics....

Liquid crystalline epoxy nanocomposite material for dental application.

Science.gov (United States)

Tai, Yun-Yuan; Hsu, Sheng-Hao; Chen, Rung-Shu; Su, Wei-Fang; Chen, Min-Huey

2015-01-01

Novel liquid crystalline epoxy nanocomposites, which exhibit reduced polymerization shrinkage and effectively bond to tooth structures, can be applied in esthetic dentistry, including core and post systems, direct and indirect restorations, and dental brackets. The purposes of this study were to investigate the properties of liquid crystalline epoxy nanocomposites including biocompatibility, microhardness, and frictional forces of bracket-like blocks with different filler contents for further clinical applications. In this study, we evaluated liquid crystalline epoxy nanocomposite materials that exhibited various filler contents, by assessing their cell activity performance using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and their microhardness with or without thermocycling. We also evaluated the frictional force between bracket-like duplicates and commercially available esthetic bracket systems using Instron 5566. The liquid crystalline epoxy nanocomposite materials showed good biocompatibility. The materials having high filler content demonstrated greater microhardness compared with commercially available bracket materials, before and after the thermocycling treatment. Thus, manufacturing processes are important to reduce frictional force experienced by orthodontic brackets. The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment. Copyright © 2014. Published by Elsevier B.V.

Ferrofluids in liquid crystalline systems

International Nuclear Information System (INIS)

Figueiredo Neto, A.M.; Liebert, L.

1989-08-01

It is a well-known fact that intermediate or mesomorphic phase may exist between the crystalline and the isotropic liquid phases. The symmetry properties of these mesophases are intermediate between those of a crystal and a liquid. In this paper, some aspects of the use of ferrofluids in thermotropic and lyotropic systems are studied both the experimental difficulties as well as the fundamental phypical phenomena involved. (A.C.A.S.) [pt

Liquid crystallinity driven highly aligned large graphene oxide composites

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of); Kim, Sang Ouk, E-mail: sangouk.kim@kaist.ac.kr [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of)

2015-04-15

Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

Autophobicity and layering behavior of thin liquid-crystalline polymer films.

NARCIS (Netherlands)

Wielen, van der M.W.J.; Cohen Stuart, M.A.; Fleer, G.J.

1998-01-01

The stability against breaking-up of thin spin-coated films of liquid-crystalline polymers depends on the film thickness and annealing temperature. This study concerns side-chain liquid-crystalline polymers, based on alternating copolymers of maleic anhydride and mesogenic alkenes. The mesogenic

21 CFR 524.2620 - Liquid crystalline trypsin, Peru balsam, castor oil.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Liquid crystalline trypsin, Peru balsam, castor... NEW ANIMAL DRUGS § 524.2620 Liquid crystalline trypsin, Peru balsam, castor oil. (a)(1) Specifications... delivered to the wound site contains 0.12 milligram of crystalline trypsin, 87.0 milligrams of Peru balsam...

Excimer fluorescence of liquid crystalline systems

Science.gov (United States)

Sakhno, Tamara V.; Khakhel, Oleg A.; Barashkov, Nikolay N.; Korotkova, Irina V.

1996-04-01

The method of synchronous scanning fluorescence spectroscopy shows a presence of dimers of pyrene in a polymeric matrix. The results suggest that excimer formation takes place with dimers in liquid crystalline systems.

Liquid crystalline thermosetting polymers as protective coatings for aerospace

OpenAIRE

Guerriero, G.L.

2012-01-01

Environmental regulations are driving the development of new aerospace coating systems, mainly to eliminate chromates and reduce volatile organic compound (VOC) emissions. Among the various potential options for new coating materials, liquid crystalline polymers (LCPs) are attractive due to their unique combination of mechanical properties and chemical resistance. Their use, however, has been limited mainly due to poor adhesion properties. Thermotropic liquid crystalline thermosets displayed ...

Influence of UV irradiation on the blue and red light photoinduced processes in azobenzene polyesters

DEFF Research Database (Denmark)

Rodríguez, F.J.; Sánchez, C.; Villacampa, B.

2004-01-01

light that yields the films into the isotropic state at room temperature (RT) was compared with the quenching from temperatures above the isotropic transition temperature Ti. UV–visible spectra of the thermally quenched films show the presence of aggregates when measured at RT. We have found that UV......Birefringence induced in a series of liquid crystalline side-chain azobenzene polyesters with different substituent groups was investigated under irradiation with 488 and 633 nm linearly polarized lights. Two different initial conditions have been used: the effect of a previous irradiation with UV...

Blending crystalline/liquid crystalline small molecule semiconductors: A strategy towards high performance organic thin film transistors

Science.gov (United States)

He, Chao; He, Yaowu; Li, Aiyuan; Zhang, Dongwei; Meng, Hong

2016-10-01

Solution processed small molecule polycrystalline thin films often suffer from the problems of inhomogeneity and discontinuity. Here, we describe a strategy to solve these problems through deposition of the active layer from a blended solution of crystalline (2-phenyl[1]benzothieno[3,2-b][1]benzothiophene, Ph-BTBT) and liquid crystalline (2-(4-dodecylphenyl) [1]benzothieno[3,2-b]benzothiophene, C12-Ph-BTBT) small molecule semiconductors with the hot spin-coating method. Organic thin film transistors with average hole mobility approaching 1 cm2/V s, much higher than that of single component devices, have been demonstrated, mainly due to the improved uniformity, continuity, crystallinity, and stronger intermolecular π-π stacking in blend thin films. Our results indicate that the crystalline/liquid crystalline semiconductor blend method is an effective way to enhance the performance of organic transistors.

Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction.

Science.gov (United States)

Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M

2016-11-02

Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular reorientations in a substance with liquid-crystalline and plastic-crystalline phases

International Nuclear Information System (INIS)

Nguyen, Xuan Phuc.

1986-05-01

Results of dielectric relaxation (DR), quasielastic neutron scattering (QNS), far infrared absorption (FIR), proton magnetic resonance (PMR), differential scanning calorimetry (DSC) and preliminary X-ray diffraction measurements on the di-n-pentyloxyazoxybenzene (5.OAOB) are presented. The measurements carried out by all these methods showed that 5.OAOB exhibits a nontypical for liquid-crystalline materials phase diagram. It has two mesophases: a nematic (N) and an ''intermediate'' crystalline phase just below it. A complex interpretation of results obtained is given. All suggestions concerning the character of reorientational motions of the molecule as a whole as well as of its segments in mesomorphic phases are analyzed. From comparison of the DR and QNS studies one can conclude that in the N phase the molecule as a whole performs rotational diffusion around the long axis (τ DR ∼ 100 ps) and at the same time the two moieties perform faster independent reorientations around N - benzene rings bonds withτ QNS ∼ 5 ps. On the basis of various experimental data it is shown that the CrI phase is a plastic-crystalline phase for which the molecule and its segments perform fast stochastic unaxial reorientations. This is the first case where the existence of such a phase in liquid-crystalline materials has been experimentally confirmed. (author)

Nonlinear optics of liquid crystalline materials

International Nuclear Information System (INIS)

Khoo, Iam Choon

2009-01-01

Liquid crystals occupy an important niche in nonlinear optics as a result of their unique physical and optical properties. Besides their broadband birefringence and transparency, abilities to self-assemble into various crystalline phases and to conform to various flexible forms and shapes, liquid crystals are compatible with almost all other optoelectronic materials and technology platforms. In both isotropic and ordered phases, liquid crystals possess extraordinarily large optical nonlinearities that stretch over multiple time scales. To date, almost all conceivable nonlinear optical phenomena have been observed in a very broad spectrum spanning the entire visible to infrared and beyond. In this review, we present a self-contained complete discussion of the optical nonlinearities of liquid crystals, and a thorough review of a wide range of nonlinear optical processes and phenomena enabled by these unique properties. Starting with a brief historical account of the development of nonlinear optical studies of the mesophases of liquid crystals, we then review various liquid crystalline materials and structures, and their nonlinear optical properties. Emphasis is placed on the nematic phase, which best exemplifies the dual nature of liquid crystals, although frequent references to other phases are also made. We also delve into recent work on novel structures such as photonic crystals, metamaterials and nanostructures and their special characteristics and emergent properties. The mechanisms and complex nonlocal dynamics of optical nonlinearities associated with laser induced director axis reorientation, thermal, density, and order parameter fluctuations, space charge field formation and photorefractivity are critically reviewed as a foundation for the discussions of various nonlinear optical processes detailed in this paper

(Citric acid–co–polycaprolactone triol) polyester

Science.gov (United States)

Thomas, Lynda V.; Nair, Prabha D.

2011-01-01

Tissue engineering holds enormous challenges for materials science, wherein the ideal scaffold to be used is expected to be biocompatible, biodegradable and possess mechanical and physical properties that are suitable for target application. In this context, we have prepared degradable polyesters in different ratios by a simple polycondensation technique with citric acid and polycaprolactone triol. Differential scanning calorimetry indicated that the materials were amorphous based the absence of a crystalline melting peak and the presence of a glass transition temperature below 37°C. These polyesters were found to be hydrophilic and could be tailor-made into tubes and films. Porosity could also be introduced by addition of porogens. All the materials were non-cytotoxic in an in vitro cytotoxicity assay and may degrade via hydrolysis to non-toxic degradation products. These polyesters have potential implications in the field of soft tissue engineering on account of their similarity of properties. PMID:23507730

Liquid Crystalline Semiconductors Materials, properties and applications

CERN Document Server

Kelly, Stephen; O'Neill, Mary

2013-01-01

This is an exciting stage in the development of organic electronics. It is no longer an area of purely academic interest as increasingly real applications are being developed, some of which are beginning to come on-stream. Areas that have already been commercially developed or which are under intensive development include organic light emitting diodes (for flat panel displays and solid state lighting), organic photovoltaic cells, organic thin film transistors (for smart tags and flat panel displays) and sensors. Within the family of organic electronic materials, liquid crystals are relative newcomers. The first electronically conducting liquid crystals were reported in 1988 but already a substantial literature has developed. The advantage of liquid crystalline semiconductors is that they have the easy processability of amorphous and polymeric semiconductors but they usually have higher charge carrier mobilities. Their mobilities do not reach the levels seen in crystalline organics but they circumvent all of t...

Phosphoric acids as amplifiers of molecular chirality in liquid crystalline media

NARCIS (Netherlands)

Eelkema, R; Feringa, BL

2006-01-01

A new system for the double amplification of the molecular chirality of simple chiral amines in achiral liquid crystalline media is described. It involves a conformationally flexible phosphoric acid based receptor that by binding to chiral amines induces chirality in the liquid crystalline matrix.

Liquid Crystalline Perylene diimides : Architecture and Charge Carrier Mobilities

NARCIS (Netherlands)

Struijk, C.W.; Sieval, A.B.; Dakhorst, J.E.J.; Dijk, van M.; Kimkes, P.; Koehorst, R.B.M.; Donker, H.

2000-01-01

The phase behavior of three N-alkyl-substituted perylene diimide derivatives is examined by differential scanning calorimetry and polarized optical microscopy. The occurrence of multiple phase transitions indicates several crystalline and several liquid crystalline phases. X-ray diffraction

Liquid crystalline solutions of cellulose in phosphoric acid for preparing cellulose yarns

NARCIS (Netherlands)

Boerstoel, H.

2006-01-01

The presen thesis describes a new process for manufacturing high tenacity and high modulus cellulose yarns. A new direct solvent for cellulose has been discovered, leading to liquid crystalline solutions. This new solvent, superphosphoric acid, rapidly dissolves cellulose. These liquid crystalline

Liquid crystalline biopolymers: A new arena for liquid crystal research

International Nuclear Information System (INIS)

Rizvi, Tasneem Zahra

2001-07-01

This paper gives a brief introduction to liquid crystals on the basis of biopolymers and reviews literature on liquid crystalline behaviour of biopolymers both in vitro and in vivo in relation to their implications in the fields of biology, medicine and material science. Knowledge in the field of biological liquid crystals is crucial for understanding complex phenomena at supramolecular level which will give information about processes involved in biological organization and function. The understanding of the interaction of theses crystals with electric, magnetic, optical and thermal fields will uncover mechanisms of near quantum-energy detection capabilities of biosystems

Liquid crystalline order of carbon nanotubes

Science.gov (United States)

Georgiev, Georgi; Ahlawat, Aditya; Mulkern, Brian; Doyle, Robert; Mongeau, Jennifer; Ogilvie, Alex

2007-03-01

Topological defects formed during phase transitions in liquid crystals provide a direct proof of the standard Cosmological model and are direct links to the Early Universe. On the other hand in Nanotechnology, carbon nanotubes can be manipulated and oriented directly by changing the liquid crystalline state of the nanotubes, in combination with organic liquid crystals. Currently there are no nano-assemblers, which makes the liquid crystal state of the nanotubes, one of the few ways of controlling them. We show the design of a fast and efficient polarized light ellipsometric system (a new modification of previous optical systems) that can provide fast quantitative real time measurements in two dimensions of the formation of topological defects in liquid crystals during phase transitions in lab settings. Our aim is to provide fundamental information about the formation of optically anisotropic structures in liquid crystals and the orientation of carbon nanotubes in electric field.

Dicyanamide Salts that Adopt Smectic, Columnar, or Bicontinuous Cubic Liquid-Crystalline Mesophases.

Science.gov (United States)

Park, Geonhui; Goossens, Karel; Shin, Tae Joo; Bielawski, Christopher W

2018-04-25

Although dicyanamide (i.e., [N(CN) 2 ] - ) has been commonly used to obtain low-viscosity, halogen-free, room-temperature ionic liquids, liquid-crystalline salts containing such anions have remained virtually unexplored. Here we report a series of amphiphilic dicyanamide salts that, depending on their structures and compositions, adopt smectic, columnar, or bicontinuous cubic thermotropic liquid-crystalline mesophases, even at room temperature in some cases. Their thermal properties were explored by polarized light optical microscopy, differential scanning calorimetry, thermogravimetric analysis (including evolved gas analysis), and variable-temperature synchrotron X-ray diffraction. Comparison of the thermal phase characteristics of these new liquid-crystalline salts featuring "V-shaped" [N(CN) 2 ] - anions with those of structural analogues containing [SCN] - , [BF 4 ] - , [PF 6 ] - , or [CF 3 SO 3 ] - anions indicated that not only the size of the counterion but also its shape should be considered in the development of mesomorphic salts. Collectively, these discoveries may be expected to facilitate the design of thermotropic ionic liquid crystals that form inverted-type bicontinuous cubic and other sophisticated liquid-crystalline phases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Structure Change on Radiation Crosslinking of Unsaturated Polyesters

International Nuclear Information System (INIS)

Ranogajec, F.

2006-01-01

During the course of crosslinking of unsaturated polyesters reacting system, that was liquid prior to reaction, gels, and becomes solid. Crosslinking reaction begins to be controlled by the change of the physical state of the system at an early stage of reaction. The kinetics can not be studied by the usual kinetical methods. In-source 60 C o gamma rays induced crosslinking of unsaturated polyester with styrene was followed directly and continuously by measuring electrical conductivity change. The results of extraction analysis proved good correlation between the change of electrical conductivity and the extent of curing. The gel content was inversely proportional to conductivity and free styrene content directly proportional to conductivity. DC-electrical conductivity has shown high sensitivity toward structural changes and enabled us to detect liquid-liquid transitions in unsaturated polyester. The upper liquid-liquid transition (T l ρ) is less known transition caused by a stepwise decrease of intramolecular short-range local order that remains above the glass and lower liquid-liquid transitions. The local order is based on secondary valent interactions and is enhanced by hydrogen bonding. The linear temperature dependence of the viscosity and dc electrical conductivity of unsaturated polyesters showed a change of slope caused by the (T l ρ). Those changes were the result of the diminishing of the local order (which includes several bond lengths) caused by breaking of the intramolecular interactions. The intramolecular nature of the (T l ρ) in the polyesters under consideration was proved by its insensitivity to crosslinking and dilution with solvents. In the corresponding temperature range, DSC thermograms shoved expected endothermic changes. The structure changes related to the (T l ρ) in the investigated polyesters were determined by 1 H NMR and NIR spectroscopy. The proton NMR indicated that the stepwise change in hydrogen bonding occurred in the

Cross-Linked Liquid Crystalline Systems From Rigid Polymer Networks to Elastomers

CERN Document Server

Broer, Dirk

2011-01-01

With rapidly expanding interest in liquid crystalline polymers and elastomers among the liquid crystal community, researchers are currently exploring the wide range of possible application areas for these unique materials, including optical elements on displays, tunable lasers, strain gauges, micro-structures, and artificial muscles. Written by respected scientists from academia and industry around the world, who are not only active in the field but also well-known in more traditional areas of research, "Cross-Linked Liquid Crystalline Systems: From Rigid Polymer Networks to Elastomers&qu

Komposit Hibrid Polyester Berpenguat Serbuk Batang Dan Serat Sabut Kelapa

OpenAIRE

Lumintang, Romels C. A; Soenoko, Rudy; Wahyudi, Slamet

2011-01-01

Sawdust coconut trunks of palm trees and fiber coconut coir are two waste materials from the processing of coconuts and coconut tree trunks sawmill waste are plentiful materials can be utilized for producing composites using polyester resins. Both each properties materials as follow polyester resin: liquid in the open air conditions, sawdust coconut and coconut coir fiber properties is lightweight and fragile nature of the polyester adhesive used as a binder (binder) between fiber coconut coi...

Biodegradation of polyester. Polyester no bunkai sei

Energy Technology Data Exchange (ETDEWEB)

Tokiwa, Y. (Agency of Industrial Science and Technology, Tokyo (Japan). Fermentation Research Inst.)

1991-09-10

Penicillium sp. 14-3 and penicillium sp. 26-1 can degrade various kinds of polyester. The results of studies made on hydrolysis of polyester by enzyme, hydrolysis of polyester by various kinds of lipase, and degradation of ester type polyurethane by microbes and lipase are introduced. For the improvement of physical properties of aliphatic polyester, aromatic-aliphatic polyester copolymers (CPE) have been synthesized to study the biodegradability. Copolymer in which a number of polyamide (nylon) are alternately introduced (CPAE) to aliphatic polyester has been developed. The result of studies made on the degradability of a blended body of PCL and natural high polymer, and on the collapsibility by lipase of high polymer materials including aliphatic polyamide are introduced. 26 refs., 5 figs., 1 tab.

Liquid Crystalline Thermosets from Ester, Ester-imide, and Ester-amide Oligomers

Science.gov (United States)

Dingemans, Theodorus J. (Inventor); Weiser, Erik S. (Inventor); St. Clair, Terry L. (Inventor)

2009-01-01

Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystaloligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oli-gomers are stable forup to an hour in the melt phase. They are highly processable by a variety of melt process shape forming and blending techniques. Once processed and shaped, the end-capped liquid crystal oigomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures.

Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level

International Nuclear Information System (INIS)

Stimson, Lorna M.

2003-01-01

Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a single dendrimer molecule in the gas phase at the atomistic level, semi-atomistic molecular dynamics of a single molecule in liquid crystalline solvents and a coarse-grained molecular dynamics study of the dendrimer in the bulk. The coarse-grained model has been developed and parameterized using the results of the atomistic and semi-atomistic work. The single molecule studies showed that the liquid crystalline dendrimer was able to change its structure by conformational changes in the flexible chains that link the mesogenic groups to the core. Structural change was seen under the application of a mean field ordering potential in the gas phase, and in the presence of liquid crystalline solvents. No liquid crystalline phases were observed for the bulk phase studies of the coarse-grained model. However, when the length of the mesogenic units was increased there was some evidence for microphase separation in these systems. (author)

Photo-responsive liquid crystalline epoxy networks with exchangeable disulfide bonds

Energy Technology Data Exchange (ETDEWEB)

Li, Yuzhan [Washington State Univ., Pullman, WA (United States); Zhang, Yuehong [Washington State Univ., Pullman, WA (United States); Rios, Orlando [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Keum, Jong K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kessler, Michael R. [Washington State Univ., Pullman, WA (United States); North Dakota State Univ., Fargo, ND (United States)

2017-07-27

The increasing demand for intelligent materials has driven the development of polymers with a variety of functionalities. However, combining multiple functionalities within one polymer is still challenging because of the difficulties encountered in coordinating different functional building blocks during fabrication. In this work, we demonstrate the fabrication of a multifunctional liquid crystalline epoxy network (LCEN) using the combination of thermotropic liquid crystals, photo-responsive azobenzene molecules, and exchangeable disulfide bonds. In addition to shape memory behavior enabled by the reversible liquid crystalline phase transition and photo-induced bending behavior resulting from the photo-responsive azobenzene molecules, the introduction of dynamic disulfide bonds into the LCEN resulted in a structurally dynamic network, allowing the reshaping, repairing, and recycling of the material.

Polymer and Polymer Gel of Liquid Crystalline Semiconductors

Institute of Scientific and Technical Information of China (English)

Teppei Shimakawa; Naoki Yoshimoto; Jun-ichi Hanna

2004-01-01

It prepared a polymer and polymer gel of a liquid crystalline (LC) semiconductor having a 2-phenylnaphthalene moiety and studied their charge carrier transport properties by the time-of-flight technique. It is found that polyacrylate having the mesogenic core moiety of 2-phenylnaphtalene (PNP-acrylate) exhibited a comparable mobility of 10-4cm2/Vs in smectic A phase to those in smectic A (SmA) phase of small molecular liquid crystals with the same core moiety, e.g., 6-(4'-octylphenyl)- 2-dodecyloxynaphthalene (8-PNP-O12), and an enhanced mobility up to 10-3cm2/Vs in the LC-glassy phase at room temperature, when mixed with a small amount of 8-PNP-O12. On the other hand, the polymer gel consisting of 20 wt %-hexamethylenediacrylate (HDA)-based cross-linked polymer and 8-PNP-O12 exhibited no degraded mobility when cross-linked at the mesophase. These results indicate that the polymer and polymer composite of liquid crystalline semiconductors provide us with an easy way to realize a quality organic semiconductor thin film for the immediate device applications.

Photoorientation of a liquid-crystalline polyester with azobenzene side groups: Effects of irradiation with linearly polarized red light after photochemical pretreatment

DEFF Research Database (Denmark)

Zebger, Ingo; Rutloh, Michael; Hoffmann, Uwe

2003-01-01

light. The polyester is characterized by smectic and nematic phases g24SX26SA34N46i and a strong tendency to form J-aggregates. The process requires a photochemical pretreatment by irradiation with UV light or an exposure to visible light of high power density to produce a certain concentration of the Z...

Liquid crystalline fiber optic colorimeter for hydrostatic pressure measurement

Science.gov (United States)

Wolinski, Tomasz R.; Bajdecki, Waldemar K.; Domanski, Andrzej W.; Karpierz, Miroslaw A.; Konopka, Witold; Nasilowski, T.; Sierakowski, Marek W.; Swillo, Marcin; Dabrowski, Roman S.; Nowinowski-Kruszelnicki, Edward; Wasowski, Janusz

2001-08-01

This paper presents results of tests performed on a fiber optic system of liquid crystalline transducer for hydrostatic pressure monitoring based on properties of colorimetry. The system employs pressure-induced deformations occurring in liquid crystalline (LC) cells configured in a homogeneous Frederiks geometry. The sensor is compared of a round LC cell placed inside a specially designed pressure chamber. As a light source we used a typical diode operating at red wavelength and modulated using standard techniques. The pressure transducer was connected to a computer with a specially designed interface built on the bas of advanced ADAM modules. Results indicate that the system offers high response to pressure with reduced temperature sensitivity and, depending on the LC cell used, can be adjusted for monitoring of low hydrostatic pressures up to 6 MPa. These studies have demonstrated the feasibility of fiber optic liquid crystal colorimeter for hydrostatic pressure sensing specially dedicated to pipe- lines, mining instrumentation, and process-control technologies.

Rotational reorganization of doped cholesteric liquid crystalline films

NARCIS (Netherlands)

Eelkema, R.; M. Pollard, M.; Katsonis, N.; Vicario, J.; J. Broer, D.; Feringa, B.L.

2006-01-01

In this paper an unprecedented rotational reorganization of cholesteric liquid crystalline films is described. This rotational reorganization results from the conversion of a chiral molecular motor dopant to an isomer with a different helical twisting power, leading to a change in the cholesteric

Effect of Liquid Crystalline Systems Containing Antimicrobial Compounds on Infectious Skin Bacteria.

Science.gov (United States)

Souza, Carla; Watanabe, Evandro; Aires, Carolina Patrícia; Lara, Marilisa Guimarães

2017-08-01

This study aimed (i) to prepare liquid crystalline systems (LCS) of glyceryl monooleate (GMO) and water containing antibacterial compounds and (ii) to evaluate their potential as drug delivery systems for topical treatment of bacterial infections. Therefore, LCS containing CPC (cetylpyridinium chloride) (LCS/CPC) and PHMB (poly(hexamethylene biguanide) hydrochloride) (LCS/PHMB) were prepared and the liquid crystalline phases were identified by polarizing light microscopy 24 h and 7 days after preparation. The in vitro drug release profile and in vitro antibacterial activity of the systems were assessed using the double layer agar diffusion method against Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Escherichia coli, and Enterococcus faecalis. The interaction between GMO and the drugs was evaluated by a drug absorption study. Stable liquid crystalline systems containing CPC and PHMB were obtained. LCS/PHMB decreased the PHMB release rate and exerted strong antibacterial activity against all the investigated bacteria. In contrast, CPC interacted with GMO so strongly that it became attached to the system; the amount released was not sufficient to exert antibacterial activity. Therefore, the studied liquid crystalline systems were suitable to deliver PHMB, but not CPC. Accordingly, it was demonstrated that GMO interacts with each drug differently, which may interfere in the final efficiency of GMO/water LCS.

Electric-field triggered controlled release of bioactive volatiles from imine-based liquid crystalline phases.

Science.gov (United States)

Herrmann, Andreas; Giuseppone, Nicolas; Lehn, Jean-Marie

2009-01-01

Application of an electric field to liquid crystalline film forming imines with negative dielectric anisotropy, such as N-(4-methoxybenzylidene)-4-butylaniline (MBBA, 1), results in the expulsion of compounds that do not participate in the formation of the liquid crystalline phase. Furthermore, amines and aromatic aldehydes undergo component exchange with the imine by generating constitutional dynamic libraries. The strength of the electric field and the duration of its application to the liquid crystalline film influence the release rate of the expelled compounds and, at the same time, modulate the equilibration of the dynamic libraries. The controlled release of volatile organic molecules with different chemical functionalities from the film was quantified by dynamic headspace analysis. In all cases, higher headspace concentrations were detected in the presence of an electric field. These results point to the possibility of using imine-based liquid crystalline films to build devices for the controlled release of a broad variety of bioactive volatiles as a direct response to an external electric signal.

Self-assembly of azobenzene based side-chain liquid crystalline ...

Indian Academy of Sciences (India)

The polymeric complexes acquitted as undivided liquid crystalline properties ... India) methanol and other solvents were purified by .... mixture was warmed to room temperature and stirred ... Polymer is soluble in DMF, CHCl3, CH2Cl2 and.

Effects of alkaline or liquid-ammonia treatment on crystalline cellulose: changes in crystalline structure and effects on enzymatic digestibility

Directory of Open Access Journals (Sweden)

Himmel Michael E

2011-10-01

Full Text Available Abstract Background In converting biomass to bioethanol, pretreatment is a key step intended to render cellulose more amenable and accessible to cellulase enzymes and thus increase glucose yields. In this study, four cellulose samples with different degrees of polymerization and crystallinity indexes were subjected to aqueous sodium hydroxide and anhydrous liquid ammonia treatments. The effects of the treatments on cellulose crystalline structure were studied, in addition to the effects on the digestibility of the celluloses by a cellulase complex. Results From X-ray diffractograms and nuclear magnetic resonance spectra, it was revealed that treatment with liquid ammonia produced the cellulose IIII allomorph; however, crystallinity depended on treatment conditions. Treatment at a low temperature (25°C resulted in a less crystalline product, whereas treatment at elevated temperatures (130°C or 140°C gave a more crystalline product. Treatment of cellulose I with aqueous sodium hydroxide (16.5 percent by weight resulted in formation of cellulose II, but also produced a much less crystalline cellulose. The relative digestibilities of the different cellulose allomorphs were tested by exposing the treated and untreated cellulose samples to a commercial enzyme mixture (Genencor-Danisco; GC 220. The digestibility results showed that the starting cellulose I samples were the least digestible (except for corn stover cellulose, which had a high amorphous content. Treatment with sodium hydroxide produced the most digestible cellulose, followed by treatment with liquid ammonia at a low temperature. Factor analysis indicated that initial rates of digestion (up to 24 hours were most strongly correlated with amorphous content. Correlation of allomorph type with digestibility was weak, but was strongest with cellulose conversion at later times. The cellulose IIII samples produced at higher temperatures had comparable crystallinities to the initial cellulose I

Synthesis and characterization of polyesters derived from glycerol and phthalic acid

Directory of Open Access Journals (Sweden)

Danilo Hansen Guimarães

2007-09-01

Full Text Available The production of polyester via polycondensation between glycerol and phthalic acid using dibutyltin dilaurate is reported. Three glycerol:phthalic acid molar ratio used for the bulk polymerization were: 2:2; 2:3 and 2:4. FTIR confirmed the esterification of glycerol by the acid for all the polymers. DSC indicated no crystallinity, although the XRD plots indicate a very incipient crystallinity for the polymers containing higher amounts of phthalic anhydride. Scanning electron microscopy results indicates high homogeneity for all the polymers prepared.

Liquid crystalline thermosetting polymers as protective coatings for aerospace

NARCIS (Netherlands)

Guerriero, G.L.

2012-01-01

Environmental regulations are driving the development of new aerospace coating systems, mainly to eliminate chromates and reduce volatile organic compound (VOC) emissions. Among the various potential options for new coating materials, liquid crystalline polymers (LCPs) are attractive due to their

Investigations on the liquid crystalline phases of cation-induced ...

Indian Academy of Sciences (India)

liquid crystalline phases of Li–DNA system could be useful in the production of ... undergo unidirectional ordering (the solution starts to become birefringent under ... was spread over the glass slides with a cover slip and sealed with a neutral ...

Electric properties of a liquid crystalline methacrylic polymer

International Nuclear Information System (INIS)

Gonzalez Henriquez, C.M.; Soto Bustamante, E.A.; Haase, W.

2009-01-01

The formation of a liquid crystalline polymer called PM6R8 is reported. The polymers were obtained with different concentration of AIBN as initiator (0.25, 0.50, 1 and 2mg in 5ml solution) and time of reaction (24, 36 and 48 hours). The compounds were characterized by 1 H-NMR, differential thermal analysis (DTA), X-ray diffractometer and pyroelectric measurements. For the polymer a smectic C 2 phase occurs over broad temperature range, which is a possible explanation for the electric signal. The arrangement of the molecules within of the crystalline lattice is related with the kinetic of precipitation. (author)

Interest of neutron scattering for the investigation of liquid-crystalline polymers

International Nuclear Information System (INIS)

Noirez, L.

1994-01-01

Small-angle Neutron scattering is the unique method which allows the determination of polymer conformation in the bulk state. This method has been applied to several kinds of liquid crystalline polymers. Results concerning side-chain liquid-crystal polymer, main-chain liquid-crystal polymer and combined liquid-crystal polymers, are reported. It is shown that the polymer conformation is largely dependent on the insertion site of the liquid crystal molecule and of the structure of the meso-phase. (author). 11 refs

Polyesters production from the mixture of phthalic acid, terephthalic and glycerol

International Nuclear Information System (INIS)

Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M.; Carvalho, R.F.

2010-01-01

Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

Induction of Liquid Crystallinity by Self-Assembled Molecular Boxes

NARCIS (Netherlands)

Piermattei, A.; Giesbers, M.; Marcelis, A.T.M.; Mendes, E.; Picken, S.J.; Crego-Calama, M.; Reinhoudt, D.N.

2006-01-01

In a hierarchical process, three molecules of a calix[4]arene (blue) and six of barbituric or cyanuric acid (green) assemble into double-rosette boxes, which assemble into columns, which in turn assemble into columnar liquid-crystalline phases (see picture). The resulting mesophases have a

Dry Powder Precursors of Cubic Liquid Crystalline Nanoparticles (cubosomes)

International Nuclear Information System (INIS)

Spicer, Patrick T.; Small, William B.; Small, William B.; Lynch, Matthew L.; Burns, Janet L.

2002-01-01

Cubosomes are dispersed nanostructured particles of cubic phase liquid crystal that have stimulated significant research interest because of their potential for application in controlled-release and drug delivery. Despite the interest, cubosomes can be difficult to fabricate and stabilize with current methods. Most of the current work is limited to liquid phase processes involving high shear dispersion of bulk cubic liquid crystalline material into sub-micron particles, limiting application flexibility. In this work, two types of dry powder cubosome precursors are produced by spray-drying: (1) starch-encapsulated monoolein is produced by spray-drying a dispersion of cubic liquid crystalline particles in an aqueous starch solution and (2) dextran-encapsulated monoolein is produced by spray-drying an emulsion formed by the ethanol-dextran-monoolein-water system. The encapsulants are used to decrease powder cohesion during drying and to act as a soluble colloidal stabilizer upon hydration of the powders. Both powders are shown to form (on average) 0.6 μm colloidally-stable cubosomes upon addition to water. However, the starch powders have a broader particle size distribution than the dextran powders because of the relative ease of spraying emulsions versus dispersions. The developed processes enable the production of nanostructured cubosomes by end-users rather than just specialized researchers and allow tailoring of the surface state of the cubosomes for broader application

Bicontinuous cubic liquid crystalline nanoparticles for oral delivery of Doxorubicin

DEFF Research Database (Denmark)

Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog

2014-01-01

PURPOSE: The present study explores the potential of bicontinous cubic liquid crystalline nanoparticles (LCNPs) for improving therapeutic potential of doxorubicin. METHODS: Phytantriol based Dox-LCNPs were prepared using hydrotrope method, optimized for various formulation components, process...

Thermotropic liquid crystalline polyazomethine nanocomposites via in situ interlayer polymerization

International Nuclear Information System (INIS)

Min, Ungki; Chang, Jin-Hae

2011-01-01

Highlights: → Nanocomposites of polyazomethine with the organoclay C 12 -MMT were synthesized by using the in situ interlayer polymerization method. → The thermal properties of the polyazomethine hybrids increase with the addition of the organoclay up to a critical content and then decrease with further organoclay loading. → Liquid crystalline compositions with 0-9 wt% organoclay have threaded Schlieren nematic textures. - Abstract: Nanocomposites of polyazomethine (PAM) with the organoclay C 12 -MMT were synthesized by using the in situ interlayer polymerization method. The variations with organoclay content of the thermal properties, morphology, and liquid crystalline mesophases of the hybrids were determined for concentrations from 0 to 9 wt% C 12 -MMT. The thermal properties and the morphologies of the PAM nanocomposites were examined by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X-ray diffractometry (XRD), transmission electron microscopy (TEM), and polarizing optical microscopy (POM). The XRD analysis and TEM micrographs show that the levels of nanosize dispersion can be controlled by varying the C 12 -MMT content. The clay particles are better dispersed in the matrix polymer at low clay contents than at high clay contents. With the exception of the glass transition temperature (T g ), the maximum enhancement in the thermal properties was found to arise at an organoclay content of 1 wt%. Further, the PAM hybrids were shown to exhibit a nematic liquid crystalline phase for organoclay contents in the range 0-9 wt%.

Nonionic diethanolamide amphiphiles with isoprenoid-type hydrocarbon chains: thermotropic and lyotropic liquid crystalline phase behaviour

Energy Technology Data Exchange (ETDEWEB)

Sagnella, Sharon M.; Conn, Charlotte E.; Krodkiewska, Irena; Drummond, Calum J. (CSIRO/MSE)

2014-09-24

The thermotropic and lyotropic liquid crystalline phase behaviour of a series of diethanolamide amphiphiles with isoprenoid-type hydrocarbon chains (geranoyl, H-farnesoyl, and phytanoyl) has been investigated. When neat, both H-farnesoyl and phytanoyl diethanolamide form a smectic liquid crystalline structure at sub-zero temperatures. In addition, all three diethanolamides exhibit a glass transition temperature at around -73 C. Geranoyl diethanolamide forms a lamellar crystalline phase with a lattice parameter of 17.4 {angstrom} following long term storage accompanied by the loss of the glass transition. In the presence of water, H-farnesoyl and phytanoyl diethanolamide form lyotropic liquid crystalline phases, whilst geranoyl diethanolamide forms an L{sub 2} phase. H-farnesoyl diethanolamide forms a fluid lamellar phase (L{sub {alpha}}) at room temperature and up to {approx} 40 C. Phytanoyl diethanolamide displays a rich mesomorphism forming the inverse diamond (Q{sub II}{sup D}) and gyroid (Q{sub II}{sup G}) bicontinuous cubic phases in addition to an L{sub {alpha}} phase.

Structural studies of different types of ferroelectric liquid crystalline substances

Czech Academy of Sciences Publication Activity Database

Obadović, D.Ž.; Stojanović, M.; Bubnov, Alexej; Éber, N.; Cvetinov, M.; Vajda, A.

2011-01-01

Roč. 35, č. 1 (2011), s. 3-13 ISSN 1450-7404 R&D Projects: GA AV ČR IAA100100911; GA AV ČR(CZ) GA202/09/0047; GA ČR(CZ) GAP204/11/0723 Grant - others:RFASI(RU) 02.740.11.5166 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectric liquid crystals * phase transition * structure of liquid crystalline phases * molecular parameters Subject RIV: BM - Solid Matter Physics ; Magnetism

Synergy in lipofection by cationic lipid mixtures: superior activity at the gel-liquid crystalline phase transition.

Science.gov (United States)

Koynova, Rumiana; Wang, Li; MacDonald, Robert C

2007-07-12

Some mixtures of two cationic lipids including phospholipid compounds (O-ethylphosphatidylcholines) as well as common, commercially available cationic lipids, such as dimethylammonium bromides and trimethylammonium propanes, deliver therapeutic DNA considerably more efficiently than do the separate molecules. In an effort to rationalize this widespread "mixture synergism", we examined the phase behavior of the cationic lipid mixtures and constructed their binary phase diagrams. Among a group of more than 50 formulations, the compositions with maximum delivery activity resided unambiguously in the solid-liquid crystalline two-phase region at physiological temperature. Thus, the transfection efficacy of formulations exhibiting solid-liquid crystalline phase coexistence is more than 5 times higher than that of formulations in the gel (solid) phase and over twice that of liquid crystalline formulations; phase coexistence occurring at physiological temperature thus appears to contribute significantly to mixture synergism. This relationship between delivery activity and physical property can be rationalized on the basis of the known consequences of lipid-phase transitions, namely, the accumulation of defects and increased disorder at solid-liquid crystalline phase boundaries. Packing defects at the borders of coexisting solid and liquid crystalline domains, as well as large local density fluctuations, could be responsible for the enhanced fusogenicity of mixtures. This study leads to the important conclusion that manipulating the composition of the lipid carriers so that their phase transition takes place at physiological temperature can enhance their delivery efficacy.

Liquid crystalline polymer nanocomposites reinforced with in-situ reduced graphene oxide

Directory of Open Access Journals (Sweden)

D. Pedrazzoli

2015-08-01

Full Text Available In this work liquid-crystalline polymer (LCP nanocomposites reinforced with in-situ reduced graphene oxide are investigated. Graphene oxide (GO was first synthesized by the Hummers method, and the kinetics of its thermal reduction was assessed. GO layers were then homogeneously dispersed in a thermotropic liquid crystalline polymer matrix (Vectran®, and an in-situ thermal reduction of GO into reduced graphene oxide (rGO was performed. Even at low rGO amount, the resulting nanocomposites exhibited an enhancement of both the mechanical properties and the thermal stability. Improvements of the creep stability and of the thermo-mechanical behavior were also observed upon nanofiller incorporation. Furthermore, in-situ thermal reduction of the insulating GO into the more electrically conductive rGO led to an important surface resistivity decrease in the nanofilled samples.

Langmuir-Blodgett films prepared from pre-formed cholestanic liquid-crystalline polymers

Energy Technology Data Exchange (ETDEWEB)

Tundo, P.; Hodge, P.; Valli, L.; Davis, F. (Venice Univ. (Italy). Dip. di Scienze Ambientali Lecce Univ. (Italy). Dip. di Scienza dei Materiali Manchester Univ. (United Kingdom). Dep. of Chemistry)

1992-01-01

A series of alternating copolymers of maleic anhydride and a-olefins functionalized through different alkyl chains with cholestanic groups were synthetised and derivatives prepared by reactions of the anhydride residues with methanol, water, dimethylamine and morpholine, respectively. The same starting functionalized a-olefins were used to prepare other suitable compounds in order to correlate the features of the liquid-crystalline behaviour of the mesogenic cholestanic group with the stability of the forthcoming polymeric or not polymeric Langmuir-Blodgett (LB) films. For some copolymers surface pressure against area per molecule isotherms are reported. In some multilayer (LB) films, the spacings between the layers were determined by the detection of BRAGG peaks by X-ray diffraction. The (LB) films of these polymers are closed packed, owing to either the polymeric skeleton or liquid-crystalline interaction.

Induction of liquid crystallinity of by self-assembled molecular boxes

NARCIS (Netherlands)

Piermattei, A.; Giesbers, Marcel; Marcelis, Antonius T.M.; Mendes, Eduardo; Picken, Stephen J.; Crego Calama, Mercedes; Reinhoudt, David

2006-01-01

Jewel-box: In a hierarchical process, three molecules of a calix[4]arene (blue) and six of barbituric or cyanuric acid (green) assemble into double-rosette boxes, which assemble into columns, which in turn assemble into columnar liquid-crystalline phases (see picture). The resulting mesophases have

Shape-memory effect of nanocomposites based on liquid-crystalline elastomers

Science.gov (United States)

Marotta, A.; Lama, G. C.; Gentile, G.; Cerruti, P.; Carfagna, C.; Ambrogi, V.

2016-05-01

In this work, nanocomposites based on liquid crystalline (LC) elastomers were prepared and characterized in their shape memory properties. For the synthesis of materials, p-bis(2,3-epoxypropoxy)-α-methylstilbene (DOMS) was used as mesogenic epoxy monomer, sebacic acid (SA) as curing agent and multi-walled carbon nanotubes (MWCNT) and graphene oxide (GO) as fillers. First, an effective compatibilization methodology was set up to improve the interfacial adhesion between the matrix and the carbonaceous nanofillers, thus obtaining homogeneous distribution and dispersion of the nanofillers within the polymer phase. Then, the obtained nanocomposite films were characterized in their morphological and thermal properties. In particular, the effect of the addition of the nanofillers on liquid crystalline behavior, as well as on shape-memory properties of the realized materials was investigated. It was found that both fillers were able to enhance the thermomechanical response of the LC elastomers, making them good candidates as shape memory materials.

Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 4 - Synthesis of side-chain liquid crystalline polycarbonates with mesogenic groups having tails of different lengths

NARCIS (Netherlands)

Jansen, J.C.; Addink, R.; Nijenhuis, K.T.; Mijs, W.J.

1999-01-01

Side-chain liquid crystalline polycarbonates with alkoxyphenylbenzoate side groups, having a short spacer and tails ranging from 1 to 8 C-atoms, were synthesized. The polymers were prepared by an organo-zinc catalysed copolymerization of carbon dioxide and mesogenic 4-alkoxyphenyl

Biodegradation of Halloysite Nanotubes-Polyester Nanocomposites Exposed to Short Term Seawater Immersion

Directory of Open Access Journals (Sweden)

Mohd Shahneel Saharudin

2017-07-01

Full Text Available Halloysite nanotubes (HNTs-polyester nanocomposites with four different concentrations were produced using solution casting technique and the biodegradation effect of short-term seawater exposure (120 h was studied. Monolithic polyester was observed to have the highest seawater absorption with 1.37%. At 0.3 wt % HNTs reinforcement, the seawater absorption dropped significantly to the lowest value of 0.77% due to increase of liquid diffusion path. For samples tested in dry conditions, the Tg, storage modulus, tensile properties and flexural properties were improved. The highest improvement of Tg was from 79.3 to 82.4 °C (increase 3.1 °C in the case of 0.3 wt % HNTs. This can be associated with the exfoliated HNTs particles, which restrict the mobility of polymer chains and thus raised the Tg. After seawater exposure, the Tg, storage modulus, tensile properties and flexural properties of polyester and its nanocomposites were decreased. The Young’s modulus of 0.3 wt % HNTs-polyester dropped 20% while monolithic polyester dropped up to 24% compared to their values in dry condition. Apart from that, 29% flexural modulus reduction was observed, which was 18% higher than monolithic polyester. In contrast, fracture toughness and surface roughness increased due to plasticization effect. The presence of various microbial communities caused gradual biodegradation on the microstructure of the polyester matrix as also evidently shown by SEM images.

Liquid crystalline epoxy nanocomposite material for dental application

Directory of Open Access Journals (Sweden)

Yun-Yuan Tai

2015-01-01

Conclusion: The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment.

Synthesis and characterization of poly(ester amide from remewable resources through melt polycondensation

Directory of Open Access Journals (Sweden)

B. B. Wang

2014-01-01

Full Text Available Biodegradable poly(ester amides (PEAs were synthesized from lactic acid and 11-aminoundecanoic acid via melt polycondensation. Molecular weights, chemical structures and thermal properties of the poly(ester amides were characterized in terms of gel permeation chromatography (GPC, Fourier transform infrared spectroscopy (FTIR, 1H nuclear magnetic resonance (1H NMR, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA, respectively. The PEAs have low molecular weights and display a lower cold crystallization temperature as well as smaller crystallinity by comparison with the pure poly(lactic acid (PLA. The incorporation of the 11-aminoundecanoic acid into the PLA chain not only improved the thermal stability but changed the decomposition process.

Lyotropic liquid crystalline phase behaviour in amphiphile-protic ionic liquid systems.

Science.gov (United States)

Chen, Zhengfei; Greaves, Tamar L; Fong, Celesta; Caruso, Rachel A; Drummond, Calum J

2012-03-21

Approximate partial phase diagrams for nine amphiphile-protic ionic liquid (PIL) systems have been determined by synchrotron source small angle X-ray scattering, differential scanning calorimetry and cross polarised optical microscopy. The binary phase diagrams of some common cationic (hexadecyltrimethyl ammonium chloride, CTAC, and hexadecylpyridinium bromide, HDPB) and nonionic (polyoxyethylene (10) oleyl ether, Brij 97, and Pluronic block copolymer, P123) amphiphiles with the PILs, ethylammonium nitrate (EAN), ethanolammonium nitrate (EOAN) and diethanolammonium formate (DEOAF), have been studied. The phase diagrams were constructed for concentrations from 10 wt% to 80 wt% amphiphile, in the temperature range 25 °C to >100 °C. Lyotropic liquid crystalline phases (hexagonal, cubic and lamellar) were formed at high surfactant concentrations (typically >50 wt%), whereas at thermal stability of the phases formed by these surfactants persisted to temperatures above 100 °C. The phase behaviour of amphiphile-PIL systems was interpreted by considering the PIL cohesive energy, liquid nanoscale order, polarity and ionicity. For comparison the phase behaviour of the four amphiphiles was also studied in water.

Degradation of Polyester Polyurethane by Bacterial Polyester Hydrolases

Directory of Open Access Journals (Sweden)

Juliane Schmidt

2017-02-01

Full Text Available Polyurethanes (PU are widely used synthetic polymers. The growing amount of PU used industrially has resulted in a worldwide increase of plastic wastes. The related environmental pollution as well as the limited availability of the raw materials based on petrochemicals requires novel solutions for their efficient degradation and recycling. The degradation of the polyester PU Impranil DLN by the polyester hydrolases LC cutinase (LCC, TfCut2, Tcur1278 and Tcur0390 was analyzed using a turbidimetric assay. The highest hydrolysis rates were obtained with TfCut2 and Tcur0390. TfCut2 also showed a significantly higher substrate affinity for Impranil DLN than the other three enzymes, indicated by a higher adsorption constant K. Significant weight losses of the solid thermoplastic polyester PU (TPU Elastollan B85A-10 and C85A-10 were detected as a result of the enzymatic degradation by all four polyester hydrolases. Within a reaction time of 200 h at 70 °C, LCC caused weight losses of up to 4.9% and 4.1% of Elastollan B85A-10 and C85A-10, respectively. Gel permeation chromatography confirmed a preferential degradation of the larger polymer chains. Scanning electron microscopy revealed cracks at the surface of the TPU cubes as a result of enzymatic surface erosion. Analysis by Fourier transform infrared spectroscopy indicated that the observed weight losses were a result of the cleavage of ester bonds of the polyester TPU.

Design and Applications of Biodegradable Polyester Tissue Scaffolds Based on Endogenous Monomers Found in Human Metabolism

Directory of Open Access Journals (Sweden)

Devin G. Barrett

2009-10-01

Full Text Available Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, xylitol, sorbitol, and lactic, sebacic, citric, succinic, α-ketoglutaric, and fumaric acids. In terms of mechanical versatility, crystallinity, hydrophobicity, and biocompatibility, polyesters synthesized partially or completely from these monomers can display a wide range of properties. The flexibility in these macromolecular properties allows for materials to be tailored according to the needs of a particular application. Along with the presence of natural monomers that allows for a high probability of biocompatibility, there is also an added benefit that this class of polyesters is more environmentally friendly than many other materials used in biomedical engineering. While the selection of monomers may be limited by nature, these polymers have produced or have the potential to produce an enormous number of successes in vitro and in vivo.

Liquid-like thermal conduction in intercalated layered crystalline solids

Science.gov (United States)

Li, B.; Wang, H.; Kawakita, Y.; Zhang, Q.; Feygenson, M.; Yu, H. L.; Wu, D.; Ohara, K.; Kikuchi, T.; Shibata, K.; Yamada, T.; Ning, X. K.; Chen, Y.; He, J. Q.; Vaknin, D.; Wu, R. Q.; Nakajima, K.; Kanatzidis, M. G.

2018-03-01

As a generic property, all substances transfer heat through microscopic collisions of constituent particles1. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations2,3. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here, we report liquid-like thermal conduction observed in the crystalline AgCrSe2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive, and are thus responsible for the intrinsically ultralow thermal conductivity. This scenario is applicable to a wide variety of layered compounds with heavy intercalants in the van der Waals gaps, manifesting a broad implication on suppressing thermal conduction. These microscopic insights might reshape the fundamental understanding on thermal transport properties of matter and open up a general opportunity to optimize performances of thermoelectrics.

White emission from liquid-crystalline copolymers containing oxadiazole moieties in the side chain

Science.gov (United States)

Kawamoto, Masuki; Tsukamoto, Takuji; Kinoshita, Motoi; Ikeda, Tomiki

2006-09-01

A liquid-crystalline polymer in the side chain was synthesized through copolymerization of a bipolar carrier-transporting monomer with a liquid-crystalline monomer containing oxadiazole moieties substituted with trifluoromethyl groups. A single-layer light-emitting diode of indium tin oxide (ITO)/copolymer/MgAg emitted white light with a maximum luminous efficiency of 0.1cd/A. The origin of the white emission in the copolymer is the electroplex between bipolar carrier-transporting moieties and strong electron-withdrawing moieties. Furthermore, a simple multilayer device with configuration of ITO/poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid)/copolymer/MgAg device showed white emission with CIE 1931 chromaticity coordinates (x,y): (0.30, 0.33).

Synthesis and characterization of sulfonated polyesters derived from glycerol; Sintese e caracterizacao de poliesteres sulfonados obtidos a partir do glicerol

Energy Technology Data Exchange (ETDEWEB)

Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica; Fiuza, R.P. [Universidade Federal da Bahia (EP/UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Quimica

2010-07-01

In this work were synthesized polyesters from glycerol and acid sulfonated phthalic previously. The materials were characterized by DSC, TGA, FTIR, SEM, XRD and XRF. The results showed effective sulfonation of phthalic acid. The presence of sulfonic groups promoted strong changes in the crystallinity of the new material makes the lens. The polyesters made from phthalic acid sulfonated combine characteristics such as heat resistance and groups that drivers potentiate the electrolyte for application in fuel cells proton exchange membrane and also for gas separation. (author)

Preparation and properties of aromatic polyester/TiO{sub 2} nanocomposites from polyethylene terephthalate

Energy Technology Data Exchange (ETDEWEB)

Santos, Leonardo Moreira dos; Carone, Carlos Leonardo Pandolfo; Einloft, Sandra Mara Oliveira; Ligabue, Rosane Angelica, E-mail: rligabue@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil). Programa de Graduacao em Engenharia e Tecnologia de Materiais

2016-01-15

The development of polyester based materials with enhanced properties as well as the use of post- consumer plastics as raw material has been an increasing market demand. This work aims the synthesis and characterization of aromatic polyesters/titanium dioxide nanocomposites from PET and using TiO{sub 2} (0, 1, 3 and 5% w/w) as filler by in situ polymerization. The results obtained by DSC, XRD and FTIR analyzes evidenced an interaction between the OH groups on the TiO{sub 2} surface with the ester groups of the polymer leading to decrease of the polymer crystallinity and of hydrophilicity. By SEM images was possible to note a homogeneous distribution of the filler into polymer matrix with 1%w/w TiO{sub 2} (average particle size of 199 nm), however for larger amounts of filler (3 and 5% TiO{sub 2}) revealed the aggregates formation. The results showed an improvement of thermal properties and hardness of the nanocomposites containing TiO{sub 2} nanoparticles compared to pristine polyester. (author)

Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.

Science.gov (United States)

Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang

2012-11-01

Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility

Synthesis and Supramolecular Chemistry of Novel Liquid Crystalline Crown Ether-Substituted Phthalocyanines : Toward Molecular Wires and Molecular Ionoelectronics

NARCIS (Netherlands)

Nostrum, Cornelus F. van; Picken, Stephen J.; Schouten, Arend-Jan; Nolte, Roeland J.M.

1995-01-01

The synthesis of the metal-free and the dihydroxysilicon derivatives of tetrakis[4’,5’-bis(decoxy)benzo-18-crown-6]phthalocyanine is described. The metal-free phthalocyanine is liquid crystalline and exhibits a crystalline phase to mesophase transition at 148 °C. The structures of the crystalline

Lattice Boltzmann simulations of liquid crystalline fluids: active gels and blue phases

OpenAIRE

Cates, M. E.; Henrich, O.; Marenduzzo, D.; Stratford, K.

2010-01-01

Lattice Boltzmann simulations have become a method of choice to solve the hydrodynamic equations of motion of a number of complex fluids. Here we review some recent applications of lattice Boltzmann to study the hydrodynamics of liquid crystalline materials. In particular, we focus on the study of (a) the exotic blue phases of cholesteric liquid crystals, and (b) active gels - a model system for actin plus myosin solutions or bacterial suspensions. In both cases lattice Boltzmann studies have...

Synthesis and characterization of polyester copolymers based on poly(butylene succinate) and poly(ethylene glycol)

International Nuclear Information System (INIS)

Zhou, Xiao-Ming

2012-01-01

A series of polyester copolymers was synthesized from 1,4-succinic acid with 1,4-butanediol and poly(ethylene glycol) through a two-step process of esterification and polycondensation in this article. The composition and physical properties of copolyesters were investigated via GPC, 1 HNMR, DSC and PLM. The copolymer composition was in good agreement with that expected from the feed composition of the reactants. The melting temperature (T m ), crystallization temperature (T c ), and crystallinity (X c ) of these copolyesters decreased gradually as the content of PEG unit increased. Otherwise, experimental results also showed that the contents of PEG in copolymers had an effect on the molecular weight, distribution, thermal properties, hydrolysis degradation properties, and crystalline morphology of polyester copolymers. - Graphical abstract: The composition of polyester copolymer was determined from the 1 H NMR spectra using the relative intensities of the proton peaks. As a sample, the 1 H NMR spectrum of polyester copolymer with 10 mol% of PEG is shown in Fig. 2: CO-(CH 2 ) 2 -CO; O-CH 2 - and C-(CH 2 ) 2 -C from the SA and BD unit at δ2.59; δ 4.08 and δ1.67; O-(CH 2 CH 2 ) n -O from the PEG unit at δ 3.61. The molar composition of polyester copolymer was measured as the area ratio of δ3.61/(δ4.08 + δ1.67) peak. The PEG unit is incorporated into the copolymers in an amount of about 9.12mol% less than that of the feed proportion. These results showed that the composition of the copolymers is in good agreement with that expected from the feed proportion. Highlights: ► The introduction of PEG unit changed the flexibility of PBS main chain. ► PEG unit did not alter the crystal form of PBS in copolymers. ► PEG unit hindered the formation of ring-banded spherulite morphology in copolymers. ► The copolyesters had good in vitro degradation performance. ► The composition ratio of PEG unit can adjust the in vitro degradation performance.

The effect of calcining temperature on the properties of 0-3 piezoelectric composites of PZT and a liquid crystalline thermosetting polymer

NARCIS (Netherlands)

Ende, D.A. van den; Groen, W.A.; Zwaag, S. van der

2011-01-01

We report on the optimisation of a recently developed high performance 0-3 piezoelectric composite comprising of the piezoelectric Lead Zirconate Titanate (PZT) powder and a liquid crystalline thermosetting matrix polymer (LCT). The matrix polymer is a liquid crystalline polymer comprising of an

Quantitative Analysis of Matrine in Liquid Crystalline Nanoparticles by HPLC

Directory of Open Access Journals (Sweden)

Xinsheng Peng

2014-01-01

Full Text Available A reversed-phase high-performance liquid chromatographic method has been developed to quantitatively determine matrine in liquid crystal nanoparticles. The chromatographic method is carried out using an isocratic system. The mobile phase was composed of methanol-PBS(pH6.8-triethylamine (50 : 50 : 0.1% with a flow rate of 1 mL/min with SPD-20A UV/vis detector and the detection wavelength was at 220 nm. The linearity of matrine is in the range of 1.6 to 200.0 μg/mL. The regression equation is y=10706x-2959 (R2=1.0. The average recovery is 101.7%; RSD=2.22%  (n=9. This method provides a simple and accurate strategy to determine matrine in liquid crystalline nanoparticle.

New theories for smectic and nematic liquid crystalline polymers

International Nuclear Information System (INIS)

Dowell, F.

1987-01-01

A summary of results from new statistical-physics theories for both backbone and side-chain liquid crystalline polymers (LCPs) and for mixtures with LCPs is presented. Thermodynamic and molecular ordering properties (including odd-even effects) have been calculated as a function of pressure, density, temperature, and molecule chemical structures (including degree of polymerization and the following properties of the chemical structures of the repeat units: lengths and shapes, intra-chain rotation energies, dipole moments, site-site polarizabilities and Lennard-Jones potentials, etc.) in nematic and multiple smectic-A LC phases and in the isotropic liquid phase. These theories can also be applied to combined LCPs. Since these theories have no ad hoc or arbitrarily adjustable parameters, these theories have been used to design new LCPs and new solvents and to predict and explain properties

Liquid crystallinity in flexible and rigid rod polymers

International Nuclear Information System (INIS)

Pickett, Galen T.; Schweizer, Kenneth S.

2000-01-01

We apply an anisotropic version of the polymer reference interaction site model (PRISM) integral equation description of flexible polymers to analyze athermal liquid crystallinity. The polymers are characterized by a statistical segment length, σ o , and by a physical hard-core thickness, d, that prevents the overlap of monomers on different chains. At small segment densities, ρ, the microscopic length scale d is irrelevant (as it must be in the universal semidilute regime), but becomes important in concentrated solutions and melts. Under the influence of the excluded volume interactions alone, the chains undergo a lyotropic, first-order isotropic-nematic transition at a concentration dependent upon the dimensionless ''aspect ratio,'' σ o /d. The transition becomes weaker as d→0, becoming second order, as has been previously shown. We extend the theory to describe the transition of rigid, thin rods, and discuss the evolution of the anisotropic liquid structure in the ordered phase. (c) 2000 American Institute of Physics

CFRP materials reinforced with LCP fibres for applications in vehicle and aircraft engineering. Final report; Faserverbundkunststoffe mit einer LCP-Faserverstaerkung fuer Anwendungen im Fahrzeug- und Flugzeugbau. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-02-11

CFRP materials reinforced with liquid crystalline polyester (LCP) fibres were produced and characterized with regard to their physical and mechanical characteristics. Compared with non-reinforced plastics, polypropylene/LCP fibre-UD laminates produced by filmstacking, epoxy resin/LCP fibre-UD laminates produced by spooling and epoxy resin composites with internal LCP fibre fleece had significantly higher strength and stiffness as well as high thermoforming resistance and waterproofness. [Deutsch] In diesem Forschungsvorhaben wurden Faserverbundkunststoffe mit einer Verstaerkungsfaser auf Basis eines thermotropen fluessigkristallinen Polyester [Liquid Crystalline Polyester, abgekuerzt LCP] hergestellt und bezueglich der physikalisch-mechanischen Eigenschaften charakterisiert. Die im `filmstacking`-Verfahren hergestellte Polypropylen/LCP-Faser-UD-Laminate und mittels Bewicklung gewonnene Epoxidharz/LCP-Faser-UD-Laminate sowie Epoxidharzverbunde mit eingearbeiteten LCP-Faservlies zeigen gegenueber den unverstaerkten Kunststoffmaterialien einen betraechtlichen Anstieg von Festigkeit und Steifigkeit. Die Faserverbunde weisen ausserdem eine hohe Waermeformbestaendigkeit und Wassersperrwirkung auf. (orig.)

Enzymatic biofuel cell based on electrodes modified with lipid liquid-crystalline cubic phases

Science.gov (United States)

Nazaruk, Ewa; Smoliński, Sławomir; Swatko-Ossor, Marta; Ginalska, Grażyna; Fiedurek, Jan; Rogalski, Jerzy; Bilewicz, Renata

Two glassy carbon electrodes modified with enzymes embedded in lyotropic liquid-crystalline cubic phase were used for the biofuel cell construction. The monoolein liquid-crystalline film allowed to avoid separators in the biofuel cell. Glucose and oxygen as fuels, and glucose oxidase and laccase as anode and cathode biocatalysts, respectively were used. The biofuel cell parameters were examined in McIlvaine buffer, pH 7 solution containing 15 mM of glucose and saturated with dioxygen. A series of mediators were tested taking into account their formal potentials, stability in the cubic phase and efficiency of mediation. Most stable was the biofuel cell based on tetrathiafulvalene (TTF) and 2,2‧-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as anode and cathode mediators, respectively. The open-circuit voltage was equal to 450 ± 40 mV. The power densities and current densities were measured for all the systems studied.

Printable, Degradable, and Biocompatible Ion Gels from a Renewable ABA Triblock Polyester and a Low Toxicity Ionic Liquid

Energy Technology Data Exchange (ETDEWEB)

Tang, Boxin; Schneiderman, Deborah K.; Bidoky, Fazel Zare; Frisbie, C.Daniel; Lodge, Timothy P. (UMM)

2017-09-15

We have designed printable, biocompatible, and degradable ion gels by combining a novel ABA triblock aliphatic polyester, poly(ε-decalactone)-b-poly(dl-lactide)-b-poly(ε-decalactone), and a low toxicity ionic liquid, 1-butyl-1-methylpyrrolidinium bistrifluoromethanesulfonylimide ([P14][TFSI]). Due to the favorable compatibility between amorphous poly(dl-lactide) and [P14][TFSI] and the insolubility of the poly(ε-decalactone), the triblock polymer forms self-assembled micellar cross-links similar to thermoplastic elastomers, which ensures similar processing conditions and mechanical robustness during the fabrication of printed electrolyte-gated organic transistor devices. Additionally, the ester backbone in the polymer structure enables efficient hydrolytic degradation of these ion gels compared to those made previously using carbon-backbone polymers.

Electromagnetic shielding mechanisms using soft magnetic stainless steel fiber enabled polyester textiles

Science.gov (United States)

Shyr, Tien-Wei; Shie, Jing-Wen

2012-11-01

This work studied the effects of conductivity, magnetic loss, and complex permittivity when using blended textiles (SSF/PET) of polyester fibers (PET) with stainless steel fibers (SSF) on electromagnetic wave shielding mechanisms at electromagnetic wave frequencies ranging from 30 MHz to 1500 MHz. The 316L stainless steel fiber used in this study had 38 vol% γ austenite and 62 vol% α' martensite crystalline phases, which was characterized by an x-ray diffractometer. Due to the magnetic and dielectric loss of soft metallic magnetic stainless steel fiber enabled polyester textiles, the relationship between the reflection/absorption/transmission behaviors of the electromagnetic wave and the electrical/magnetic/dielectric properties of the SSF and SSF/PET fabrics was analyzed. Our results showed that the electromagnetic interference shielding of the SSF/PET textiles show an absorption-dominant mechanism, which attributed to the dielectric loss and the magnetic loss at a lower frequency and attributed to the magnetic loss at a higher frequency, respectively.

Solvent-free directed patterning of a highly ordered liquid crystalline organic semiconductor via template-assisted self-assembly for organic transistors.

Science.gov (United States)

Kim, Aryeon; Jang, Kwang-Suk; Kim, Jinsoo; Won, Jong Chan; Yi, Mi Hye; Kim, Hanim; Yoon, Dong Ki; Shin, Tae Joo; Lee, Myong-Hoon; Ka, Jae-Won; Kim, Yun Ho

2013-11-20

Highly ordered organic semiconductor micropatterns of the liquid-crystalline small molecule 2,7-didecylbenzothienobenzothiophene (C10 -BTBT) are fabricated using a simple method based on template-assisted self-assembly (TASA). The liquid crystallinity of C10 -BTBT allows solvent-free fabrication of high-performance printed organic field-effect transistors (OFETs). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vapor-Liquid Sol-Gel Approach to Fabricating Highly Durable and Robust Superhydrophobic Polydimethylsiloxane@Silica Surface on Polyester Textile for Oil-Water Separation.

Science.gov (United States)

Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Zhang, Lin; Wang, Jing; Liao, Xiaofeng; Zeng, Xingrong

2017-08-23

Large-scale fabrication of superhydrophobic surfaces with excellent durability by simple techniques has been of considerable interest for its urgent practical application in oil-water separation in recent years. Herein, we proposed a facile vapor-liquid sol-gel approach to fabricating highly durable and robust superhydrophobic polydimethylsiloxane@silica surfaces on the cross-structure polyester textiles. Scanning electron microscopy and Fourier transform infrared spectroscopy demonstrated that the silica generated from the hydrolysis-condensation of tetraethyl orthosilicate (TEOS) gradually aggregated at microscale driven by the extreme nonpolar dihydroxyl-terminated polydimethylsiloxane (PDMS(OH)). This led to construction of hierarchical roughness and micronano structures of the superhydrophobic textile surface. The as-fabricated superhydrophobic textile possessed outstanding durability in deionized water, various solvents, strong acid/base solutions, and boiling/ice water. Remarkably, the polyester textile still retained great water repellency and even after ultrasonic treatment for 18 h, 96 laundering cycles, and 600 abrasion cycles, exhibiting excellent mechanical robustness. Importantly, the superhydrophobic polyester textile was further applied for oil-water separation as absorption materials and/or filter pipes, presenting high separation efficiency and great reusability. Our method to construct superhydrophobic textiles is simple but highly efficient; no special equipment, chemicals, or atmosphere is required. Additionally, no fluorinated slianes and organic solvents are involved, which is very beneficial for environment safety and protection. Our findings conceivably stand out as a new tool to fabricate organic-inorganic superhydrophobic surfaces with strong durability and robustness for practical applications in oil spill accidents and industrial sewage emission.

Synthesis, characterization and photoinduction of optical anisotropy in liquid crystalline diblock azo-copolymers

NARCIS (Netherlands)

Forcen, P.; Oriol, L.; Sanchez, S.; Alcala, R.; Hvilsted, S.; Jankova, K.; Loos, J.

2007-01-01

Diblock copolymers with polymethyl methacrylate and side chain liquid crystalline (LC) azopolymethacrylate blocks were synthesized by atom transfer radical polymerization (ATRP). The azobenzene content in these copolymers ranges from 52 to 7 wt %. For an azo content down to 20% they exhibit a LC

Novel lecithin-integrated liquid crystalline nanogels for enhanced cutaneous targeting of terconazole: development, in vitro and in vivo studies

Directory of Open Access Journals (Sweden)

Elnaggar YSR

2016-10-01

Full Text Available Yosra SR Elnaggar,1,2 Sara M Talaat,1 Mohammed Bahey-El-Din,3 Ossama Y Abdallah1 1Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, 2Department of Pharmaceutics, Faculty of Pharmacy and Drug Manufacturing, Pharos University in Alexandria, 3Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt Abstract: Terconazole (Tr is the first marketed, most active triazole for vaginal candidiasis. Owing to poor skin permeation and challenging physicochemical properties, Tr was not employed for the treatment of cutaneous candidiasis. This is the first study to investigate the relevance of novel lecithin-integrated liquid crystalline nano-organogels (LCGs to improve physicochemical characteristics of Tr in order to enable its dermal application in skin candidiasis. Ternary phase diagram was constructed using lecithin/capryol 90/water to identify the region of liquid crystalline organogel. The selected organogel possessed promising physicochemical characteristics based on particle size, rheological behavior, pH, loading efficiency, and in vitro antifungal activity. Microstructure of the selected organogel was confirmed by polarized light microscopy and transmission electron microscopy. Ex vivo and in vivo skin permeation studies revealed a significant 4.7- and 2.7-fold increase in the permeability of Tr-loaded LCG when compared to conventional hydrogel. Moreover, acute irritation study indicated safety and compatibility of liquid crystalline organogel to the skin. The in vivo antifungal activity confirmed the superiority of LCG over the conventional hydrogel for the eradication of Candida infection. Overall, lecithin-based liquid crystalline organogel confirmed its potential as an interesting dermal nanocarrier for skin targeting purpose. Keywords: terconazole, liquid crystalline, organogel, skin targeting, skin mycosis

Novel lecithin-integrated liquid crystalline nanogels for enhanced cutaneous targeting of terconazole: development, in vitro and in vivo studies

Science.gov (United States)

Elnaggar, Yosra SR; Talaat, Sara M; Bahey-El-Din, Mohammed; Abdallah, Ossama Y

2016-01-01

Terconazole (Tr) is the first marketed, most active triazole for vaginal candidiasis. Owing to poor skin permeation and challenging physicochemical properties, Tr was not employed for the treatment of cutaneous candidiasis. This is the first study to investigate the relevance of novel lecithin-integrated liquid crystalline nano-organogels (LCGs) to improve physicochemical characteristics of Tr in order to enable its dermal application in skin candidiasis. Ternary phase diagram was constructed using lecithin/capryol 90/water to identify the region of liquid crystalline organogel. The selected organogel possessed promising physicochemical characteristics based on particle size, rheological behavior, pH, loading efficiency, and in vitro antifungal activity. Microstructure of the selected organogel was confirmed by polarized light microscopy and transmission electron microscopy. Ex vivo and in vivo skin permeation studies revealed a significant 4.7- and 2.7-fold increase in the permeability of Tr-loaded LCG when compared to conventional hydrogel. Moreover, acute irritation study indicated safety and compatibility of liquid crystalline organogel to the skin. The in vivo antifungal activity confirmed the superiority of LCG over the conventional hydrogel for the eradication of Candida infection. Overall, lecithin-based liquid crystalline organogel confirmed its potential as an interesting dermal nanocarrier for skin targeting purpose. PMID:27822033

Novel lecithin-integrated liquid crystalline nanogels for enhanced cutaneous targeting of terconazole: development, in vitro and in vivo studies.

Science.gov (United States)

Elnaggar, Yosra Sr; Talaat, Sara M; Bahey-El-Din, Mohammed; Abdallah, Ossama Y

Terconazole (Tr) is the first marketed, most active triazole for vaginal candidiasis. Owing to poor skin permeation and challenging physicochemical properties, Tr was not employed for the treatment of cutaneous candidiasis. This is the first study to investigate the relevance of novel lecithin-integrated liquid crystalline nano-organogels (LCGs) to improve physicochemical characteristics of Tr in order to enable its dermal application in skin candidiasis. Ternary phase diagram was constructed using lecithin/capryol 90/water to identify the region of liquid crystalline organogel. The selected organogel possessed promising physicochemical characteristics based on particle size, rheological behavior, pH, loading efficiency, and in vitro antifungal activity. Microstructure of the selected organogel was confirmed by polarized light microscopy and transmission electron microscopy. Ex vivo and in vivo skin permeation studies revealed a significant 4.7- and 2.7-fold increase in the permeability of Tr-loaded LCG when compared to conventional hydrogel. Moreover, acute irritation study indicated safety and compatibility of liquid crystalline organogel to the skin. The in vivo antifungal activity confirmed the superiority of LCG over the conventional hydrogel for the eradication of Candida infection. Overall, lecithin-based liquid crystalline organogel confirmed its potential as an interesting dermal nanocarrier for skin targeting purpose.

Functionalized Nanoporous Polymer Membranes with Well-Defined Pore Architectures via Lyotropic Liquid-Crystalline Monomers

National Research Council Canada - National Science Library

Gin, Douglas

1997-01-01

.... Two lyotropic liquid-crystalline monomer platforms have been synthesized. The interchannel separations in the polymerizable materials can be varied in the 30-40 A range by the choice of counterion on the ionic headgroup of the monomers...

Emergence of liquid crystalline order in the lowest Landau level of a quantum Hall system with internal anisotropy

Science.gov (United States)

Ciftja, Orion

2018-05-01

It has now become evident that interplay between internal anisotropy parameters (such as electron mass anisotropy and/or anisotropic coupling of electrons to the substrate) and electron-electron correlation effects can create a rich variety of possibilities especially in quantum Hall systems. The electron mass anisotropy or material substrate effects (for example, the piezoelectric effect in GaAs) can lead to an effective anisotropic interaction potential between electrons. For lack of knowledge of realistic ab-initio potentials that may describe such effects, we adopt a phenomenological approach and assume that an anisotropic Coulomb interaction potential mimics the internal anisotropy of the system. In this work we investigate the emergence of liquid crystalline order at filling factor ν = 1/6 of the lowest Landau level, a state very close to the point where a transition from the liquid to the Wigner solid happens. We consider small finite systems of electrons interacting with an anisotropic Coulomb interaction potential and study the energy stability of an anisotropic liquid crystalline state relative to its isotropic Fermi-liquid counterpart. Quantum Monte Carlo simulation results in disk geometry show stabilization of liquid crystalline order driven by an anisotropic Coulomb interaction potential at all values of the interaction anisotropy parameter studied.

Thermoresponsive Membrane Based on Thermotropic Liquid Crystalline Cholesteryl - (L-lacticacidn System: Study of Its Drug Permeability

Directory of Open Access Journals (Sweden)

Massoumeh Bagheri

2013-01-01

Full Text Available The rapidly increasing interest in functional materials with reversibly switchable physico- chemical properties has led to significant work on the development of stimuli responsive membranes. Thermotropic liquid crystals with their exceptional properties have potentials for drug-delivery applications. Thermoresponsive liquid-crystal-embedded membranes were investigated for the purpose of developing the drug delivery systems with thermal stimuli response. Drug release occurs at temperatures above the phase transition temperature of thermotropic liquid crystals. Therefore, they can control drug release in response to small temperature changes. In this work, the biocompatible and thermotropic liquid crystalline polymer cholesteryl-(L-lactic acidn ,CLAn (n=30, was synthesized with accurate control of molecular weight via ring opening polymerization method. Polymerization of L-lactide was carried out in the presence of cholesterol as an initiator and catalytic amount of tin (II octoate (Sn(Oct2 at 150°C in 5 h. The number-average degree of polymerization of CLA 30 was obtained from 1H NMR spectroscopy. The phase transition behavior of liquid crystalline CLA30 was established by differential scanning calorimetry and polarizing optical microscopy. The resulting liquid crystalline CLA30 was subsequently utilized to prepare CLA30 -embedded cellulose nitrate membrane by adsorption method. The CLA30-embedded cellulose nitrate membrane was used by an in-vitro drug penetration studies. Acetaminophen was used as a model drug. The permeation study was carried out at different temperatures around glass transition temperature of polymer CLA30 (37, 45 and 40°C, respectively. The results show that the CLA30 -embedded cellulose nitrate membranes exhibit thermo-responsive sensitivity with controlled drug permeation.

Highly tilted liquid crystalline materials possessing a direct phase transition from antiferroelectric to isotropic phase

Energy Technology Data Exchange (ETDEWEB)

Milewska, K.; Drzewiński, W. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Czerwiński, M., E-mail: mczerwinski@wat.edu.pl [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Dąbrowski, R. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Piecek, W. [Institute of Applied Physics, Military University of Technology, 00-908 Warsaw (Poland)

2016-03-01

Pure compounds and multicomponent mixtures with a broad temperature range of high tilted liquid crystalline antiferroelectric phase and a direct phase transition from antiferroelectric to isotropic phase, were obtained. X-ray diffraction analysis confirms these kinds of materials form a high tilted anticlinic phase, with a fixed layer spacing and very weak dependency upon temperature, after the transition from the isotropic phase. Due to this, not only pure orthoconic antiferroelectric liquid crystals but also those with a moderate tilt should generate a good dark state. Furthermore, due to the increased potential for forming anticlinic forces, such materials could minimize a commonly observed asymmetry of a rise and fall switching times at a surface stabilized geometry. - Highlights: • The new class of liquid crystalline materials with the direct SmC{sub A}*. • Iso phase transition were obtained. • Materials possess the layer spacing fixed and very weak dependent upon temperature. • Smectic layers without shrinkage are observed. • A good dark state can be generate in SSAFLC.

Thermotropic liquid crystalline polyesters derived from bis-(4 ...

Indian Academy of Sciences (India)

Administrator

industry, construction industry, food containers as well as .... fluid. Excess thionyl chloride was removed by normal dis- tillation. The crude acid chloride was purified by double ... with mechanical stirrer, nitrogen inlet, and calcium chlo-.

Novel Biodegradable Polyesters. Synthesis and Application as Drug Carriers for the Preparation of Raloxifene HCl Loaded Nanoparticles

Directory of Open Access Journals (Sweden)

Evangelos Karavas

2009-07-01

Full Text Available Raloxifene HCl is a drug with poor bioavailability and poor water solubility. Furthermore nο pharmaceutically acceptable organic solvent has been reported before to dilute the drug. It was observed that Raloxifene HCl can be diluted in a solvent mixture of acetone/water or ethanol/water. The aim of this study was to use biodegradable polymers in order to prepare Raloxifene HCl nanoparticles. For this purpose a series of novel biodegradable poly(ethylene succinate-co-propylene adipate P(ESu-co-PAd polyesters were synthesized following the polycondensation method and further, poly(ethylene succinate (PESu and poly(propylene adipate (PPAd were used. The prepared polyesters were characterized by intrinsic viscosity measurements, end group analysis, enzymatic hydrolysis, Nuclear Magnetic Resonance Spectroscopy (1Η-NMR and 13C-NMR and Wide-angle X-ray Diffractometry (WAXD. The drug nanoparticles have been prepared by a variation of the co-precipitation method and were studied by Wide-angle X-ray Diffractometry (WAXD, FTIR spectrometry, light scattering size distribution, Scanning Electron Microscopy (SEM and release behavior measurements. The interactions between the polymers and the drug seem to be limited, so the drug occurs in crystalline form in all nanoparticles. The size of the nanoparticles seems to be in the range of 150-350 nm, depending on the polymer that was used. The drug release depends on the melting point and degree of crystallinity of the polyesters used. An initial high release rate was recorded followed by very slow rates of controlled release.

From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

Directory of Open Access Journals (Sweden)

Maria Helena Godinho

2014-06-01

Full Text Available Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR, Rheology coupled with NMR (Rheo-NMR, rheology, optical methods, Magnetic Resonance Imaging (MRI, Wide Angle X-rays Scattering (WAXS, were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

Intensification of polyester synthesis by continuous reactive distillation

NARCIS (Netherlands)

Shah, M.R.

2011-01-01

The thesis starts with a brief overview of unsaturated polyesters. In particular, the usage of raw materials, the application of unsaturated polyester resins, and, the worldwide supply and demand of the unsaturated polyester resins are discussed. Unsaturated polyester is traditionally produced in a

Liquid crystalline systems for transdermal delivery of celecoxib: in vitro drug release and skin permeation studies.

Science.gov (United States)

Estracanholli, Eder André; Praça, Fabíola Silva Garcia; Cintra, Ana Beatriz; Pierre, Maria Bernadete Riemma; Lara, Marilisa Guimarães

2014-12-01

Liquid crystalline systems of monoolein/water could be a promising approach for the delivery of celecoxib (CXB) to the skin because these systems can sustain drug release, improve drug penetration into the skin layers and minimize side effects. This study evaluated the potential of these systems for the delivery of CXB into the skin based on in vitro drug release and skin permeation studies. The amount of CXB that permeated into and/or was retained in the skin was assayed using an HPLC method. Polarizing light microscopy studies showed that liquid crystalline systems of monoolein/water were formed in the presence of CXB, without any changes in the mesophases. The liquid crystalline systems decreased drug release when compared to control solution. Drug release was independent of the initial water content of the systems and CXB was released from cubic phase systems, irrespective of the initial water content. The systems released the CXB following zero-order release kinetics. In vitro drug permeation studies showed that cubic phase systems allowed drug permeation and retention in the skin layers. Cubic phase systems of monoolein/water may be promising vehicles for the delivery of CXB in/through the skin because it improved CXB skin permeation compared with the control solution.

Liquid crystalline composites toward organic photovoltaic application (Conference Presentation)

Science.gov (United States)

Shimizu, Yo; Sosa-Vargas, Lydia; Shin, Woong; Higuchi, Yumi; Itani, Hiromichi; Kawano, Koki; Dao, Quang Duy; Fujii, Akihiko; Ozaki, Masanori

2017-02-01

Liquid crystalline semiconductor is an interesting category of organic electronic materials and also has been extensively studied in terms of "Printed Electronics". For the wider diversity in research toward new applications, one can consider how to use a combination of miscibility and phase separation in liquid crystals. Here we report discotic liquid crystals in making a composite of which structural order is controlled in nano-scale toward photovoltaic applications. Discotic columnar LCs were studied on their resultant molecular order and carrier transport properties. Liquid crystals of phthalocyanine and its analogues which exhibit columnar mesomorphism with high carrier mobility (10-1 cm2/Vs) were examined with making binary phase diagrams and the correlation to carrier transport properties by TOF measurements was discussed. The shape-analogues in chemical structure shows a good miscibility even for the different lattice-type of columnar arrangement and the carrier mobility is mostly decrease except for a case of combination with a metal-free and the metal complex. For the mixtures with non-mesogenic C60 derivatives, one sees a phase-separated structure due to its immiscibility, though the columnar order is remained in a range of component ratio.Especially, in a range of the ratio, it was observed the phase separated C60 derivatives are fused into the matrix of columnar bundles, indicating C60 derivatives could be diffused in columnar arrays in molecular level.

Development and evaluation of exemestane-loaded lyotropic liquid crystalline gel formulations

OpenAIRE

Musa, Muhammad Nuh; David, Sheba Rani; Zulkipli, Ihsan Nazurah; Mahadi, Abdul Hanif; Chakravarthi, Srikumar; Rajabalaya, Rajan

2017-01-01

Introduction: The use of liquid crystalline (LC) gel formulations for drug delivery has considerably improved the current delivery methods in terms of bioavailability and efficacy. The purpose of this study was to develop and evaluate LC gel formulations to deliver the anti-cancer drug exemestane through transdermal route. Methods: Two LC gel formulations were prepared by phase separation coacervation method using glyceryl monooleate (GMO), Tween 80 and Pluronic® F127 (F127). The formulations...

Polyamine structural effects on the induction and stabilization of liquid crystalline DNA: potential applications to DNA packaging, gene therapy and polyamine therapeutics.

Science.gov (United States)

Saminathan, M; Thomas, Thresia; Shirahata, Akira; Pillai, C K S; Thomas, T J

2002-09-01

DNA undergoes condensation, conformational transitions, aggregation and resolubilization in the presence of polyamines, positively charged organic molecules present in all cells. Under carefully controlled environmental conditions, DNA can also transform to a liquid crystalline state in vitro. We undertook the present work to examine the ability of spermidine, N4-methylspermidine, spermine, N1-acetylspermine and a group of tetramine, pentamine and hexamine analogs of spermine to induce and stabilize liquid crystalline DNA. Liquid crystalline textures were identified under a polarizing microscope. In the absence of polyamines, calf thymus DNA assumed a diffused, planar cholesteric phase with entrapped bubbles when incubated on a glass slide at 37 degrees C. In the presence of spermidine and spermine, the characteristic fingerprint textures of the cholesteric phase, adopting a hexagonal order, were obtained. The helical pitch was 2.5 micro m. The final structures were dendrimeric and crystalline when DNA was treated with spermine homologs and bis(ethyl) derivatives. A cholesteric structure was observed when DNA was treated with a hexamine at 37 degrees C. This structure changed to a hexagonal dendrimer with fluidity on prolonged incubation. These data show a structural specificity effect of polyamines on liquid crystalline phase transitions of DNA and suggest a possible physiological function of natural polyamines.

40 CFR 721.8082 - Polyester polyurethane acrylate.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyester polyurethane acrylate. 721... Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as polyester polyurethane acrylate...

Intestinal mucus and juice glycoproteins have a liquid crystalline structure

International Nuclear Information System (INIS)

Denisova, E.A.; Lazarev, P.I.; Vazina, A.A.; Zheleznaya, L.A.

1985-01-01

X-ray diffraction patterns have been obtained from the following components of canine gastrointestinal tract: (1) native small intestine mucus layer; (2) the precipitate of the flocks formed in the duodenal juice with decreasing pH; (3) concentrated solutions of glycoproteins isolated from the duodenal juice. The X-ray patterns consist of a large number of sharp reflections of spacings between about 100 and 4 A. Some reflections are common for all components studied. All the patterns are interpreted as arising from the glycoprotein molecules ordered into a liquid crystalline structure. (author)

Induced liquid-crystalline ordering in solutions of stiff and flexible amphiphilic macromolecules: Effect of mixture composition

International Nuclear Information System (INIS)

Glagolev, Mikhail K.; Vasilevskaya, Valentina V.; Khokhlov, Alexei R.

2016-01-01

Impact of mixture composition on self-organization in concentrated solutions of stiff helical and flexible macromolecules was studied by means of molecular dynamics simulation. The macromolecules were composed of identical amphiphilic monomer units but a fraction f of macromolecules had stiff helical backbones and the remaining chains were flexible. In poor solvents the compacted flexible macromolecules coexist with bundles or filament clusters from few intertwined stiff helical macromolecules. The increase of relative content f of helical macromolecules leads to increase of the length of helical clusters, to alignment of clusters with each other, and then to liquid-crystalline-like ordering along a single direction. The formation of filament clusters causes segregation of helical and flexible macromolecules and the alignment of the filaments induces effective liquid-like ordering of flexible macromolecules. A visual analysis and calculation of order parameter relaying the anisotropy of diffraction allow concluding that transition from disordered to liquid-crystalline state proceeds sharply at relatively low content of stiff components.

Synthesis of Isothianaphthene (ITN and 3,4-Ethylenedioxy-Thiophene (EDOT-Based Low-Bandgap Liquid Crystalline Conjugated Polymers

Directory of Open Access Journals (Sweden)

Hiromasa Goto

2013-05-01

Full Text Available Copolymers, consisting of isothianaphthene and phenylene derivatives with liquid crystal groups, were synthesized via Migita-Kosugi-Stille polycondensation reaction. IR absorption, UV-vis optical absorption, and PL spectroscopy measurements were carried out. Thermotropic liquid crystallinity of the polymers with bandgap of ~2.5 eV was confirmed.

Polarized Emission of Wholly Aromatic Bio-Based Copolyesters of a Liquid Crystalline Nature

Directory of Open Access Journals (Sweden)

Daisaku Kaneko

2011-05-01

Full Text Available A novel thermotropic liquid crystalline polymers poly{3-benzylidene amino-4-hydroxybenzoic acid (3,4-BAHBA-co-trans-4-hydroxycinnamic acid (4HCA: trans-coumaric acid} (Poly(3,4-BAHBA-co-4HCA, was synthesized by the thermal polycondensation of 4HCA and 3,4-BAHBA, which was synthesized by a reaction of 3-amino-4-hydroxybenzoic acid (3,4-AHBA with benzaldehyde. When the 4HCA compositions of Poly(3,4-BAHBA-co-4HCAs were above 55 mol%, the copolymers showed a nematic, liquid crystalline phase. Differential scanning calorimetry (DSC measurements of the copolymers showed a high glass transition temperature of more than 100 °C, sufficient for use in engineering plastics. Furthermore, the copolymers showed photoluminescence in an N-methylpyrrolidone (NMP solution under ultraviolet (UV light with a wavelength of 365 nm. Oriented film of Poly(3,4-BAHBA-co-4HCA with a 4HCA composition of 75 mol% emitted polarized light, which was confirmed by fluorescent spectroscopy equipped with parallel and crossed polarizers.

Structural aspects of fish skin collagen which forms ordered arrays via liquid crystalline states.

Science.gov (United States)

Giraud-Guille, M M; Besseau, L; Chopin, C; Durand, P; Herbage, D

2000-05-01

The ability of acid-soluble type I collagen extracts from Soleidae flat fish to form ordered arrays in condensed phases has been compared with data for calf skin collagen. Liquid crystalline assemblies in vitro are optimized by preliminary treatment of the molecular population with ultrasounds. This treatment requires the stability of the fish collagen triple helicity to be controlled by X-ray diffraction and differential scanning calorimetry and the effect of sonication to be evaluated by viscosity measurements and gel electrophoresis. The collagen solution in concentrations of at least 40 mg ml(-1) showed in polarized light microscopy birefringent patterns typical of precholesteric phases indicating long-range order within the fluid collagen phase. Ultrastructural data, obtained after stabilization of the liquid crystalline collagen into a gelated matrix, showed that neutralized acid-soluble fish collagen forms cross-striated fibrils, typical of type I collagen, following sine wave-like undulations in precholesteric domains. These ordered geometries, approximating in vivo situations, give interesting mechanical properties to the material.

Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

Directory of Open Access Journals (Sweden)

Ivan Stojanović

2018-03-01

Full Text Available Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispensable solvent emission reduction is the application of powder coatings. This study evaluates the corrosion performance and surface morphology of polyester and epoxy–polyester powder coatings. Electrochemical impedance spectroscopy (EIS, open circuit potential (OCP measurement, salt spray chamber and humidity chamber testing followed by adhesion testing were used to investigate the protective properties of powder coatings. Scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDX was used to analyse the surface morphology and chemical composition, whereas the microstructure and coating uniformity were determined by optical microscope examination. The research revealed a negative influence of coating surface texture on coating thickness and consequently a lack of barrier and adhesion properties. The epoxy–polyester powder coating showed a better performance than the polyester coating. All tested coatings showed uniform structure.

Castor Oil-Based Biodegradable Polyesters.

Science.gov (United States)

Kunduru, Konda Reddy; Basu, Arijit; Haim Zada, Moran; Domb, Abraham J

2015-09-14

This Review compiles the synthesis, physical properties, and biomedical applications for the polyesters based on castor oil and ricinoleic acid. Castor oil has been known for its medicinal value since ancient times. It contains ∼90% ricinoleic acid, which enables direct chemical transformation into polyesters without interference of other fatty acids. The presence of ricinoleic acid (hydroxyl containing fatty acid) enables synthesis of various polyester/anhydrides. In addition, castor oil contains a cis-double bond that can be hydrogenated, oxidized, halogenated, and polymerized. Castor oil is obtained pure in large quantities from natural sources; it is safe and biocompatible.

Application of eco-friendly antimicrobial finish butea monosperma leaves on fabric properties of polyester and cotton/polyester

International Nuclear Information System (INIS)

Sadaf, S.; Saeed, M.; Kalsoom, S.; Saeed, M.

2017-01-01

The study was aimed to check the effect of eco-friendly antimicrobial finish on 100% polyester and 50/50 cotton/polyester woven fabrics. The leaves' extract of Butea monosperma was used as an eco-friendly antimicrobial finish. The fabric was first desized, scoured, bleached and washed then antimicrobial finish was applied by using pad dry cure method. The aesthetic, comfort and mechanical fabrics properties were checked before and after applying antimicrobial finish. Under aesthetic property stiffness and smoothness appearance was checked, under comfort related property absorbency and air permeability was checked and under mechanical property tear and tensile strength was checked. The antimicrobial finish was checked by using ASTEM E2149 Shake Flask method. The AATCC and ISO standard testing methods were used for checking fabric properties. One way ANOVA statistical test was applied for analysis of results. Antimicrobial finish has increased aesthetic (stiffness, smoothness appearance), comfort (absorbency, air permeability) and mechanical (tensile and tear strengths) properties of polyester and cotton/polyester fabrics. The antimicrobial finish was effective on both 100% polyester and 50/50 cotton/polyester fabrics up to 25 washes. This study is beneficial to medical industry, paramedical staff, sports wears, home furnishing as well as common people. (author)

Functional bio-based polyesters by enzymatic polymerization

DEFF Research Database (Denmark)

Daugaard, Anders Egede; Hoffmann, Christian; Andersen, Christian

During recent years enzymatic polymerization has become increasingly popular as an alternative to classical polyesterification processes. The high regioselectivity observed for lipases permits preparation of novel polyesters with a high number of functional groups.1 This is particularly interesting...... polymerization was applied to prepare functional water soluble polyesters based on dimethyl itaconate and poly(ethyleneglycol).2 The monomer permits postfunctionalization using thiol-ene chemistry or aza-michael additions, which was used to illustrate the possibilites of preparing functional hydrogels. Hydrogels...... based on the polyesters were shown to be degradable and could be prepared either from the pure polyester or from prefunctionalized polyesters, though the thiol-ene reactions were found to be less effective. Since then a new monomer, trans-2,5-dihydroxy-3-pentenoic acid methyl ester (DPM) has been...

Test procedures for polyester immobilized salt-containing surrogate mixed wastes

International Nuclear Information System (INIS)

Biyani, R.K.; Hendrickson, D.W.

1997-01-01

These test procedures are written to meet the procedural needs of the Test Plan for immobilization of salt containing surrogate mixed waste using polymer resins, HNF-SD-RE-TP-026 and to ensure adequacy of conduct and collection of samples and data. This testing will demonstrate the use of four different polyester vinyl ester resins in the solidification of surrogate liquid and dry wastes, similar to some mixed wastes generated by DOE operations

Liquid crystalline tactoids: ordered structure, defective coalescence and evolution in confined geometries

Science.gov (United States)

Wang, Pei-Xi; MacLachlan, Mark J.

2017-12-01

Tactoids are liquid crystalline microdroplets that spontaneously nucleate from isotropic dispersions, and transform into macroscopic anisotropic phases. These intermediate structures have been found in a range of molecular, polymeric and colloidal liquid crystals. Typically only studied by polarized optical microscopy, these ordered but easily deformable microdroplets are now emerging as interesting components for structural investigations and developing new materials. In this review, we highlight the structure, property and transformation of tactoids in different compositions, but especially cellulose nanocrystals. We have selected references that illustrate the diversity and most exciting developments in tactoid research, while capturing the historical development of this field. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

Computer simulation of confined and flexoelectric liquid crystalline systems

International Nuclear Information System (INIS)

Barmes, F.

2003-01-01

In this Thesis, systems of confined and flexoelectric liquid crystal systems have been studied using molecular computer simulations. The aim of this work was to provide a molecular model of a bistable display cell in which switching is induced through the application of directional electric field pulses. In the first part of this Thesis, the study of confined systems of liquid crystalline particles has been addressed. Computation of the anchoring phase diagrams for three different surface interaction models showed that the hard needle wall and rod-surface potentials induce both planar and homeotropic alignment separated by a bistability region, this being stronger and wider for the rod-surface varant. The results obtained using the rod-sphere surface model, in contrast, showed that tilled surface arrangements can be induced by surface absorption mechanisms. Equivalent studies of hybrid anchored systems showed that a bend director structure can be obtained in a slab with monostable homeotropic anchoring at the top surface and bistable anchoring at the bottom, provided that the slab height is sufficiently large and the top homeotropic anchoring is not too strong. In the second part of the Thesis, the development of models for tapered (pear-shaped) mesogens has been addressed. The first model considered, the truncated Stone expansion model, proved to be unsuccessful in that it did not display liquid crystalline phases. This drawback was then overcome using the alternative parametric hard Gaussian overlap model which was found to display a much richer phase behaviour. With a molecular elongation k = 5, both nematic and interdigitated smectic A 2 phases were obtained. In the final part of this Thesis, the knowledge acquired from the two previous studies was united in an attempt to model a bistable display cell. Switching between the hybrid aligned nematic and vertical states of the cell was successfully performed using pear shaped particles with both dielectric and

Macromolecular crowding-assisted fabrication of liquid-crystalline imprinted polymers.

Science.gov (United States)

Zhang, Chen; Zhang, Jing; Huang, Yan-Ping; Liu, Zhao-Sheng

2015-04-01

A macromolecular crowding-assisted liquid-crystalline molecularly imprinted monolith (LC-MIM) was prepared successfully for the first time. The imprinted stationary phase was synthesized with polymethyl methacrylate (PMMA) or polystyrene (PS) as the crowding agent, 4-cyanophenyl dicyclohexyl propylene (CPCE) as the liquid-crystal monomer, and hydroquinidine as the pseudo-template for the chiral separation of cinchona alkaloids in HPLC. A low level of cross-linker (26%) has been found to be sufficient to achieve molecular recognition on the crowding-assisted LC-MIM due to the physical cross-linking of mesogenic groups in place of chemical cross-linking, and baseline separation of quinidine and quinine could be achieved with good resolution (R(s) = 2.96), selectivity factor (α = 2.16), and column efficiency (N = 2650 plates/m). In contrast, the LC-MIM prepared without crowding agents displayed the smallest diastereoselectivity (α = 1.90), while the crowding-assisted MIM with high level of cross-linker (80%) obtained the greatest selectivity factor (α = 7.65), but the lowest column efficiency (N = 177 plates/m).

Collagen films with stabilized liquid crystalline phases and concerns on osteoblast behaviors

Energy Technology Data Exchange (ETDEWEB)

Tang, Minjian; Ding, Shan; Min, Xiang; Jiao, Yanpeng, E-mail: tjiaoyp@jnu.edu.cn; Li, Lihua; Li, Hong; Zhou, Changren, E-mail: tcrz9@jnu.edu.cn

2016-01-01

To duplicate collagen's in vivo liquid crystalline (LC) phase and investigate the relationship between the morphology of LC collagen and osteoblast behavior, a self-assembly method was introduced for preparing collagen films with a stabilized LC phase. The LC texture and topological structure of the films before and after stabilization were observed with polarizing optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The relationship between the collagen films and osteoblast behavior was studied with the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide method, proliferation index detection, alkaline phosphatase measurements, osteocalcin assay, inverted microscopy, SEM observation, AFM observation, and cytoskeleton fluorescence staining. The results showed that the LC collagen film had continuously twisting orientations in the cholesteric phase with a typical series of arced patterns. The collagen fibers assembled in a well-organized orientation in the LC film. Compared to the non-LC film, the LC collagen film can promote cell proliferation, and increase ALP and osteocalcin expression, revealing a contact guide effect on osteoblasts. - Highlights: • Collagen film with liquid crystalline (LC) phase was observed by POM, SEM and AFM. • The effect of LC collagen film on osteoblasts behaviors was studied in detail. • LC collagen film promoted osteoblast proliferation and osteogenesis activity.

Understanding changes in cellulose crystalline structure of lignocellulosic biomass during ionic liquid pretreatment by XRD.

Science.gov (United States)

Zhang, Jiafu; Wang, Yixun; Zhang, Liye; Zhang, Ruihong; Liu, Guangqing; Cheng, Gang

2014-01-01

X-ray diffraction (XRD) was used to understand the interactions of cellulose in lignocellulosic biomass with ionic liquids (ILs). The experiment was designed in such a way that the process of swelling and solubilization of crystalline cellulose in plant cell walls was followed by XRD. Three different feedstocks, switchgrass, corn stover and rice husk, were pretreated using 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) at temperatures of 50-130°C for 6h. At a 5 wt.% biomass loading, increasing pretreatment temperature led to a drop in biomass crystallinity index (CrI), which was due to swelling of crystalline cellulose. After most of the crystalline cellulose was swollen with IL molecules, a low-order structure was found in the pretreated samples. Upon further increasing temperature, cellulose II structure started to form in the pretreated biomass samples as a result of solubilization of cellulose in [C4mim][OAc] and subsequent regeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

LIQUID CRYSTALLINE POLYMERS FROM VANILLIC ACID: SYNTHESIS, PROPERTIES, AND APPLICATIONS.

NARCIS (Netherlands)

Wilsens, Karel

2017-01-01

Thermotropic polyesters are an important class of materials for high erformance applications. Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compression-molded

Polyester projects for India, Pakistan

International Nuclear Information System (INIS)

Siddiqi, R.

1993-01-01

India's Indo Rama Synthetics (Bombay) is planning a $186-million integrated polyester fiber and filament complex at Nagpur, Maharashtra. The complex will have annual capacities for 38,000 m.t. of polyester chips by polycondensation, 25,000 m.t. of polyester staple fiber, and 12,000 m.t. of polyester blended yarn. The company is negotiating with the main world suppliers of polycondensation technology. The first stage of the project is slated to begin production by the end of this year and be fully completed by 1994. In Pakistan, National Fibers Ltd. (PNF; Karachi) has signed a deal with Zimmer (Frankfurt) for technology, procurement, construction, and support work to expand polyester staple fiber capacity from 14,000 m.t./year to 52,000 m.t./year. The technology involves a continuous polymerization process. The project also calls for improvements to PNF's existing batch plant. It is scheduled for completion by the end of 1994. Total cost of the project is estimated at Rs1.745 billion ($70 million), out of which the foreign exchange component is Rs1.05 billion. The Islamic Development Bank (Jeddah; Saudi Arabia) has already approved a $27-million slice of the financing, while the balance of the foreign exchange loan is being arranged through suppliers credit. Local currency loans will be provided by other financial institutions in Pakistan

Hydrogen Bond Induces Hierarchical Self-Assembly in Liquid-Crystalline Block Copolymers.

Science.gov (United States)

Huang, Shuai; Pang, Linlin; Chen, Yuxuan; Zhou, Liming; Fang, Shaoming; Yu, Haifeng

2018-03-01

Microphase-separated structures of block copolymers (BCs) with a size of sub-10 nm are usually obtained by hydrogen-bond-induced self-assembly of BCs through doping with small molecules as functional additives. Here, fabrication of hierarchically self-assembled sub-10 nm structures upon microphase separation of amphiphilic liquid-crystalline BCs (LCBCs) at the existence of hydrogen bonds but without any dopants is reported. The newly introduced urethane groups in the side chain of the hydrophobic block of LCBCs interact with the ether groups of the hydrophilic poly(ethylene oxide) (PEO) block, leading to imperfect crystallization of the PEO blocks. Both crystalline and amorphous domains coexist in the separated PEO phase, enabling a lamellar structure to appear inside the PEO nanocylinders. This provides an elegant method to fabricate controllable sub-10 nm microstructures in well-defined polymer systems without the introduction of any dopants. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers

Energy Technology Data Exchange (ETDEWEB)

Ramírez-Hernández, Abelardo; Hur, Su-Mi; Armas-Pérez, Julio; Cruz, Monica; de Pablo, Juan

2017-03-01

Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano-and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.

Vehicles of inverted hexagonal liquid crystalline lipid phases self-assembled at room temperature

Czech Academy of Sciences Publication Activity Database

Angelov, Borislav; Angelova, A.; Garamus, V. M.; Lesieur, S.

2013-01-01

Roč. 15, 3/4 (2013), s. 211-215 ISSN 1454-4164 R&D Projects: GA ČR GAP208/10/1600 Institutional support: RVO:61389013 Keywords : liquid crystalline lipid nanoparticles * small angle X-ray scattering * cross-polarised light optical microscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.563, year: 2013 http://joam.inoe.ro/index.php?option=magazine&op=view&idu=3179&catid=76

A new series of two-ring-based side chain liquid crystalline polymers: synthesis and mesophase characterization

CSIR Research Space (South Africa)

Reddy, GSM

2013-05-01

Full Text Available A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings...

Analysis of structural changes influence on radiation crosslinking of unsaturated polyester resins

International Nuclear Information System (INIS)

Pucic, I.; Ranogajec, F.

1998-01-01

Complete text of publication follows. DC-electrical conductivity has shown high sensitivity toward structural changes, especially to some low intensity transitions such as liquid-liquid transitions that are difficult to observe. It also showed favorable properties for monitoring of crosslinking of unsaturated polyester resins. However, when the rates were calculated using commonly applied formula: k lnσ =ln[(ln σ t - ln σ o )/(ln σ ∞ - ln σ o )] the sensitivity decreased. The extents of the reaction were shifted on time axis compared to non-logarithmic conductivity data and extraction analysis results. The logarithmic data had pronounced scattering at the end of the reaction so it was very difficult to determine end point of reaction and almost impossible to detect vitrification point. Some other features that can be seen on conductivity plot were lost. Therefore the results of DC-electrical conductivity monitoring of radiation and thermally initiated crosslinking of unsaturated polyester resins were interpreted in the same manner as the data collected by other non-electrical methods, using 'raw' data instead of its logarithmic form: k σ = ln [(σ t - σ o )/(σ ∞ - σ o )]. By this modification of data analysis the full sensitivity of electrical conductivity method to structural changes in reacting system was proven. Lower data scattering allowed observation of dose rate influences. The apparent rate constants calculated from conductivity itself showed the influence of upper liquid-liquid transition on the rate of radiation induced reaction that could not be seen if the logarithm of conductivity was used

Polyester Apparel Cutting Waste as Insulation Material

OpenAIRE

Trajković, Dušan; Jordeva, Sonja; Tomovska, Elena; Zafirova, Koleta

2017-01-01

Polyester waste is the dominant component of the clothing industry waste stream, yet its recycling in this industry is rarely addressed. This paper proposes using polyester cutting waste as an insulation blanket for roofing and buildings’ internal walls in order to reduce environmental pollution. The designed textile structures used waste cuttings from different polyester fabrics without opening the fabric to fibre. Thermal insulation, acoustic insulation, fire resistance and biodegradation o...

Thermal degradation of polymer systems having liquid crystalline oligoester segment

Directory of Open Access Journals (Sweden)

Renato Matroniani

Full Text Available Abstract Block copolymers and blends comprised by liquid crystalline oligoester and polystyrene were prepared and their thermal stability were characterized by thermogravimetric analysis (TGA. The samples have shown three main decomposition temperatures due to (1 lost of flexible chain and decomposition of mesogenic segment, (2 decomposition of polystyrene and (3 final decomposition of oligoester rigid segment. Both copolymers and polymer blends presented lower thermal stability compared to polystyrene and oligoester. The residual mass after heating at 600 °C in copolymers and polymer blends were lower than those found in the oligoesters. A degradative process of aromatic segments of oligoester induced by decomposition of polystyrene is suggested.

Surface modification of polyester biomaterials for tissue engineering

International Nuclear Information System (INIS)

Jiao Yanpeng; Cui Fuzhai

2007-01-01

Surfaces play an important role in a biological system for most biological reactions occurring at surfaces and interfaces. The development of biomaterials for tissue engineering is to create perfect surfaces which can provoke specific cellular responses and direct new tissue regeneration. The improvement in biocompatibility of biomaterials for tissue engineering by directed surface modification is an important contribution to biomaterials development. Among many biomaterials used for tissue engineering, polyesters have been well documented for their excellent biodegradability, biocompatibility and nontoxicity. However, poor hydrophilicity and the lack of natural recognition sites on the surface of polyesters have greatly limited their further application in the tissue engineering field. Therefore, how to introduce functional groups or molecules to polyester surfaces, which ideally adjust cell/tissue biological functions, becomes more and more important. In this review, recent advances in polyester surface modification and their applications are reviewed. The development of new technologies or methods used to modify polyester surfaces for developing their biocompatibility is introduced. The results of polyester surface modifications by surface morphological modification, surface chemical group/charge modification, surface biomacromolecule modification and so on are reported in detail. Modified surface properties of polyesters directly related to in vitro/vivo biological performances are presented as well, such as protein adsorption, cell attachment and growth and tissue response. Lastly, the prospect of polyester surface modification is discussed, especially the current conception of biomimetic and molecular recognition. (topical review)

Polystyrene/Hyperbranched Polyester Blends and Reactive Polystyrene/Hyperbranched Polyester Blends

National Research Council Canada - National Science Library

Mulkern, Thomas

1999-01-01

.... In this work, the incorporation of HBPs in thermoplastic blends was investigated. Several volume fractions of hydroxyl functionalized hyperbranched polyesters were melt blended with nonreactive polystyrene (PS...

Volume phase transitions of cholesteric liquid crystalline gels.

Science.gov (United States)

Matsuyama, Akihiko

2015-05-07

We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.

Volume phase transitions of cholesteric liquid crystalline gels

Energy Technology Data Exchange (ETDEWEB)

Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp [Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502 (Japan)

2015-05-07

We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.

Liquid crystalline systems containing Vitamin E TPGS for the controlled transdermal nicotine delivery

Directory of Open Access Journals (Sweden)

Lívia Neves Borgheti-Cardoso

Full Text Available ABSTRACT Transdermal nicotine patches have been used in smoking cessation therapy, suggested for the treatment of skin disorders with eosinophilic infiltration and have been found to improve attention performance in patients with Alzheimer's disease and age-associated memory impairment. However, skin irritation with extended patch use is still a problem. The aim of this work was to develop a simple to prepare liquid crystalline system containing vitamin E TPGS that would be able to control nicotine delivery and reduce irritation and sensitization problems. The liquid crystalline phases were macroscopically characterized by visual analysis and examined microscopically under a polarized light microscope. Topical and transdermal delivery of nicotine were investigated in vitro using porcine ear skin mounted on a Franz diffusion cell. Nicotine skin permeation from the developed cubic phase followed zero-order kinetics (r = 0.993 and was significantly enhanced after 12 h when compared to the control formulation (nicotine solution (p < 0.05 (138.86 ± 20.44 and 64.91 ± 4.06 μg/cm2, respectively. Cubic phase was also able to target viable skin layers in comparison to control solution (8.18 ± 1.89 and 2.63 ± 2.51 μg/cm2, respectively. Further studies to evaluate skin sensitization and irritation are now necessary.

Polyesters production from the mixture of phthalic acid, terephthalic and glycerol; Producao de poliesteres a partir da mistura de acido ftalico, tereftalico e glicerol

Energy Technology Data Exchange (ETDEWEB)

Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M., E-mail: adrianaequfba@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Carvalho, R.F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Ambiental Urbana

2010-07-01

Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

New liquid crystalline materials based on two generations of dendronised cyclophosphazenes.

Science.gov (United States)

Jiménez, Josefina; Laguna, Antonio; Gascón, Elena; Sanz, José Antonio; Serrano, José Luis; Barberá, Joaquín; Oriol, Luis

2012-12-21

A divergent approach was used for the synthesis of dendritic structures based on a cyclotriphosphazene core with 12 or 24 hydroxyl groups, by starting from [N(3)P(3)(OC(6)H(4)OH-4)(6)] and using an acetal-protected 2,2-di(hydroxymethyl)propionic anhydride as the acylating agent. Hydroxyl groups in these first- and second-generation dendrimers, G1-(OH)(12) or G2-(OH)(24), were then condensed in turn with mono- or polycatenar pro-mesogenic acids to study their ability to promote self-assembly into liquid crystalline structures. Reactions were monitored by using (31)P{(1)H} and (1)H NMR spectroscopy and the chemical structure of the resulting materials was confirmed by using different spectroscopic techniques and mass spectrometry (MALDI-TOF MS). The results were in accordance with monodisperse, fully functionalised cyclotriphosphazene dendrimers. Thermal and liquid crystalline properties were studied by using optical microscopy, differential scanning calorimetry and X-ray diffraction. The dendrimer with 12 4-pentylbiphenyl mesogenic units gives rise to columnar rectangular organisation, whereas the one with 24 pentylbiphenyl units does not exhibit mesomorphic behaviour. In the case of materials that contain polycatenar pro-mesogenic units with two aromatic rings (A4 vs. A5), the incorporation of a short flexible spacer connected to the periphery of the dendron (acid A5) was needed to achieve mesomorphic organisation. In this case, both dendrimer generations G1 A5 and G2 A5 exhibit a hexagonal columnar mesophase. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrospinning of microbial polyester for cell culture

Energy Technology Data Exchange (ETDEWEB)

Kwon, Oh Hyeong [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Lee, Ik Sang [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Ko, Young-Gwang [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Meng, Wan [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Jung, Kyung-Hye [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Kang, Inn-Kyu [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Ito, Yoshihiro [Kanagawa Academy of Science and Technology, KSP East 309, Sakado 3-2-1, Takatsu-ku, Kawasaki 213-0012 (Japan)

2007-03-01

Biodegradable and biocompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a copolymer of microbial polyester, was fabricated as a nanofibrous mat by electrospinning. The specific surface area and the porosity of electrospun PHBV nanofibrous mat were determined. When the mechanical properties of flat film and electrospun PHBV nanofibrous mats were investigated, both the tensile modulus and strength of electrospun PHBV were less than those of cast PHBV film. However, the elongation ratio of nanofiber mat was higher than that of the cast film. The structure of electrospun nanofibers using PHBV-trifluoroethanol solutions depended on the solution concentrations. When x-ray diffraction patterns of bulk PHBV before and after electrospinning were compared, the crystallinity of PHBV was not significantly affected by the electrospinning process. Chondrocytes adhered and grew on the electrospun PHBV nanofibrous mat better than on the cast PHBV film. Therefore, the electrospun PHBV was considered to be suitable for cell culture.

Synthetic polyester-hydrolyzing enzymes from thermophilic actinomycetes.

Science.gov (United States)

Wei, Ren; Oeser, Thorsten; Zimmermann, Wolfgang

2014-01-01

Thermophilic actinomycetes produce enzymes capable of hydrolyzing synthetic polyesters such as polyethylene terephthalate (PET). In addition to carboxylesterases, which have hydrolytic activity predominantly against PET oligomers, esterases related to cutinases also hydrolyze synthetic polymers. The production of these enzymes by actinomycetes as well as their recombinant expression in heterologous hosts is described and their catalytic activity against polyester substrates is compared. Assays to analyze the enzymatic hydrolysis of synthetic polyesters are evaluated, and a kinetic model describing the enzymatic heterogeneous hydrolysis process is discussed. Structure-function and structure-stability relationships of actinomycete polyester hydrolases are compared based on molecular dynamics simulations and recently solved protein structures. In addition, recent progress in enhancing their activity and thermal stability by random or site-directed mutagenesis is presented. © 2014 Elsevier Inc. All rights reserved.

Effect of gamma irradiation on poly(butylene naphthalate) based polyesters

International Nuclear Information System (INIS)

Malavasi, I.; Consolati, G.; Quasso, F.; Soccio, M.; Gigli, M.; Negrin, M.; Macerata, E.; Giacobbo, F.; Lotti, N.; Munari, A.; Mariani, M.

2016-01-01

The present work investigates the effect of gamma radiation on the properties of three naphthalate-based polyesters, i.e. poly(butylene naphthalate) (PBN), poly(diethylene naphthalate) (PDEN) and poly(thiodiethylene naphthalate) (PTDEN). In addition, the analogous terephthalate-based polymers of PDEN and PTDEN, i.e. poly(diethylene terephthalate) (PDET) and poly(thiodiethylene terephthalate) (PTDET), are also investigated, in order to check the effect of a lower number of aromatic rings. All the polymers, irradiated in air at different absorbed doses, were characterized by several techniques. The data obtained indicate that all the polymers, except PBN, show a decrease of molecular weight with the dose increase. The thermal behavior and the morphology confirm the previous results and show that the higher the crystallinity degree and number of aromatic rings, the higher the radiation resistance. The introduction of heteroatoms decreases the ability of a polymer to crystallize due to a reduction of polymer chain symmetry, thus worsening their radiation resistance. - Highlights: • Gamma irradiation of polyesters with different number of aromatic rings was studied. • Effect of gamma radiation on PBN, PDEN, PTDEN, PDET, and PTDET was investigated. • Irradiated polymers were studied by GPC, DSC and PALS. • Introduction of heteroatoms decreases polymers radiation resistance. • Presence of double aromatic ring confers a higher stability with increasing doses.

Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes.

Science.gov (United States)

Nakajima-Kambe, T; Shigeno-Akutsu, Y; Nomura, N; Onuma, F; Nakahara, T

1999-02-01

Polyurethane (PUR) is a polymer derived from the condensation of polyisocyanate and polyol and it is widely used as a base material in various industries. PUR, in particular, polyester PUR, is known to be vulnerable to microbial attack. Recently, environmental pollution by plastic wastes has become a serious issue and polyester PUR had attracted attention because of its biodegradability. There are many reports on the degradation of polyester PUR by microorganisms, especially by fungi. Microbial degradation of polyester PUR is thought to be mainly due to the hydrolysis of ester bonds by esterases. Recently, polyester-PUR-degrading enzymes have been purified and their characteristics reported. Among them, a solid-polyester-PUR-degrading enzyme (PUR esterase) derived from Comamonas acidovorans TB-35 had unique characteristics. This enzyme has a hydrophobic PUR-surface-binding domain and a catalytic domain, and the surface-binding domain was considered as being essential for PUR degradation. This hydrophobic surface-binding domain is also observed in other solid-polyester-degrading enzymes such as poly(hydroxyalkanoate) (PHA) depolymerases. There was no significant homology between the amino acid sequence of PUR esterase and that of PHA depolymerases, except in the hydrophobic surface-binding region. Thus, PUR esterase and PHA depolymerase are probably different in terms of their evolutionary origin and it is possible that PUR esterases come to be classified as a new solid-polyester-degrading enzyme family.

Comparison of alignment tensors generated for native tRNAVal using magnetic fields and liquid crystalline media

International Nuclear Information System (INIS)

Latham, Michael P.; Hanson, Paul; Brown, Darin J.; Pardi, Arthur

2008-01-01

Residual dipolar couplings (RDCs) complement standard NOE distance and J-coupling torsion angle data to improve the local and global structure of biomolecules in solution. One powerful application of RDCs is for domain orientation studies, which are especially valuable for structural studies of nucleic acids, where the local structure of a double helix is readily modeled and the orientations of the helical domains can then be determined from RDC data. However, RDCs obtained from only one alignment media generally result in degenerate solutions for the orientation of multiple domains. In protein systems, different alignment media are typically used to eliminate this orientational degeneracy, where the combination of RDCs from two (or more) independent alignment tensors can be used to overcome this degeneracy. It is demonstrated here for native E. coli tRNA Val that many of the commonly used liquid crystalline alignment media result in very similar alignment tensors, which do not eliminate the 4-fold degeneracy for orienting the two helical domains in tRNA. The intrinsic magnetic susceptibility anisotropy (MSA) of the nucleobases in tRNA Val was also used to obtain RDCs for magnetic alignment at 800 and 900 MHz. While these RDCs yield a different alignment tensor, the specific orientation of this tensor combined with the high rhombicity for the tensors in the liquid crystalline media only eliminates two of the four degenerate orientations for tRNA Val . Simulations are used to show that, in optimal cases, the combination of RDCs obtained from liquid crystalline medium and MSA-induced alignment can be used to obtain a unique orientation for the two helical domains in tRNA Val

Temperature-Responsive Luminescent Solar Concentrators: Tuning Energy Transfer in a Liquid Crystalline Matrix.

Science.gov (United States)

Sol, Jeroen A H P; Dehm, Volker; Hecht, Reinhard; Würthner, Frank; Schenning, Albertus P H J; Debije, Michael G

2018-01-22

Temperature-responsive luminescent solar concentrators (LSCs) have been fabricated in which the Förster resonance energy transfer (FRET) between a donor-acceptor pair in a liquid crystalline solvent can be tuned. At room temperatures, the perylene bisimide (PBI) acceptor is aggregated and FRET is inactive; while after heating to a temperature above the isotropic phase of the liquid crystal solvent, the acceptor PBI completely dissolves and FRET is activated. This unusual temperature control over FRET was used to design a color-tunable LSC. The device has been shown to be highly stable towards consecutive heating and cooling cycles, making it an appealing device for harvesting otherwise unused solar energy. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

On the molecular anisotropy of liquid crystalline and flexible polymer systems

Science.gov (United States)

van Horn, Brett L.

The demand for products of ever increasing quality or for novel applications has required increasing attention to or manipulation of the anisotropy of manufactured parts. Oriented plastics are used everywhere from recording film to automotive body parts to monofilament fishing line. Liquid crystals are also used in a wide array of applications including their dominance in the flat panel display industry, color changing temperature sensors, and woven bullet resistant fabrics. Anisotropy can also be detrimental, for instance sometimes leading to poor fracture resistance or low yield stress along specific directions. Controlling and measuring anisotropy of materials has become increasingly important, but doing so is wrought with challenges. Measuring physical properties of isotropic liquids, such as water or most oils can be done in a straightforward fashion. Their viscosities and densities, for example, have unique values under a given set of conditions. With anisotropic fluids, like liquid crystals, the viscosity, for instance, will not only depend upon temperature, concentration, etc. but also upon the direction of observation, degree of anisotropy, source of anisotropy, and so forth. This added degree of complexity complicates our ability to define the state of the material at which the measurements are made and generally necessitates the use of more sophisticated measurement strategies or techniques. This work presents techniques and tools for investigating anisotropy in liquid crystalline and stretched polymeric systems. Included are the use of conoscopy for the determination of birefringence and orientation of nematic liquid crystals and stretched polymers, the shear response of flow aligning nematic liquid crystal monodomains, and the design of a novel linear rheometer that allows for in situ optical or scattering investigations.

Studies on the Synthesis,Characterization and Properties of the Reactive Thermotropic Liquid Crystalline Polymer

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

1 Introduction Four species of reactive thermotropic liquid crystalline polymer (LCMC) with different relative molecular weight were synthesized in this work (see scheme 1, n=2, 6, 10, ∞.n means number of repeat structure unit). Their structure, morphology and properties were investigated systemically by differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Wide-angle X-ray diffraction (WAXD), polarizing opticalmicroscopy (POM) and ubb...

Blends of polyester ionomers with polar polymers: Interactions, reactions, and compatibilization

Science.gov (United States)

Boykin, Timothy Lamar

The compatibility of amorphous and semicrystalline polyester ionomers with various polar polymers (i.e., polyesters and polyamides) has been investigated for their potential use as minor component compatibilizers. The degree of compatibility (i.e., ranging from incompatible to miscible) between the polyester ionomers and the polar polymers was determined by evaluating the effect of blend composition on the melting behavior and phase behavior of binary blends. In addition, the origin of compatibility and/or incompatibility for each of the binary blends (i.e., polyamide/ionomer and polyester/ionomer) was determined by evaluating blends prepared by both solution and melt mixed methods. Subsequent to investigation of the binary blends, the effect of polyester ionomer addition on the compatibility of polyamide/polyester blends was investigated by evaluating the mechanical properties and phase morphology of ionomer compatibilized polyamide/polyester blends. Polyester ionomers (amorphous and semicrystalline) were shown to exhibit a high degree of compatibility (even miscibility) with polyamides, such as nylon 6,6 (N66). Compatibility was attributed to specific interactions between the metal counterion of the polyester ionomer and the amide groups of N66. The degree of compatibility (or miscibility) was shown to be dependent on the counterion type of the ionomer, with the highest degree exhibited by blends containing the divalent form of the polyester ionomers. Although polyester ionomers were shown to exhibit incompatibility with both poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), increasing the time of melt processing significantly enhanced the compatibility of the polyester ionomers with both PET and PBT. The observed enhancement in compatibility was attributed to ester-ester interchange between the polyester blend components, which was confirmed by NMR spectroscopy. The addition of polyester ionomers as a minor component compatibilizer (i

Preparation and applications of wood-polyester composites

International Nuclear Information System (INIS)

Czvikovszky, T.

1982-01-01

Optimum processing parameters were searched for the pilot-scale production of wood-polyester composites by irradiation of resin-impregnated wood material. The radiation initiation of the following systems were examined in wood and without wood matrix: methyl methacrylate, mixture of styrene and acrylonitryle, and their combination with unsaturated polyester. In the most cases the over-all rate of the complete polymerization process in wood matrix is proportional to the square root of the initiation rate. The parameters of the radiation technology of wood-polyester composites have been determined, using 260 TBq (7 kCi) 60 Co radiation source. A pilot plant has been constructed using an underwater irradiation system of 1.85 PBq (50 kCi) 60 Co. The successful production rate of 200 kg wood-polyester composite per day, as well as the application tests have demonstrated the technical feasibility of this new structural material. (author)

Microbial degradation of aliphatic and aliphatic-aromatic co-polyesters.

Science.gov (United States)

Shah, Aamer Ali; Kato, Satoshi; Shintani, Noboru; Kamini, Numbi Ramudu; Nakajima-Kambe, Toshiaki

2014-04-01

Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(L-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments.

Synthesis and characterization of polyesters from renewable cardol ...

African Journals Online (AJOL)

Bulletin of the Chemical Society of Ethiopia ... The preparation and thermal characteristics of new polyesters from cardol, a renewable monomer ... All prepared polyesters were insoluble in common laboratory solvents at room temperature.

Radiation effects on biodegradable polyesters

International Nuclear Information System (INIS)

Hiroshi Mitomo; Darmawan Darwis; Fumio Yoshii; Keizo Makuuchi

1999-01-01

Poly(3-hydroxybutyrate) [P(3HB)] and its copolymer poly(3-hydroxybutyrate-co-3hydroxyvalerate) [P(3HB-co-3HV)] are microbial biodegradable polyesters produced by many types of bacteria. Poly(butylene succinate) (PBS) and poly(E-caprolactone) (PCL) are also biodegradable synthetic polyesters which have been commercialized. These thermoplastics are expected for wide usage in environmental protection and blocompatible applications. Radiation grafting of hydrophilic monomers onto many polymers, e.g., polyethylene and polypropylene has been studied mainly for biomedical applications. In the present study, radiation-induced graft polymerization of vinyl monomers onto PHB and P(3HB-co-3HV) was carried out and improvement of their properties was studied. Changes in the properties and biodegradability were compared with the degree of grafting. Radiation-induced crosslinking of PBS and PCL which relatively show thermal and irradiation stability was also carried out to improve their thermal stability or processability. Irradiation to PBS and PCL mainly resulted in crosslinking and characterization of these crosslinked polyesters was investigated

The orientation-enhancing effect of diphenyl aluminium phosphate nanorods in a liquid-crystalline epoxy matrix ordered by magnetic field

Czech Academy of Sciences Publication Activity Database

Mossety-Leszczak, B.; Strachota, Beata; Strachota, Adam; Steinhart, Miloš; Šlouf, Miroslav

2015-01-01

Roč. 72, November (2015), s. 238-255 ISSN 0014-3057 Institutional support: RVO:61389013 Keywords : liquid-crystalline epoxy resins * magnetic field orientation * nanocomposites Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.485, year: 2015

Liquid crystalline polymers from renewable resources: Synthesis, characterization, and applications in composites.

NARCIS (Netherlands)

Wilsens, Karel

2017-01-01

Thermotropic polyesters are an important class of materials for high erformance applications. Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compression-molded

Evaluation of Microemulsion and Lamellar Liquid Crystalline Systems for Transdermal Zidovudine Delivery.

Science.gov (United States)

Carvalho, André Luis Menezes; Silva, José Alexsandro da; Lira, Ana Amélia Moreira; Conceição, Tamara Matos Freire; Nunes, Rogéria de Souza; de Albuquerque Junior, Ricardo Luiz Cavalcanti; Sarmento, Victor Hugo Vitorino; Leal, Leila Bastos; de Santana, Davi Pereira

2016-07-01

This study proposed to investigate and to compare colloidal carrier systems containing Zidovudine (3'-azido-3'-deoxythymidine) (AZT) for transdermal administration and optimization of antiretroviral therapy. Microemulsion (ME) and lamellar phase (LP) liquid crystal were obtained and selected from pseudoternary diagrams previously developed. Small-angle X-ray scattering and rheology analysis confirmed the presence of typical ME and liquid crystalline structures with lamellar arrangement, respectively. Both colloidal carrier systems, ME, and LP remained stable, homogeneous, and isotropic after AZT addition. In vitro permeation study (using pig ear skin) showed that the amount of permeated drug was higher for ME compared to the control and LP, obtaining a permeation enhancing effect on the order of approximately 2-fold (p drug permeation without causing apparent skin irritation. On the order hand, LP functioned as a drug reservoir reducing AZT partitioning into the skin. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Rheological Behavior of Bentonite-Polyester Dispersions

Science.gov (United States)

Abu-Jdayil, Basim; Al-Omari, Salah Addin

2013-07-01

The rheological behavior of a bentonite clay dispersed in unsaturated polyester was investigated. The effects of the solid content and particle size on the steady and transient rheological properties of the dispersions were studied. In addition, two types of bentonite with different Na+/Ca+2 ratio were used in this study. The Herschel-Bulkley and the Weltman models were used to describe the apparent viscosity of the bentonite-polyester composite in relation to the shear rate and shearing time. The bentonite-polyester dispersions were found to exhibit both Newtonian and non-Newtonian behavior. The transition from a Newtonian to a Bingham plastic and then to a shear-thinning material with a yield stress was found to depend on the solid concentration, the particle size, and the type of bentonite. At a low solid content, the apparent viscosity of the bentonite dispersion increased linearly with solid concentration. But a dramatic increase in the apparent viscosity beyond a solid content of 20 wt.% was observed. On the other hand, a thixotropic behavior was detected in bentonite-polyester dispersions with a high solid content and a low particle size. However, this behavior was more pronounced in dispersions with a high Na+/Ca+2 ratio.

Liquid crystalline polymers IX Main chain thermotropic poly (azomethine – ethers containing thiazole moiety linked with polymethylene spacers

Directory of Open Access Journals (Sweden)

2007-04-01

Full Text Available A new homologous series of thermally stable thermotropic liquid crystalline poly(azomethine-ethers based on thiazole moiety were synthesized by solution polycondensation of 4,4`-diformyl-α,ω-diphenoxyalkanes, I–IV or 4,4`-diformyl-2,2`-dimethoxy-α,ω-diphenoxyalkanes V–VIII with the new bis(2-aminothiazole monomer X. A model compound XI was synthesized from X with benzaldehyde and characterized by elemental and spectral analyses. The inherent viscosities of the resulting polymers were in the range 0.43–1.34 dI/g. All the poly(azomethine-ethers were insoluble in common organic solvents but dissolved completely in concentrated H2SO4 and formic acid. The mesomorphic properties of these polymers were studied as a function of the diphenoxyalkane space length. Their thermotropic liquid crystalline properties were examined by DSC and optical polarizing microscopy and demonstrated that the resulting polymers form nematic mesophases over wide temperature ranges. The thermogravimetric analyses of those polymers were evaluated by TGA and DSC measurements and correlated to their structural units. X-ray analysis showed that polymers having some degree of crystallinity in the region 2θ = 5–60°. In addition, the morphological properties of selected examples were tested by scanning electron microscopy.

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

OpenAIRE

Saed, Mohand O.; Torbati, Amir H.; Nair, Devatha P.; Yakacki, Christopher M.

2016-01-01

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addi...

Radiation processed composite materials of wood and elastic polyester resins

International Nuclear Information System (INIS)

Tapolcai, I.; Czvikovszky, T.

1983-01-01

The radiation polymerization of multifunctional unsaturated polyester-monomer mixtures in wood forms interpenetrating network system. The mechanical resistance (compression, abrasion, hardness, etc.) of these composite materials are generally well over the original wood, however the impact strength is almost the same or even reduced, in comparison to the wood itself. An attempt is made using elastic polyester resins to produced wood-polyester composite materials with improved modulus of elasticity and impact properties. For the impregnation of European beech wood two types of elastic unsaturated polyester resins were used. The exothermic effect of radiation copolymerization of these resins in wood has been measured and the dose rate effects as well as hardening dose was determined. Felxural strength and impact properties were examined. Elastic unsaturated polyester resins improved the impact strength of wood composite materials. (author)

The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

Energy Technology Data Exchange (ETDEWEB)

Tylkowski, Bartosz; Castelao, Nuria [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Giamberini, Marta, E-mail: marta.giamberini@urv.net [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Garcia-Valls, Ricard [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Reina, Jose Antonio [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, Carrer Marcel.li Domingo s/n, E-43007, Tarragona (Spain); Gumi, Tania [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain)

2012-02-01

We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion Registered-Sign N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH. - Highlights: Black-Right-Pointing-Pointer We prepared oriented membranes based on a liquid crystalline columnar polyether. Black-Right-Pointing-Pointer In this structure, the inner polyether chain could work as an ion channel. Black-Right-Pointing-Pointer We obtained membranes by casting a chloroform solution in the presence of water. Black-Right-Pointing-Pointer Membranes showed good proton permeability due to the presence of oriented channels.

The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

International Nuclear Information System (INIS)

Tylkowski, Bartosz; Castelao, Nuria; Giamberini, Marta; Garcia-Valls, Ricard; Reina, José Antonio; Gumí, Tània

2012-01-01

We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion® N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH. - Highlights: ► We prepared oriented membranes based on a liquid crystalline columnar polyether. ► In this structure, the inner polyether chain could work as an ion channel. ► We obtained membranes by casting a chloroform solution in the presence of water. ► Membranes showed good proton permeability due to the presence of oriented channels.

Sensing of environmental pollutant by conductive composite from prepared from hyperbranched polymer-grafted carbon black and crystalline polymer

International Nuclear Information System (INIS)

Taniguchi, Y.; Chen, J.; Ogawa, M.; Yokoyama, K.; Shimizu, H.; Tsubokawa, N.; Maekawa, Y.; Yoshida, M.

2002-01-01

Complete text of publication follows. The hyperbranched (HB) polymer-grafted (PG) carbon blacks (CB) have the possibility of utilizing as a support of catalyst and enzyme, and a curing agent of epoxy resin, because they have much terminal amino or hydroxyl groups. The postgrafting of crystalline polymer onto HB PG CB and the sensing of environmental pollutant by the conductive composite prepared from the polymer-postgrafted CB was discussed. The grafting of poly(amidoamide) onto CB surface was achieved by repeating either Michael addition of methyl acrylate to amino group on the surface or the amidation of the resulting terminal methyl ester group with ethylene diamine. HB polyester onto CB surface was grafted by stepwise growth of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) from surface carboxyl and hydroxyl groups on CB as a core in the presence of p-toluenesulfonic acid (p-TSA). The one-pot grafting of HB polyester onto CB as core was also achieved by the polycondensation of bis-MPA in the presence of p-TSA. Postgrafting of crystalline polymer onto HB polymer-grafted CB was achieved by the reaction of terminal amino or hydroxyl groups of grafted chain with COCl-terminated crystalline polymer. The electric resistance of the composite prepared from crystalline polymer-postgrafted CB was found to increase drastically in hexane, containing environmental pollutant, such as chloroform and trichloroethane, and returned immediately to the initial resistance when it was transferred into pure hexane. Based on the above results, it is concluded that the composite can be used as a novel sensor for environmental pollutant in solution

Droplet snap-off in fluids with nematic liquid crystalline ordering

International Nuclear Information System (INIS)

Verhoeff, A A; Lekkerkerker, H N W

2012-01-01

We studied the snap-off of nematic liquid crystalline droplets originating from the Rayleigh-Taylor instability at the isotropic-nematic interface in suspensions of charged gibbsite in water and sterically stabilized gibbsite in bromotoluene. We found that droplet snap-off strongly depends on the director field structure inside the thinning neck, which is determined by the ratio of the splay elastic constant and the anchoring strength of the nematic phase to the droplet interface relative to the thickness of the thinning neck. If anchoring is weak, which is the case for aqueous gibbsite, this ratio is comparable to the thickness of the breaking thread. As a result, the thinning neck and pending drop have a uniform director field and droplet snap-off is determined by the viscous properties of the liquid crystal as well as by thermal fluctuations of the interface. On the other hand, in sterically stabilized gibbsite where anchoring is strong, this ratio is significantly smaller than the neck thickness. In this case, the neck has an escaped radial director field and the neck thinning is retarded close to snap-off due to a topological energy barrier involved in the separation of the droplet from the thread. (paper)

Alignment engineering in liquid crystalline elastomers: Free-form microstructures with multiple functionalities

Energy Technology Data Exchange (ETDEWEB)

Zeng, Hao; Cerretti, Giacomo; Wiersma, Diederik S., E-mail: camilla.parmeggiani@lens.unifi.it, E-mail: wiersma@lens.unifi.it [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Wasylczyk, Piotr [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Faculty of Physics, Institute of Experimental Physics, University of Warsaw, ul. Hoza 69, Warszawa 00-681 (Poland); Martella, Daniele [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Chimica “Ugo Schiff,” University of Florence, via della Lastruccia 3-13, 50019 Sesto Fiorentino (Italy); Parmeggiani, Camilla, E-mail: camilla.parmeggiani@lens.unifi.it, E-mail: wiersma@lens.unifi.it [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); CNR-INO, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy)

2015-03-16

We report a method to fabricate polymer microstructures with local control over the molecular orientation. Alignment control is achieved on molecular level in a structure of arbitrary form that can be from 1 to 100 μm in size, by fixing the local boundary conditions with micro-grating patterns. The method makes use of two-photon polymerization (Direct Laser Writing) and is demonstrated specifically in liquid-crystalline elastomers. This concept allows for the realization of free-form polymeric structures with multiple functionalities which are not possible to realize with existing techniques and which can be locally controlled by light in the micrometer scale.

Isohexide and Sorbitol-Derived, Enzymatically Synthesized Renewable Polyesters with Enhanced Tg.

Science.gov (United States)

Gustini, Liliana; Lavilla, Cristina; de Ilarduya, Antxon Martínez; Muñoz-Guerra, Sebastián; Koning, Cor E

2016-10-10

Sugar-based polyesters derived from sorbitol and isohexides were obtained via solvent-free enzymatic catalysis. Pendant hydroxyl groups, coming from the sorbitol units, were present along the polyester backbone, whereas the two isohexides, namely, isomannide and isoidide dimethyl ester monomers, were selected to introduce rigidity into the polyester chains. The feasibility of incorporating isomannide as a diol compared to the isoidide dimethyl ester as acyl-donor via lipase-catalyzed polycondensation was investigated. The presence of bicyclic units resulted in enhanced T g with respect to the parent sorbitol-containing polyester lacking isohexides. The different capability of the two isohexides to boost the thermal properties confirmed the more flexible character provided by the isoidide diester derivative. Solvent-borne coatings were prepared by cross-linking the sugar-based polyester polyols with polyisocyanates. The increased rigidity of the obtained sugar-based polyester polyols led to an enhancement in hardness of the resulting coatings.

Aliphatic polyesters for medical imaging and theranostic applications.

Science.gov (United States)

Nottelet, Benjamin; Darcos, Vincent; Coudane, Jean

2015-11-01

Medical imaging is a cornerstone of modern medicine. In that context the development of innovative imaging systems combining biomaterials and contrast agents (CAs)/imaging probes (IPs) for improved diagnostic and theranostic applications focuses intense research efforts. In particular, the classical aliphatic (co)polyesters poly(lactide) (PLA), poly(lactide-co-glycolide) (PLGA) and poly(ɛ-caprolactone) (PCL), attract much attention due to their long track record in the medical field. This review aims therefore at providing a state-of-the-art of polyester-based imaging systems. In a first section a rapid description of the various imaging modalities, including magnetic resonance imaging (MRI), optical imaging, computed tomography (CT), ultrasound (US) and radionuclide imaging (SPECT, PET) will be given. Then, the two main strategies used to combine the CAs/IPs and the polyesters will be discussed. In more detail we will first present the strategies relying on CAs/IPs encapsulation in nanoparticles, micelles, dendrimers or capsules. We will then present chemical modifications of polyesters backbones and/or polyester surfaces to yield macromolecular imaging agents. Finally, opportunities offered by these innovative systems will be illustrated with some recent examples in the fields of cell labeling, diagnostic or theranostic applications and medical devices. Copyright © 2015 Elsevier B.V. All rights reserved.

Photoorientation of a liquid crystalline polyester with azobenzene side groups

DEFF Research Database (Denmark)

Zebger, I; Rutloh, M; Hoffmann, U

2002-01-01

segments in the side- and main-chain. The very high values of the normalized linear dichroism up to 0.8 and the birefringence (above 0.3) are due to the interaction of photoorientation and thermotropic self-organization. The induction of anisotropy shows a pronounced dependence on the power density...

The effect of glassfibre, graphite and MoS2 on the tribological performance of a liquid crystalline polymer

NARCIS (Netherlands)

Dufour, P.R.; de Gee, A.W.J.; Kingma, J.A.; Mens, J.W.M.

1992-01-01

A thermotropic liquid crystalline polymer (LCP) with a high melting point of approximately 400 °C, unfilled and filled with glassfibre, MoS2 or graphitic carbon was tested in dry sliding contact with steel. Three different test methods were applied, i.e. measurement of coefficient of friction and

Influence of Carbon Nano Tubes on the Thermo-Mechanical Properties of Unsaturated Polyester Nanocomposite

International Nuclear Information System (INIS)

Alam, A K M Moshiul; Beg, M D H; Yunus, Rosli Mohd

2015-01-01

To date nano fillers are renowned reinforcing agent for polymer materials. In this work, unsaturated polyester (UPR) nanocomposites were fabricated by 0.1, 0.3 and 0.5 wt% multi walled carbon nanotubes (MWCNTs) through solution dispersion and casting method. The influence of MWCNT content was investigated by thermo-mechanical properties. Dispersion of nanotubes was observed by fracture morphology. The strength of nanocomposites rose with raising the CNT content. Moreover, DSC thermograms of nanocomposites represent noticeable improvement of glass transition temperature (T g ), melting temperature (T m ) and enthalpy (ΔH m ). Micro-crystallinity of nanocomposites increased with increasing the CNT content. Moreover, the stiffness increased with increasing the CNT content. (paper)

Influence of structures of polymer backbones on cooperative photoreorientation behavior of p-cyanoazobenzene side chains

DEFF Research Database (Denmark)

Han, Mina; Kidowaki, Masatoshi; Ichimura, Kunihiro

2001-01-01

Photoinduced orientational behavior of a polymethacrylate (CN6) and a polyester (p6a12) with p-cyanoazobenzene side chains was studied to reveal the structural effect of the liquid crystalline polymer backbones. Irradiation with linearly polarized W light resulted in the reorientation of the azob...

Carboxylated Polyurethanes Containing Hyperbranched Polyester Soft Segments

Directory of Open Access Journals (Sweden)

Žigon, M.

2006-09-01

Full Text Available hyperbranched polyester soft segments (HB PU with functional carboxylic groups in order to enable the preparation of stable HB PU dispersions. Carboxylated hyperbranched polyurethanes were synthesized using a hyperbranched polyester based on 2,2-bis(methylolpropionic acid of the fourth pseudo-generation (Boltorn H40 and hexamethylene (HDI or isophorone diisocyanate (IPDI. The reactivity of hyperbranched polyester with HDI was lower than expected, possibly due to the presence of less reactive hydroxyl groups in the linear repeat units. A gel was formed at mole ratios rNCO/OH = 1:2 or 1:4. The synthesis of HB PU was performed with partly esterified hyperbranched polyester with lowered hydroxyl functionality. The carboxyl groups were incorporated in the HB PU backbone by reaction of residual hydroxyl groups with cis-1,2-cyclohexanedicarboxylic anhydride. HB PU aqueous dispersions were stable at least for two months, although their films were brittle. The tensile strength and Young's modulus of blends of linear and HB PU decreased with increasing content of HB PU whereas elongation at break remained nearly constant, which was explained in terms of looser chain packing due to more open tree-like hyperbranched structures.

Mean-field theory of photoinduced molecular reorientation in azobenzene liquid crystalline side-chain polymers

DEFF Research Database (Denmark)

Pedersen, T.G.; Johansen, P.M.

1997-01-01

. The theory provides an explanation for the high long-term stability of the photoinduced anisotropy as well as a theoretical prediction of the temporal behavior of photoinduced birefringence. The theoretical results agree favorably with measurements in the entire range of writing intensities used......A novel mean-field theory of photoinduced reorientation and optical anisotropy in liquid crystalline side-chain polymers is presented and compared with experiments, The reorientation mechanism is based on photoinduced trans cis isomerization and a multidomain model of the material is introduced...

Hyperbranched polyester polyol plasticized tapioca starch/low density polyethylene blends

Energy Technology Data Exchange (ETDEWEB)

Guzman, Manuel; Giraldo, Diego; Murillo, Edwin, E-mail: edwinalbertomurillo@gmail.com [Universidad de Antioquia, Medellin (Colombia); Universidad Francisco de Paula Santander, San Jose de Cucuta (Colombia)

2017-01-15

n this work, low density polyethylene (LDPE)/plasticised starch (TPS) blends were prepared. The TPS employed in this study was obtained by plasticization of tapioca starch with a hyperbranched polyester polyol. Differential scanning calorimetry analysis showed that the melting temperature increased with the TPS content. The opposite effect was exhibited in the crystallization temperature and additional changes were not observed during the heating. X-ray diffraction analysis showed a reduction in intensity of the peak at Bragg’s angle 17.5°, proving a diminution on A type crystallinity with the increasing amount of LDPE. Micrographs obtained by scanning electron microscopy exhibited starch granules without destructure. TPS acted as a filler to LDPE, since the mechanical properties (Young's modulus and tensile strength) improved ostensibly. The Young' modulus and tensile strength decreased with the amount of LDPE, however, the elongation at break exhibited an opposite behavior. (author)

Hyperbranched polyester polyol plasticized tapioca starch/low density polyethylene blends

Directory of Open Access Journals (Sweden)

Manuel Guzmán

Full Text Available Abstract In this work, low density polyethylene (LDPE/plasticized starch (TPS blends were prepared. The TPS employed in this study was obtained by plasticization of tapioca starch with a hyperbranched polyester polyol. Differential scanning calorimetry analysis showed that the melting temperature increased with the TPS content. The opposite effect was exhibited in the crystallization temperature and additional changes were not observed during the heating. X-ray diffraction analysis showed a reduction in intensity of the peak at Bragg’s angle 17.5°, proving a diminution on A type crystallinity with the increasing amount of LDPE. Micrographs obtained by scanning electron microscopy exhibited starch granules without destructure. TPS acted as a filler to LDPE, since the mechanical properties (Young’s modulus and tensile strength improved ostensibly. The Young’ modulus and tensile strength decreased with the amount of LDPE, however, the elongation at break exhibited an opposite behavior.

Hyperbranched polyester polyol plasticized tapioca starch/low density polyethylene blends

International Nuclear Information System (INIS)

Guzman, Manuel; Giraldo, Diego; Murillo, Edwin

2017-01-01

n this work, low density polyethylene (LDPE)/plasticised starch (TPS) blends were prepared. The TPS employed in this study was obtained by plasticization of tapioca starch with a hyperbranched polyester polyol. Differential scanning calorimetry analysis showed that the melting temperature increased with the TPS content. The opposite effect was exhibited in the crystallization temperature and additional changes were not observed during the heating. X-ray diffraction analysis showed a reduction in intensity of the peak at Bragg’s angle 17.5°, proving a diminution on A type crystallinity with the increasing amount of LDPE. Micrographs obtained by scanning electron microscopy exhibited starch granules without destructure. TPS acted as a filler to LDPE, since the mechanical properties (Young's modulus and tensile strength) improved ostensibly. The Young' modulus and tensile strength decreased with the amount of LDPE, however, the elongation at break exhibited an opposite behavior. (author)

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

KAUST Repository

Abdellah, Mohamed H.

2018-05-18

Utilization of sustainable and environmentally friendly solvents for the preparation of membranes has attracted growing interest in recent years. In this work, a polyester thin film composite solvent resistant nanofiltration (SRNF) membrane is prepared by interfacial polymerization on a cellulose support. The cellulose support is prepared by nonsolvent‐induced phase separation from a dope solution containing an ionic liquid as an environmentally friendly solvent (negligible vapor pressure). The polyester film is formed via the interfacial reaction between quercetin, a plant‐derived polyphenol, and terephthaloyl chloride. Alpha‐pinene is used as a green alternative solvent to dissolve terephthaloyl chloride (TPC) while quercetin is dissolved in a 0.2 m NaOH solution. The interfacial polymerization reaction is successfully confirmed by Fourier transform infrared and X‐ray photoelectron spectroscopy while scanning electron and atomic force microscopy are used to characterize the membrane structure. The composite membrane shows an outstanding performance with a molecular weight cut‐off around 330 Da combined with a dimethylformamide (DMF) permeance up to 2.8 L m−2 bar−1 h−1. The membrane is stable in strong aprotic solvents such as DMF offering potential application in the pharmaceutical and petrochemical industries.

Thermal, crystallinity and morphological studies of the filled RBD palm kernel oil polyurethane foam

International Nuclear Information System (INIS)

Khairiah Badri; Sahrim Ahmad; Sarani Zakaria

2000-01-01

The synthesis of RBD palm kernel oil (PKO) polyurethane polyol and the polyurethane foam has well been documented. However, less study has been put in discovering the thermal properties and crystallinity of the foam. It is also an initiative to investigate the effect of oil palm empty fruit bunch (EFB) and sorbitol as fillers in the polyurethane (PU) foam to these properties. Thermogravimetric (TGA) investigation of the PKO PU foam was performed to study their decompositions. The semi-crystalline nature of EFB-filled PU was confirmed by x-ray diffratogram and DSC thermogram of glass transition temperature, T g . The x-ray diffraction (XRD) study of the unfilled PU showed a broad amorphous halo, indicative of absence of crystallinity in the polymer, which has been explained as due to strong hydrogen bonding in the hard phase. Overall crystallinity decreases with an increase in the polyester content in agreement with the XRD results. The crystallinity however, increases with the inclusion of EFB in the polyurethane system. This study was followed by the observation of the surface morphologies of the PKO PU foam with and without fillers. The scanning electron micrographs verified the finding on the improved k-factor values. (Author)

Air-drying paint compositions comprising carbohydrate-based polyesters and polyester preparation

NARCIS (Netherlands)

Oostveen, E.A.; Weijnen, J.; Haveren, van J.; Gillard, M.

2003-01-01

The invention relates to a polyester obtainable by transesterification or interesterification of:(i) a carbohydrate or an acyl ester thereof, (ii) an alkyl ester of a drying fatty acid, semi-drying fatty acid or mixture thereof; and (iii) an alkyl ester of a non aromatic polycarboxylic acid. The

Holographic memories

DEFF Research Database (Denmark)

Ramanujam, P.S.; Berg, R.H.; Hvilsted, Søren

1999-01-01

A Two-dimensional holographic memory for archival storage is described. Assuming a coherent transfer function, an A4 page can be stored at high resolution in an area of 1 mm(2). Recently developed side-chain liquid crystalline azobenzene polyesters are found to be suitable media for holographic...

LIQUID CRYSTALLINE BEHAVIOR OF HYDROXYPROPYL CELLULOSE ESTERIFIED WITH 4-ALKOXYBENZOIC ACID.

Directory of Open Access Journals (Sweden)

Yehia Fahmy

2010-07-01

Full Text Available A series of 4- alkyoxybenzoyloxypropyl cellulose (ABPC-n samples was synthesized via the esterification of hydroxypropyl cellulose (HPC with 4-alkoxybenzoic acid bearing different numbers of carbon atoms. The molecular structure of the ABPC-n was confirmed by Fourier transform infrared (FT-IR spectroscopy and 1H NMR spectroscopy. The liquid crystalline (LC phases and transitions behaviors were investigated using differential scanning calorimetry (DSC, polarized light microscopy (PLM, and refractometry. It was found that the glass transition (Tg and clearing (Tc temperatures decrease with increase of the alkoxy chain length. It was observed that the derivatives with an odd number of carbon atoms are non-mesomorphic. This series of ABPC-n polymers exhibit characteristic features of cholesteric LC phases between their glass transition and isotropization temperatures.

Magnetic Field Alignment of PS-P4VP: a Non-Liquid Crystalline Coil-Coil Block Copolymer

Science.gov (United States)

Rokhlenko, Yekaterina; Zhang, Kai; Larson, Steven; Gopalan, Padma; O'Hern, Corey; Osuji, Chinedum

2015-03-01

Magnetic fields provide the ability to control alignment of self-assembled soft materials such as block copolymers. Most prior work in this area has relied on the presence of ordered assemblies of anisotropic liquid crystalline species to ensure sufficient magnetic anisotropy to drive alignment. Recent experiments with poly(styrene-b-4-vinylpyridine), a non-liquid crystalline BCP, however, show field-induced alignment of a lamellar microstructure during cooling across the order-disorder transition. Using in situ x-ray scattering, we examine the roles of field strength and cooling rate on the alignment response of this low MW coil-coil BCP. Alignment is first observed at field strengths as low as 1 Tesla and improves markedly with both increasing field strength and slower cooling. We present a geometric argument to illustrate the origin of a finite, non-trivial magnetic susceptibility anisotropy for highly stretched surface-tethered polymer chains and corroborate this using coarse-grained molecular dynamics simulations. We rationalize the magnetic field response of the system in terms of the mobility afforded by the absence of entanglements, the intrinsic anisotropy resulting from the stretched polymer chains and sterically constrained conjugated rings, and the large grain size in these low molecular weight materials.

Degradation of microbial polyesters.

Science.gov (United States)

Tokiwa, Yutaka; Calabia, Buenaventurada P

2004-08-01

Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

Procedure for the fabrication of a cross-linked polyester material

International Nuclear Information System (INIS)

D'Alelio, G.F.

1972-01-01

The procedures are described for the production of a cross-linked polyester material by means of the irradiation of a radiosensitive polyester with a dose of over 0.5 megarad and under 8 megarads high energy, ionising radiation, corresponding to at least 100,000 ev. The polyester is of the telomerised diacrylpolyester type, and may be in a mixture containing about 1% of a coplymerisable aliphatic monomer, or about 30-90% of an unsaturated aliphatic alkyd resin. (JIW)

Active Mesogenic Droplets: Impact of Liquid Crystallinity and Collective Behavior

Science.gov (United States)

Bahr, Christian

Droplets of common mesogenic compounds show a self-propelled motion when immersed in aqueous solutions containing ionic surfactants at concentrations well above the critical micelle concentration. After introducing some general properties of this type of artificial microswimmer, we focus on two topics: the influence of liquid crystallinity on the swimming behavior and the collective behavior of ensembles of a larger number of droplets. The mesogenic properties are not essential for the basic mechanism of self-propulsion, nevertheless they considerably influence the swimming behavior of the droplets. For instance, the shape of the trajectories strongly depends on whether the droplets are in the nematic or isotropic state. The droplet swimmers are also ideally suited for the study of collective behavior: Microfluidics enables the generation of large numbers of identical swimmers and we can tune their buoyancy. We report on the collective behavior in three-dimensional environments. Supported by the Deutsche Forschungsgemeinschaft (SPP 1726 ``Microswimmers'').

On the “Tertiary Structure” of Poly-Carbenes; Self-Assembly of sp3-Carbon-Based Polymers into Liquid-Crystalline Aggregates

NARCIS (Netherlands)

Franssen, N.G.M.; Ensing, B.; Hegde, M.; Dingemans, T.J.; Norder, B.; Picken, S.J.; Alberda van Ekenstein, G.O.R.; van Eck, E.R.H.; Elemans, J.A.A.W; Vis, M.; Reek, J.N.H.; de Bruin, B.

2013-01-01

The self-assembly of poly(ethylidene acetate) (st-PEA) into van der Waals-stabilized liquid-crystalline (LC) aggregates is reported. The LC behavior of these materials is unexpected, and unusual for flexible sp(3)-carbon backbone polymers. Although the dense packing of polar ester functionalities

Radiation flame proofing of polyester/cotton blends

International Nuclear Information System (INIS)

Liepins, R.; Surles, J.R.; Morosoff, N.; Stannett, V.T.; Barker, R.H.

1977-01-01

Methodology has been developed for the grafting of vinyl functional organobromide and organophosphorus compounds on polyester fibers and 50/50 PET/cotton fabric. Procedures were developed for localized grafting of vinyl bromide (VBr) and diethylvinylphosphonate (DEVP) upon PET fibers. Oxygen index was used to evaluate the effect of the location of VBr and DEVP within the filament upon their flame retardance efficiencies. For the various bromine homopolymer grafts the apparent thermal stability of the graft and its flame retardance efficiency may be related to the alpha aliphatic hydrogen to bromine ratio. Using results from the polyester studies, techniques were devised for the treatment of 50/50 polyester/ cotton fabrics. Both homopolymer and copolymer grafts were evaluated but the greatest degree of success was attained using mixtures of phosphorus and bromine containing monomers. The results of these studies will be reviewed and their implications for development as commercial textile treatments discussed. (author)

Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

Directory of Open Access Journals (Sweden)

Hiep Dinh Nguyen

2016-10-01

Full Text Available A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA were polymerized using an immobilized Candida antarctica lipase B (CALB and the potential for an enzymatic synthesis of alkyds was investigated. The developed method enables the use of both glycerol and also pentaerythritol (for the first time as the alcohol source and was found to be very robust. This allows simple variations in the molar mass and structure of the polyester without premature gelation, thus enabling easy tailoring of the branched polyester structure. The postpolymerization crosslinking of the polyesters illustrates their potential as binders in alkyds. The formed films had good UV stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition.

Sandwich-cell-type bulk-heterojunction organic solar cells utilizing liquid crystalline phthalocyanine

Science.gov (United States)

Nakata, Yuya; Usui, Toshiki; Nishikawa, Yuki; Nekelson, Fabien; Shimizu, Yo; Fujii, Akihiko; Ozaki, Masanori

2018-03-01

Sandwich-cell-type bulk-heterojunction organic solar cells utilizing the liquid crystalline phthalocyanine, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2), have been fabricated and their photovoltaic properties have been studied. The short-circuit current (J SC) and power conversion efficiency (PCE) depended on the blend ratio of donor and acceptor molecules, and the maximum performance, such as J SC of 3.4 mA/cm2 and PCE of 0.67%, was demonstrated, when the blend ratio of the acceptor was 10 mol %. The photovoltaic properties were discussed by taking the relationship between the column axis direction of C6PcH2 and the carrier mobility in the active layer into consideration.

Synthesis and Properties of Some polyurethane/ Partially Aromatic Polyester Casting Samples

International Nuclear Information System (INIS)

Sadek, E.M.; Mazroua, A.M.; Emam, A.S.; Motawie, A.M.

2005-01-01

A series of partially aromatic terephthalate polyesters were synthesized by melt transesterification of dimethyl terephthalate with various types of aliphatic diol compounds in 1:1.1 molar ratio. Ethylene-, di-, tri-, tetra ethylene glycol and polyethylene glycol with different molecular weights 1000, 4000, 6000 as well as the prepared dihydroxy natural rubber were used. Another series of partially aromatic adipate and sebacate polyesters based on the prepared bisphenol A and its tetrabromo derivative were also synthesized by direct polycondensation esterification with adipic and sebacic acid. Polyurethane with NCO/OH ratio equal 4 was prepared from the reaction of 2,4 toluene diisocyanate with polyethylene glycol 1000. The prepared polyurethane was mixed with different weight percentages (2, 4, 6, 8, 10 or 12 % w/w) of the prepared partially aromatic polyesters to give polyurethane/polyester compositions. Mechanical and electrical properties as well as water and chemical resistance of the prepared film samples with thickness 3-4 mm were determined and compared with those of polyurethane film sample without polyester. The data indicate that 10 % w/w of the added partially aromatic polyester increases polyurethane tensile strength, improves its insulation properties and hydrolytic stability as well as its chemical resistance. Film samples based on bisphenol A impart excellent properties as compared with those based on aliphatic glycol species and dihydroxy natural rubber. Keywords: Partially aromatic polyesters, Dimethyl terephthalate, Glycols, Bisphenol A, Tetrabromo bisphenol A, Natural rubber, Adipic acid, Sebacic acid, Polyurethane, Casting

Process for the production of a dianhydrohexitol based polyester

NARCIS (Netherlands)

2008-01-01

Process for the production of a polyester by the polycondensation of a mixture comprising isoidide, and a dicarboxylic acid or dicarboxylic acid anhydride, wherein the reaction is performed in the melt of the monomers and wherein these monomers are not activated. The polyesters based on one or more

Synthesis, properties and applications of biodegradable polymers derived from diols and dicarboxylic acids: from polyesters to poly(ester amide)s.

Science.gov (United States)

Díaz, Angélica; Katsarava, Ramaz; Puiggalí, Jordi

2014-04-25

Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology

Energy Technology Data Exchange (ETDEWEB)

Yang Xiaoyi, E-mail: yangxiaoyi@buaa.edu.cn [Department of Thermal Energy Engineering, BeiHang University, Beijing 100191 (China)

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology

International Nuclear Information System (INIS)

Yang Xiaoyi

2009-01-01

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology.

Science.gov (United States)

Yang, Xiaoyi

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Wettability and Impact Performance of Wood Veneer/Polyester Composites

Directory of Open Access Journals (Sweden)

Shayesteh Haghdan

2015-07-01

Full Text Available Fiber-reinforced thermosetting composites have been of interest since the 1940s due to their ease of use in processing, fast curing times, and high specific stiffness and strength. While the use of plant fibers in a polyester matrix has been thoroughly studied, only limited information is available regarding using wood as reinforcement. In this study, composites of thin wood veneer and a polyester matrix were made and the difficulties in the lamination and curing processes were investigated. Sheets of Douglas fir, maple, and oak veneers using a catalyzed polyester resin were assembled as unidirectional, balanced, and unbalanced cross-ply laminates. These were compared to control specimens using glass fiber as reinforcement. The impact properties of the samples, with respect to the laminate thicknesses, were characterized using a drop-weight impact tester. The wettability and surface roughness of unsanded and sanded wood veneers were also investigated. Results showed that Douglas fir cross-ply laminates had an impact energy equivalent to glass fiber laminates, making them an interesting alternative to synthetic fiber composites. Wood/polyester laminates absorbed a considerable amount of energy through a higher number of fracture modes. The balanced lay-up limited twisting of the wood/polyester composites. The lowest contact angle and highest wettability were observed in unsanded Douglas fir veneers.

Polyester polymer concrete overlay.

Science.gov (United States)

2013-01-01

Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

Assessment of the radiation resistance of some aromatic polyesters

International Nuclear Information System (INIS)

Choi, E.J.; Hill, D.J.T.; Kim, K.Y.

1998-01-01

Full text: For many applications, polyesters have more useful properties than vinyl polymers, and they can be degraded to their monomer components and recycled. In addition, aromatic polyesters are known to display a resistance to high temperatures and high-energy ionizing radiation. Recently, we have reported the γ-radiolysis for some aromatic polyesters at low radiation dose; The G-values of radical formation at 77 K were determined to be in the range 0.38∼0.46 for the polyesters of bisphenol A with fluorine substitution at isopropylidene units and in the range 0.71∼1.18 for the polyesters of halogenated bisphenol A with decamethylene segments. While the radiation sensitivities of the latter polymers were dependent on the position and content of halogen substitution, those of the former polymers were slightly dependent on these factors as assessed by the G-values at 77 K. We also have studied the radiolysis of the commercial aromatic polyesters (UP) and polycarbonate (PC). UP has been found to be more radiation stable than PC with respect to the total yield of radicals formed. The G-values for radical formation at 77K was determined to be 0.31 and 0.5 for UP and PC, respectively. In this work, we have prepared poly(ethylene-, butylene- or decalene-terephthalate)s (PET, PBT or PDT) and poly(ethylene-, buthylene- or decalene-2,6-naphthalenedicarboxylate)s (PEN, PBN or PDN) by standard melt polymerization methods, and have examined their γ-radiolysis at 77 K or room temperature, and in vacuum or air, through the applications of ESR spectroscopy and thermal analysis. Inherent viscosities of the polyesters used for the radiation studies were in the range of 0.16∼0.69 dL/g. The values of G(R) indicates that PEN-related polymers have more radiation stable than PET-related polymers and the E, B and D order is one of decreasing stability as one might expect. The significant decrease in the G(R)-values of the polyester being in the range of 0.1∼0.41 at 77 K by

Synthesis and degradation kinetics of a novel polyester containing bithiazole rings

Energy Technology Data Exchange (ETDEWEB)

He, W., E-mail: hwdut2003@yahoo.com [Research Center of Plastic Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); State Key Laboratory of Robotics (China); Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Jiang, Y.Y. [Research Center of Plastic Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); State Key Laboratory of Robotics (China); Luyt, A.S. [Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Ocaya, R.O. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Ge, T.J. [Research Center of Plastic Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); State Key Laboratory of Robotics (China)

2011-10-20

Highlights: {yields} A novel Schiff base type polyester was synthesized and characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction spectroscopy. {yields} Thermal degradation of the polyester in nitrogen has been studied at several heating rates by thermogravimetric analysis. {yields} The activation energies were calculated by different methods. And the possible conversation function was estimated. {yields} The life time estimates for the polyester can be determined and the results demonstrate that the polymer possesses good thermal resistance. - Abstract: A novel Schiff base type polyester containing 2,2'-diamino-4,4'-bithiazole (DABT) was prepared by low-temperature interface polycondensation of 1,4-benzenedicarbonyl dichloride with 4,4'-(4,4'-bithiazole-2,2'-diylbis(imine-2,1-diyl) diphenol (BDDP), which is derived from a 2,2'-diamino-4,4'-bithiazole (DABT) Schiff base reacted with a 4-hydroxybenzaldehyde monomer. The newly generated polyester was characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction spectroscopy. The thermal decomposition was investigated in nitrogen atmosphere using thermogravimetric analysis. The activation energies of the decomposition step of the polyester were calculated through the isoconversional methods of Kissinger-Akahira-Sunose (K-A-S) and the iterative equation. In order to estimate the reaction model that best describes the experimental data, the use of an empirical kinetic equation based on that proposed by Sestak-Berggren was investigated here. On the basis of the kinetic data, the life time estimates for the polyester generated from the weight loss of 5%, 10%, and 15% were also constructed.

Biobased functional polyesters for coating applications: Synthesis, characterization and application

NARCIS (Netherlands)

Noordover, B.A.J.; Duchateau, R.; Koning, C.E.; Benthem, van R.A.T.M.; Ming, W.; Haveren, van J.; Es, van D.S.

2007-01-01

Thermosetting coating systems contain polyesters as binders. A crucial property of these polymers is their functionality. During coating application, the polyesters are cross-linked in situ, which means that each polymer chain needs a sufficient no. of reactive end-groups. Renewable monomers are

Unravelling the distinct crystallinity and thermal properties of suberin compounds from Quercus suber and Betula pendula outer barks.

Science.gov (United States)

Sousa, Andreia F; Gandini, Alessandro; Caetano, Ana; Maria, Teresa M R; Freire, Carmen S R; Neto, Carlos Pascoal; Silvestre, Armando J D

2016-12-01

The main purpose of this study was to investigate the potential of suberin (a naturally occurring aromatic-aliphatic polyester ubiquitous to the vegetable realm) as a renewable source of chemicals and, in particular, to assess their physical properties. A comparison between cork and birch suberin fragments obtained by conventional depolymerisation processes (hydrolysis or methanolysis) is provided, focusing essentially on their thermal and crystallinity properties. It was found that suberin fragments obtained by the hydrolysis depolymerisation of birch had a high degree of crystallinity, as indicated by their thermal analysis and corroborated by the corresponding XRD diffractions, as opposed to hydrolysis-depolymerised cork suberin counterparts, which were essentially amorphous. Copyright © 2016 Elsevier B.V. All rights reserved.

Physico-chemical studies of gamma-irradiated polyester. Impregnated cement mortar composite

International Nuclear Information System (INIS)

Ismail, M.R.; Afifi, M.S.

1998-01-01

The effect of impregnation time on the physico-chemical and mechanical properties of polyester-cement mortar composite has been investigated. The samples were soaked in unsaturated polyester resin containing 40% styrene monomer at impregnation times ranging from 1-15 hours and then exposed to 50 kGy of γ-irradiation. The effects on polymer loading, compressive strength, apparent porosity, and water absorption in addition to IR spectra and TGA of the samples were studied. It was found that, the polymer loading and compressive strength increase with the increased of soaking time up to 4 hours and there is no significant improvement of the polymer loading and strength. Whereas, the apparent porosity and water absorption behave in an opposite direction. These are attributed to the presence of polymer in the pores of the samples. IR spectra showed that, new bands appeared as result of the reaction between polyester and set cement. TGA showed that, the polyester cement composite has higher thermal stability as a compared to irradiated polyester. (author)

Oleic Acid Based Polyesters of Trimethylolpropane and Pentaerythritol for Bio lubricant Application

International Nuclear Information System (INIS)

Hamizah Ammarah Mahmud; Nadia Salih; Jumat Salimon

2015-01-01

The production of polyesters based on oleic acid and trimethylolpropane (TMP) or pentaerythritol (PE) as potential bio lubricant were carried out. The esterification processes between oleic acid with TMP or PE were carried out using sulfuric acid as a catalyst. The esterification process produced high yield between 92 %-94 % w/w respectively. The formation of polyesters was confirmed using gas chromatography (GC-FID), Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The polyesters were analyzed for basic lubrication physicochemical properties. The results showed that polyesters of both TMP and PE having high viscosity index between 200-309, good pour points ranging from -42 to -59 degree Celsius and high flash points of 280 - 300 degree Celsius respectively. The polyesters also showed good thermal oxidative stability with TGA onset temperatures above 180 degree Celsius. In general both products are plausible to be used as bio lubricant for industrial application. (author)

New theories for smectic and nematic liquid-crystal polymers: Backbone LCPs [liquid crystalline polymers] and their mixtures and side-chain LCPs

International Nuclear Information System (INIS)

Dowell, F.

1987-01-01

A summary of predictions and explanations from statistical-physics theories for both backbone and side-chain liquid crystalline polymers (LCPs) and for mixtures with backbone LCPs are presented. Trends in the thermodynamic and molecular ordering properties have been calculated as a function of pressure, density, temperature, and molecule chemical structures (including degree of polymerization and the following properties of the chemical structures of the repeat units: lengths and shapes, intra-chain rotation energies, dipole moments, site-site polarizabilities and Lennard-Jones potentials, etc.) in nematic and multiple smectic-A LC phases and in the isotropic liquid phase. The theoretical results are found to be in good agreement with existing experimental data. These theories can also be applied to combined LCPs. Since these theories have no ad hoc or arbitrarily adjustable parameters, these theories can be used to design new LCPs and new solvents as well as to predict and explain properties. 27 refs., 4 tabs

Life-cycle assessment of textiles manufacture of polyester shirt (VB)

DEFF Research Database (Denmark)

Othman, Samer; Peter, Oduro Justice; Hassan, Osama

1998-01-01

According to the EDIP (Environmental Design of Industrial Products), It is made possible to perform resource and environmental profile analysis of the 100% polyester shirt. In order to understand the true life-cycle consequences, life-cycle analysis of a typical 100% polyester shirt was carried out...

Probing the Texture of the Calamitic Liquid Crystalline Dimer of 4-(4-Pentenyloxybenzoic Acid

Directory of Open Access Journals (Sweden)

Maher A. Qaddoura

2010-01-01

Full Text Available The liquid crystalline dimer of 4-(4-pentenyloxybenzoic acid, a member of the n-alkoxybenzoic acid homologous series, was synthesized using potassium carbonate supported on alumina as catalyst. The acid dimer complex exhibited three mesophases; identified as nematic, smectic X1 and smectic X2. Phase transition temperatures and the corresponding enthalpies were recorded using differential scanning calorimetry upon both heating and cooling. The mesophases were identified by detailed texture observations by variable temperature polarized light microscopy. The nematic phase was distinguished by a fluid Schlieren texture and defect points (four and two brushes while the smectic phases were distinguished by rigid marble and mosaic textures, respectively.

Corrosion Protection Performance of Polyester-Melamine Coating with Natural Wood Fiber Using EIS Analysis

Energy Technology Data Exchange (ETDEWEB)

Shin, PyongHwa; Shon, MinYoung [Pukyong National University, Busan (Korea, Republic of); Jo, DuHwan [POSCO, Gwangyang (Korea, Republic of)

2016-04-15

In the present study, polyester-melamine coating systems with natural wood fiber (NWF) were prepared and the effects of NWF on the corrosion protectiveness of the polyester-melamine coating were examined using EIS analysis. From the results, higher average surface roughness was observed with increase of NWF content. Water diffusivity and water uptake into the polyester-melamine coatings with NWF were much higher than that into the pure polyester-melamine coating. The decrease in the impedance modulus |Z| was associated with the localized corrosion on carbon steel, confirming that corrosion protection of the polyester-melamine coatings with NWF well agrees with its water transport behavior.

Effect of doxorubicin on the order and dynamics of the acyl chains of anionic and zwitterionic phospholipids in liquid-crystalline mixed model membranes

NARCIS (Netherlands)

Wolf, de F.A.; Nicolaij, K.; Kruijff, de B.

1992-01-01

We investigated the effect of the antineoplastic drug doxorubicin on the order of the acyl chains in liquid-crystalline mixed bilayers consisting of dioleoylphosphatidylserine (DOPS) or -phosphatidic acid (DOPA), and dioleoylphosphatidylcholine (DOPC) or - hosphatidylethanolamine (DOPE). Previous

Obtaining polyester from glycerin for synthesis of polyurethanes

International Nuclear Information System (INIS)

Breves, Rodolfo A.; Ghesti, Grace F.; Sales, Maria J.A.

2014-01-01

The use of renewable resources has been increasing, due to the development of materials that have viable applications that are environmentally friendly. In this paper, a polyester was synthesized from glycerin, with the addition of adipic acid in a molar ratio of 1: 1.5, with dilauryl tin catalyst, which was added in proportions of 1 to 3% obtained PUs from castor oil (Ricinus communis) and MDI (diphenyl methane diisocyanate). The materials were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance "1H NMR, thermogravimetry (TG) and derivative thermogravimetry (DTG). The reaction for obtaining the polyester was confirmed by FTIR, the absorption band between 1708-1730 cm"-"1 and "1H NMR, in the region 1.4 to 1.8 ppm and 2.2 to 2.6 ppm. The thermal decomposition of polyester occurred with temperature above 300 ° C. PUs showed similar thermal stability. (author)

Some problems of the statistical theory of polymeric lyotropic liquid crystals

International Nuclear Information System (INIS)

Grosberg, A.Yu.; Khokhlov, A.R.

1980-06-01

In this article we consider some topics of the statistical physics of liquid-crystalline phase in the solutions of stiff chain macromolecules. Among these topics are: the problem of the phase diagram for the liquid-crystalline transition in the solutions of completely stiff macromolecules (rigid rods); conditions of formation of the liquid-crystalline phase in the solutions of semiflexible macromolecules; possibility of the intramolecular liquid-crystalline ordering in semiflexible macromolecules; structure of intramolecular liquid crystals and dependence of the properties of the liquid-crystalline phase on the microstructure of the polymer chain. (author)

Hyperbranched polyester polyol modified with polylactic acid as a compatibilizer for plasticized tapioca starch/polylactic acid blends

Directory of Open Access Journals (Sweden)

Ricardo Mesias

2018-03-01

Full Text Available Abstract A hyperbranched polyester polyol of the second generation (HBP2 was modified with polylactic acid (HBP2-g-PLA and employed as a compatibilizer for plasticized tapioca starch (TPS/polylactic acid (PLA blends. The effect of the compatibilizer HBP2- g-PLA was evaluated in comparison to the control sample (TPS/PLA blend without HBP2-g-PLA. The torque value of the TPS/PLA blends with HBP2- g-PLA was lower than that of the control sample, while thermal stability and crystallinity followed opposite behavior. The glass transition temperature (Tg and degree of crystallinity of the TPS/PLA blends with HBP2-g-PLA decreased with increasing mass fraction of HBP2-g-PLA. By scanning electron microscopy (SEM, it was observed that the morphology of the TPS/PLA blends with HBP2-g -PLA was more homogeneous than that of the control sample, confirming that HBP2- g-PLA acted as a compatibilizer and plasticizing agent to the TPS/PLA blends. Rheological analysis of the compatibilized TPS/PLA blends indicated the presence of microstructure.

Radiation cured polyester compositions containing metal-properties

Science.gov (United States)

Szalińska, H.; Pietrzak, M.; Gonerski, A.

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them.

Radiation cured polyester compositions containing metal-properties

International Nuclear Information System (INIS)

Szalinska, H.; Pietrzak, M.; Gonerski, A.

1987-01-01

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60 Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them. (author)

Mesomorphous versus traces of crystallinity: The itraconazole example

Energy Technology Data Exchange (ETDEWEB)

Atassi, Faraj, E-mail: fatassi@yahoo.com; Behme, Robert J.; Patel, Phenil J.

2013-12-20

Highlights: • Characterizing partially disordered pharmaceuticals is very challenging due to the fact that more than one discrete disordered phase can be present. • Dynamic mechanical analysis and dielectric analysis are extremely helpful in characterizing pharmaceutical mesophases (liquid crystals). • Thermotropic pharmaceutical mesophases, often mistaken as amorphous or partially crystalline, can show different phases of liquid crystallinity at different temperature. • Liquid crystalline pharmaceutical materials often show amorphous behavior along with other characteristics specific to mesomorphous materials. • The thermal and mechanical history of pharmaceutical disordered samples has a significant effect on their phase composition. - Abstract: Characterizing disordered pharmaceutical materials can be challenging, especially materials with partially disordered structures that lose one or two directional order (mesophases) and do not fit the traditional characterization categories of amorphous, crystalline or a combination of the two. Itraconazole, an antifungal agent, was chosen as a model compound that, when quench cooled, exhibits atypical disordered structure. Five different analytical tools were used to map out the molecular structure of this material and how it changes with changing temperature. X-ray diffraction showed some remnant crystallinity while dielectric analysis, dynamic mechanical analysis, DSC and hot stage microscopy gave more detailed molecular structure of the disordered material and explained all temperature related structural changes. The characterization of mesomorphous Itraconazole described here will help characterize a wide range of pharmaceuticals that exhibit thermotropic (temperature induced) mesomorphism at the molecular level.

Mesomorphous versus traces of crystallinity: The itraconazole example

International Nuclear Information System (INIS)

Atassi, Faraj; Behme, Robert J.; Patel, Phenil J.

2013-01-01

Highlights: • Characterizing partially disordered pharmaceuticals is very challenging due to the fact that more than one discrete disordered phase can be present. • Dynamic mechanical analysis and dielectric analysis are extremely helpful in characterizing pharmaceutical mesophases (liquid crystals). • Thermotropic pharmaceutical mesophases, often mistaken as amorphous or partially crystalline, can show different phases of liquid crystallinity at different temperature. • Liquid crystalline pharmaceutical materials often show amorphous behavior along with other characteristics specific to mesomorphous materials. • The thermal and mechanical history of pharmaceutical disordered samples has a significant effect on their phase composition. - Abstract: Characterizing disordered pharmaceutical materials can be challenging, especially materials with partially disordered structures that lose one or two directional order (mesophases) and do not fit the traditional characterization categories of amorphous, crystalline or a combination of the two. Itraconazole, an antifungal agent, was chosen as a model compound that, when quench cooled, exhibits atypical disordered structure. Five different analytical tools were used to map out the molecular structure of this material and how it changes with changing temperature. X-ray diffraction showed some remnant crystallinity while dielectric analysis, dynamic mechanical analysis, DSC and hot stage microscopy gave more detailed molecular structure of the disordered material and explained all temperature related structural changes. The characterization of mesomorphous Itraconazole described here will help characterize a wide range of pharmaceuticals that exhibit thermotropic (temperature induced) mesomorphism at the molecular level

Sustainable coatings from bio-based, enzymatically synthesized polyesters with enhanced functionalities

NARCIS (Netherlands)

Gustini, L.; Lavilla, C.; Finzel, L.; Noordover, B.A.J.; Hendrix, M.M.R.M.; Koning, C.E.

2016-01-01

Bio-based sorbitol-containing polyester polyols were synthesized via enzymatic polycondensation. The selectivity of the biocatalyst for primary vs. secondary hydroxyl groups allowed for the preparation of close to linear renewable polyester polyols with enhanced hydroxyl functionalities, both as

Self-assembled liquid crystalline nanoparticles as a novel ophthalmic delivery system for dexamethasone: Improving preocular retention and ocular bioavailability.

Science.gov (United States)

Gan, Li; Han, Shun; Shen, Jinqiu; Zhu, Jiabi; Zhu, Chunliu; Zhang, Xinxin; Gan, Yong

2010-08-30

The object of this study was to design novel self-assembled liquid crystalline nanoparticles (cubosomes) as an ophthalmic delivery system for dexamethasone (DEX) to improve its preocular retention and ocular bioavailability. DEX cubosome particles were produced by fragmenting a cubic crystalline phase of monoolein and water in the presence of stabilizer Poloxamer 407. Small angle X-ray diffraction (SAXR) profiles revealed its internal structure as Pn3m space group, indicating the diamond cubic phase. In vitro, the apparent permeability coefficient of DEX administered in cubosomes exhibited a 4.5-fold (F1) and 3.5-fold (F2) increase compared to that of Dex-Na phosphate eye drops. Preocular retention studies revealed that the retention of cubosomes was significantly longer than that of solution and carbopol gel, with AUC(0-->180min) of Rh B cubosomes being 2-3-fold higher than that of the other two formulations. In vivo pharmacokinetics in aqueous humor was evaluated by microdialysis, which indicated a 1.8-fold (F1) increase in AUC(0-->240min) of DEX administered in cubosomes relative to that of Dex-Na phosphate eye drops, with about an 8-fold increase compared to that of DEX suspension. Corneal cross-sections after incubation with DEX cubosomes demonstrated an unaffected corneal structure and tissue integrity, which indicated the good biocompatibility of DEX cubosomes. In conclusion, self-assembled liquid crystalline nanoparticles might represent a promising vehicle for effective ocular drug delivery. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Cubic liquid crystalline nanoparticles containing a polysaccharide from Ulva fasciata with potent antihyperlipidaemic activity

Directory of Open Access Journals (Sweden)

Azza A. Matloub

2018-02-01

Full Text Available The present study involves the preparation of cubic liquid crystalline nanoparticles (cubsomes for liver targeting to assess the potential of a formulated bioactive polysaccharide isolated from the hot aqueous extract of Ulva fasciata as an alternative natural agent with anti-hyperlipidaemic activity. Cubosomal nanoparticles were prepared by disrupting the cubic gel phase of the polysaccharide and water in the presence of a surfactant. Different lipid matrices and stabilizers were tested. All the formulations were in the nanosize range and showed sufficient negative charge to inhibit the aggregation of the cubosomes. Drug entrapment efficiencies (EEs% were determined and in vitro release studies were performed. Transmission electron microscopy (TEM and differential scanning calorimetry were used to analyze the loaded cubosomal nanoparticles containing glyceryl monostearate (GMO 2.25 g, poloxamer 407 (0.25 g and 50 mg of the polysaccharide. A preclinical study comparing the cubic liquid crystalline nanoparticles containing polysaccharide to fluvastatin as a reference drug in hyperlipidaemic rats was conducted. The rats treated with the polysaccharide- loaded cubosomes showed significant decreases in total cholesterol (TC, triglycerides (TG and total lipid (TL compared to the untreated HL rats. In addition, oxidative stress and antioxidant biomarkers were measured in the HL rats. Compared to the untreated HL rats, the cubosome treated rats showed a significant reduction in malondialdehyde (MDA, whereas insignificant changes were detected in nitric oxide (NO, glutathione (GSH levels and total antioxidant capacity (TAC. Further, vascular and intercellular adhesion molecules (VCAM, ICAM, and myeloperoxidase were demonstrated. A histopathological examination was conducted to study the alterations in histopathological lesions and to document the biochemical results. In conclusion, this study demonstrates the superiority of using a natural lipid

Reactive distillation: an attractive alternative for the synthesis of unsaturated polyester

NARCIS (Netherlands)

Shah, M.R.; Zondervan, E.; Oudshoorn, M.L.; Haan, de A.B.

2011-01-01

Unsaturated polyester is traditionally produced in a batch wise operating reaction vessel connected to a distillation unit. An attractive alternative for the synthesis of unsaturated polyester is a reactive distillation. To value such alternative synthesis route reliable process models need to be

Preparation and Characterization of Liquid Crystalline Polyurethane/Al2O3/Epoxy Resin Composites for Electronic Packaging

Directory of Open Access Journals (Sweden)

Shaorong Lu

2012-01-01

Full Text Available Liquid crystalline polyurethane (LCPU/Al2O3/epoxy resin composites were prepared by using LCPU as modifier. The mechanical properties, thermal stability, and electrical properties of the LCPU/Al2O3/epoxy resin composites were investigated systematically. The thermal oxidation analysis indicated that LCPU/Al2O3/epoxy resin composites can sustain higher thermal decomposition temperature. Meanwhile, coefficient of thermal expansion (CTE was also found to decrease with addition of LCPU and nano-Al2O3.

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles-The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

DEFF Research Database (Denmark)

Nilsson, Christa; Ostergaard, Jesper; Larsen, Susan Weng

2014-01-01

of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based...

Thermal Degradation Mechanism of a Thermostable Polyester Stabilized with an Open-Cage Oligomeric Silsesquioxane

Directory of Open Access Journals (Sweden)

Yolanda Bautista

2017-12-01

Full Text Available A polyester composite was prepared through the polymerization of an unsaturated ester resin with styrene and an open-cage oligomeric silsesquioxane with methacrylate groups. The effect of the open-cage oligomeric silsesquioxane on the thermal stability of the thermostable polyester was studied using both thermogravimetric analysis and differential thermal analysis. The results showed that the methacryl oligomeric silsesquioxane improved the thermal stability of the polyester. The decomposition mechanism of the polyester/oligomer silsesquioxane composite was proposed by Fourier transform infrared spectroscopy (FTIR analysis of the volatiles.

Poly(ester amide)s based on (L)-lactic acid oligomers and α-amino acids: influence of the α-amino acid side chain in the poly(ester amide)s properties.

Science.gov (United States)

Fonseca, Ana C; Coelho, Jorge F J; Valente, Joana F A; Correia, Tiago R; Correia, Ilídio J; Gil, Maria H; Simões, Pedro N

2013-01-01

Novel biodegradable and low cytotoxic poly(ester amide)s (PEAs) based on α-amino acids and (L)-lactic acid (L-LA) oligomers were successfully synthesized by interfacial polymerization. The chemical structure of the new polymers was confirmed by spectroscopic analyses. Further characterization suggests that the α-amino acid plays a critical role on the final properties of the PEA. L-phenylalanine provides PEAs with higher glass transition temperature, whereas glycine enhances the crystallinity. The hydrolytic degradation in PBS (pH = 7.4) at 37 °C also depends on the α-amino acid, being faster for glycine-based PEAs. The cytotoxic profiles using fibroblast human cells indicate that the PEAs did not elicit an acute cytotoxic effect. The strategy presented in this work opens the possibility of synthesizing biodegradable PEAs with low citotoxicity by an easy and fast method. It is worth to mention also that the properties of these materials can be fine-tuned only by changing the α-amino acid.

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

Directory of Open Access Journals (Sweden)

Joscha Vollmeyer

2014-04-01

Full Text Available A series of shape-persistent phenylene–ethynylene–naphthylene–butadiynylene macrocycles with different extraannular alkyl groups and intraannular bridges is synthesized by oxidative Glaser-coupling of the appropriate precursors. The intraannular bridges serve in this case as templates that reduce the oligomerization even when the reaction is not performed under pseudo high-dilution conditions. The extraannular as well as the intraannular substituents have a strong influence on the thermal behavior of the compounds. With branched alkyl chains at the periphery, the macrocycles exhibit liquid crystalline (lc phases when the interior is empty or when the length of the alkyl bridge is just right to cross the ring. With a longer alkyl or an oligoethylene oxide bridge no lc phase is observed, most probably because the mesogene is no longer planar.

76 FR 11268 - Certain Polyester Staple Fiber From Korea and Taiwan

Science.gov (United States)

2011-03-01

... Polyester Staple Fiber From Korea and Taiwan AGENCY: United States International Trade Commission. ACTION... Korea and Taiwan. SUMMARY: The Commission hereby gives notice that it has instituted reviews pursuant to... the antidumping duty orders on certain polyester staple fiber from Korea and Taiwan would be likely to...

Synthesis, characterization and ESR study of polyesters containing isomeric naphthylene units by gamma irradiation

International Nuclear Information System (INIS)

Choi, B.K.; Hill, D.J.T.; Choi, E.J.; Ahn, H.K.

1998-01-01

Full text: Aromatic polyesters containing naphthalene groups have interesting properties because the geometry of the naphthalene group can provide many of the structural features for the polymer chain. In this study we synthesized six polyesters from 4,4 ' - (hexafluoroisopropyl-idene)bis(benzoic acid) and isomeric naphthylene-diols. An ESR study of the radicals formed on gamma radiolysis of the polyesters has been undertaken to investigate their relative radiation sensitivities. The structures of the polyesters were characterized by means of IR spectroscopy. Inherent viscosities were measured in the range of 0.11 - 0.46 dL/g. Thermal properties of polyesters were determined by DSC and TGA thermograms, respectively. All polyesters were irradiated in an AECL Gamma cell with a dose rate of approximately 6.7kGy h -1 to doses in the range of 0 - 15kGy at 77K and 300K, respectively. In order to identify other radicals present at 77K, annealing studies were utilized by taking advantage of the different reactivities of these radicals

Rewritable azobenzene polyester for polarization holographic data storage

DEFF Research Database (Denmark)

Kerekes, A; Sajti, Sz.; Loerincz, Emoeke

2000-01-01

Optical storage properties of thin azobenzene side-chain polyester films were examined by polarization holographic measurements. The new amorphous polyester film is the candidate material for the purpose of rewritable holographic memory system. Temporal formation of anisotropic and topographic...... gratings was studied in case of films with and without a hard protective layer. We showed that the dominant contribution to the diffraction efficiency comes from the anisotropy in case of expositions below 1 sec even for high incident intensity. The usage of the same wavelength for writing, reading...

The biomechanical evaluation of polyester as a tension band for the internal fixation of patellar fractures.

LENUS (Irish Health Repository)

McGreal, G

2012-02-03

We use a braided polyester suture in place of cerclage wire in tension band fixations. The objective of this study was to test the biomechanical properties of this technique. Sixteen cadaveric patellae were fractured and repaired by modified tension band fixation. Eight were fixed using eighteen gauge stainless steel wire as a tension band and eight using braided polyester. All specimens were subjected to tensile testing. Polyester was 75.0% as strong as wire. For dynamic testing, the patellae of seven cadaveric knees were fractured and then fixed with polyester tension bands. These were mounted in a device capable of extending the knees from 90 degrees to neutral against an applied force. None of the fixations failed. Three of the specimens fixed using 18 gauge stainless steel wire were compared with three fixed using polyester over 2000 cycles of knee flexion and extension. Polyester performed as well as wire. We conclude that polyester is an acceptable alternative to wire in tension band fixation.

H-Bond stabilized columnar discotic liquid crystals

NARCIS (Netherlands)

Paraschiv, I.

2007-01-01

Since 1977, more than 2300 publications on discotic (disk-like) liquid crystalline materials have appeared. Discotic liquid crystals, which usually consist of polyaromatic molecules surrounded by long peripheral alkyl tails, can form liquid crystalline mesophases in a wide temperature range. Within

Scanning electron microscope investigations of nuclear pore filters in polyester foils

International Nuclear Information System (INIS)

Hopfe, J.

1980-01-01

In order to understand and characterize the action of nuclear pore filters it is necessary to know their surface, as well as their bulk, structure. In the present work, investigations of the surface structure (pore size, pore density, pore distribution) and of the pore geometry, especially in the bulk of the filters, are carried out by scanning electron microscopic (SEM) studies. The preparation technique needed is liquid-nitrogen freeze-fracturing followed by a conductive-coating step. Nuclear pore filters studied in this paper were produced by a track etching technique. Laboratory specimens were obtained by bombarding 10 μm thick polyester foils with Xe-ions and a subsequent etching with 20% NaOH. The SEM results are shown and discussed. (author)

Study on the improvement of hydrophilic character on polyvinylalcohol treated polyester fabric

Directory of Open Access Journals (Sweden)

S. Pitchai

2014-12-01

Full Text Available Polyester fabric was treated with polyvinyl alcohol in alkaline medium. The moisture regain, water retention and wettability of the PVA treated polyester fabric were tested. The PVA treated PET fabric was dyed with disperse dye. The presence of PVA in the treated PET fabric was assessed by spot test. The treated fabric was also characterized by scanning electron microscope, FTIR and differential scanning calorimetry. The PVA treated polyester fabric showed improved hydrophilic character over intact and sodium hydroxide treated PET fabrics.

Characterizing the sorption of polybrominated diphenyl ethers (PBDEs) to cotton and polyester fabrics under controlled conditions

Energy Technology Data Exchange (ETDEWEB)

Saini, Amandeep [Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada); Rauert, Cassandra [School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Simpson, Myrna J. [Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada); Harrad, Stuart [School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Diamond, Miriam L., E-mail: miriam.diamond@utoronto.ca [Department of Earth Sciences, 22 Russell Street, University of Toronto, Toronto, ON M5S 3B1 (Canada); Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada)

2016-09-01

Cotton and polyester, physically and chemically different fabrics, were characterized for sorption of gas-phase polybrominated diphenyl ethers (PBDEs). Scanning electron microscopic (SEM) images and BET specific surface area (BET-SSA) analysis showed cotton's high microsurface area; NMR analysis showed richness of hexose- and aromatic-carbon in cotton and polyester, respectively. Cotton and polyester sorbed similar concentrations of gas-phase PBDEs in chamber studies, when normalized to planar surface area. However, polyester concentrations were 20–50 times greater than cotton when normalized to BET-SSA, greater than the 10 times difference in BET-SSA. The difference in sorption between cotton and polyester is hypothesized to be due to ‘dilution’ due to cotton's large BET-SSA and/or greater affinity of PBDEs for aromatic-rich polyester. Similar fabric-air area normalized distribution coefficients (K'{sub D}, 10{sup 3} to 10{sup 4} m) for cotton and polyester support air-side controlled uptake under non-equilibrium conditions. K'{sub D} values imply that 1 m{sup 2} of cotton or polyester fabrics would sorb gas-phase PBDEs present in 10{sup 3} to 10{sup 4} m{sup 3} of equivalent air volume at room temperature over one week, assuming similar air flow conditions. Sorption of PBDEs to fabrics has implications for their fate indoors and human exposure. - Highlights: • Sorption of gas-phase PBDEs by cotton and polyester fabrics • Similar sorption to cotton and polyester per unit planar surface area • Greater sorption by polyester/BET-SSA; cotton's dilution or polyester’s affinity • 1 m{sup 2} fabric sorbs PBDEs in 10{sup 3} to 10{sup 4} m{sup 3} of equivalent air volume • Clothing likely a large indoor sink of PBDEs and influence human exposure.

The radiation chemistry of symmetric aliphatic polyesters

International Nuclear Information System (INIS)

Babanalbandi, A.; Hill, D.J.T.; Pomery, P.J.; Whittaker, A.K.

1996-01-01

Full text: Naturally occurring, symmetric polyesters, including polyglycolic acid, polylactic acid and polyhydroxybutyrate, have found biomedical applications in areas as diverse as the controlled release of pharmaceuticals and the manufacture of surgical sutures. As biomedical products, the materials require sterilization by high energy radiation. This has provided the motivation for the present work. D'Alelio et al. have reported that linear, asymmetric polyesters undergo scission on irradiation, but that branched polyesters containing a methyl group in the diol segments undergo crosslinking. However, for the symmetric polyhydroxybutyrate, Carswell-Pomerantz et al. have reported that only scission occurs on radiolysis, with the evolution of CO and CO 2 as a result of the loss of ester linkages. These workers also found that G(CO + CO 2 ) was approximately equal to G(S) for this polyester. By contrast, Collett et al. have reported that G(S) = 1.26 and G(X) = 0.53 for polylactic acid, which indicates that the polymer undergoes nett crosslinking on radiolysis to form a gel. They have also reported that poly(lactic-co-glycolic acid) should form a gel on radiolysis, since G(S) = 1.66 and G(X) = 0.65 for a 1:1 copolymer composition. In the present work the radiolysis of polylactic acid and poly(lactic-co-glycolic acid) have been reinvestigated in order to resolve the differences between the work of Collett et al. and that of Carswell-Pomerantz et al. In these studies, ESR has been used to study the radicals formed, GPC has been used to investigate scission and crosslinking, GC has been used to study the small molecule volatile products and NMR spectroscopy has been used to identify and measure the new chemical structures formed in the polymers

Liquid phase and supercooled liquid phase welding of bulk metallic glasses

International Nuclear Information System (INIS)

Kawamura, Y.

2004-01-01

Recent progress on welding in bulk metallic glasses (BMGs) has been reviewed. BMGs have been successfully welded to BMGs or crystalline metals by liquid phase welding using explosion, pulse-current and electron-beam methods, and by supercooled liquid phase welding using friction method. Successful welding of the liquid phase methods was due to the high glass-forming ability of the BMGs and the high concentration of welding energy in these methods. In contrast, the supercooled liquid phase welding was successful due to the thermally stable supercooled liquid state of the BMGs and the superplasticity and viscous flow of the supercooled liquid. The successful welding of BMGs to BMGs and crystalline materials is promising for the future development of BMGs as engineering materials

Biodegradation of Polyester Polyurethane by Endophytic Fungi▿

Science.gov (United States)

Russell, Jonathan R.; Huang, Jeffrey; Anand, Pria; Kucera, Kaury; Sandoval, Amanda G.; Dantzler, Kathleen W.; Hickman, DaShawn; Jee, Justin; Kimovec, Farrah M.; Koppstein, David; Marks, Daniel H.; Mittermiller, Paul A.; Núñez, Salvador Joel; Santiago, Marina; Townes, Maria A.; Vishnevetsky, Michael; Williams, Neely E.; Vargas, Mario Percy Núñez; Boulanger, Lori-Ann; Bascom-Slack, Carol; Strobel, Scott A.

2011-01-01

Bioremediation is an important approach to waste reduction that relies on biological processes to break down a variety of pollutants. This is made possible by the vast metabolic diversity of the microbial world. To explore this diversity for the breakdown of plastic, we screened several dozen endophytic fungi for their ability to degrade the synthetic polymer polyester polyurethane (PUR). Several organisms demonstrated the ability to efficiently degrade PUR in both solid and liquid suspensions. Particularly robust activity was observed among several isolates in the genus Pestalotiopsis, although it was not a universal feature of this genus. Two Pestalotiopsis microspora isolates were uniquely able to grow on PUR as the sole carbon source under both aerobic and anaerobic conditions. Molecular characterization of this activity suggests that a serine hydrolase is responsible for degradation of PUR. The broad distribution of activity observed and the unprecedented case of anaerobic growth using PUR as the sole carbon source suggest that endophytes are a promising source of biodiversity from which to screen for metabolic properties useful for bioremediation. PMID:21764951

Small Angle Neutron Scattering Studies on Blends of Poly (Styrene-ran-Vinyl Phenol) with Liquid Crystalline Polyurethane

Science.gov (United States)

Mehta, Rujul

2005-03-01

Molecular composites, composed of uniformly dispersed rigid-rod liquid crystalline polymer (LCP) molecules in a flexible amorphous polymer matrix, have remained hitherto elusive due to a scarcity of miscible systems containing a LCP and an amorphous polymer. The production of such a blend, with an experimentally accessible miscibility window, has become possible by modifying the architecture of the flexible polymer, so as to induce favorable intermolecular hydrogen bonding. Specifically, liquid crystalline polyurethanes (LCPU) are found to be miscible with a copolymer of styrene and vinyl phenol; with optimum hydrogen bonding between the carbonyl groups of the urethane linkages and the hydroxyl groups present in the styrenic matrix. Availability of a truly miscible molecular composite presents a unique opportunity of studying the confirmation of polymer chains containing rigid-rods that are uniformly dispersed in a flexible coil matrix. A system consisting of the LCPU and the deuterated styrenic copolymer containing 20% vinyl phenol is examined by Small Angle Neutron Scattering at the National Center for Neutron Research at Gaithersburg and Technology, and the Institute of Solid State Research (IFF) at Jülich. Scattering curves for neat dPS-VPh did not fit the Debye-Bueche model; indicating complex structure. A two correlation length Debye-Bueche model was considered to accommodate for this nonlinear behavior. This model utilizes four fitting parameters, including two correlation lengths a1 and a2, corresponding to a Debye-Bueche model and Guinier model.

The effect of the stretching of PLA extruded films on their crystallinity and gas barrier properties

Science.gov (United States)

Guinault, A.; Menary, G. H.; Courgneau, C.; Griffith, D.; Ducruet, V.; Miri, V.; Sollogoub, C.

2011-05-01

Driven by environmental concerns, new polymers based on renewable resources are arriving on the market to replace conventional polymers, obtained from petroleum, for different applications like food packaging. One of the most prominent polymers among these materials is poly(lactic acid) (PLA), a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the USA) or sugarcanes (in the rest of the world). However this polymer presents different disadvantages and especially low gas barrier properties [1]. Thermal crystallization can be used to increase its gas barrier properties but long times are necessary [2] and are not compatible with an industrial process. Another way to increase the gas barrier properties consists in stretching the film in order to increase its crystallinity and so its diffusion coefficient. We have prepared stretched PLA films with different stretch ratio and we have studied the effect of the stretching parameters on the gas barrier properties of PLA films. Finally we compared this process with the isothermal crystallization process by taking into account the crystallinity degree and the crystalline morphology.

76 FR 58040 - Certain Polyester Staple Fiber From Korea and Taiwan

Science.gov (United States)

2011-09-19

... Polyester Staple Fiber From Korea and Taiwan Determination On the basis of the record \\1\\ developed in the... antidumping duty orders on certain polyester staple fiber from Korea and Taiwan would be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably...

How ionic species structure influences phase structure and transitions from protic ionic liquids to liquid crystals to crystals.

Science.gov (United States)

Greaves, Tamar L; Broomhall, Hayden; Weerawardena, Asoka; Osborne, Dale A; Canonge, Bastien A; Drummond, Calum J

2017-12-14

The phase behaviour of n-alkylammonium (C6 to C16) nitrates and formates has been characterised using synchrotron small angle and wide angle X-ray scattering (SAXS/WAXS), differential scanning calorimetry (DSC), cross polarised optical microscopy (CPOM) and Fourier transform infrared spectroscopy (FTIR). The protic salts may exist as crystalline, liquid crystalline or ionic liquid materials depending on the alkyl chain length and temperature. n-Alkylammonium nitrates with n ≥ 6 form thermotropic liquid crystalline (LC) lamellar phases, whereas n ≥ 8 was required for the formate series to form this LC phase. The protic ionic liquid phase showed an intermediate length scale nanostructure resulting from the segregation of the polar and nonpolar components of the ionic liquid. This segregation was enhanced for longer n-alkyl chains, with a corresponding increase in the correlation length scale. The crystalline and liquid crystalline phases were both lamellar. Phase transition temperatures, lamellar d-spacings, and liquid correlation lengths for the n-alkylammonium nitrates and formates were compared with those for n-alkylammonium chlorides and n-alkylamines. Plateau regions in the liquid crystalline to liquid phase transition temperatures as a function of n for the n-alkylammonium nitrates and formates are consistent with hydrogen-bonding and cation-anion interactions between the ionic species dominating alkyl chain-chain van der Waals interactions, with the exception of the mid chained hexyl- and heptylammonium formates. The d-spacings of the lamellar phases for both the n-alkylammonium nitrates and formates were consistent with an increase in chain-chain layer interdigitation within the bilayer-based lamellae with increasing alkyl chain length, and they were comparable to the n-alkylammonium chlorides.

[Analysis of anatomical pieces preservation with polyester resin for human anatomy study].

Science.gov (United States)

de Oliveira, Ítalo Martins; Mindêllo, Marcela Maria Aguiar; Martins, Yasmin de Oliveira; da Silva Filho, Antônio Ribeiro

2013-01-01

To evaluate the use of polyester resin in preserving anatomical specimens for the study of human anatomy. We used 150 anatomical specimens, comprised of unfixed (fresh), fixed in 10% formalin and vascular casts of organs injected with vinyl acetate and polyester resin. The solution used consisted of polyester resin with the diluent styrene monomer and catalyst (peroxol). After embedding in this solution, models in transparent resin were obtained, allowing full observation of structures and conservation of the specimens used. upon evaluation of the specimens, we observed a high degree of transparency, which promoted a complete visualization of structures with perfect preservation of the anatomy. The average time for the completion of the embedding was 48 hours. Only 14 specimens (9.3%) were lost during the preparation. Polyester resin can be used for preserving anatomical specimens for teaching human anatomy in a practical, aesthetic and durable way.

Nanostructured liquid crystalline particles as an alternative delivery vehicle for plant agrochemicals.

Science.gov (United States)

Nadiminti, Pavani P; Dong, Yao D; Sayer, Chad; Hay, Phillip; Rookes, James E; Boyd, Ben J; Cahill, David M

2013-03-13

Agrochemical spray formulations applied to plants are often mixed with surfactants that facilitate delivery of the active ingredient. However, surfactants cause phytotoxicity and off-target effects in the environment. We propose the use of nanostructured liquid crystalline particles (NLCP) as an alternative to surfactant-based agrochemical delivery. For this, we have compared the application of commercial surfactants, di (2-ethylhexyl) sulfosuccinate and alkyl dimethyl betaine, with NLCP made from phytantriol, at concentrations of 0.1%, 1% and 5% on the adaxial surface of leaves of four plant species Ttriticum aestivum (wheat), Zea mays (maize), Lupinus angustifolius (lupin), and Arabidopsis thaliana. In comparison with the application of surfactants there was less phytotoxicity on leaves of each species following treatment with NLCP. Following treatment of leaves with NLCP analysis of cuticular wax micromorphology revealed less wax solubilization in the monocot species. The results clearly show that there are advantages in the use of NLCP rather than surfactants for agrochemical delivery.

Chemical and enzymatic catalytic routes to polyesters and oligopeptides biobased materials

Science.gov (United States)

Zhu, Jianhui

and physico-mechanical properties for two series of linear polyurethane elastomers built from polyol polyesters which contain bio-based o-hydroxytetradecanoic acid (o-HOC14) repeat units. Varied quantities of o-HOC14 was converted by a condensation polymerization catalyzed by titanium tetraisopropoxide (Ti[OiPr]4) to polyester polyol with Mn around 2K. By end-cap the polyols with excess amount of 1,4-butanediol, low number of carbonyl end group can be achieved so that the polyols can be further used as soft segment of thermoplastic polyurethanes (TPU). We have studied the thermo-mechanical properties of two-series polyurethanes with different polyester polyols or polyester polyols mixtures. With increasing amount of o-HOC14 content in the soft segment polyols of polyurethanes, tensile strength of the polyurethanes kept increasing from 30MPa to 470MPa while at the same time their elongation ratio decreased from 900% to 300%. Their mechanical behavior shifted from elastomer to semi-crystalline plastic. In the second section about polyether polyurethanes, PC14-OH and poly(tetrahydrofuran) mixtures were used as soft segment in linear polyurethane elastomer synthesis. Similar thermal and mechanical property changing trends were observed with increasing amount of PC14-OH up to 30 wt% of total soft segments. In this study, the functions of PC14-OH in thermoplastic polyurethane elastomers were identified, and there are several benefits of incorporating this long chain fatty acid. In the third study, seven amphiphilic alternating oligopeptides were synthesized via chemo-enzymatic routes. Four proteases (papain, bromelain, alpha-chymotrypsin, and trypsin) were evaluated to determine their efficiency in synthesizing alternating peptides. The first series is hydrophobic-anionic alternating oligopeptides targeting for self assembly smart material design. So far, beta-sheet secondary structure of the anionic alternating oligopeptides was not observed very clearly at low p

Flame Retardance and Physical Properties of Novel Cured Blends of Unsaturated Polyester and Furan Resins

Directory of Open Access Journals (Sweden)

Baljinder Kaur Kandola

2015-02-01

Full Text Available Novel blends of two furan resins with an unsaturated polyester have been prepared and cured by parallel free radical (for the unsaturated polyester and acid-catalysed crosslinking (for the furan resin to give co-cured composite materials. Although these materials have inferior physical properties, such as low Tg and low storage modulus compared with those of unsaturated polyester and furan resins alone, they show markedly improved flame retardance compared with that of the normally highly flammable unsaturated polyester. This increased flame retardance arises from a condensed phase mechanism in which the furanic component forms a semi-protective char, reducing rates of thermal degradation and total heat release and heat of combustion. The blends also burn with reduced smoke output compared with that from unsaturated polyester alone.

Effects of Alkali Treatment and Polyisocyanate Crosslinking on the Mechanical Properties of Kraft Fiber-Reinforced Unsaturated Polyester Composites

Directory of Open Access Journals (Sweden)

Zhenhua Gao

2014-08-01

Full Text Available The effects of alkali treatment and polyisocyanate crosslinking on the mechanical properties of kraft fiber-reinforced UPE composites were investigated by means of tensile evaluation, SEM analysis, and XRD analysis. The results indicated that the alkali treatment decreased the tensile strength of the prepared composite before aging from 121 MPa to 97 MPa due to the decreased degree of crystallinity of the alkali-treated kraft fiber. Polyisocyanate crosslinking could apparently improve the mechanical properties and stability in terms of a 43% increase of non-aged tensile strength and 52% increase of hydrothermal-aged tensile strength compared with the controlled composite without crosslinking modification, which was attributable to the formation of strong chemical bonding between the interfaces of kraft fiber and polyester.

Method of processing radioactive liquid waste

International Nuclear Information System (INIS)

Hasegawa, Akira; Kuribayashi, Hiroshi; Soda, Kenzo; Mihara, Shigeru.

1988-01-01

Purpose: To obtain satisfactory plastic solidification products rapidly and smoothly by adding oxidizers to radioactive liquid wastes. Method: Sulfuric acid, etc. are added to radioactive liquid wastes to adjust the pH value of the liquid wastes to less than 3.0. Then, ferrous sulfates are added such that the iron concentration in the liquid wastes is 100 mg/l. Then, after adjusting pH suitably to the drying powderization by adding alkali such as hydroxide, the liquid wastes are dried and powderized. The resultant powder is subjected to plastic solidification by using polymerizable liquid unsaturated polyester resins as the solidifying agent. The thus obtained solidification products are stable in view of the physical property such as strength or water proofness, as well as stable operation is possible even for those radioactive liquid wastes in which the content ingredients are unknown. (Takahashi, M.)

Properties and performance of flax yarn/thermoplastic polyester composites

DEFF Research Database (Denmark)

Madsen, Bo; Mehmood, Shahid

2012-01-01

Aiming at demonstrating the potential of unidirectional natural fiber-reinforced thermoplastic composites in structural applications, textile flax yarn/thermoplastic polyester composites with variable fiber volume fractions have been manufactured by a filament-winding process followed by a vacuum......-assisted compression molding process. The microstructure of the composites shows that the flax fiber yarns are well impregnated by the polyester matrix, and this supports the measured low porosity content of the composites. The experimental tensile modulus and ultimate tensile stress of the composites in the axial...

Polyester textile functionalization through incorporation of pH/thermo-responsive microgels. Part II: polyester functionalization and characterization

NARCIS (Netherlands)

Glampedaki, P.; Calvimontes, A.; Dutschk, Victoria; Warmoeskerken, Marinus

2012-01-01

A new approach to functionalize the surface of polyester textiles is described in this study. Functionalization was achieved by incorporating pH/temperature-responsive polyelectrolyte microgels into the textile surface layer using UV irradiation. The aim of functionalization was to regulate

Polyester Polyols from Waste PET Bottles for Polyurethane Rigid Foams

OpenAIRE

Evtimova, Rozeta; Lozeva, Yordanka; Schmidt, Karl-Heinz; Wotzka, Michael; Wagner, Peter; Behrendt, Gerhard

2003-01-01

This paper describes a modified process to produce polyester polyols from PET wastes derived from the “bottle fraction residue” of the German Dual System (DSD) [11] employing a waste oligoester condensate of the polyesterification process with the addition of some glycols of longer chain and occasional modification with further dicarboxylic acids to produce polyester polyols of a broad range of properties which are further reacted to form polyurethane or polyisocyanurate rigid foams for insul...

Drug Release and Skin Permeation from Lipid Liquid Crystalline Phases

Science.gov (United States)

Costa-Balogh, F. O.; Sparr, E.; Sousa, J. J. S.; Pais, A. A. C. C.

We have studied drug release and skin permeation from several different liquid crystalline lipid formulations that may be used to control the respective release rates. We have studied the release and permeation through human skin of a water-soluble and amphiphilic drug, propranolol hydrochloride, from several formulations prepared with monoolein and phytantriol as permeation enhancers and controlled release excipients. Diolein and cineol were added to selected formulations. We observed that viscosity decreases with drug load, wich is compatible with the occurrence of phase changes. Diolein stabilizes the bicontinuous cubic phases leading to an increase in viscosity and sustained release of the drug. The slowest release was found for the cubic phases with higher viscosity. Studies on skin permeation showed that these latter formulations also presented lower permeability than the less viscous monoolein lamellar phases. Formulations containing cineol originated higher permeability with higher enhancement ratios. Thus, the various formulations are adapted to different circumstances and delivery routes. While a slow release is usually desired for drug sustained delivery, the transdermal route may require a faster release. Lamellar phases, which are less viscous, are more adapted to transdermal applications. Thus, systems involving lamellar phases of monoolein and cineol are good candidates to be used as skin permeation enhancers for propranolol hydrochloride.

Supramolecular liquid crystalline π-conjugates: the role of aromatic π-stacking and van der Waals forces on the molecular self-assembly of oligophenylenevinylenes.

Science.gov (United States)

Goel, Mahima; Jayakannan, M

2010-10-07

Here, we report a unique design strategy to trace the role of aromatic π-stacking and van der Waals interactions on the molecular self-organization of π-conjugated building blocks in a single system. A new series of bulky oligophenylenevinylenes (OPVs) bearing a tricyclodecanemethylene (TCD) unit in the aromatic π-core with flexible long methylene chains (n = 0-12 and 16) in the longitudinal position were designed and synthesized. The OPVs were found to be liquid crystalline, and their enthalpies of phase transitions (also entropies) showed odd-even oscillation with respect to the number of carbon atoms in alkyl chains. OPVs with an even number of methylene units in the side chains showed higher enthalpies with respect to their highly packed solid structures compared to odd-numbered ones. Polarized light microscopic analysis confirmed the formation of cholesteric liquid crystalline (LC) phases of fan shaped textures with focal conics in OPVs with 5 ≤ n ≤ 9. OPVs with longer alkyl chains (OPV-10 to OPV-12) produced a birefringence pattern consisting of dark and bright ring-banded suprastructures. The melting temperature followed a sigmoidal trend, indicating the transformation of molecular self-organization in OPVs from solid to ring-banded suprastructures via cholesteric LC intermediates. At longer alkyl chain lengths, the van der Waals interactions among the alkyl chains became predominant and translated the mesogenic effect across the lamellae; as a consequence, the lamellae underwent twisted self-organization along the radial growth direction of the spherulites to produce bright and dark bands. Scanning electron microscope (SEM) analysis of cholesteric LC and ring-banded textures strongly supported the existence of twisted lamellae in the OPVs with ring-banded textures. Variable temperature X-ray diffraction analysis confirmed the reversibility of the molecular self-organization in the solid state and also showed the existence of the higher ordered

New UV-curable acrylated polyester prepolymers from palm oil based products

International Nuclear Information System (INIS)

Mohd Azam Ali; Ooi, T.L.; Salmiah Ahmad; Umaru, S.I.; Mohd Ishak, Z.A.

1999-01-01

Acrylated polyester prepolymers (PEPP-1 and PEPP-2) were synthesized from palm oil and its products. UV-curing and characteristic properties of UV-cured films of synthesized polyester resins were studied. The characteristic properties studied include pendulum hardness, gel content, FT-IR analysis, tensile strength and elongation at break. The materials have good potential for the production of radiation curable coating applications

Composite Preparation of Wood Dust-Polyester-Coconut Choir Fiber Mixture for Particle Board

International Nuclear Information System (INIS)

Danu, Sugiarto; Darsono; Padmono; Betty, Angesti

2002-01-01

Experiment on the use of γ-ray of Co 60 radiation has been used for curing of composite which made of wood dust, unsaturated polyester resin and coconut coir mixture. Composite was prepared by mixing of wood dust, polyester and coconut coir at a various mixture composition. Concentration of polyesters were 50, 55 and 60 % by weight based on saw dust and polyester mixture. Irradiation was conducted using 27,6 kCi acti vity Co 60 at a dose rate of 5 kGy/hrs and dose of 8, 10 and 12 kGy. Composite was also prepared conventionally by using peroxide catalyst. Parameters observed were density, pencil hardness and compression strength Experimental results showed that optimum condition wus achieved at irradiation dose of 12 kGy, polyester concentration of 60 % and coconut coir fiber of 4 %. In this condition, the density, hardness and compression strength were 1,115 g/cm 3, 5 Hand 6,815 kN/cm2 respectively. Density, hardness of composite prepared by radiation were almost the same whereas the compression strength was higher than that of composite prepared by conventional method

Nuclear magnetic resonance structure investigations on crosslinked polyesters

International Nuclear Information System (INIS)

Grobelny, J.

1999-01-01

Styrene-crosslinked mixed polyesters derived from maleic anhydride, 2,2-di(4-hydroxypropoxyphenyl)propane, oligo(propylene oxide) and 1,2-propylene glycol were investigated by high-resolution solid-state 13 C NMR spectroscopy. The structural modifications accompanying crosslinking were characterized in terms of spin-lattice relaxation times as a function of unsaturated polyester composition. Copolymerization and crosslinking effects were individually evaluated and the latter effect was related to variations in crosslinking density associated with the chemical structure of the unsaturated prepolymer. As the crosslinking effect is suppressed, the mechanical properties undergo expected changes, e.g., impact strength is increased and modulus of elasticity in tension is decreased. (author)

The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy.

Science.gov (United States)

Tasei, Yugo; Tanigawa, Fumikazu; Kawamura, Izuru; Fujito, Teruaki; Sato, Motoyasu; Naito, Akira

2015-04-14

Microwave heating effects are widely used in the acceleration of organic, polymerization and enzymatic reactions. These effects are primarily caused by the local heating induced by microwave irradiation. However, the detailed molecular mechanisms associated with microwave heating effects on the chemical reactions are not yet well understood. This study investigated the microwave heating effect of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) in liquid crystalline and isotropic phases using in situ microwave irradiation nuclear magnetic resonance (NMR) spectroscopy, by obtaining (1)H NMR spectra of MBBA under microwave irradiation. When heated simply using the temperature control unit of the NMR instrument, the liquid crystalline MBBA was converted to the isotropic phase exactly at its phase transition temperature (Tc) of 41 °C. The application of microwave irradiation at 130 W for 90 s while maintaining the instrument temperature at 20 °C generated a small amount of isotropic phase within the bulk liquid crystal. The sample temperature of the liquid crystalline state obtained during microwave irradiation was estimated to be 35 °C by assessing the linewidths of the (1)H NMR spectrum. This partial transition to the isotropic phase can be attributed to a non-equilibrium local heating state induced by the microwave irradiation. The application of microwave at 195 W for 5 min to isotropic MBBA while maintaining an instrument temperature of 50 °C raised the sample temperature to 160 °C. In this study, the MBBA temperature during microwave irradiation was estimated by measuring the temperature dependent chemical shifts of individual protons in the sample, and the different protons were found to indicate significantly different temperatures in the molecule. These results suggest that microwave heating polarizes bonds in polar functional groups, and this effect may partly explain the attendant acceleration of organic reactions.

Synthesis, Characterization and Photoinduction of Optical Anisotropy in Liquid Crystalline Diblock Azo-Copolymers

DEFF Research Database (Denmark)

Forcén, P; Oriol, L; Sánchez, C

2007-01-01

Diblock copolymers with polymethyl methacrylate and side chain liquid crystalline WC) azopolymethacrylate blocks were synthesized by atom transfer radical polymerization (ATRP). The azobeazene content in these copolymers ranges from 52 to 7 wt %. For an azo conteat dowri to 20% they exhibit a LC...... anisotropy induced in these films by illumination with linearly polarized 488 nm light was studied and the resuits compared with those of the azo homopolymer and of a random copolymer with a similar composition. The formation of azo aggregates inside the azo blocks is strongly reduced in going from...... the homopolymer to the copolymers. Photoinduced azo orientation perpendicular to the 488 nm light polarization was found in aH the polymers. The orientational order parameter is very similar in the homopolymer and in the block copolymers with an azo content down to 20 wt %, while it is much lower in the random...

New theory for competing interactions and microstructures in partially-ordered (liquid-crystalline) phases

International Nuclear Information System (INIS)

Dowell, F.

1987-01-01

A summary of results from a unique statistical-physics theory to predict and explain competing interactions and resulting microstructures in some partially-ordered [in this case, liquid-crystalline (LC)] phases is presented. The static aspects of both partial orientational and partial positional ordering of the molecules into various microstructures in these phases (including the incommensurate smectic-Ad phase) can be understood in terms of various competing interactions (both entropic and energetic) involved in the packing together of the different molecular sub-units at given pressures and temperatures. These microstructures are predicted and explained (using no ad hoc or arbitrarily adjustable parameter) as a function of molecule chemical structure [including lengths and shapes (from bond lengths and angles), intramolecular rotations, site-site polarizabilities and pair potentials, dipole moments, etc]. Theoretical results are presented for the nematic, re-entrant nematic, smectic-Ad, and smectic-Al LC phases and the isotropic phase

Photoinduced Deformation of Azobenzene Polyester Films

DEFF Research Database (Denmark)

Bublitz, D.; Helgert, M.; Fleck, B.

2000-01-01

We investigate two types of azobenzene side-chain polyesters which have shown opposite behaviour in light-induced surface grating formation experiments. Thin films of these polymers prepared on a water surface undergo opposite changes of shape under the influence of polarized light. We propose...

Micro-thermal analysis of polyester coatings

NARCIS (Netherlands)

Fischer, H.R.

2010-01-01

The application and suitability of micro-thermal analysis to detect changes in the chemical and physical properties of coating due to ageing and especially photo-degradation is demonstrated using a model polyester coating based on neopentyl glycol isophthalic acid. The changes in chemical structure

Tensile strength of woven yarn kenaf fiber reinforced polyester composites

OpenAIRE

A.E. Ismail; M.A. Che Abdul Aziz

2015-01-01

This paper presents the tensile strength of woven kenaf fiber reinforced polyester composites. The as-received yarn kenaf fiber is weaved and then aligned into specific fiber orientations before it is hardened with polyester resin. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses. Two important parameters are studied such as fiber orientations and number of layers. According to the results, it is shown that...

Eco-friendly surface modification on polyester fabrics by esterase treatment

Energy Technology Data Exchange (ETDEWEB)

Wu, Jindan; Cai, Guoqiang; Liu, Jinqiang; Ge, Huayun; Wang, Jiping, E-mail: jipingwanghz@gmail.com

2014-03-01

Graphical abstract: - Highlights: • We used a simple and easy way to measure the enzyme activity. • We studied the mechanism by characterizing the chemical changes in the surface of fabric. • We studied the advantages in surface wettability, fiber integrity and mechanical performance of cutinase treated fabrics. • Cutinase pretreated fibers exhibited much improved fabric wicking and better fiber integrity comparing to alkali treated ones. • Cutinase pretreatment technology promotes energy conservation and emission reduction. - Abstract: Currently, traditional alkali deweighting technology is widely used to improve the hydrophilicity of polyester fabrics. However, the wastewater and heavy chemicals in the effluent cause enormous damage to the environment. Esterase treatment, which is feasible in mild conditions with high selectivity, can provide a clean and efficient way for polyester modification. Under the optimum conditions, the polyester fabric hydrolysis process of esterase had a linear kinetics. X-ray photoelectron spectrometry (XPS) results showed that hydroxyl and carboxyl groups were produced only on the surface of modified fiber without changing the chemical composition of the bulk. These fibers exhibited much improved fabric wicking, as well as greatly improved oily stain removal performance. Compared to the harsh alkali hydrolysis, the enzyme treatment led to smaller weight loss and better fiber integrity. The esterase treatment technology is promising to produce higher-quality polyester textiles with an environmental friendly approach.

Temperature-triggered release of a liquid cross-linker micro-encapsulated in a glassy polymer for low temperature curing

NARCIS (Netherlands)

Senatore, D.; Cate, ten A.T.; Laven, J.; Benthem, van R.A.T.M.; With, de G.

2013-01-01

In order to prevent a liquid epoxy cross-linker from premature, Arrhenius-law predicted, reaction with an acid-functional polyester resin, the liquid cross-linker has been physically separated from the resin by encapsulation while release is only possible by a temperature-controlled trigger. The

The axial crushes behaviour on foam-filled round Jute/Polyester composite tubes

Science.gov (United States)

Othman, A.; Ismail, A. E.

2018-04-01

The present paper investigates the effect of axial loading compression on jute fibre reinforced polyester composite round tubes. The specimen of composite tube was fabricated by hand lay-up method of 120 mm length with fix 50.8 mm inner diameter to determine the behaviour of energy absorption on number of layers of 450 angle fibre and internally reinforced with and without foam filler material. The foam filler material used in this studies were polyurethane (PU) and polystyrene (PE) with average of 40 and 45 kg/m3 densities on the axial crushing load against displacement relations and on the failure modes. The number of layers of on this study were two; three and four were selected to calculate the crush force efficiency (CFE) and the specific energy absorption (SEA) of the composite tubes. Result indicated that the four layers’ jute/polyester show significant value in term of crushing load compared to 2 and 3 layers higher 60% for 2 layer and 3% compared to 3 layers. It has been found that the specific energy absorption of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 10% to 12% than empty and polyurethane (PU) foam tubes. The increase in the number of layers from two to four increases the mean axial load from 1.01 KN to 3.60 KN for empty jute/polyester and from 2.11 KN to 4.26 KN for the polyurethane (PU) foam-filled jute/polyester tubes as well as for 3.60 KN to 5.58 KN for the polystyrene (PE) foam-filled jute/polyester. The author’s found that the failure of mechanism influence the characteristic of curve load against displacement obtained and conclude that an increasing number of layers and introduce filler material enhance the capability of specific absorbed energy.

Radiation-resistance of polyurethane pipes for cooling liquid in BES III

International Nuclear Information System (INIS)

Li Xunfeng; Zheng Lifang; Ji Quan; Wu Ping; Wang Li

2009-01-01

Gamma ray radiation and neutron radiation are predominant in the working conditions of BES III, and the radiation-resistance aging of polyurethane pipes is very important in this condition, as the pipes of cooling liquid for beam pipe and SCQ (superconducting quadrupole) vacuum pipe in BESIII. Polyester polyurethane pipes and polyether polyurethane pipes were irradiated by gamma ray and neutron. The radiation doses were as much as ten years' doses in BES. Pressure test, FTIR and thermal analysis were used to study the radiation-resistance of these two kinds of polyurethane pipes. The results show that the radiation-resistance and thermal stability of polyester polyurethane pipes are prior to those of polyether polyurethane pipes, and the pressure resistance of polyester polyurethane pipes is almost maintained after the irradiation by gamma ray and neutron, but the polyether polyurethane pipes can be aged and ruptured after the irradiation by neutron. (authors)

Investigation of Mechanical Properties of Unidirectional Steel Fiber/Polyester Composites: Experiments and Micromechanical Predictions

DEFF Research Database (Denmark)

Raghavalu Thirumalai, Durai Prabhakaran; Løgstrup Andersen, Tom; Bech, Jakob Ilsted

2016-01-01

the role of material and process parameters on material properties. Two types of SFRP were studied: polyester resin reinforced by both steel fabric containing unidirectional fibers and steel fibers wound on a metal frame with 0° orientations. The effects of the fiber volume fraction and the role of polymer......The article introduces steel fiber reinforced polymer composites, which is considered new for composite product developments. These composites consist of steel fibers or filaments of 0.21 mm diameter embedded in a polyester resin. The goal of this investigation is to characterize the mechanical...... performance of steel fiber reinforced polyester composites at room temperature. The mechanical properties of unidirectional steel fiber reinforced polyester composites (SFRP) are evaluated experimentally and compared with the predicted values by micro-mechanical models. These predictions help to understand...

Crystalline liquids: the blue phases

Science.gov (United States)

Wright, David C.; Mermin, N. David

1989-04-01

The blue phases of cholesteric liquid crystals are liquids that exhibit orientational order characterized by crystallographic space-group symmetries. We present here a pedagogical introduction to the current understanding of the equilibrium structure of these phases accompanied by a general overview of major experimental results. Using the Ginzburg-Landau free energy appropriate to the system, we first discuss in detail the character and stability of the usual helical phase of cholesterics, showing that for certain parameter ranges the helical phase is unstable to the appearance of one or more blue phases. The two principal models for the blue phases are two limiting cases of the Ginzburg-Landau theory. We explore each limit and conclude with some general considerations of defects in both models and an exact minimization of the free energy in a curved three-dimensional space.

Liquid crystal polyester-carbon fiber composites

Science.gov (United States)

Chung, T. S.

1984-01-01

Liquid crystal polymers (LCP) have been developed as a thermoplastic matrix for high performance composites. A successful melt impregnation method has been developed which results in the production of continuous carbon fiber (CF) reinforced LCP prepreg tape. Subsequent layup and molding of prepreg into laminates has yielded composites of good quality. Tensile and flexural properties of LCP/CF composites are comparable to those of epoxy/CF composites. The LCP/CF composites have better impact resistance than the latter, although epoxy/CF composites possess superior compression and shear strength. The LCP/CF composites have good property retention until 200 F (67 % of room temperature value). Above 200 F, mechanical properties decrease significantly. Experimental results indicate that the poor compression and shear strength may be due to the poor interfacial adhesion between the matrix and carbon fiber as adequate toughness of the LCP matrix. Low mechanical property retention at high temperatures may be attributable to the low beta-transition temperature (around 80 C) of the LCP matrix material.

Recent Advances in the Design of Water Based-Flame Retardant Coatings for Polyester and Polyester-Cotton Blends

Directory of Open Access Journals (Sweden)

Jenny Alongi

2016-10-01

Full Text Available Over the last ten years a new trend of research activities regarding the flame retardancy of polymeric materials has arisen. Indeed, the continuous search for new flame retardant systems able to replace the traditional approaches has encouraged alternative solutions, mainly centred on nanotechnology. In this context, the deposition of nanostructured coatings on fabrics appears to be the most appealing and performance suitable approach. To this aim, different strategies can be exploited: from the deposition of a single monolayer consisting of inorganic nanoparticles (single-step adsorption to the building-up of more complex architectures derived from layer by layer assembly (multi-step adsorption. The present paper aims to review the application of such systems in the field of polyester and polyester-cotton blend fabrics. The results collated by the authors are discussed and compared with those published in the literature on the basis of the different deposition methods adopted. A critical analysis of the advantages and disadvantages exhibited by these approaches is also presented.

Stimuli-responsive liquid crystalline materials

NARCIS (Netherlands)

Debije, M.G.; Schenning, A.P.H.J.; Hashmi, Saleem

2016-01-01

Stimuli-responsive materials which respond to triggers from the environment by changing their properties are one of the focal points in materials science. For precise functional properties, well-defined hierarchically ordered supramolecular materials are crucial. The self-assembly of liquid crystals

Thermal studies of poly(esters) containing silicon or germanium in the main chain

International Nuclear Information System (INIS)

Tagle, L.H.; Terraza, C.; Valenzuela, P.; Leiva, A.; Urzua, M.

2005-01-01

The thermal properties of poly(esters) containing Si and/or Ge in the main chain derived from the acid dichlorides bis(4-chloroformyl-phenyl)-dimethyl-silane, bis(4-chloroformyl-phenyl)-dimethyl-germane, bis(4-chloroformyl-phenyl)-diphenyl-silane and bis(4-chloroformyl-phenyl)-diphenyl-silane, and the diphenols bis(4-hydroxyphenyl)-dimethyl-silane, bis(4-hydroxyphenyl)-dimethyl-germane, bis(4-hydroxyphenyl)-diphenyl-silane and bis(4-hydroxyphenyl)-diphenyl-germane were studied by differential scanning calorimetry and dynamic thermogravimetry. Poly(esters) with two Si atoms in the main chain showed higher values of T g than those with two Ge atoms, and the same was observed for poly(esters) with phenyl groups bonded to the heteroatoms, instead of those with methyl groups. Thermal decomposition temperatures were also higher for those poly(esters) with two Si atoms in the main chain and those in which the heteroatom is bonded to phenyl groups, due to the higher polarity of the Si-C bond in front of the Ge-C

Polyester fabric coated with Ag/ZnO composite film by magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Yuan, Xiaohong, E-mail: yxhong1981_2004@126.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Faculty of Clothing and Design, Minjiang University, Fuzhou 350121, Fujian (China); Xu, Wenzheng, E-mail: xwz8199@126.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Huang, Fenglin, E-mail: windhuang325@163.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Chen, Dongsheng, E-mail: mjuchen@126.com [Faculty of Clothing and Design, Minjiang University, Fuzhou 350121, Fujian (China); Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China)

2016-12-30

Highlights: • Ag/ZnO composite film was successfully deposited on polyester fabric by magnetron sputtering technique. • Ag film was easily oxidized into Ag{sub 2}O film in high vacuum oxygen environment. • The zinc film coated on the surface of Ag film before RF reactive sputtering could protect the silver film from oxidation. • Polyester fabric coated with Ag/ZnO composite film can obtained structural color. • The anti-ultraviolet and antistatic properties of polyester fabric coated with Ag/ZnO composite film all were good. - Abstract: Ag/ZnO composite film was successfully deposited on polyester fabric by using direct current (DC) magnetron sputtering and radio frequency (RF) magnetron reaction sputtering techniques with pure silver (Ag) and zinc (Zn) targets. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited film on the fabric. It was found that the zinc film coated on Ag film before RF reactive sputtering could protect the silver film from oxidation. Anti-ultraviolet property and antistatic property of the coated samples using different magnetron sputtering methods were also investigated. The experimental results showed that Ag film was oxidized into in Ag{sub 2}O film in high vacuum oxygen environment. The deposition of Zn film on the surface of the fabric coated with Ag film before RF reactive sputtering, could successfully obtained Ag/ZnO composite film, and also generated structural color on the polyester fabric.

Alignment technology and applications of liquid crystal devices

CERN Document Server

Takatoh, Kohki; Hasegawa, Ray; Koden, Mitsushiro; Itoh, Nobuyuki; Hasegawa, Masaki

2005-01-01

Alignment phenomena are characteristic of liquid crystalline materials, and understanding them is critically important in understanding the essential features and behavior of liquid crystals and the performance of Liquid Crystal Devices (LCDs). Furthermore, in LCD production lines, the alignment process is of practical importance. Alignment Technologies and Applications of Liquid Crystal Devices demonstrates both the fundamental and practical aspects of alignment phenomena in liquid crystals. The physical basis of alignment phenomena is first introduced in order to aid the understanding of the various physical phenomena observed in the interface between liquid crystalline materials and alignment layer surfaces. Methods for the characterization of surfaces, which induce the alignment phenomena, and of the alignment layer itself are introduced. These methods are useful for the research of liquid crystalline materials and devices in academic research as well as in industry. In the practical sections, the alignme...

A study on effect of ATH on Euphorbia coagulum modified polyester banana fiber composite

Science.gov (United States)

Kumari, Sanju; Rai, Bhuvneshwar; Kumar, Gulshan

2018-02-01

Fiber reinforced polymer composites are used for building and structural applications due to their high strength. In conventional composites both the binder and the reinforcing fibers are synthetic or either one of the material is natural. In the present study coagulum of Euphorbia royleana has been used for replacing polyester resinas binder in polyester banana composite. Euphorbia coagulum (driedlatex) is rich in resinous mass (60-80%), which are terpenes and polyisoprene (10-20%). Effect of varying percentage of coagulum content on various physico-mechanical properties of polyester-banana composites has been studied. Since banana fiber is sensitive to water due to presence of polar group, banana composite undergoes delamination and deterioration under humid condition. Alkali treated banana fiber along with coagulum content has improved overall mechanical properties and reduction in water absorption. The best physico-mechanical properties have been achieved on replacing 40% of polyester resin by coagulum. An increase of 50% in bending strength, 30% bending modulus and 45% impact strength as well as 68% decrease in water absorption was observed. Incorporation of 20% ATH as flame retardant in coagulum modified banana polyester composite enhanced limiting oxygen index from 20.6 to 26.8% and smoke density reduced up to 40%. This study presents the possibility of utilization of renewable materials for environmental friendly composite development as well as to find out alternative feedstock for petroleum products. Developed Euphorbia latex modified banana polyester composites can have potential utility in hardboard, partition panel, plywood and automotive etc.

Neutron shielding performance of water-extended polyester

International Nuclear Information System (INIS)

Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Hernandez-Davila, V.M.; Gallego, E.; Lorente, A.

2006-01-01

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

Neutron shielding performance of water-extended polyester

Energy Technology Data Exchange (ETDEWEB)

Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Nuclear Studies (Mexico); Vega Carrillo, H.R.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Electric Engineering Academic Units (Mexico); Gallego, E.; Lorente, A. [Madrid Univ. Politecnica, cNuclear Engineering Department (Mexico)

2006-07-01

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

Isothermal relaxation current and microstructure changes of thermally aged polyester films impregnated by epoxy resin

Science.gov (United States)

Jiang, Xiongwei; Sun, Potao; Peng, Qingjun; Sima, Wenxia

2018-01-01

In this study, to understand the effect of thermal aging on polymer films degradation, specimens of polyester films impregnated by epoxy resin with different thermal aging temperatures (80 and 130 °C) and aging times (500, 1600, 2400 and 3000 h) are prepared, then charge de-trapping properties of specimens are investigated via the isothermal relaxation current (IRC) measurement, the distributions of trap level and its corresponding density are obtained based on the modified IRC model. It is found that the deep trap density increases remarkably at the beginning of thermal aging (before 1600 h), but it decreases obviously as the aging degree increases. At elevated aging temperature and, in particular considering the presence of air gap between two-layer insulation, the peak densities of deep traps decrease more significant in the late period of aging. It can be concluded that it is the released energy from de-trapping process leads to the fast degradation of insulation. Moreover, after thermal aging, the microstructure changes of crystallinity and molecular structures are analyzed via the x-ray diffraction experiment and Fourier transform infrared spectrometer. The results indicate that the variation of the deep trap density is closely linked with the changes of microstructure, a larger interface of crystalline/amorphous phase, more defects and broken chains caused by thermal aging form higher deep trap density stored in the samples.

Hard sphere-like glass transition in eye lens α-crystallin solutions.

Science.gov (United States)

Foffi, Giuseppe; Savin, Gabriela; Bucciarelli, Saskia; Dorsaz, Nicolas; Thurston, George M; Stradner, Anna; Schurtenberger, Peter

2014-11-25

We study the equilibrium liquid structure and dynamics of dilute and concentrated bovine eye lens α-crystallin solutions, using small-angle X-ray scattering, static and dynamic light scattering, viscometry, molecular dynamics simulations, and mode-coupling theory. We find that a polydisperse Percus-Yevick hard-sphere liquid-structure model accurately reproduces both static light scattering data and small-angle X-ray scattering liquid structure data from α-crystallin solutions over an extended range of protein concentrations up to 290 mg/mL or 49% vol fraction and up to ca. 330 mg/mL for static light scattering. The measured dynamic light scattering and viscosity properties are also consistent with those of hard-sphere colloids and show power laws characteristic of an approach toward a glass transition at α-crystallin volume fractions near 58%. Dynamic light scattering at a volume fraction beyond the glass transition indicates formation of an arrested state. We further perform event-driven molecular dynamics simulations of polydisperse hard-sphere systems and use mode-coupling theory to compare the measured dynamic power laws with those of hard-sphere models. The static and dynamic data, simulations, and analysis show that aqueous eye lens α-crystallin solutions exhibit a glass transition at high concentrations that is similar to those found in hard-sphere colloidal systems. The α-crystallin glass transition could have implications for the molecular basis of presbyopia and the kinetics of molecular change during cataractogenesis.

Effect of Argon Plasma Treatment Variables on Wettability and Antibacterial Properties of Polyester Fabrics

Science.gov (United States)

Senthilkumar, Pandurangan; Karthik, Thangavelu

2016-04-01

In this research work, the effect of argon plasma treatment variables on the comfort and antibacterial properties of polyester fabric has been investigated. The SEM micrographs and FTIR analysis confirms the modification of fabric surface. The Box-Behnken design was used for the optimization of plasma process variables and to evaluate the effects and interactions of the process variables, i.e. operating power, treatment time and distance between the electrodes on the characteristics of polyester fabrics. The optimum conditions of operating power 600 W, treatment time 30 s, and the distance between the electrodes of 2.8 mm was arrived using numerical prediction tool in Design-Expert software. The plasma treated polyester fabrics showed better fabric characteristics particularly in terms of water vapour permeability, wickability and antibacterial activity compared to untreated fabrics, which confirms that the modified structure of polyester fabric.

Reactions and Interactions in Liquid Crystalline Media

Science.gov (United States)

1991-10-30

nematic lyophases of potassium laurate, myristyl tri methylammonium bromide or sodium decylsulfate with 1-decanol and 23 water. A strong retardation of the...crystalline polyacrylate crosslinked elastomers were synthesized. 198c 0 0 96 0 0 0O-(CH12 ) 2 -0O(k 97 Crosslinking, up to 10% of structural units produced...in their isotropic state and they work as the transporting phase for the azo-crown ether molecules. The permeation of K+ from a potassium p

A critical review of algal biomass: A versatile platform of bio-based polyesters from renewable resources.

Science.gov (United States)

Noreen, Aqdas; Zia, Khalid Mahmood; Zuber, Mohammad; Ali, Muhammad; Mujahid, Mohammad

2016-05-01

Algal biomass is an excellent renewable resource for the production of polymers and other products due to their higher growth rate, high photosynthetic efficiency, great potential for carbon dioxide fixation, low percentage of lignin and high amount of carbohydrates. Algae contain unique metabolites which are transformed into monomers suitable for development of novel polyesters. This review article mainly focuses on algal bio-refinery concept for polyester synthesis and on exploitation of algae-based biodegradable polyester blends and composites in tissue engineering and controlled drug delivery system. Algae-derived hybrid polyester scaffolds are extensively used for bone, cartilage, cardiac and nerve tissue regeneration due to their biocompatibility and tunable biodegradability. Microcapsules and microspheres of algae-derived polyesters have been used for controlled and continuous release of several pharmaceutical agents and macromolecules to produce humoral and cellular immunity with efficient intracellular delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

Crystallinity and properties of C60 nanotubes improved by annealing and alcohol-soaking

Science.gov (United States)

Naito, K.; Matsuishi, K.

2009-04-01

Well-uniformed C60 nanotubes were grown at -20 °C with irradiation of red light using C60-saturated pyridine solution and isopropyl alcohol by a liquid-liquid interfacial precipitation method without ultrasonic pulverization. We attempted to improve their crystallinity by two post-treatments; thermal annealing and alcohol-soaking. The crystallinity of as-grown and dried C60 nanotubes, which was poor due to the evaporation of solvent molecules from crystals in the drying process, was improved by annealing around 220 °C for 5 hours in vacuum. Dramatic improvement of crystallinity of as-grown samples was achieved by soaking into methanol and then drying in air. Raman, infrared and X-ray diffraction results suggest that the methanol-soaked samples exhibit a solvated tetragonal structure. The crystallinity improved by methanol-soaking did not degrade after removal of methanol molecules from samples by thermal annealing. Photo-polymerization of the structurally-improved C60 nanotubes was examined to investigate an effect of crystallinity on the polymerization kinetics.

Crystallinity and properties of C60 nanotubes improved by annealing and alcohol-soaking

International Nuclear Information System (INIS)

Naito, K; Matsuishi, K

2009-01-01

Well-uniformed C 60 nanotubes were grown at -20 deg. C with irradiation of red light using C 60 -saturated pyridine solution and isopropyl alcohol by a liquid-liquid interfacial precipitation method without ultrasonic pulverization. We attempted to improve their crystallinity by two post-treatments; thermal annealing and alcohol-soaking. The crystallinity of as-grown and dried C 60 nanotubes, which was poor due to the evaporation of solvent molecules from crystals in the drying process, was improved by annealing around 220 deg. C for 5 hours in vacuum. Dramatic improvement of crystallinity of as-grown samples was achieved by soaking into methanol and then drying in air. Raman, infrared and X-ray diffraction results suggest that the methanol-soaked samples exhibit a solvated tetragonal structure. The crystallinity improved by methanol-soaking did not degrade after removal of methanol molecules from samples by thermal annealing. Photo-polymerization of the structurally-improved C 60 nanotubes was examined to investigate an effect of crystallinity on the polymerization kinetics.

Smectic order and backbone anisotropy of a side-chain liquid crystalline polymer by Small-Angle Neutron Scattering

Science.gov (United States)

Noirez, L.; Pépy, G.; Keller, P.; Benguigui, L.

1991-07-01

We have simultaneously measured, for the first time, the extension of the polymer backbone of a side-chain liquid crystalline polymer and the intensity of the 001 Bragg reflection, which gives the smectic order parameter Psi as a function of temperature in the smectic phase. We have qualitatively demonstrated that the more the smectic phase is ordered, the more the polymer backbone is localized between the mesogenic layers. It is shown that the Landau theory allows us to relate the radius of gyration parallel to the magnetic field of the polymer backbone to the smectic order parameter. We also show that the Renz-Warner theory is suitable at low temperatures.

Dipeptide-based polyphosphazene and polyester blends for bone tissue engineering.

Science.gov (United States)

Deng, Meng; Nair, Lakshmi S; Nukavarapu, Syam P; Jiang, Tao; Kanner, William A; Li, Xudong; Kumbar, Sangamesh G; Weikel, Arlin L; Krogman, Nicholas R; Allcock, Harry R; Laurencin, Cato T

2010-06-01

Polyphosphazene-polyester blends are attractive materials for bone tissue engineering applications due to their controllable degradation pattern with non-toxic and neutral pH degradation products. In our ongoing quest for an ideal completely miscible polyphosphazene-polyester blend system, we report synthesis and characterization of a mixed-substituent biodegradable polyphosphazene poly[(glycine ethyl glycinato)(1)(phenyl phenoxy)(1)phosphazene] (PNGEG/PhPh) and its blends with a polyester. Two dipeptide-based blends namely 25:75 (Matrix1) and 50:50 (Matrix2) were produced at two different weight ratios of PNGEG/PhPh to poly(lactic acid-glycolic acid) (PLAGA). Blend miscibility was confirmed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Both blends resulted in higher tensile modulus and strength than the polyester. The blends showed a degradation rate in the order of Matrix2PLAGA in phosphate buffered saline at 37 degrees C over 12 weeks. Significantly higher pH values of degradation media were observed for blends compared to PLAGA confirming the neutralization of PLAGA acidic degradation by polyphosphazene hydrolysis products. The blend components PLAGA and polyphosphazene exhibited a similar degradation pattern as characterized by the molecular weight loss. Furthermore, blends demonstrated significantly higher osteoblast growth rates compared to PLAGA while maintaining osteoblast phenotype over a 21-day culture. Both blends demonstrated improved biocompatibility in a rat subcutaneous implantation model compared to PLAGA over 12 weeks. (c) 2010 Elsevier Ltd. All rights reserved.

Synthesis and characterization of saturated polyester and ...

Indian Academy of Sciences (India)

but which can actually be used for processes, which pro- duce interesting ... ing the synthesis of saturated polyester (from GPET waste). This has been done for the .... The solid product obtained from the glycolysis of PET was bis(hydroxy ethyl ...

Recent developments and future prospects on bio-based polyesters derived from renewable resources: A review.

Science.gov (United States)

Zia, Khalid Mahmood; Noreen, Aqdas; Zuber, Mohammad; Tabasum, Shazia; Mujahid, Mohammad

2016-01-01

A significantly growing interest is to design a new strategy for development of bio-polyesters from renewable resources due to limited fossil fuel reserves, rise of petrochemicals price and emission of green house gasses. Therefore, this review aims to present an overview on synthesis of biocompatible, biodegradable and cost effective polyesters from biomass and their prospective in different fields including packaging, coating, tissue engineering, drug delivery system and many more. Isosorbide, 2,4:3,5-di-O-methylene-d-mannitol, bicyclic diacetalyzed galactaric acid, 2,5-furandicarboxylic acid, citric, 2,3-O-methylene l-threitol, dimethyl 2,3-O-methylene l-threarate, betulin, dihydrocarvone, decalactone, pimaric acid, ricinoleic acid and sebacic acid, are some important monomers derived from biomass which are used for bio-based polyester manufacturing, consequently, replacing the petrochemical based polyesters. The last part of this review highlights some recent advances in polyester blends and composites in order to improve their properties for exceptional biomedical applications i.e. skin tissue engineering, guided bone regeneration, bone healing process, wound healing and wound acceleration. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of fibre treatments on mechanical properties of short Sansevieria cylindrica/polyester composites

International Nuclear Information System (INIS)

Sreenivasan, V.S.; Ravindran, D.; Manikandan, V.; Narayanasamy, R.

2012-01-01

Highlights: ► Fibre treatments were performed to improve interfacial bond between SCF and matrix. ► Mechanical properties of treated SCFP composites are greater than USCFP composites. ► PSCFP composites show maximum mechanical properties among treated SCFP composites. ► SEM analysis revealed that the wetting of PSCFs by the polyester resin was good. ► KMnO 4 treatment is ideal treatment for SCFs to get optimum mechanical properties. -- Abstract: In the present study, to improve the interfacial bond between Sansevieria cylindrica fibres (SCFs) and polyester matrix, chemical surface treatments have been performed on the fibres. Treatments including alkali, benzoyl peroxide, potassium permanganate and stearic acid were carried out to modify the fibre surface. Raw and each type of treated SCF samples were utilised separately for fabricating the composites. The mechanical properties of composites prepared from the chemically treated SCFs are found to be much better than those of the untreated ones. Potassium-permanganate-treated S. cylindrica fibre/polyester (PSCFP) composites showed optimum mechanical properties among the treated S. cylindrica fibre/polyester (SCFP) composites. The surface morphologies of fracture surfaces of composites were recorded using scanning electron microscopy (SEM). The SEM micrographs reveal that interfacial bonding between potassium-permanganate-treated SCF (PSCF) and polyester matrix has significantly improved, suggesting that better dispersion of PSCF into the matrix has occurred upon potassium permanganate treatment of SCF.

THERMAL DEGRADATION OF THERMOTROPIC LIQUID CRYSTALLINE TERPOLYESTERS BASED ON VANILLIC ACID, p-HYDROXYBENZOIC ACID AND POLY(ETHYLENE TEREPHTHALATE)

Institute of Scientific and Technical Information of China (English)

LI Xingui; HUANG Meirong; GUAN Guihe; SUN Tong

1993-01-01

Nine thermotropic liquid crystalline terpolyesters based on vanillic acid(V), p-hydroxybenzoic acid(H) and poly(ethylene terephthalate)(E) were investigated by thermogravimetry to ascertain their thermostability and the kinetic parameters for thermal degradation. Overall activation energy data of the degradation had been calculated over the range 5～70% weight loss. The temperatures and the activation energy of the degradation lie in the ranges of 384～394 ℃ at a heating rate of 1 ℃/min and 176～205 KJ/mol at the weight loss of 5%, respectively, which suggests that the terpolyesters have good thermostability.

Effect of Hydroxyl Monomers on the Enzymatic Degradation of Poly(ethylene succinate, Poly(butylene succinate, and Poly(hexylene succinate

Directory of Open Access Journals (Sweden)

Zhenhui Bai

2018-01-01

Full Text Available Poly(ethylene succinate (PES, poly(butylene succinate (PBS, and poly(hexylene succinate (PHS, were synthesized using succinic acid and different dihydric alcohols as materials. Enzymatic degradability by cutinase of the three kinds of polyesters was studied, as well as their solid-state properties. The biodegradation behavior relied heavily on the distance between ester groups, crystallinity, and the hydrophilicity-hydrophobicity balance of polyester surfaces. The weight loss through degradation of the three kinds of polyesters with different hydroxyl monomers took place in the order PHS > PBS > PES. The degradation behavior of the polyesters before and after degradation was analyzed by scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The decrease in relative intensity at 1800–1650 estedpolyesters were degraded simultaneously. The frequencies of the crystalline and amorphous bands were almost identical before and after degradation. Thus, enzymatic degradation did not change the crystalline structure but destroyed it, and the degree of crystallinity markedly decreased. The molecular weight and polydispersity index only changed slightly. The thermal stability of the three kinds of polyesters decreased during enzymatic degradation.

Preparation and properties of high storage stability polyester polyol dispersion for two-component waterborne polyurethane coating

Science.gov (United States)

Hao, H.; Hu, J. Q.; Wang, F.; Tu, W. P.

2017-01-01

A new type of polyester polyol dispersion with good storage stability was prepared based on a hydrophilic monomer 5-sodium sulfodimethyl isophthalate (5-SIPM), and frequently-used monomers such as neopentyl glycol (NPG), dimethyl terephthalate (DMT), dimethyl phthalate (DMP) and trimethylolpropane (TMP) by the transpolycondensation and polycondensation method. The polyester polyol dispersion was characterized by FTIR and GPC. The proper content of these monomers were determined by the performance of polyester dispersion: the content of TMP was 15wt%, the content of NPG was 7.5wt% and the hydrophilic monomer 5-SIPM content was 5wt%. Two-component waterborne polyurethane (2K-WPU) coatings were prepared by Bayhydur® XP2487/1 and polyester polyol dispersions, which were stored before and after at 40 ° for 6 weeks, the prepared films have no differences in drying time, adhesion, pencil hardness, gloss and chemical resistance, the result also reveals that the polyester polyol dispersion have excellent storage stability resistance.

Neutron shielding performance of water-extended polyester

International Nuclear Information System (INIS)

Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Gallegoc, E.; Lorentec, A.; Hernandez-Davila, V.M.

2006-01-01

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (M.C.N.P. code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

Mechanical Characterization of Cotton Fiber/Polyester Composite Material

Directory of Open Access Journals (Sweden)

Altaf Hussain Rajper

2014-04-01

Full Text Available Development of composite from natural fiber for lower structural application is growing for long-term sustainable perspective. Cotton fiber composite material has the added advantages of high specific strength, corrosion resistance, low cost and low weight compared to glass fiber on the expense of internal components of IC engines. The primary aim of the research study is to examine the effect of the cotton fiber on mechanical properties of lower structural applications when added with the polyester resin. In this paper composite material sample has been prepared by hand Lay-Up process. A mould is locally developed in the laboratory for test sample preparation. Initially samples of polyester resin with appropriate ratio of the hardener were developed and tested. At the second stage yarns of cotton fiber were mixed with the polyester resin and sample specimens were developed and tested. Relative effect of the cotton as reinforcing agent was examined and observed that developed composite specimen possess significant improvement in mechanical properties such as tensile strength was improved as 19.78 % and modulus of elasticity was increased up to 24.81%. Through this research it was also observed that developed composite material was of ductile nature and its density decreases up to 2.6%. Results from this study were compared with relevant available advanced composite materials and found improved mechanical properties of developed composite material

Bicontinuous liquid crystals

CERN Document Server

Lynch, Mathew L

2005-01-01

PrefaceIntroduction AcknowledgmentsBicontinuous Cubic Liquid Crystalline Materials: A Historical Perspective and Modern Assessment; Kr̄e LarssonIntermediate Phases; Michael C. Holmes and Marc S. LeaverCubic Phases and Human Skin: Theory and Practice; Steven Hoath and Lars NorlňThe Relationship between Bicontinuous Inverted Cubic Phases and Membrane Fusion; D.P. SiegelAspects of the Differential Geometry and Topology of Bicontinuous Liquid-Crystalline Phases; Robert W. CorkeryNovel L3 Phases and Their Macroscopic Properties; R. Beck and H. HoffmannBicontinuous Cubic Phases of Lipids with Entra

Acetalised Galactarate Polyesters: Interplay between Chemical Structure and Polymerisation Kinetics

Directory of Open Access Journals (Sweden)

Ionela Gavrila

2018-02-01

Full Text Available In spite of the progress that has made so far in the recent years regarding the synthesis of bio-based polymers and in particular polyesters, only few references address the optimisation of these new reactions with respect to conversion and reaction time. Related to this aspect, we here describe the transesterification reaction of two different acetalised galactarate esters with a model aliphatic diol, 1,6-hexanediol. The kinetics of these two apparently similar reactions is compared, with a focus on the conversion while varying the concentration of a di-butyltin oxide catalyst (DBTO, respectively, the used N2 flow-rate. During the first stage of polymerisation, the molecular weight of the end-products is more than doubled when using a 250 mL/min flow as opposed to an almost static N2 pressure. Additionally, the resulted pre-polymers are subjected to further polycondensation and the comparison between the obtained polyesters is extended to their thermal, mechanical and dielectrical characterisation. The influence of the acetal groups on the stability of the polyesters in acidic conditions concludes the study.

Effect of structural parameters on burning behavior of polyester fabrics having flame retardancy property

Science.gov (United States)

Çeven, E. K.; Günaydın, G. K.

2017-10-01

The aim of this study is filling the gap in the literature about investigating the effect of yarn and fabric structural parameters on burning behavior of polyester fabrics. According to the experimental design three different fabric types, three different weft densities and two different weave types were selected and a total of eighteen different polyester drapery fabrics were produced. All statistical procedures were conducted using the SPSS Statistical software package. The results of the Analysis of Variance (ANOVA) tests indicated that; there were statistically significant (5% significance level) differences between the mass loss ratios (%) in weft and mass loss ratios (%) in warp direction of different fabrics calculated after the flammability test. The Student-Newman-Keuls (SNK) results for mass loss ratios (%) both in weft and warp directions revealed that the mass loss ratios (%) of fabrics containing Trevira CS type polyester were lower than the mass loss ratios of polyester fabrics subjected to washing treatment and flame retardancy treatment.

Development of a readily recyclable sound insulation material made of polyester fibers. Application of the PET fibers from plastic bottles; Recycle kanona jidoshayo polyester sei kyuon zairyo no kaihatsu. Shiyozumi pet bottle zai no insulator zai eno tekiyo

Energy Technology Data Exchange (ETDEWEB)

Nemoto, K; Watanabe, K; Sugawara, H; Minemura, Y [Nissan Motor Co. Ltd., Tokyo (Japan)

1997-10-01

We have developed new polyester sound-absorbing materials made of fine and modified-cross-section polyester fabric. They provide noticeably higher sound-absorbing performance than traditional materials. Another feature of the new materials is their excellent recyclability since they are made of polyester. Application of the new materials to the dash silencer and the floor carpeting produced a great improvement in sound-insulation performance with less weight. 2 refs., 7 figs.

Synthesis of Improved Polyester Resins.

Science.gov (United States)

1979-07-05

of this page) 21. No. of Pages 22. Price* Unclassified Unclassified 83 For sale by the National Technical Information Service, Springfield. Virginia...low sensitivity .... ........... 68 B2B C-scan of carbon fiber reinforced polyester Laminate #2 at high sensitivity ..... .......... 68 B3A C-scan of...right corner, but it is obscured by the delamination. Figure B2B shows the same composite at a 12 decibel increase in sensitivity. The image now shows

Photoinduced anisotropy in a family of amorphous azobenzene polyesters for optical storage

DEFF Research Database (Denmark)

Nedelchev, Lian; Matharu, Avtar S.; Hvilsted, Søren

2003-01-01

of E1aX polymers characterized by two-ring aromatic substituent in the main chain is a good candidate for optical data storage media. A recording energy of approximately 2 J/cm(2) is sufficient to induce high refractive-index modulations of Deltan = 0.13 in these materials, which is retained even......We investigate parameters associated with optical data storage in a variety of amorphous side-chain azobenzene-containing polyesters denoted as E1aX. The polyesters possess a common cyano-substituted azobenzene chromophore as a side chain, but differ in their main-chain polyester composition....... Seventeen different polymers from the E1aX family divided into four classes, depending on the type of the main-chain substituent (one-, two-, and three-ring aromatic or alicyclic) have been thoroughly investigated. Various parameters characterizing the photoinduced birefringence in these materials...

Simulation on the Performance of a Driven Fan Made by Polyester/Epoxy interpenetrate polymer network (IPN)

Science.gov (United States)

Fahrul Hassan, Mohd; Jamri, Azmil; Nawawi, Azli; Zaini Yunos, Muhamad; Fauzi Ahmad, Md; Adzila, Sharifah; Nasrull Abdol Rahman, Mohd

2017-08-01

The main purpose of this study is to investigate the performance of a driven fan design made by Polyester/Epoxy interpenetrate polymer network (IPN) material that specifically used for turbocharger compressor. Polyester/Epoxy IPN is polymer plastics that was used as replacements for traditional polymers and has been widely used in a variety of applications because of their limitless conformations. Simulation based on several parameters which are air pressure, air velocity and air temperature have been carried out for a driven fan design performance of two different materials, aluminum alloy (existing driven fan design) and Polyester/Epoxy IPN using SolidWorks Flow Simulation software. Results from both simulations were analyzed and compared where both materials show similar performance in terms of air pressure and air velocity due to similar geometric and dimension, but Polyester/Epoxy IPN produces lower air temperature than aluminum alloy. This study shows a preliminary result of the potential Polyester/Epoxy IPN to be used as a driven fan design material. In the future, further studies will be conducted on detail simulation and experimental analysis.

Nanoscience with liquid crystals from self-organized nanostructures to applications

CERN Document Server

Li, Quan

2014-01-01

This book focuses on the exciting topic of nanoscience with liquid crystals: from self-organized nanostructures to applications. The elegant self-organized liquid crystalline nanostructures, the synergetic characteristics of liquid crystals and nanoparticles, liquid crystalline nanomaterials, synthesis of nanomaterials using liquid crystals as templates, nanoconfinement and nanoparticles of liquid crystals are covered and discussed, and the prospect of fabricating functional materials is highlighted. Contributions, collecting the scattered literature of the field from leading and active player

Study of the properties and biodegradability of polyester/starch blends submitted to microbial attack

International Nuclear Information System (INIS)

Vinhas, Gloria M.; Almeida, Yeda M.B. de; Lima, Maria Alice Gomes de Andrade; Santos, Livia Almeida

2007-01-01

This work deals with the biodegradation of blends of poly(beta-hydroxybutyrate)/starch and poly(beta-hydroxybutyrate-cohydroxyvalerate)/ starch. The blends were obtained by evaporation of the solvent in the mixture of the polymers in chloroform. Tests were carried out in presence of micro-organisms which acted as biodegradation agents. The blends were consumed as carbon substrate and the production of CO 2 was evaluated in the process. In addition, the polyesters' mechanical properties were reduced by the incorporation of starch in its structure. ( 1 H) NMR and infrared spectroscopy detected some characteristic polyester degradation groups in the polyesters' chemical structure, thus confirming the alteration suffered by it. (author)

Solid-State Polymerization of Poly(Ethylene Furanoate Biobased Polyester, II: An Efficient and Facile Method to Synthesize High Molecular Weight Polyester Appropriate for Food Packaging Applications

Directory of Open Access Journals (Sweden)

Nejib Kasmi

2018-04-01

Full Text Available The goal of this study was to synthesize, through a facile strategy, high molecular weight poly(ethylene furanoate (PEF, which could be applicable in food packaging applications. The efficient method to generate PEF with high molecular weight consists of carrying out a first solid-state polycondensation under vacuum for 6 h reaction time at 205 °C for the resulting polymer from two-step melt polycondensation process, which is catalyzed by tetrabutyl titanate (TBT. A remelting step was thereafter applied for 15 min at 250 °C for the obtained polyester. Thus, the PEF sample was ground into powder, and was then crystallized for 6 h at 170 °C. This polyester is then submitted to a second solid-state polycondensation (SSP carried out at different reaction times (1, 2, 3.5, and 5 h and temperatures 190, 200, and 205 °C, under vacuum. Ultimately, a significant increase in intrinsic viscosity is observed with only 5 h reaction time at 205 °C during the second SSP being needed to obtain very high molecular weight PEF polymer greater than 1 dL/g, which sufficient for manufacturing purposes. Intrinsic viscosity (IV, carboxyl end-group content (–COOH, and thermal properties, via differential scanning calorimetry (DSC, were measured for all resultant polyesters. Thanks to the post-polymerization process, DSC results showed that the melting temperatures of the prepared PEF samples were steadily enhanced in an obvious way as a function of reaction time and temperature increase. It was revealed, as was expected for all SSP samples, that the intrinsic viscosity and the average molecular weight of PEF polyester increased with increasing SSP time and temperature, whereas the number of carboxyl end-group concentration was decreased. A simple kinetic model was also developed and used to predict the time evolution of polyesters IV, as well as the carboxyl and hydroxyl end-groups of PEF during the SSP.

Clinical outcomes after parastomal hernia repair with a polyester monofilament composite mesh

DEFF Research Database (Denmark)

Oma, E; Pilsgaard, B; Jorgensen, L N

2018-01-01

with intraperitoneal placement of a polyester monofilament macroporous composite mesh. METHODS: Data on all patients undergoing parastomal hernia repair with Parietex™ Composite Parastomal Mesh at our institution during a 4-year period were examined. Patients with urostomy were excluded. A team of three experienced...... chronic pain. CONCLUSION: In this study, we found low rates of recurrence and chronic pain following parastomal hernia repair using intraperitoneal reinforcement with a polyester monofilament composite mesh....

Polyester-Based (Bio)degradable Polymers as Environmentally Friendly Materials for Sustainable Development

Science.gov (United States)

Rydz, Joanna; Sikorska, Wanda; Kyulavska, Mariya; Christova, Darinka

2014-01-01

This review focuses on the polyesters such as polylactide and polyhydroxyalkonoates, as well as polyamides produced from renewable resources, which are currently among the most promising (bio)degradable polymers. Synthetic pathways, favourable properties and utilisation (most important applications) of these attractive polymer families are outlined. Environmental impact and in particular (bio)degradation of aliphatic polyesters, polyamides and related copolymer structures are described in view of the potential applications in various fields. PMID:25551604

Distance-dependent metal enhanced fluorescence by flowerlike silver nanostructures fabricated in liquid crystalline phase

Science.gov (United States)

Zhang, Ying; Yang, Chengliang; Zhang, Guiyang; Peng, Zenghui; Yao, Lishuang; Wang, Qidong; Cao, Zhaoliang; Mu, Quanquan; Xuan, Li

2017-10-01

Flowerlike silver nanostructure substrates were fabricated in liquid crystalline phase and the distance dependent property of metal enhanced fluorescence for such substrate was studied for the first time. The distance between silver nanostructures and fluorophore was controlled by the well-established layer-by-layer (LbL) technique constructing alternate layers of poly (allylamine hydrochloride) (PAH) and poly (sodium 4-styrenesulfonate) (PSS). The Rhodamine 6G (R6G) molecules were electrostatically attached to the outmost negative charged PSS layer. The fluorescence enhancement factor of flowerlike nanostructure substrate increased firstly and then decreased with the distance increasing. The best enhanced fluorescence intensity of 71 fold was obtained at a distance of 5.2 nm from the surface of flowerlike silver nanostructure. The distance for best enhancement effect is an instructive parameter for the applications of such substrates and could be used in the practical MEF applications with the flowerlike nanostructure substrates fabricated in such way which is simple, controllable and cost-effective.

The Degradation of Mechanical Properties in Halloysite Nanoclay-Polyester Nanocomposites Exposed in Seawater Environment

Directory of Open Access Journals (Sweden)

Mohd Shahneel Saharudin

2016-01-01

Full Text Available Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nanocomposites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nanoclay-polyester nanocomposites. Results confirmed that the addition of halloysite nanoclay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nanoclay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease. Young’s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease. The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease. The impact toughness dropped from 0.71 kJ/m2 to 0.48 kJ/m2 (32% decrease. Interestingly, the fracture toughness KIC increased with the addition of halloysite nanoclay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nanoclay-matrix interface influenced by seawater absorption and agglomeration of halloysite nanoclay.

Adsorption of uranium ions by crosslinked polyester resin functionalized with acrylic acid from aqueous solutions

International Nuclear Information System (INIS)

Cemal Oezeroglu; Niluefer Metin

2012-01-01

In this paper, the crosslinked polyester resin containing acrylic acid functional groups was used for the adsorption of uranium ions from aqueous solutions. For this purpose, the crosslinked polyester resin of unsaturated polyester in styrene monomer (Polipol 353, Poliya) and acrylic acid as weight percentage at 80 and 20%, respectively was synthesized by using methyl ethyl ketone peroxide (MEKp, Butanox M60, Azo Nobel)-cobalt octoate initiator system. The adsorption of uranium ions on the sample (0.05 g copolymer and 5 mL of U(VI) solution were mixed) of the crosslinked polyester resin functionalized with acrylic acid was carried out in a batch reactor. The effects of adsorption parameters of the contact time, temperature, pH of solution and initial uranium(VI) concentration for U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid were investigated. The adsorption data obtained from experimental results depending on the initial U(VI) concentration were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The adsorption capacity and free energy change were determined by using D-R isotherm. The obtained experimental adsorption data depending on temperature were evaluated to calculate the thermodynamic parameters of enthalpy (ΔH o ), entropy (ΔS o ) and free energy change (ΔG o ) for the U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid from aqueous solutions. The obtained adsorption data depending on contact time were analyzed by using adsorption models such as the modified Freundlich, Elovich, pseudo-first order and pseudo-second-order kinetic models. (author)

Catalyst Influence on Undesired Side Reactions in the Polycondensation of Fully Bio-Based Polyester Itaconates

Directory of Open Access Journals (Sweden)

Ina Schoon

2017-12-01

Full Text Available Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation conditions used on an industrial scale. The α,β-unsaturated double bond of the itaconic acid is prone to side reactions that can lead to the gelation of the polyester resin under standard conditions. This is especially true when bio-based diols such as 1,3-propanediol or 1,4-butanediol are used to obtain resins that are 100% derived from renewable resources. It was observed in earlier studies that high amounts of these aliphatic diols in the polyester lead to low conversion and gelation of the resins. In this work, a catalytic study using different diols was performed in order to elucidate the reasons for this behavior. It was shown that the choice of catalyst has a crucial influence on the side reactions occurring during the polycondensation reactions. In addition, the side reactions taking place were identified and suppressed. These results will allow for the synthesis of polyester itaconates on a larger scale, setting the stage for their industrial application.

Influence of the substituent on azobenzene side-chain polyester optical storage materials

DEFF Research Database (Denmark)

Pedersen, M; Hvilsted, Søren; Holme, NCR

1999-01-01

, chloro, and bromo. C-13 NMR spectroscopic and molecular mass investigations substantiate good film forming characteristics. The optical storage performance of thin polyester films are investigated through polarization holography. The resulting diffraction efficiency is mapped and discussed as a function...... of irradiation power and exposure time. Polytetradecanedioates with cyano-, nitro-, methyl-, fluoro-, or trinuoromethyl-azobenzene reach more than 50% diffraction efficiency. Investigations of anisotropy induced at different temperatures reveal that the polyesters are only photosensitive in a narrow temperature...

Micro-thermal analysis of polyester coatings

Science.gov (United States)

Fischer, Hartmut R.

2010-04-01

The application and suitability of micro-thermal analysis to detect changes in the chemical and physical properties of coating due to ageing and especially photo-degradation is demonstrated using a model polyester coating based on neopentyl glycol isophthalic acid. The changes in chemical structure like chain scission and cross-linking are manifested by a shift of the LTA detectable Tg and by a change of the slope of the part of the LTA graph responsible for the penetration of the hot sensor into the material after passing the glass transition temperature. As such LTA is a valuable tool to have a quick look into coating surfaces and especially their ageing. The photo-degradation of polyester in air leads to the formation of a cross-linked network at a surface layer of about 3-4 μm coupled with an increase in hardness and of the glass transition temperature by ˜90 K, the effect is less drastic for a photo-degradation in a nitrogen environment. Moreover, the presence of a non-equilibrium dense surface layer with a higher Tg formed during the drying of the coating formulation and the film solidification can be shown.

Study on Energy Absorption Capacity of Steel-Polyester Hybrid Fiber Reinforced Concrete Under Uni-axial Compression

Science.gov (United States)

Chella Gifta, C.; Prabavathy, S.

2018-05-01

This work presents the energy absorption capacity of hybrid fiber reinforced concrete made with hooked end steel fibers (0.5 and 0.75%) and straight polyester fibers (0.5, 0.8, 1.0 and 2.0%). Compressive toughness (energy absorption capacity) under uni-axial compression was evaluated on 100 × 200 mm size cylindrical specimens with varying steel and polyester fiber content. Efficiency of the hybrid fiber reinforcement is studied with respect to fiber type, size and volume fractions in this investigation. The vertical displacement under uni-axial compression was measured under the applied loads and the load-deformation curves were plotted. From these curves the toughness values were calculated and the results were compared with steel and polyester as individual fibers. The hybridization of 0.5% steel + 0.5% polyester performed well in post peak region due to the addition of polyester fibers with steel fibers and the energy absorption value was 23% greater than 0.5% steel FRC. Peak stress values were also higher in hybrid series than single fiber and based on the results it is concluded that hybrid fiber reinforcement improves the toughness characteristics of concrete without affecting workability.

Dual quantification of dapivirine and maraviroc in cervicovaginal secretions from ophthalmic tear strips and polyester-based swabs via liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis.

Science.gov (United States)

Parsons, Teresa L; Emory, Joshua F; Seserko, Lauren A; Aung, Wutyi S; Marzinke, Mark A

2014-09-01

Topical microbicidal agents are being actively pursued as a modality to prevent HIV viral transmission during sexual intercourse. Quantification of antiretroviral agents in specimen sources where antiviral activity is elicited is critical, and drug measurements in cervicovaginal fluid can provide key information on local drug concentrations. Two antiretroviral drugs, dapivirine and maraviroc, have gained interest as vaginal microbicidal agents, and rugged methods are required for their quantification in cervicovaginal secretions. Cervicovaginal fluid spiked with dapivirine and maraviroc were applied to ophthalmic tear strips or polyester-based swabs to mimic collection procedures used in clinical studies. Following sample extraction and the addition of isotopically labeled internal standards, samples were subjected to liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis using a Waters BEH C8, 50mm×2.1mm, 1.7μm particle size column, on an API 4000 mass analyzer operated in selective reaction monitoring mode. The method was validated according to FDA Bioanalytical Method Validation guidelines. Due to the disparate saturation capacity of the tested collection devices, the analytical measuring ranges for dapivirine and maravirocin cervicovaginal fluid on the ophthalmic tear strip were 0.05-25ng/tear strip, and 0.025-25ng/tear strip, respectively. As for the polyester-based swab, the analytical measuring ranges were 0.25-125ng/swab for dapivirine and 0.125-125ng/swab for maraviroc. Dilutional studies were performed for both analytes to extended ranges of 25,000ng/tear strip and 11,250ng/swab. Standard curves were generated via weighted (1/x(2)) linear or quadratic regression of calibrators. Precision, accuracy, stability and matrix effects studies were all performed and deemed acceptable according to the recommendations of the FDA Bioanalytical Method Validation guidelines. A rugged LC-MS/MS method for the dual quantification of dapivirine and

Nano-biocomposites based on synthetic aliphatic polyesters and nanoclay

CSIR Research Space (South Africa)

Ojijo, Vincent O

2014-05-01

Full Text Available This article gives an overview of the recent developments in the preparation, characterisation, properties, crystallisation behaviour, and melt rheology of clay-containing composites of biodegradable synthetic aliphatic polyesters such as poly...

Radioluminescence of polyester resin modified with acrylic acid and its salts

Science.gov (United States)

Szalińska, H.; Wypych, M.; Pietrzak, M.; Szadkowska-Nicze, M.

Polimal-109 polyester resin and its compounds containing acrylic acid and its salts such as: sodium, potassium, magnesium, calcium, barium, iron, cobalt, copper and manganese acrylates were studied by the radioluminescence method, including isothermal luminescence (ITL) at a radiation temperature of 77 K, thermoluminescence (RTL) and spectral distributions of isothermal luminescence. Measurements of optical absorption at 77 K before and after irradiation of the investigated samples were also carried out. The results obtained have shown that metal ions play a significant part in the processes taking place in the polyester matrix under the influence of γ 60Co radiation.

Radioluminescence of polyester resin modified with acrylic acid and its salts

International Nuclear Information System (INIS)

Szalinska, H.; Wypych, M.; Pietrzak, M.; Szadkowska-Nicze, M.

1987-01-01

Polimal-109 polyester resin and its compounds containing acrylic acid and its salts such as: sodium, potassium, magnesium, calcium, barium, iron, cobalt, copper and manganese acrylates were studied by the radioluminescence method, including isothermal luminescence (ITL) at a radiation temperature of 77 K, thermoluminescence (RTL) and spectral distributions of isothermal luminescence. Measurements of optical absorption at 77K before and after irradiation of the investigated samples were also carried out. The results obtained have shown that metal ions play a significant part in the processes taking place in the polyester matrix under the influence of γ 60 Co radiation. (author)

Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

Science.gov (United States)

Özkan, İ.; Duru Baykal, P.

2017-10-01

In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

Photoinduced Circular Anisotropy in Side-Chain Azobenzene Polyesters

DEFF Research Database (Denmark)

Nikolova, L.; Todorov, T.; Ivanov, M.

1997-01-01

We report for the first time the inducing of large circular anisotropy in previously unoriented films of side-chain azobenzene polyesters on illumination with circularly polarized light at a wavelength of 488 nm. The circular dichroism and optical activity are measured simultaneously in real time...

Prevention of primary vascular graft infection with silver-coated polyester graft in a porcine model

DEFF Research Database (Denmark)

Gao, H; Sandermann, J; Prag, J

2010-01-01

To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model.......To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model....

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

Directory of Open Access Journals (Sweden)

Xiaoling Liu

2013-01-01

Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

Glycation precedes lens crystallin aggregation

International Nuclear Information System (INIS)

Swamy, M.S.; Perry, R.E.; Abraham, E.C.

1987-01-01

Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [ 3 H]NaBH 4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

Protoenzymes: the case of hyperbranched polyesters

Science.gov (United States)

Mamajanov, Irena; Cody, George D.

2017-11-01

Enzymes are biopolymeric complexes that catalyse biochemical reactions and shape metabolic pathways. Enzymes usually work with small molecule cofactors that actively participate in reaction mechanisms and complex, usually globular, polymeric structures capable of specific substrate binding, encapsulation and orientation. Moreover, the globular structures of enzymes possess cavities with modulated microenvironments, facilitating the progression of reaction(s). The globular structure is ensured by long folded protein or RNA strands. Synthesis of such elaborate complexes has proven difficult under prebiotically plausible conditions. We explore here that catalysis may have been performed by alternative polymeric structures, namely hyperbranched polymers. Hyperbranched polymers are relatively complex structures that can be synthesized under prebiotically plausible conditions; their globular structure is ensured by virtue of their architecture rather than folding. In this study, we probe the ability of tertiary amine-bearing hyperbranched polyesters to form hydrophobic pockets as a reaction-promoting medium for the Kemp elimination reaction. Our results show that polyesters formed upon reaction between glycerol, triethanolamine and organic acid containing hydrophobic groups, i.e. adipic and methylsuccinic acid, are capable of increasing the rate of Kemp elimination by a factor of up to 3 over monomeric triethanolamine. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Reactive modification of polyesters and their blends

Science.gov (United States)

Wan, Chen

2004-12-01

As part of a broader research effort to investigate the chemical modification of polyesters by reactive processing a low molecular weight (MW) unsaturated polyester (UP) and a higher MW saturated polyester, polyethylene terephthalate (PET), alone or blended with polypropylene (PP) were melt processed in a batch mixer and continuous twin screw extruders. Modification was monitored by on-line rheology and the products were characterized primarily by off-line rheology, morphology and thermal analysis. Efforts were made to establish processing/property relationships and provide an insight of the accompanying structural changes. The overall response of the reactively modified systems was found to be strongly dependent on the component characteristics, blend composition, type and concentrations of reactive additives and processing conditions. The work concluded that UP can be effectively modified through reactive melt processing. Its melt viscosity and MW can be increased through chemical reactions between organic peroxides (POX) and chain unsaturation or between MgO and carboxyl/hydroxyl end groups. Reactive blending of PP/UP blends through peroxide modification gave finer and more uniform morphology than unreacted blends and at a given PP/UP weight ratio more thermoplastic elastomers-like rheological behavior. This is due to the continuously decreasing viscosity ratio of PP/UP towards unity by the competing reactions between POX and the blend components and formation of PP-UP copolymers which serve as in-situ compatibilizers to promote better interfacial adhesion. Kinetics of the competing reactions were analyzed through a developed model. In addition to POX concentration and mixing efficiency, rheology and morphology of UP/PP bends were significantly affected by the addition of inorganic and organic coagents. Addition of coagents such as a difunctional maleimide, MgO and/or an anhydride functionalized PP during reactive blending offers effective means for tailoring

Entrapment of curcumin into monoolein-based liquid crystalline nanoparticle dispersion for enhancement of stability and anticancer activity

Directory of Open Access Journals (Sweden)

Baskaran R

2014-06-01

Full Text Available Rengarajan Baskaran,1 Thiagarajan Madheswaran,2 Pasupathi Sundaramoorthy,1 Hwan Mook Kim,1 Bong Kyu Yoo1 1College of Pharmacy, Gachon University, Incheon, South Korea; 2College of Pharmacy Yeungnam University, Gyeongsan, South Korea Abstract: Despite the promising anticancer potential of curcumin, its therapeutic application has been limited, owing to its poor solubility, bioavailability, and chemical fragility. Therefore, various formulation approaches have been attempted to address these problems. In this study, we entrapped curcumin into monoolein (MO-based liquid crystalline nanoparticles (LCNs and evaluated the physicochemical properties and anticancer activity of the LCN dispersion. The results revealed that particles in the curcumin-loaded LCN dispersion were discrete and monodispersed, and that the entrapment efficiency was almost 100%. The stability of curcumin in the dispersion was surprisingly enhanced (about 75% of the curcumin survived after 45 days of storage at 40°C, and the in vitro release of curcumin was sustained (10% or less over 15 days. Fluorescence-activated cell sorting (FACS analysis using a human colon cancer cell line (HCT116 exhibited 99.1% fluorescence gating for 5 µM curcumin-loaded LCN dispersion compared to 1.36% for the same concentration of the drug in dimethyl sulfoxide (DMSO, indicating markedly enhanced cellular uptake. Consistent with the enhanced cellular uptake of curcumin-loaded LCNs, anticancer activity and cell cycle studies demonstrated apoptosis induction when the cells were treated with the LCN dispersion; however, there was neither noticeable cell death nor significant changes in the cell cycle for the same concentration of the drug in DMSO. In conclusion, entrapping curcumin into MO-based LCNs may provide, in the future, a strategy for overcoming the hurdles associated with both the stability and cellular uptake issues of the drug in the treatment of various cancers. Keywords: liquid

Lanthanide Phytanates: Liquid-Crystalline Phase Behavior, Colloidal Particle Dispersions, and Potential as Medical Imaging Agents

Energy Technology Data Exchange (ETDEWEB)

Conn, Charlotte E.; Panchagnula, Venkateswarlu; Weerawardena, Asoka; Waddington, Lynne J.; Kennedy, Danielle F.; Drummond, Calum J. (CSIRO/MHT); (CSIRO/MSE)

2010-08-23

Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy. Several of the hydrated salts form a liquid-crystalline hexagonal columnar mesophase at room temperature, and samarium(III) phytanate forms this phase even in the absence of water. Select lanthanide phytanates were dispersed in water, and cryo-TEM images indicate that some structure has been retained in the dispersed phase. NMR relaxivity measurements were conducted on these systems. It has been shown that a particulate dispersion of gadolinium(III) phytanate displays proton relaxivity values comparable to those of a commercial contrast agent for magnetic resonance imaging and a colloidal dispersion of europium(III) phytanate exhibits the characteristics of a fluorescence imaging agent.

Lanthanide Phytanates: Liquid-Crystalline Phase Behavior, Colloidal Particle Dispersions, and Potential as Medical Imaging Agents

International Nuclear Information System (INIS)

Conn, Charlotte E.; Panchagnula, Venkateswarlu; Weerawardena, Asoka; Waddington, Lynne J.; Kennedy, Danielle F.; Drummond, Calum J.

2010-01-01

Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy. Several of the hydrated salts form a liquid-crystalline hexagonal columnar mesophase at room temperature, and samarium(III) phytanate forms this phase even in the absence of water. Select lanthanide phytanates were dispersed in water, and cryo-TEM images indicate that some structure has been retained in the dispersed phase. NMR relaxivity measurements were conducted on these systems. It has been shown that a particulate dispersion of gadolinium(III) phytanate displays proton relaxivity values comparable to those of a commercial contrast agent for magnetic resonance imaging and a colloidal dispersion of europium(III) phytanate exhibits the characteristics of a fluorescence imaging agent.

Quasi-static axial crushes on woven jute/polyester AA6063T52 composite tubes

Science.gov (United States)

Othman, A.; Ismail, AE

2018-04-01

Quasi-static axial loading have been studied in this paper to determine the behaviour of jute/polyester wrapped on aluminium alloy 6063T52. The filler material also was include into crush box specimen, which is polyurethane (PU) and polystyrene (PE) rigid foam at ranging 40 and 45 kg/m3 densities. All specimen profile was fabricated using hand layup techniques and the length of each specimen were fixed at 100 mm as well as diameter and width of the tube at 50.8 mm. The two types of tubular cross-section were studied of round and square thin-walled profiles and the angle of fibre at 450 were analysed for four layers. Thin walled of aluminium was 1.9 mm and end frontal of each specimen of composite were chamfered at 450 to prevent catastrophic failure mode. The specific absorbed energy (SEA) and crush force efficiency (CFE) were analyses for each specimen to see the behaviour on jute/polyester wrapped on metallic structure can give influence the energy management for automotive application. Result show that the four layers’ jute/polyester with filler material show significant value in term of specific absorbed energy compared empty and polyurethane profiles higher 26.66% for empty and 15.19% compared to polyurethane profiles. It has been found that the thin walled square profile of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 27.42% to 13.13% than empty and polyurethane (PU) foam tubes. An introduce filler material onto thin walled composite profiles gave major advantage increases the mean axial load of 31.87% from 32.94 kN to 48.35 kN from empty to polystyrene thin walled round jute/polyester profiles and 31.7% from 23.11 KN to 33.84 kN from empty to polystyrene thin walled square jute/polyester profiles. Failure mechanisms of the axially loaded composite tubes were also observed and discussed.

Effect of nanomodified polyester resin on hybrid sandwich laminates

International Nuclear Information System (INIS)

Anbusagar, NRR.; Giridharan, P.K.; Palanikumar, K.

2014-01-01

Highlights: • Effect of nanomodified polyester resin on hybrid sandwich laminates is evaluated. • The hybrid sandwich laminates are fabricated with varying wt% of nanoclay. • Flexural, impact and moisture absorbtion properties are evaluated for hybrid composites. • Scanning electron microscopy is utilized to analyze the dispersion of clay and fractured surfaces of the nanocomposites. - Abstract: Effect of nanoclay modified polyester resin on flexural, impact, hardness and water absorption properties of untreated woven jute and glass fabric hybrid sandwich laminates have been investigated experimentally. The hybrid sandwich laminates are prepared by hand lay-up manufacturing technique (HL) for investigation. All hybrid sandwich laminates are fabricated with a total of 10 layers, by varying the extreme layers and wt% of nanoclay in polyester resin so as to obtain four different combinations of hybrid sandwich laminates. For comparison of the composite with hybrid composite, jute fiber reinforced composite laminate also fabricated. X-ray diffraction (XRD) results obtained from samples with nanoclay indicated that intergallery spacing of the layered clay increases with matrix. Scanning electron microscopy (SEM) gave a morphological picture of the cross-sections and energy dispersive X-ray spectroscopy (EDS) allowed investigating the elemental composition of matrix in composites. The testing results indicated that the flexural properties are greatly increased at 4% of nanoclay loading while impact, hardness and water absorption properties are increased at 6% of nanoclay loading. A plausible explanation for high increase of properties has also been discussed

Corona Glow Discharge Plasma Treatment for Hidrophylicity Improvement of Polyester and Cotton Fabrics

Science.gov (United States)

Susan, A. I.; Widodo, M.; Nur, M.

2017-07-01

The effects of irradiation by a corona glow discharge plasma on hidrophylicity properties of polyester and cotton fabrics were investigated. We used a corona glow discharge plasma reactor with multiple points to plane electrodes, which was generated by a high voltage DC. Factors that affect the hidrophylicity properties were identified and evaluated as functions of irradiation parameters, which include duration of treatment, distance between electrodes, and bias voltage. It was readily observed from SEM examinations that plasma changed the surface morphology of both polyester and cotton fibers, giving result to an increased roughness to both of them. Results also showed that the hidrophylicityof polyester and cotton fabrics improved by the treatment, which is proportional to the time of treatment and voltage, but inversely proportional to the distance between electrodes. Time of treatment that provided the optimum enhancement of hidrophylicity for cotton is 15 minutes which improved the wetting time from 8.16 seconds to 1.26 seconds. For polyester, it took 15 minutes of irradiation time to improve the wetting time from 7340 seconds to 2905 seconds. The optimum distance between electrodes for both fabrics in this study was found to be 2 cm. Further analysis showed that the improved hidrophylicity properties is due to the creation of surface radicals by free radicals in the plasma leading to the formation of new water-attracting functional groups on the fiber surface.

Novel organometallic aromatic polyester based on ferrocene

Institute of Scientific and Technical Information of China (English)

Wei

2010-01-01

A novel polyester containing ferrocenyl was prepared by low-temperature interface polycondensation of 1,1'-ferrocenedi-carboxylic acid chloride with 4-(4-hydroxyphenyl)-2,3-phthalazin-l-one(DHPZ), which is a twisted non-coplanar heterocyclic bisphenol-like monomer. The newly generated polymer was evaluated based on characterization of its solubility, viscosity measurements, elemental analysis, FTIR spectroscopy, differential scanning calorimetric and thermogravimetric studies.

Minimalistic Liquid-Assisted Route to Highly Crystalline α-Zirconium Phosphate.

Science.gov (United States)

Cheng, Yu; Wang, Xiaodong Tony; Jaenicke, Stephan; Chuah, Gaik-Khuan

2017-08-24

Zirconium phosphates have potential applications in areas of ion exchange, catalysis, photochemistry, and biotechnology. However, synthesis methodologies to form crystalline α-zirconium phosphate (Zr(HPO 4 ) 2 ⋅H 2 O) typically involve the use of excess phosphoric acid, addition of HF or oxalic acid and long reflux times or hydrothermal conditions. A minimalistic sustainable route to its synthesis has been developed by using only zirconium oxychloride and concentrated phosphoric acid to form highly crystalline α-zirconium phosphate within hours. The morphology can be changed from platelets to rod-shaped particles by fluoride addition. By varying the temperature and time, α-zirconium phosphate with particle sizes from nanometers to microns can be obtained. Key features of this minimal solvent synthesis are the excellent yields obtained with high atom economy under mild conditions and ease of scalability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sulfonation of polyester fabrics by gaseous sulfur oxide activated by UV irradiation

International Nuclear Information System (INIS)

Kordoghli, Bessem; Khiari, Ramzi; Mhenni, Mohamed Farouk; Sakli, Faouzi; Belgacem, Mohamed Naceur

2012-01-01

Highlights: ► In this paper, an original technique was present to improve the hydrophilic properties of polyester fibres. ► The modification of PET fabric was carried out using gaseous sulfur trioxide activated by UV irradiations. ► We fully characterized the modified and untreated fabrics. - Abstract: This paper describes an original technique aiming to improve the hydrophilic properties of polyester fibres. In this method, the sulfonation of the aromatic rings is carried out using gaseous sulfur trioxide activated by UV irradiations. Thus, exposing the polyester textile fabric to the UVC light (wavelength around 254 nm) under a stream of sulfur trioxide leads to the fixation of -SO 3 H groups. The amounts of the fixed sulfonate groups depended on the reaction conditions. Evidence of grafting deduced from the measurements of hygroscopic properties was carried out by contact angle measurement, moisture regain as well as by measuring the rate of retention. SEM and FT-IR analysis, DSC and DTA/TGA thermograms showed that no significant modifications have occurred in the bulk of the treated PET fabrics.

Soil-release behaviour of polyester fabrics after chemical modification with polyethylene glycol

Science.gov (United States)

Miranda, T. M. R.; Santos, J.; Soares, G. M. B.

2017-10-01

The fibres cleanability depends, among other characteristics, on their hydrophilicity. Hydrophilic fibres are easy-wash materials but hydrophobic fibres are difficult to clean due to their higher water-repellent surfaces. This type of surfaces, like polyester (PET), produce an accumulation of electrostatic charges, which favors adsorption and retention of dirt. Thus, the polyester soil-release properties can be increased by finishing processes that improve fiber hydrophilicity. In present study, PET fabric modification was described by using poly(ethylene glycol) (PEG) and N,N´-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) chemically modified resin. Briefly, the modification process was carried out in two steps, one to hydrolyse the polyester and create hydroxyl and carboxylic acid groups on the surface and other to crosslink the PEG chains. The resulting materials were characterized by contact angle, DSC and FTIR-ATR methods. Additionally, the soil release behavior and the mechanical properties of modified PET were evaluated. For the best process conditions, the treated PET presented 0° contact angle, grade 5 stain release and acceptable mechanical performance.

Thread angle dependency on flame spread shape over kenaf/polyester combined fabric

Science.gov (United States)

Azahari Razali, Mohd; Sapit, Azwan; Nizam Mohammed, Akmal; Nor Anuar Mohamad, Md; Nordin, Normayati; Sadikin, Azmahani; Faisal Hushim, Mohd; Jaat, Norrizam; Khalid, Amir

2017-09-01

Understanding flame spread behavior is crucial to Fire Safety Engineering. It is noted that the natural fiber exhibits different flame spread behavior than the one of the synthetic fiber. This different may influences the flame spread behavior over combined fabric. There is a research has been done to examined the flame spread behavior over kenaf/polyester fabric. It is seen that the flame spread shape is dependent on the thread angle dependency. However, the explanation of this phenomenon is not described in detail in that research. In this study, explanation about this phenomenon is given in detail. Results show that the flame spread shape is dependent on the position of synthetic thread. For thread angle, θ = 0°, the polyester thread is breaking when the flame approach to the thread and the kenaf thread tends to move to the breaking direction. This behavior produces flame to be ‘V’ shape. However, for thread angle, θ = 90°, the polyester thread melts while the kenaf thread decomposed and burned. At this angle, the distance between kenaf threads remains constant as flame approaches.

Dsc cure kinetics of an unsaturated polyester resin using empirical kinetic model

International Nuclear Information System (INIS)

Abdullah, I.

2015-01-01

In this paper, the kinetics of curing of unsaturated polyester resin initiated with benzoyl peroxide was studied. In case of unsaturated polyester (UP) resin, isothermal test alone could not predict correctly the curing time of UP resin. Therefore, isothermal kinetic analysis through isoconventional adjustment was used to correctly predict the curing time and temperature of UP resin. Isothermal kinetic analysis through isoconversional adjustment indicated that 97% of UP resin cures in 33 min at 120 degree C. Curing of UP resin through microwaves was also studied and found that 67% of UP resin cures in 1 min at 120 degree C. The crosslinking reaction of UP resin is so fast at 120 degree C that it becomes impossible to predict correctly the curing time of UP resin using isothermal test and the burial of C=C bonds in microgels makes it impossible to be fully cured by microwaves at 120 degree C. The rheological behaviour of unsaturated polyester resin was also studied to observe the change in viscosity with respect to time and temperature. (author)

PH-Induced Nanosegregation of Ritonavir to Lyotropic Liquid Crystal of Higher Solubility Than Crystalline Polymorphs

International Nuclear Information System (INIS)

Rodriguez-Spong, B.; Acciacca, A.; Fleisher, D.; Rodriguez-Hornedo, N.

2009-01-01

Birefringent spherical vesicles of ritonavir (RTV) are formed by increasing the pH of aqueous solutions from 1 to 3 or to 7 and by addition of water to ethanol solutions at room temperature. Increasing the pH creates supersaturation levels of 30--400. Upon this change in pH, the solutions become translucent, implying that some kind of RTV assembly was formed. Small spherical vesicles of narrow size distribution are detectable only after a few hours by optical microscopy. The vesicles show similar X-ray diffraction patterns and differential scanning calorimetry (DSC) behavior to amorphous RTV prepared by melt-quenching crystalline RTV. Examination by polarized optical microscopy suggests that these are lyotropic liquid crystalline (LLC) assemblies. Small-angle X-ray scattering and synchrotron X-ray diffraction further support the presence of orientational order that is associated with a nematic structure. RTV self-organizes into various phases as a result of the supersaturation created in aqueous solutions. The LLC vesicles do not fuse but slowly transform to the polymorphs of RTV (in days), Form I and finally Form II. Amorphous RTV in aqueous suspension also undergoes a transformation to a mesophase of similar morphology. Transformation pathways are consistent with measured dissolution rates and solubilities: amorphous > LLC >> Form I > Form II. The dissolution and solubility of LLC is slightly lower than that of the amorphous phase and about 20 times higher than that of Form II. RTV also self-assembles at the air/water interface as indicated by the decrease in surface tension of aqueous solutions. This behavior is similar to that of amphiphilic molecules that induce LLC formation.

Formulation and development of bicontinuous nanostructured liquid crystalline particles of efavirenz.

Science.gov (United States)

Avachat, Amelia M; Parpani, Shreekrishna S

2015-02-01

Efavirenz is a lipophilic non-nucleoside reverse transcriptase inhibitor used in the first-line pediatric therapeutic cocktail. Due to its high lipophilicity (logP = 5.4) and poor aqueous solubility (intrinsic water solubility = 8.3 μg/mL) efavirenz has low bioavailability. A 30 mg/mL solution in a medium-chain triglyceride vehicle is the only pediatric formulation available with an oral bioavailability 20% lower than the solid form. The current work was aimed at formulating and characterizing liquid crystal nanoparticles for oral delivery of efavirenz to improve oral bioavailability, provide sustained release, minimize side effects and drug resistance. Formulation of cubosomes was done by two methods; sonication and spray drying. Sonication gave highest entrapment efficiency and least particle size. Further, monoolein was substituted with phytantriol as monoolein gets degraded in the presence of lipase when administered orally with consequent loss of liquid crystalline structure. It was confirmed that there was no difference in particle size, entrapment efficiency and nature of product formed by using monoolein or phytantriol. The best formulation was found to be F9, having particle size 104.19 ± 0.21 nm and entrapment efficiency 91.40 ± 0.10%. In vitro release at the end of 12h was found to be 56.45% and zeta potential to be -23.14 mV which stabilized the cubic phase dispersions. It was further characterized for TEM, small angle X-ray scattering (SAXS), DSC and stability studies. SAXS revealed Pn3m space group, indicating a diamond cubic phase which was further confirmed by TEM. Pharmacokinetics of EFV was studied in male Wistar rats. EFV-loaded cubosome dispersions exhibited 1.93 and 1.62-fold increase in peak plasma concentration (Cmax) and 1.48 and 1.42-fold increase in AUC in comparison to that of a suspension prepared with the contents of EFV capsules suspended in 1.5% carboxymethylcellulose PBS solution (pH 5.0), and an EFV solution in medium

The Degradation of Mechanical Properties in Halloysite Nano clay-Polyester Nano composites Exposed in Seawater Environment

International Nuclear Information System (INIS)

Saharudin, M.S.; Saharudin, M. Sh.; Wei, J.; Shyha, I.; Inam, F.

2016-01-01

Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nano composites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nano clay-polyester nano composites. Results confirmed that the addition of halloysite nano clay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nano clay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease). Young s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease). The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease). The impact toughness dropped from 0.71 kJ/m"2 to 0.48 kJ/m"2 (32% decrease). Interestingly, the fracture toughnessκ_1C increased with the addition of halloysite nano clay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nano clay-matrix interface influenced by seawater absorption and agglomeration of halloysite nano clay.

Attenuation of Thermal Neutrons by Crystalline Silicon

International Nuclear Information System (INIS)

Adib, M.; Habib, N.; Ashry, A.; Fathalla, M.

2002-01-01

A simple formula is given which allows to calculate the contribution of the total neutron cross - section including the Bragg scattering from different (hkt) planes to the neutron * transmission through a solid crystalline silicon. The formula takes into account the silicon form of poly or mono crystals and its parameters. A computer program DSIC was developed to provide the required calculations. The calculated values of the total neutron cross-section of perfect silicon crystal at room and liquid nitrogen temperatures were compared with the experimental ones. The obtained agreement shows that the simple formula fits the experimental data with sufficient accuracy .A good agreement was also obtained between the calculated and measured values of polycrystalline silicon in the energy range from 5 eV to 500μ eV. The feasibility study on using a poly-crystalline silicon as a cold neutron filter and mono-crystalline as a thermal neutron one is given. The optimum crystal thickness, mosaic spread, temperature and cutting plane for efficiently transmitting the thermal reactor neutrons, while rejecting both fast neutrons and gamma rays accompanying the thermal ones for the mono crystalline silicon are also given

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chunming, E-mail: zcm1229@126.com [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Sunvim Grp Co Ltd, Gaomi 261500 (China); Zhao, Meihua; Wang, Libing; Qu, Lijun [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Men, Yajing [Sunvim Grp Co Ltd, Gaomi 261500 (China)

2017-04-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

International Nuclear Information System (INIS)

Zhang, Chunming; Zhao, Meihua; Wang, Libing; Qu, Lijun; Men, Yajing

2017-01-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Electrically Reconfigurable Liquid Crystalline Mirrors (Postprint)

Science.gov (United States)

2018-04-24

focus on dynamic reconfiguration of the reflection band gap of polymer-stabilized cholesteric liquid crystals (PSCLCs). Recent research has reported the...public release: distribution unlimited. © 2018 AMERICAN CHEMICAL SOCIETY (STINFO COPY) AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING...MONITORING AGENCY ACRONYM(S) Air Force Research Laboratory Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH

Structure, mechanical and thermal behaviour of mixtures of polyester resin and dental ceramic waste

Science.gov (United States)

Peña Rodríguez, G.; Martínez Maldonado, L.; Dulce Moreno, H. J.

2016-02-01

The tensile strength and bending strength, structure and thermal behaviour of mixtures of polyester resin (P-2000) and powders (ASTM sieve 200, dental ceramic wastes (dentals impressions, alginate and gypsum) was reported. The samples consisted of mixtures with percentage weights of 50-50%, 60-40%, 70-30%, 80-20%, 90-10%, where the resin was the majority phase, the Mekc (4% wt) was used as catalyst. The structure was studied using SEM and XRD, the thermal behaviour using DSC, TGA and DMA, while the mechanical strength was tested using standards ASTM D790 and D638. Irregular morphology and presence of small agglomerations was observed, with particle sizes between 29.63 and 38.67μm, the presence of different phases of calcium sulphate was found, and that to the increasing the concentration of the powder, the materials becomes more crystalline, increasing its density. An average service temperature of 69.15±4.60°C was found. Vickers hardness values are reported in ranges from 18.65 to 27.96. Considering the elastic modules was established that the materials become more rigid by having more powder concentration.

Dyeing of Polyester with Disperse Dyes: Part 2. Synthesis and Dyeing Characteristics of Some Azo Disperse Dyes for Polyester Fabrics

Directory of Open Access Journals (Sweden)

Alya M. Al-Etaibi

2016-06-01

Full Text Available The goal of this study was to utilize carrier for accelerating the rate of dyeing not only to enhance dyeing of polyester fabrics dyed with disperse dyes 3a,b, but also to save energy. Both the color strength expressed as dye uptake and the fastness properties of the dyed fabrics were evaluated.

Liquid alloys: New perspectives and challenges

International Nuclear Information System (INIS)

Saboungi, M.L.; Leonard, S.R.; Johnson, G.K.; Price, D.L.

1987-12-01

In this paper, we will focus on one of many unusual liquid semiconducting alloys, K-Pb. The thermodynamic and electrical properties will be discussed and analyzed in terms of a disorder model introduced first by Wagner for crystalline semiconductors. The structure of the equiatomic alloy will be presented; interpretation of the first sharp diffraction peak in the total structure factor is based on the local structures in the crystalline phase and should be viewed as an example of the interrelation between the solid and liquid properties

Liquid crystals for organic thin-film transistors

Science.gov (United States)

Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-Ichi

2015-04-01

Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), for FETs and synthesize it. This material provides uniform and molecularly flat polycrystalline thin films reproducibly when SmE precursor thin films are crystallized, and also exhibits high durability of films up to 200 °C. In addition, the mobility of FETs is dramatically enhanced by about one order of magnitude (over 10 cm2 V-1 s-1) after thermal annealing at 120 °C in bottom-gate-bottom-contact FETs. We anticipate the use of SmE liquid crystals in solution-processed FETs may help overcome upcoming difficulties with novel technologies for printed electronics.

Modification of unsaturated polyester resins using nano-size core ...

African Journals Online (AJOL)

Modification of unsaturated polyester resins using nano-size core-shell particles. MO Munyati, PA Lovell. Abstract. No Abstract Available Journal of Science and Technology Special Edition 2004: 24-31. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

Liquid metal–organic frameworks

Energy Technology Data Exchange (ETDEWEB)

Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A.; Chapman, Karena W.; Keen, David A.; Bennett, Thomas D.; Coudert, François-Xavier

2017-10-09

Metal–organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including ‘defective by design’ crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study the melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.

Liquid metal-organic frameworks

Science.gov (United States)

Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A.; Chapman, Karena W.; Keen, David A.; Bennett, Thomas D.; Coudert, François-Xavier

2017-11-01

Metal-organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including `defective by design’ crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study the melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.

Development of Multifunctional Ultra-Nonlinear Liquids and Liquid Crystals for Sensor Protection Applications

National Research Council Canada - National Science Library

Khoo, I. C

2008-01-01

.... Significant breakthroughs have been achieved in developing supra-nonlinear liquid crystalline films that possess extraordinarily large photorefractive responses, low switching thresholds and useful...

Liquid crystals for organic transistors (Conference Presentation)

Science.gov (United States)

Hanna, Jun-ichi; Iino, Hiroaki

2016-09-01

Liquid crystals are a new type of organic semiconductors exhibiting molecular orientation in self-organizing manner, and have high potential for device applications. In fact, various device applications have been proposed so far, including photosensors, solar cells, light emitting diodes, field effect transistors, and so on.. However, device performance in those fabricated with liquid crystals is less than those of devices fabricated with conventional materials in spite of unique features of liquid crystals. Here we discuss how we can utilize the liquid crystallinity in organic transistors and how we can overcome conventional non-liquid crystalline organic transistor materials. Then, we demonstrate high performance organic transistors fabricated with a smectic E liquid crystal of Ph-BTBT-10, which show high mobility of over 10cm2/Vs and high thermal durability of over 200oC in OFETs fabricated with its spin-coated polycrystalline thin films.

Prediction and design of first super-strong liquid-crystalline polymers

International Nuclear Information System (INIS)

Dowell, F.

1989-01-01

This paper presents the details of the theoretical prediction and design (atom by atom, bond by bond) of the molecule chemical structures of the first candidate super-strong liquid-crystalline polymers (SS LCPs). These LCPs are the first LCPs designed to have good compressive strengths, as well as to have tensile strengths and tensile moduli significantly larger than those of existing strong LCPs (such as Kevlar). The key feature of this new class of LCPs is that the exceptional strength is three dimensional on a microscopic, molecular level (thus, on a macroscopic level), in contrast to present LCPs (such as Kevlar) with their one-dimensional exceptional strength. These SS LCPs also have some solubility and processing advantages over existing strong LCPs. These SS LCPs are specially-designed combined LCPs such that the side chains of a molecule interdigitate with the side chains of other molecules. This paper also presents other essential general and specific features required for SS LCPs. Considerations in the design of SS LCPs include the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and side chains, the degree of polymerization, the length of the side chains, the regularity of spacing of the side chains along the backbone, the interdigitation of side chains in submolecular strips, the packing of the side chains on one or two sides of the backbone, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and side chains for easy alignment

Sulfonation of polyester fabrics by gaseous sulfur oxide activated by UV irradiation

Energy Technology Data Exchange (ETDEWEB)

Kordoghli, Bessem [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); Textile Research Laboratory (LRT) - ISET Kasr Hellal, University of Monastir (Tunisia); Khiari, Ramzi, E-mail: khiari_ramzi2000@yahoo.fr [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); LGP2 - Laboratory of Pulp and Paper Science, 461, Rue de la Papeterie - BP 65, 38402 Saint Martin d' Heres Cedex (France); Mhenni, Mohamed Farouk [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); Sakli, Faouzi [Textile Research Laboratory (LRT) - ISET Kasr Hellal, University of Monastir (Tunisia); Belgacem, Mohamed Naceur [LGP2 - Laboratory of Pulp and Paper Science, 461, Rue de la Papeterie - BP 65, 38402 Saint Martin d' Heres Cedex (France)

2012-10-01

Highlights: Black-Right-Pointing-Pointer In this paper, an original technique was present to improve the hydrophilic properties of polyester fibres. Black-Right-Pointing-Pointer The modification of PET fabric was carried out using gaseous sulfur trioxide activated by UV irradiations. Black-Right-Pointing-Pointer We fully characterized the modified and untreated fabrics. - Abstract: This paper describes an original technique aiming to improve the hydrophilic properties of polyester fibres. In this method, the sulfonation of the aromatic rings is carried out using gaseous sulfur trioxide activated by UV irradiations. Thus, exposing the polyester textile fabric to the UVC light (wavelength around 254 nm) under a stream of sulfur trioxide leads to the fixation of -SO{sub 3}H groups. The amounts of the fixed sulfonate groups depended on the reaction conditions. Evidence of grafting deduced from the measurements of hygroscopic properties was carried out by contact angle measurement, moisture regain as well as by measuring the rate of retention. SEM and FT-IR analysis, DSC and DTA/TGA thermograms showed that no significant modifications have occurred in the bulk of the treated PET fabrics.

Lipid-Based Liquid Crystalline Nanoparticles Facilitate Cytosolic Delivery of siRNA via Structural Transformation.

Science.gov (United States)

He, Shufang; Fan, Weiwei; Wu, Na; Zhu, Jingjing; Miao, Yunqiu; Miao, Xiaran; Li, Feifei; Zhang, Xinxin; Gan, Yong

2018-04-11

RNA interference (RNAi) technology has shown great promise for the treatment of cancer and other genetic disorders. Despite the efforts to increase the target tissue distribution, the safe and effective delivery of siRNA to the diseased cells with sufficient cytosolic transport is another critical factor for successful RNAi clinical application. Here, the constructed lipid-based liquid crystalline nanoparticles, called nano-Transformers, can transform thestructure in the intracellular acidic environment and perform high-efficient siRNA delivery for cancer treatment. The developed nano-Transformers have satisfactory siRNA loading efficiency and low cytotoxicity. Different from the traditional cationic nanocarriers, the endosomal membrane fusion induced by the conformational transition of lipids contributes to the easy dissociation of siRNA from nanocarriers and direct release of free siRNA into cytoplasm. We show that transfection with cyclin-dependent kinase 1 (CDK1)-siRNA-loaded nano-Transformers causes up to 95% reduction of relevant mRNA in vitro and greatly inhibits the tumor growth without causing any immunogenic response in vivo. This work highlights that the lipid-based nano-Transformers may become the next generation of siRNA delivery system with higher efficacy and improved safety profiles.

A novel polyester composite nanofiltration membrane formed by interfacial polymerization of pentaerythritol (PE) and trimesoyl chloride (TMC)

Science.gov (United States)

Cheng, Jun; Shi, Wenxin; Zhang, Lanhe; Zhang, Ruijun

2017-09-01

A novel polyester thin film composite nanofiltration (NF) membrane was prepared by interfacial polymerization of pentaerythritol (PE) and trimesoyl chloride (TMC) on polyethersulfone (PES) supporting membrane. The performance of the polyester composite NF membrane was optimized by regulating the preparation parameters, including reaction time, pH of the aqueous phase solution, pentaerythritol concentration and TMC concentration. A series of characterization, including permeation experiments, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential analyzer and chlorine resistance experiments, were employed to study the properties of the optimized membrane. The results showed that the optimized polyester composite NF membrane exhibited very high rejection of Na2SO4 (98.1%), but the water flux is relatively low (6.1 L/m2 h, 0.5 MPa, 25 °C). The order of salt rejections is Na2SO4 > MgSO4 > MgCl2 > NaCl, which indicated the membrane was negatively charged, just consistent with the membrane zeta potential results. After treating by NaClO solutions with different concentrations (100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm) for 48 h, the results demonstrated that the polyester NF membrane had good chlorine resistance. Additionally, the polyester TFC NF membrane exhibits good long-term stability.

Lyotropic liquid crystal preconcentrates for the treatment of periodontal disease.

Science.gov (United States)

Fehér, A; Urbán, E; Eros, I; Szabó-Révész, P; Csányi, E

2008-06-24

The aim of our study was to develop water-free lyotropic liquid crystalline preconcentrates, which consist of oils and surfactants with good physiological tolerance and spontaneously form lyotropic liquid crystalline phase in aqueous environment. In this way these preconcentrates having low viscosity can be injected into the periodontal pocket, where they are transformed into highly viscous liquid crystalline phase, so that the preparation is prevented from flowing out of the pocket due to its great viscosity, while drug release is controlled by the liquid crystalline texture. In order to follow the structure alteration upon water absorption polarization microscopical and rheological examinations were performed. The water absorption mechanism of the samples was examined by the Enslin-method. Metronidazole-benzoate was used as active agent the release of which was characterized via in vitro investigations performed by means of modified Kirby-Bauer disk diffusion method. On the grounds of the results it can be stated that the 4:1 mixture of the investigated surfactants (Cremophor EL, Cremophor RH40) and oil (Miglyol 810) formed lyotopic liquid crystalline phases upon water addition. Polarization microscopic examinations showed that samples with 10-40% water content possessed anisotropic properties. On the basis of water absorption, rheological and drug release studies it can be concluded that the amount of absorbed water and stiffness of lyotropic structure influenced by the chemical entity of the surfactant exerted major effect on the drug release.

Purification and Properties of a Polyester Polyurethane-Degrading Enzyme from Comamonas acidovorans TB-35

OpenAIRE

Akutsu, Yukie; Nakajima-Kambe, Toshiaki; Nomura, Nobuhiko; Nakahara, Tadaatsu

1998-01-01

A polyester polyurethane (PUR)-degrading enzyme, PUR esterase, derived from Comamonas acidovorans TB-35, a bacterium that utilizes polyester PUR as the sole carbon source, was purified until it showed a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This enzyme was bound to the cell surface and was extracted by addition of 0.2% N,N-bis(3-d-gluconamidopropyl)deoxycholamide (deoxy-BIGCHAP). The results of gel filtration and SDS-PAGE showed that the PUR este...

Impact behaviour of Napier/polyester composites under different energy levels

Energy Technology Data Exchange (ETDEWEB)

Fahmi, I., E-mail: fahmi-unimap@yahoo.com; Majid, M. S. Abdul, E-mail: shukry@unimap.edu.my; Afendi, M., E-mail: afendirojan@unimap.edu.my; Haameem, J. M.A., E-mail: mhaameem@gmail.com [School of Mechatronic Engineering, Universiti Malaysia Perlis, Arau (Malaysia); Haslan, M., E-mail: haslan@sirim.my; Helmi, E. A., E-mail: hilmi@sirim.my [Advanced Material Research Centre (AMREC), SIRIM Berhad, Kulim (Malaysia)

2016-07-19

The effects of different energy levels on the impact behaviour of Napier fibre/polyester reinforced composites were investigated. Napier fibre was extracted using traditional water retting process to be utilized as reinforcing materials in polyester composite laminates. 25% fibre loading composite laminates were prepared and impacted at three different energy levels; 2.5,5 and 7.5 J using an instrumented drop weight impact testing machine (IMATEK IM10). The outcomes show that peak force and contact time increase with increased impact load. The energy absorption was then calculated from the force displacement curve. The results indicated that the energy absorption decreases with increasing energy levels of the impact. Impacted specimens were observed visually for fragmentation fracture using an optical camera to identify the failure mechanisms. Fracture fragmentation pattern from permanent dent to perforation with radial and circumferential was observed.

Tensile strength of woven yarn kenaf fiber reinforced polyester composites

Directory of Open Access Journals (Sweden)

A.E. Ismail

2015-12-01

Full Text Available This paper presents the tensile strength of woven kenaf fiber reinforced polyester composites. The as-received yarn kenaf fiber is weaved and then aligned into specific fiber orientations before it is hardened with polyester resin. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses. Two important parameters are studied such as fiber orientations and number of layers. According to the results, it is shown that fiber orientations greatly affected the ultimate tensile strength but it is not for modulus of elasticity for both types of layers. It is estimated that the reductions of both ultimate tensile strength and Young’s modulus are in the range of 27.7-30.9% and 2.4-3.7% respectively, if the inclined fibers are used with respect to the principal axis.

Fabrication of narrow surface relief features in a side-chain azobenzene polyester with a scanning near-field microscope

DEFF Research Database (Denmark)

Ramanujam, P.S.; Holme, N. C. R.; Pedersen, M.

2001-01-01

We show that it is possible to fabricate topographic submicron features in a side-chain azobenzene polyester with a scanning near-field optical microscope, Through irradiation at a wavelength of 488 run at intensity levels of 12 W/cm(2), topographic features as narrow as 240 nm and as high as 6 nm...... have been reproducibly recorded in a thin film of the polyester. These observations are consistent with the fact that at low intensities peaks are produced evolving into formation of trenches at high intensities in the case of amorphous side-chain azobenzene polyesters. This may find applications...

Development auxiliaries for dyeing polyester with disperse dyes at low temperatures

Science.gov (United States)

Carrion-Fite, F. J.; Radei, S.

2017-10-01

High-molecular weight organic compounds known as carriers are widely used to expedite polyester dyeing at atmospheric pressure at 100 °C. However, carriers are usually poorly biodegradable and can partially plasticize fibres. Also, dyeing at temperatures above 100 °C in the absence of a carrier entails using expensive equipment. In this work, we developed an alternative method for dyeing polyester at temperatures below 100 °C that reduces energy expenses, dispenses with the need to invest in new equipment and avoids the undesirable effects of non-biodegradable carriers. The method uses disperse dyes in a microemulsion containing a low proportion of a non-toxic organic solvent and either of two alternative development auxiliaries (coumarin and o-vanillin) that is prepared with the aid of ultrasound.

Influence of Immersion Conditions on The Tensile Strength of Recycled Kevlar®/Polyester/Low-Melting-Point Polyester Nonwoven Geotextiles through Applying Statistical Analyses

Directory of Open Access Journals (Sweden)

Jing-Chzi Hsieh

2016-05-01

Full Text Available The recycled Kevlar®/polyester/low-melting-point polyester (recycled Kevlar®/PET/LPET nonwoven geotextiles are immersed in neutral, strong acid, and strong alkali solutions, respectively, at different temperatures for four months. Their tensile strength is then tested according to various immersion periods at various temperatures, in order to determine their durability to chemicals. For the purpose of analyzing the possible factors that influence mechanical properties of geotextiles under diverse environmental conditions, the experimental results and statistical analyses are incorporated in this study. Therefore, influences of the content of recycled Kevlar® fibers, implementation of thermal treatment, and immersion periods on the tensile strength of recycled Kevlar®/PET/LPET nonwoven geotextiles are examined, after which their influential levels are statistically determined by performing multiple regression analyses. According to the results, the tensile strength of nonwoven geotextiles can be enhanced by adding recycled Kevlar® fibers and thermal treatment.

Oxygen transport as a structure probe for heterogeneous polymeric systems

Science.gov (United States)

Hu, Yushan

Although permeability of small molecules is often measured as an important performance property, deeper analysis of the transport characteristics provides insight into polymer structure, especially if used in combination with other characterization techniques. Transport of small gas molecules senses the permeable amorphous structure and probes the nature of free volume. This work focuses on oxygen transport, supplemented with other methods of physical analysis, as a probe for: (1) the nature of free volume and crystalline morphology in the crystallized glassy state, (2) the nature of free volume and hierarchical structure in liquid crystalline polymers, and (3) the role of dispersed polyamide phase geometry on oxygen barrier properties of poly(ethylene terephthalate) (PET)/polyamide blends. In the first part, the improvement in oxygen-barrier properties of glassy polyesters by crystallization was examined. Examples included poly(ethylene naphthalate) (PEN), and a copolymer based on PET in which 55 mol% terephthalate was replaced with 4,4'-bibenzoate. Explanation of the unexpectedly high solubility of crystallized PEN required a two-phase transport model consisting of an impermeable crystalline phase of constant density and a permeable amorphous phase of variable density. The resulting relationship between oxygen solubility and amorphous phase density was consistent with free volume concepts of gas sorption. In the second part, oxygen barrier properties of liquid crystalline (LC) polyesters based on poly(diethylene glycol 4,4'-bibenzoate) (PDEGBB) were studied. This study extended the 2-phase transport model for oxygen transport of non-LC crystalline polymers to a smectic LCP. It was possible to systematically vary the solid state structure of (PDEGBB) from LC glass to crystallized LC glass. The results were consistent with a liquid crystalline state intermediate between the permeable amorphous glass and the impermeable 3-dimensional crystal. In this interpretation

Polymer Analysis by Liquid Chromatography/Electrospray Ionization Time-of-Flight Mass Spectrometry.

Science.gov (United States)

Nielen, M W; Buijtenhuijs, F A

1999-05-01

Hyphenation of liquid chromatography (LC) techniques with electrospray ionization (ESI) orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry (MS) provides both MS-based structural information and LC-based quantitative data in polymer analysis. In one experimental setup, three different LC modes are interfaced with MS:  size-exclusion chromatography (SEC/MS), gradient polymer elution chromatography (GPEC/MS), and liquid chromatography at the critical point of adsorption (LCCC/MS). In SEC/MS, both absolute mass calibration of the SEC column based on the polymer itself and determination of monomers and end groups from the mass spectra are achieved. GPEC/MS shows detailed chemical heterogeneity of the polymer and the chemical composition distribution within oligomer groups. In LCCC/MS, the retention behavior is primarily governed by chemical heterogeneities, such as different end group functionalities, and quantitative end group calculations can be easily made. The potential of these methods and the benefit of time-of-flight analyzers in polymer analysis are discussed using SEC/MS of a polydisperse poly(methyl methacrylate) sample, GPEC/MS of dipropoxylated bisphenol A/adipic acid polyester resin, LCCC/MS of alkylated poly(ethylene glycol), and LCCC/MS of terephthalic acid/neopentyl glycol polyester resin.

A quasimechanism of melt acceleration in the thermal decomposition of crystalline organic solids

Energy Technology Data Exchange (ETDEWEB)

Henson, Bryan F [Los Alamos National Laboratory

2009-01-01

It has been know for half a century that many crystalline organic solids undergo an acceleration in the rate of thermal decomposition as the melting temperature is approached. This acceleration terminates at the melting point, exhibiting an Arrhenius-like temperature dependence in the faster decomposition rate from the liquid phase. This observation has been modeled previously using various premelting behaviors based on e.g. freezing point depression induced by decomposition products or solvent impurities. These models do not, however, indicate a mechanism for liquid formation and acceleration which is an inherent function of the bulk thermodynamics of the molecule. Here we show that such an inherent thermodynamic mechanism for liquid formation exists in the form of the so-called quasi-liquid layer at the solid surface. We explore a kinetic mechanism which describes the acceleration of rate and is a function of the free energies of sublimation and vaporization. We construct a differential rate law from these thermodynamic free energies and a normalized progress variable. We further construct a reduced variable formulation of the model which is a simple function of the metastable liquid activity below the melting point, and show that it is applicable to the observed melt acceleration in several common organic crystalline solids. A component of the differential rate law, zero order in the progress variable, is shown to be proportional to the thickness of the quasiliquid layer predicted by a recent thermodynamic theory for this phenomenon. This work therefore serves not only to provide new insight into thermal decomposition in a broad class or organic crystalline solids, but also further validates the underlying thermodynamic nature of the phenomenon of liquid formation on the molecular surface at temperatures below the melting point.

Enhanced thermal and mechanical properties of epoxy composites by mixing thermotropic liquid crystalline epoxy grafted graphene oxide

Directory of Open Access Journals (Sweden)

B. Qi

2014-07-01

Full Text Available Graphene oxide (GO sheets were chemically grafted with thermotropic liquid crystalline epoxy (TLCP. Then we fabricated composites using TLCP-g-GO as reinforcing filler. The mechanical properties and thermal properties of composites were systematically investigated. It is found that the thermal and mechanical properties of the composites are enhanced effectively by the addition of fillers. For instance, the composites containing 1.0 wt% of TLCP-g-GO present impact strength of 51.43 kJ/m2, the tensile strength of composites increase from 55.43 to 80.85 MPa, the flexural modulus of the composites increase by more than 48%. Furthermore, the incorporation of fillers is effective to improve the glass transition temperature and thermal stability of the composites. Therefore, the presence of the TLCP-g-GO in the epoxy matrix could make epoxy not only stronger but also tougher.

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

KAUST Repository

Abdellah, Mohamed H.; Perez Manriquez, Liliana; Puspasari, Tiara; Scholes, Colin A.; Kentish, Sandra E.; Peinemann, Klaus-Viktor

2018-01-01

Utilization of sustainable and environmentally friendly solvents for the preparation of membranes has attracted growing interest in recent years. In this work, a polyester thin film composite solvent resistant nanofiltration (SRNF) membrane

Molecular structure of the discotic liquid crystalline phase of hexa-peri-hexabenzocoronene/oligothiophene hybrid and their charge transport properties

International Nuclear Information System (INIS)

Bag, Saientan; Maingi, Vishal; Maiti, Prabal K.; Yelk, Joe; Glaser, Matthew A.; Clark, Noel A.; Walba, David M.

2015-01-01

Using atomistic molecular dynamics simulation, we study the discotic columnar liquid crystalline (LC) phases formed by a new organic compound having hexa-peri-Hexabenzocoronene (HBC) core with six pendant oligothiophene units recently synthesized by Nan Hu et al. [Adv. Mater. 26, 2066 (2014)]. This HBC core based LC phase was shown to have electric field responsive behavior and has important applications in organic electronics. Our simulation results confirm the hexagonal arrangement of columnar LC phase with a lattice spacing consistent with that obtained from small angle X-ray diffraction data. We have also calculated various positional and orientational correlation functions to characterize the ordering of the molecules in the columnar arrangement. The molecules in a column are arranged with an average twist of 25° having an average inter-molecular separation of ∼5 Å. Interestingly, we find an overall tilt angle of 43° between the columnar axis and HBC core. We also simulate the charge transport through this columnar phase and report the numerical value of charge carrier mobility for this liquid crystal phase. The charge carrier mobility is strongly influenced by the twist angle and average spacing of the molecules in the column

Measurement of salivary cortisol--effects of replacing polyester with cotton and switching antibody

DEFF Research Database (Denmark)

Hansen, Ase Marie; Garde, Anne Helene; Persson, Roger

2008-01-01

measurements in our laboratory were affected by: 1) changes in the tampon material and 2) changes in the antibody of the analytical kit. In study 1, saliva from healthy subjects (n = 19) was split and spiked to Salivette polyester and cotton tampons, respectively, and treated as ordinary samples before being...... analysed for cortisol using a Spectria RIA kit for cortisol. In study 2, 68 anonymous saliva samples were analysed with the Spectria Cortisol RIA kit both before and after the manufacturer changed the antibody. The change from polyester to cotton tampons reduced the measured concentration of salivary...

Chirality under confinement - multidimensional constraints in liquid crystalline materials

NARCIS (Netherlands)

Sleczkowski, P.B.

2014-01-01

The first part of the thesis is devoted to studies of the self-assembled monolayers of discotic liquid crystals by the STM measurements at the liquid/solid interface. For the case of a model H5T molecule the self-assembled monolayers have evidenced both: point and organizational types of chirality,

Gamma-irradiation effects to posttranslational modification and chaperon function of bovine α-crystalline

International Nuclear Information System (INIS)

Hiroki, K; Matsumoto, S.; Awakura, M.; Fujii, N.

2001-01-01

The formation of D-asparate (D-Asp) in αA-crystallin of the aged human eye and the cataract crystalline lens has been reported. Crystalline lens keeps the transparency by forming α-crystallin which consists of a high order association of αA-and αB-crystallin. Bovine α-crystallin for investigating a chaperone function which protects the crystalline lens from getting to opaque or disordered agglutination with heat or light, is irradiated by gamma-ray (Co-60) at 0, 1, 2, 3, and 4 kGy, respectively. The irradiated bovine α-crystallin are analyzed with electrophoresis, gel permeation chromatograph, and UV absorption spectrometer for checking on the agglutination and the isomerization of macromolecules. Oxidation of methionine residues (Met-1) and isomerization of asparagine residues (Asp-151) in the αA-crystallin are ascertained in molecular levels with reversed phase liquid chromatography. The Met-1 oxidation and the Asp-151 isomerization depend on gamma-irradiation doses. It is thought that OH radical and H radical in water generated by the irradiation lead to the oxidation and the isomerization. Stereoinversion in the α-crystallin following to such a chemical change are considered to lead to the agglutination of polymer and the reduction of chaperon function. (M. Suetake)

Plasma treatment of polyester fabric to impart the water repellency ...

Indian Academy of Sciences (India)

test method 39 (1971). ... pilot production line [7]. It is found that prior .... experiment was set up for testing the absorbancy of modified polyester fabric as in case of .... New Delhi for providing the research grant under TAPTEC scheme. We are ...

Mechanical properties of water hyacinth fibers – polyester composites before and after immersion in water

International Nuclear Information System (INIS)

Abral, H.; Kadriadi, D.; Rodianus, A.; Mastariyanto, P.; Ilhamdi; Arief, S.; Sapuan, S.M.; Ishak, M.R.

2014-01-01

Highlights: • Moisture absorption of water hyacinth (WH) fibers was measured. • WH fibers polyester composites immersed in water decreased mechanical properties. • Improvement fibers fraction in polyester increases mechanical properties. - Abstract: This study reported moisture absorption of untreated and treated individual water hyacinth (WH) fibers as well as comparison the mechanical properties of WH fibers – unsaturated polyester (UPR) matrix composites after and before immersion in water. The result shows that the individual WH fibers treated with various alkali concentration did not exhibit significantly decreases of their moisture absorption. SEM photograph in cross section of the treated WH fibers shows swollen cell wall containing more nano and micro hollows. Tensile and flexure strength of the wet composite samples are lower than that of dried ones. However, increases volume fraction of the WH fibers in UPR matrix affected slightly on enhancement mechanical properties of the composite samples

Sup(1)H n.m.r. relaxation of radiation induced crosslinking in polyester-styrene systems

International Nuclear Information System (INIS)

Andreis, M.; Veksli, Z.; Ranogajec, F.; Hedvig, P.

1989-01-01

The structure and dynamics of a network formed by radiation induced crosslinking of polyesters based on 1,6-hexane diol and 1,2-propylene glycol and maleic anhydride (HDF and PGF, respectively) with styrene is studied by proton pulsed n.m.r. spectroscopy. The dependence of spin-lattice, T 1 , and spin-spin, T 2 , relaxation times on the structure of polyester chain, molar ratios of styrene to polyester unsaturations and the radiation doses are analysed in terms of network formation and structure, and their effect on molecular motion. Above the gel point, at temperatures above the glass transition, the presence of two T 2 components reflects the heterogeneity of the network structure in both resins. Parallel with the n.m.r. relaxation measurements the crosslink density was determined from the extracted gel phase or double bonds (fumaric and styrene) participating in the crosslinking process. (author)

Synthesis and Characterization of Ferroelectric Liquid Crystalline Organosiloxanes Containing 4-(4-undecanyloxy bi-phenyl-1-carboxyloxyphenyl (2S,3S-2-chloro-3-methylvalerate and 4-(4-undecanyloxybenzoyloxybiphenyl (2S,3S-2-chloro-3-methylvalerate

Directory of Open Access Journals (Sweden)

Chih-Hung Lin

2013-10-01

Full Text Available A series of new organosiloxane ferroelectric liquid crystalline (FLC materials have been synthesized, and their mesomorphic and physical properties have been characterized. Four new disiloxanes and trisiloxanes, containing biphenyl 4-hydroxybenzoate and phenyl 4-hydroxybiphenylcarboxylate as mesogenic units and eleven methylene unit as spacers and (2S,3S-2-chloro-3-methylvalerate unit as chiral end groups. The molecule, using three phenyl ring as a mesogenic unit, formulates much wider liquid crystalline phase temperature ranges than that of a two phenyl ring unit. The phenyl arrangement differences of mesogenic unit result in the greater differences of the liquid crystal phase formation. The siloxane molecule induction is helpful to the more regular smectic phase formation and smectic phase stabilization, such as chiral SC (SC* and SB phases. The siloxane molecule is helpful to reduce the phase transition temperature and broaden the liquid crystal temperature range of the SC* phase and, simultaneously, it will not induce chain crystallization phenomenon and dilute the Ps value. The synthesis and characterization of the new FLCs materials, which exhibit a room temperature SC* phase and higher spontaneous polarization are presented.

Development and evaluation of exemestane-loaded lyotropic liquid crystalline gel formulations.

Science.gov (United States)

Musa, Muhammad Nuh; David, Sheba Rani; Zulkipli, Ihsan Nazurah; Mahadi, Abdul Hanif; Chakravarthi, Srikumar; Rajabalaya, Rajan

2017-01-01

Introduction: The use of liquid crystalline (LC) gel formulations for drug delivery has considerably improved the current delivery methods in terms of bioavailability and efficacy. The purpose of this study was to develop and evaluate LC gel formulations to deliver the anti-cancer drug exemestane through transdermal route. Methods: Two LC gel formulations were prepared by phase separation coacervation method using glyceryl monooleate (GMO), Tween 80 and Pluronic® F127 (F127). The formulations were characterized with regard to encapsulation efficiency (EE), vesicle size, Fourier transform infrared (FTIR) spectroscopy, surface morphology (using light and fluorescence microscopy), in vitro release, ex vivo permeation, in vitro effectiveness test on MDA-MB231 cancer cell lines and histopathological analysis. Results: Results exhibited that the EE was 85%-92%, vesicle size was 119.9-466.2 nm while morphology showed spherical vesicles after hydration. An FTIR result also revealed that there was no significant shift in peaks corresponding to Exemestane and excipients. LC formulations release the drug from cellulose acetate and Strat-MTM membrane from 15%-88.95%, whereas ex vivo permeation ranges from 37.09-63%. The in vitro effectiveness study indicated that even at low exemestane concentrations (12.5 and 25 μg/mL) the formulations were able to induce cancer cell death, regardless of the surfactant used. Histopathological analysis thinning of the epidermis as the formulations penetrate into the intercellular regions of squamous cells. Conclusion: The results conjectured that exemestane could be incorporated into LC gels for the transdermal delivery system and further preclinical studies such as pharmacokinetic and pharmacodynamic studies will be carried out with suitable animal models.

A method for producing liquid paraffin

Energy Technology Data Exchange (ETDEWEB)

Dorodnova, V.S.; Martynenko, A.G.; Pereverzev, A.N.

1983-01-01

In the known method (Sp) for producing liquid paraffins (ZhP) through processing an oil fraction by crystalline carbamide in the presence of a solvent with subsequent removal of the formed complex (Km) of KA with the liquid paraffins from the deparaffinized product, staged washing and decomposition of the complex with isolation of the liquid paraffins, in order to increase the output of liquid paraffin and to improve its quality, beta,beta'-dichlorethyl ether (khloreks) in a mixture with methylethyl ketone (MEK) or methylisobutyl ketone in a ratio of 1 is used as the solvent, the processing by the crystalline carbamide is conducted with the addition of 180 to 260 percent solvent to raw material (Sr) and the washing of the composition is conducted by a solvent in the first stage and by methylethyl ketone or methylisobutyl ketone in the second stage. The crystalline carbamide for the complex formation is taken in a conversion of 60 to 70 percent for the raw material for observing the raw material to solvent ratio of from 1 to 1.8 to 2.6 to 0.6 to 0.6. The temperature in the zone of formation of the complex is maintained at 5 to 35 degrees. The presence of beta,beta'-dichlorethyl ether, which has high selectivity relative to aromatic hydrocarbons (ArU) and to resinous compounds provides for a sharp reduction in the adsorption of the undesired components on the surface of the granules of the complex and the crystalline carbamide and to a reduction in the portion of the alkylaromatic hydrocarbons (UV) extracted into the complex, which leads to a substantial improvement in the quality of the obtained liquid paraffins.

Study of compounds emitted during thermo-oxidative decomposition of polyester fabrics

Directory of Open Access Journals (Sweden)

Dzięcioł Małgorzata

2016-03-01

Full Text Available Compounds emitted during thermo-oxidative decomposition of three commercial polyester fabrics for indoor outfit and decorations (upholstery, curtains were studied. The experiments were carried out in a flow tubular furnace at 600°C in an air atmosphere. During decomposition process the complex mixtures of volatile and solid compounds were emitted. The main volatile products were carbon oxides, benzene, acetaldehyde, vinyl benzoate and acetophe-none. The emitted solid compounds consisted mainly of aromatic carboxylic acids and its derivatives, among which the greatest part took terephthalic acid, monovinyl terephthalate and benzoic acid. The small amounts of polycyclic aromatic hydrocarbons were also emitted. The emission profiles of the tested polyester fabrics were similar. The presence of toxic compounds indicates the possibility of serious hazard for people during fire.

3D printing of new biobased unsaturated polyesters by microstereo-thermal-lithography

International Nuclear Information System (INIS)

Gonçalves, Filipa A M M; Costa, Cátia S M F; Fabela, Inês G P; Simões, Pedro N; Serra, Arménio C; Coelho, Jorge F J; Farinha, Dina; Faneca, Henrique; Bártolo, Paulo J

2014-01-01

New micro three-dimensional (3D) scaffolds using biobased unsaturated polyesters (UPs) were prepared by microstereo-thermal-lithography (μSTLG). This advanced processing technique offers indubitable advantages over traditional printing methods. The accuracy and roughness of the 3D structures were evaluated by scanning electron microscopy and infinite focus microscopy, revealing a suitable roughness for cell attachment. UPs were synthesized by bulk polycondensation between biobased aliphatic diacids (succinic, adipic and sebacic acid) and two different glycols (propylene glycol and diethylene glycol) using fumaric acid as the source of double bonds. The chemical structures of the new oligomers were confirmed by proton nuclear magnetic resonance spectra, attenuated total reflectance Fourier transform infrared spectroscopy and matrix assisted laser desorption/ionization-time of flight mass spectrometry. The thermal and mechanical properties of the UPs were evaluated to determine the influence of the diacid/glycol ratio and the type of diacid in the polyester’s properties. In addition an extensive thermal characterization of the polyesters is reported. The data presented in this work opens the possibility for the use of biobased polyesters in additive manufacturing technologies as a route to prepare biodegradable tailor made scaffolds that have potential applications in a tissue engineering area. (paper)

Development of sugar palm yarn/glass fibre reinforced unsaturated polyester hybrid composites

Science.gov (United States)

Nurazzi, N. Mohd; Khalina, A.; Sapuan, S. Mohd; Rahmah, M.

2018-04-01

This study investigates the effect of fibre hybridization for sugar palm yarn fibre with glass fibre reinforced with unsaturated polyester composites. In this work, unsaturated polyester resin are reinforced with fibre at a ratio of 70:30 wt% and 60:40 wt%. The hybrid composites were characterized in terms of physical (density and water absorption), mechanical (tensile, flexural and compression) and thermal properties through thermal gravimetry analysis (TGA). Density determination showed that density increased with higher wt% of glass fibre. The inherently higher density of glass fibre increased the density of hybrid composite. Resistance to water absorption is improved upon the incorporation of glass fibre and the hybrid composites were found to reach equilibrium absorption at days 4 and 5. As for mechanical performance, the highest tensile strength, tensile modulus, flexural strength, flexural modulus and compression strength were obtained from 40 wt% of fibres reinforcement with ratio of 50:50 wt% of sugar palm yarn fibre and glass fibre reinforced unsaturated polyester composites. The increase of glass fibre loading had a synergistic effect on the mechanical properties to the composites structure due to its superior strength and modulus. The thermal stability of hybrid composites was improved by the increase of onset temperature and the reduction of residues upon increase in temperature.

Thermal Aging of Unsaturated Polyester Composite Reinforced with E-Glass Nonwoven Mat

Directory of Open Access Journals (Sweden)

Hossain Milon

2017-12-01

Full Text Available An experiment was carried out using glass fiber (GF as reinforcing materials with unsaturated polyester matrix to fabricate composite by hand layup technique. Four layers of GF were impregnated by polyester resin and pressed under a load of 5 kg for 20 hours. The prepared composite samples were treated by prolonged exposure to heat for 1 hour at 60-150°C and compared with untreated GF-polyester composite. Different mechanical test of the fabricated composite were investigated. The experiment depicted significant improvement in the mechanical properties of the fabricated composite resulted from the heat treatment. The maximum tensile strength of 200.6 MPa is found for 90°C heat-treated sample. The mechanical properties of the composite do seem to be very affected negatively above 100°C. Water uptake of the composite was carried out and thermal stability of the composite was investigated by thermogravimetric analysis, and it was found that the composite is stable up to 600°C. Fourier transform infrared spectroscopy shows the characteristic bond in the composite. Finally, the excellent elevated heat resistant capacity of glass-fiber-reinforced polymeric composite shows the suitability of its application to heat exposure areas such as kitchen furniture materials, marine, and electric board.

The effect of mechanical loads on the degradation of aliphatic biodegradable polyesters.

Science.gov (United States)

Li, Ying; Chu, Zhaowei; Li, Xiaoming; Ding, Xili; Guo, Meng; Zhao, Haoran; Yao, Jie; Wang, Lizhen; Cai, Qiang; Fan, Yubo

2017-06-01

Aliphatic biodegradable polyesters have been the most widely used synthetic polymers for developing biodegradable devices as alternatives for the currently used permanent medical devices. The performances during biodegradation process play crucial roles for final realization of their functions. Because physiological and biochemical environment in vivo significantly affects biodegradation process, large numbers of studies on effects of mechanical loads on the degradation of aliphatic biodegradable polyesters have been launched during last decades. In this review article, we discussed the mechanism of biodegradation and several different mechanical loads that have been reported to affect the biodegradation process. Other physiological and biochemical factors related to mechanical loads were also discussed. The mechanical load could change the conformational strain energy and morphology to weaken the stability of the polymer. Besides, the load and pattern could accelerate the loss of intrinsic mechanical properties of polymers. This indicated that investigations into effects of mechanical loads on the degradation should be indispensable. More combination condition of mechanical loads and multiple factors should be considered in order to keep the degradation rate controllable and evaluate the degradation process in vivo accurately. Only then can the degradable devise achieve the desired effects and further expand the special applications of aliphatic biodegradable polyesters.

Effect of the concentration of magnetite on the structure, electrical and magnetic properties of a polyester resin-based composite

Directory of Open Access Journals (Sweden)

Gabriel Peña-Rodriguez

2018-01-01

Full Text Available This study reports the effect of the concentration of magnetite powders (Fe3O4 on the electrical and magnetic properties of a resin-based composite of thermoset polyester. The samples were prepared by the casting method at different concentrations: 60-40, 70-30, 80-20, 90-10 and 100-0 (% in weight, where the primary phase was resin and the secondary, Fe3O4 powders. The crystalline structure was studied using X-ray diffraction and surface characterization was carried out applying the scanning electron microscopy technique. The electrical response was measured by electric polarization curves as a function of the electric field; and the volumetric electrical resistivity, by an electrometer. The magnetic response was determined by magnetization curves as a function of temperature and intensity of the applied magnetic field. The structural analysis indicates that crystallinity increases as higher concentrations of Fe3O4 are added to the samples. The electrical characterization of the material reveals that the volumetric resistivity decreases as the content of magnetite increases. These reactions indicate an insulation-conductor transition with increasing dielectric constant values. The magnetic characterization presents a linear increase of the saturation of magnetization and magnetic moment as a function of the amount of magnetite added to the polymer matrix, whereas the coercivity shows behaviors of soft magnetic materials for T ˃ Tv and for T < Tv, where Tv represents the temperature of Verwey.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Tang, Xiaoning [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Tian, Mingwei [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); Qu, Lijun, E-mail: lijunqu@126.com [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); Zhu, Shifeng [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Guo, Xiaoqing [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); Han, Guangting [Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); and others

2014-10-30

Highlights: • Multifunctional knit polyester fabric was facile fabricated by the combination of pad-dry-cure process and in situ chemical polymerization route. • High electrical conductivity and efficient water-repellent properties were endowed to the polymer nanocomposite coated fabric. • The polymer nanocomposite coated fabric also performed efficient and durable photocatalytic activities under the illumination of ultraviolet light. - Abstract: Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

International Nuclear Information System (INIS)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting

2014-01-01

Highlights: • Multifunctional knit polyester fabric was facile fabricated by the combination of pad-dry-cure process and in situ chemical polymerization route. • High electrical conductivity and efficient water-repellent properties were endowed to the polymer nanocomposite coated fabric. • The polymer nanocomposite coated fabric also performed efficient and durable photocatalytic activities under the illumination of ultraviolet light. - Abstract: Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric

Enhanced antitumor efficacy and counterfeited cardiotoxicity of combinatorial oral therapy using Doxorubicin- and Coenzyme Q10-liquid crystalline nanoparticles in comparison with intravenous Adriamycin

DEFF Research Database (Denmark)

Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog

2014-01-01

and strong synergism for combination at 1:10 dose ratio owing to higher cellular uptake, nuclear colocalization, higher apoptotic index and 8-OHdG levels. The prophylactic antitumor efficacy of the CoQ10-LCNPs was also established using tumor induction and progression studies. Finally, therapeutic antitumor......, with Dox-induced-cardiotoxicity was completely counterfeited in combination. In nutshell, LCNPs pose great potential in improving the therapeutic efficacy of drugs by oral route of administration. FROM THE CLINICAL EDITOR: This study describes the use of liquid crystalline nanoparticles containing coenzyme...

Cationization and gamma irradiation effects on the dyeability of polyester fabric towards disperse dyes

Energy Technology Data Exchange (ETDEWEB)

Zohdy, Maged H. [Department of Radiation Chemistry, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)]. E-mail: mhzohdy@yahoo.com

2005-06-01

The effect of hydrazine hydrate (HZH) treatment and/or gamma irradiation on the dyeing, mechanical and thermal properties of polyester fabrics (PET) was studied. The different factors that may affect the dyeing performance, such as concentrations of HZH, benzyl alcohol and pH values, were investigated. In this regard, the colour strength of untreated polyester fabrics dyed with the dyestuffs Dispersol blue BR, Dispersol orange B2R and Dispersol red B2B was found to be 10.34, 10.76 and 10.12 compared to 24.61, 24.90 and 23.00 in the case of irradiated and HZH-treated polyester fabrics, respectively. These colour strength values were achieved by preirradiation at a dose of 75kGy followed by treatment with 15mll-1 of HZH. Thermogravimetric analysis (TGA) showed that the thermal decomposition stability was improved by using gamma irradiation and the treatment with HZH as indicated by the calculated activation energies. FT-IR spectroscopy showed that the treatment with HZH acts as cationizer prior to dyeing with disperse dyes.

Cationization and gamma irradiation effects on the dyeability of polyester fabric towards disperse dyes

International Nuclear Information System (INIS)

Zohdy, Maged H.

2005-01-01

The effect of hydrazine hydrate (HZH) treatment and/or gamma irradiation on the dyeing, mechanical and thermal properties of polyester fabrics (PET) was studied. The different factors that may affect the dyeing performance, such as concentrations of HZH, benzyl alcohol and pH values, were investigated. In this regard, the colour strength of untreated polyester fabrics dyed with the dyestuffs Dispersol blue BR, Dispersol orange B2R and Dispersol red B2B was found to be 10.34, 10.76 and 10.12 compared to 24.61, 24.90 and 23.00 in the case of irradiated and HZH-treated polyester fabrics, respectively. These colour strength values were achieved by preirradiation at a dose of 75kGy followed by treatment with 15mll-1 of HZH. Thermogravimetric analysis (TGA) showed that the thermal decomposition stability was improved by using gamma irradiation and the treatment with HZH as indicated by the calculated activation energies. FT-IR spectroscopy showed that the treatment with HZH acts as cationizer prior to dyeing with disperse dyes

Construction of 2D transparent micromodels in polyester resin with porosity similar to carrots

Directory of Open Access Journals (Sweden)

Rodrigo Emilio Díaz

2011-12-01

Full Text Available Microscopic visualization, especially in transparent micromodels, can provide valuable information to understand the transport phenomena at pore scale in different process occurring in porous materials (food, timber, soils, etc.. Micromodels studies focus mainly on the observation of multi-phase flow, which presents a greater proximity to reality. The aim of this study was to study the process of flexography and its application in the manufacture of polyester resin transparent micromodels and its application to carrots. Materials used to implement a flexo station for micromodels construction were thermoregulated water bath, exposure chamber to UV light, photosensitive substance (photopolymer, RTV silicone polyester resin, and glass plates. In this paper, data on size distribution of a particular kind of carrot we used, and a transparent micromodel with square cross-section as well as a Log-normal pore size distribution with pore radii ranging from 10 to 110 µm (average of 22 µm and micromodel size of 10 × 10 cm were built. Finally, it stresses that it has successfully implemented the protocol processing 2D polyester resin transparent micromodels.

Transport of Liquid Phase Organic Solutes in Liquid Crystalline Membranes

OpenAIRE

Han, Sangil

2010-01-01

Porous cellulose nitrate membranes were impregnated with 8CB and PCH5 LCs (liquid crystals) and separations of solutes dissolved in aqueous phases were performed while monitoring solute concentration via UV-VIS spectrometry. The diffusing organic solutes, which consist of one aromatic ring and various functional groups, were selected to exclude molecular size effects on the diffusion and sorption. We studied the effects on solute transport of solute intra-molecular hydrogen bonding and so...

Chemical structures and thermal properties of polyesters obtained from different samples of bio diesel epoxidized

International Nuclear Information System (INIS)

Samios, Dimitrios; Reiznautt, Quelen B.; Nicolau, Aline; Martini, Denise D.; Chagas, Arthur L. das

2009-01-01

In this work new structures from oligo esters and polyesters from different oils (olive oil, sunflower oil and linseed oil) were synthesized and characterized. Oligo esters and polyesters were synthesized from the reaction of fatty acid methyl epoxy-esters, obtained from different oils, with cis-1,2-cyclohexanedicarboxylic anhydride in the presence of triethylamine (TEA). Different amounts of the resin 1,4-butanediol diglycidyl ether (BDGE) were added in order to increase the capacity of crosslinking. The molar ratio of BDGE used in system was between 0 and 0.066. The intermediate structures, as well as the oligo esters and polyesters produced, were analyzed by using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance ( 1 H - NMR). The thermal behavior of the products was realized through differential scanning calorimetry and Thermogravimetric analyses. The presence of BDGE in the materials chains increases the bonding capacity resulting in a higher molecular weight material which presents good thermal stability. (author)

Enhancing osteogenic differentiation of MC3T3-E1 cells by immobilizing RGD onto liquid crystal substrate

International Nuclear Information System (INIS)

Wu, Shaopeng; Yang, Xiaohui; Li, Wenqiang; Du, Lin; Zeng, Rong; Tu, Mei

2017-01-01

To understand the effects of GRGDF modification on MC3T3-E1 cell behavior, we cultured these cells onto a biomimetic liquid crystalline matrix modified with GRGDF peptide (OPC-GA-RGD). Successful immobilization of GRGDF on the liquid crystalline surface was verified by fluorescent labeling, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). OPC-GA-RGDs retained its liquid crystalline feature after surface modification. The RGD-immobilized OPC substrate was hardly beneficial to initial cell adhesion but could support long-term cell survival. The enhancement in cell proliferation did not correlate with RGD density. The lower GRGDF density immobilized on the liquid crystalline OPC matrix (OPC-GA-RGD3) promoted cell adhesion, proliferation, ALP expression level and mineralization, suggesting that both the viscoelasticity-based mechanical stimuli and receptor/ligand-based biochemical cue synergistically modulate MC3T3-E1 cell behavior. - Highlight: • A novel type of GRGDF-immobilized liquid crystalline matrices was fabricated and served as a substrate for the in vitro culture of MC3T3-E1 cells. • The lower RGD density might provide a better condition for initial cell adhesion and proliferation, up-regulation of ALP expression levels, and mineralization. • The intrinsic liquid crystalline feature of OPC matrix, instead of RGD efficiency, promoted initial cell adhesion. • Properties of the liquid crystalline OPC matrix together with the stable receptor-ligand binging synergistically modulated MC3T3-E1 cell behavior.

Enhancing osteogenic differentiation of MC3T3-E1 cells by immobilizing RGD onto liquid crystal substrate

Energy Technology Data Exchange (ETDEWEB)

Wu, Shaopeng; Yang, Xiaohui; Li, Wenqiang; Du, Lin; Zeng, Rong; Tu, Mei, E-mail: tumei@jnu.edu.cn

2017-02-01

To understand the effects of GRGDF modification on MC3T3-E1 cell behavior, we cultured these cells onto a biomimetic liquid crystalline matrix modified with GRGDF peptide (OPC-GA-RGD). Successful immobilization of GRGDF on the liquid crystalline surface was verified by fluorescent labeling, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). OPC-GA-RGDs retained its liquid crystalline feature after surface modification. The RGD-immobilized OPC substrate was hardly beneficial to initial cell adhesion but could support long-term cell survival. The enhancement in cell proliferation did not correlate with RGD density. The lower GRGDF density immobilized on the liquid crystalline OPC matrix (OPC-GA-RGD3) promoted cell adhesion, proliferation, ALP expression level and mineralization, suggesting that both the viscoelasticity-based mechanical stimuli and receptor/ligand-based biochemical cue synergistically modulate MC3T3-E1 cell behavior. - Highlight: • A novel type of GRGDF-immobilized liquid crystalline matrices was fabricated and served as a substrate for the in vitro culture of MC3T3-E1 cells. • The lower RGD density might provide a better condition for initial cell adhesion and proliferation, up-regulation of ALP expression levels, and mineralization. • The intrinsic liquid crystalline feature of OPC matrix, instead of RGD efficiency, promoted initial cell adhesion. • Properties of the liquid crystalline OPC matrix together with the stable receptor-ligand binging synergistically modulated MC3T3-E1 cell behavior.

Characterization of material composite marble-polyester

Directory of Open Access Journals (Sweden)

Corpas, F. A.

2002-12-01

Full Text Available In this work we characterize a new material composite, formed with a polyester and crushed white marble mixture. The final purpose is double: to obtain a material for applications sufficiently competitive after an economic viability study, increasing the yield of the main commodity, using waste marble and improving the jobs in the quarries area. From the results obtained, we deduce then that this material could be used to inside and outside adornment.

En este trabajo, caracterizamos un nuevo material compuesto, formado con una mezcla de poliéster y de mármol blanco triturado. El propósito final es doble: por un lado obtener un material para aplicaciones lo suficientemente competitivas como para que se pueda iniciar un estudio económico de viabilidad, aumentando el rendimiento de la materia prima y mejorando las salidas laborales de las comarcas extractoras. Para la caracterización del material se ha determinado el porcentaje adecuado de poliéster. Así como las propiedades mecánicas (flexión, compresión y dureza, químicas, fatiga térmica y su influencia a la exposición solar In order to characterized of material, we have determined the suitable porcentage of polyester Also we have carried out a study of the mechanical (stretching, resistance to traction, hardeness and thermal fatigue chemicals properties and solar radiation influence. De los resultados obtenidos, este material podría ser utilizado para ornamentación tanto de interior como de exterior.

PHB, crystalline and amorphous magnesium alloys: Promising candidates for bioresorbable osteosynthesis implants?

Energy Technology Data Exchange (ETDEWEB)

Celarek, Anna [Institute for Building Construction and Technology E-206-4, Vienna University of Technology, Karlsplatz 13, 1040 Vienna (Austria); Kraus, Tanja [Department of Paediatric Orthopaedics, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz (Austria); Tschegg, Elmar K., E-mail: elmar.tschegg@tuwien.ac.at [Institute for Building Construction and Technology E-206-4, Vienna University of Technology, Karlsplatz 13, 1040 Vienna (Austria); Fischerauer, Stefan F. [Department of Paediatric and Adolescent Surgery, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz (Austria); Stanzl-Tschegg, Stefanie [Department of Material Sciences and Process Engineering, Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Str. 82, 1190 Vienna (Austria); Uggowitzer, Peter J. [Department of Materials, Laboratory for Metal Physics and Technology, ETH Zurich, 8093 Zurich (Switzerland); Weinberg, Annelie M. [Department of Paediatric and Adolescent Surgery, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz (Austria)

2012-08-01

In this study various biodegradable materials were tested for their suitability for use in osteosynthesis implants, in particular as elastically stable intramedullary nails for fracture treatment in paediatric orthopaedics. The materials investigated comprise polyhydroxybutyrate (PHB), which belongs to the polyester family and is produced by microorganisms, with additions of ZrO{sub 2} and a bone graft substitute; two crystalline magnesium alloys with significantly different degradation rates ZX50 (MgZnCa, fast) and WZ21 (MgYZnCa, slow); and MgZnCa bulk metallic glasses (BMG). Push-out tests were conducted after various implantation times in rat femur meta-diaphysis to evaluate the shear forces between the implant material and the bone. The most promising materials are WZ21 and BMG, which exhibit high shear forces and push-out energies. The degradation rate of ZX50 is too fast and thus the alloy does not maintain its mechanical stability long enough during the fracture-healing period. PHB exhibits insufficient mechanical properties: it degrades very slowly and the respective low shear forces and push-out energy levels are unsatisfactory. - Highlights: Black-Right-Pointing-Pointer In-vivo (rat model) investigation of biodegradable materials suitable for ESIN. Black-Right-Pointing-Pointer Materials: polymer PHB, crystalline Mg ZX50 and Mg WZ21, MgZnCa bulk metallic glasses. Black-Right-Pointing-Pointer Evaluated interface shear strength, push-out energies, stiffness, histology. Black-Right-Pointing-Pointer Mg WZ21 suitable, other materials only after alterations.

PHB, crystalline and amorphous magnesium alloys: Promising candidates for bioresorbable osteosynthesis implants?

International Nuclear Information System (INIS)

Celarek, Anna; Kraus, Tanja; Tschegg, Elmar K.; Fischerauer, Stefan F.; Stanzl-Tschegg, Stefanie; Uggowitzer, Peter J.; Weinberg, Annelie M.

2012-01-01

In this study various biodegradable materials were tested for their suitability for use in osteosynthesis implants, in particular as elastically stable intramedullary nails for fracture treatment in paediatric orthopaedics. The materials investigated comprise polyhydroxybutyrate (PHB), which belongs to the polyester family and is produced by microorganisms, with additions of ZrO 2 and a bone graft substitute; two crystalline magnesium alloys with significantly different degradation rates ZX50 (MgZnCa, fast) and WZ21 (MgYZnCa, slow); and MgZnCa bulk metallic glasses (BMG). Push-out tests were conducted after various implantation times in rat femur meta-diaphysis to evaluate the shear forces between the implant material and the bone. The most promising materials are WZ21 and BMG, which exhibit high shear forces and push-out energies. The degradation rate of ZX50 is too fast and thus the alloy does not maintain its mechanical stability long enough during the fracture-healing period. PHB exhibits insufficient mechanical properties: it degrades very slowly and the respective low shear forces and push-out energy levels are unsatisfactory. - Highlights: ► In-vivo (rat model) investigation of biodegradable materials suitable for ESIN. ► Materials: polymer PHB, crystalline Mg ZX50 and Mg WZ21, MgZnCa bulk metallic glasses. ► Evaluated interface shear strength, push-out energies, stiffness, histology. ► Mg WZ21 suitable, other materials only after alterations.

Characterization of polyester composites from recycled polyethylene terephthalate reinforced with empty fruit bunch fibers

International Nuclear Information System (INIS)

Tan, Chiachun; Ahmad, Ishak; Heng, Muichin

2011-01-01

Highlights: → Unsaturated polyester resin (UPR) was synthesized from recycled PET. → Effect of surface treatment on EFB/UPR was studied. → Treatment on EFB improved the mechanical and thermal properties. → Treatment on EFB also improved fiber-matrix interaction. -- Abstract: Unsaturated polyester resin (UPR) was synthesized from recycled polyethylene terephthalate (PET) which acted as a matrix for the preparation of UPR/empty fruit bunch fibers (EFB) composite. Chemical recycling on fine pieces of PET bottles were conducted through glycolysis process using ethylene glycol. The unsaturated polyester resin (UPR) was then prepared by reacting the glycolysed product with maleic anhydride. FTIR analysis of glycolyzed product and prepared UPR showed that cross-links between unsaturated polyester chain and styrene monomer occurred at the unsaturated sites which resulted in the forming of cross-linking network. The preparation of UPR/EFB composite was carried out by adding EFB into prepared UPR matrix. The effects of surface treatment on EFB with sodium hydroxide solution (NaOH), silane coupling agent and maleic anhydride (MA) were then studied. The experimental results showed that treated EFB have higher values of tensile and impact strength compared with untreated EFB. The best results were obtained for silane treatment followed by MA and NaOH treatments where the tensile strength was increased by about 21%, 18% and 13% respectively. SEM micrographs of the tensile fracture surfaces of UPR/EFB composite also proved that treatment on EFB has increased the interfacial adhesion between the fiber and UPR matrix compared to the untreated UPR/EFB composite.

Modeling Textural Processes during Self-Assembly of Plant-Based Chiral-Nematic Liquid Crystals

Directory of Open Access Journals (Sweden)

Yogesh K. Murugesan

2010-12-01

Full Text Available Biological liquid crystalline polymers are found in cellulosic, chitin, and DNA based natural materials. Chiral nematic liquid crystalline orientational order is observed frozen-in in the solid state in plant cell walls and is known as a liquid crystal analogue characterized by a helicoidal plywood architecture. The emergence of the plywood architecture by directed chiral nematic liquid crystalline self assembly has been postulated as the mechanism that leads to optimal cellulose fibril organization. In natural systems, tissue growth and development takes place in the presence of inclusions and secondary phases leaving behind characteristic defects and textures, which provide a unique testing ground for the validity of the liquid crystal self-assembly postulate. In this work, a mathematical model, based on the Landau-de Gennes theory of liquid crystals, is used to simulate defect textures arising in the domain of self assembly, due to presence of secondary phases representing plant cells, lumens and pit canals. It is shown that the obtained defect patterns observed in some plant cell walls are those expected from a truly liquid crystalline phase. The analysis reveals the nature and magnitude of the viscoelastic material parameters that lead to observed patterns in plant-based helicoids through directed self-assembly. In addition, the results provide new guidance to develop biomimetic plywoods for structural and functional applications.

Solvation Dynamics in Different Phases of the Lyotropic Liquid Crystalline System.

Science.gov (United States)

Roy, Bibhisan; Satpathi, Sagar; Gavvala, Krishna; Koninti, Raj Kumar; Hazra, Partha

2015-09-03

Reverse hexagonal (HII) liquid crystalline material based on glycerol monooleate (GMO) is considered as a potential carrier for drugs and other important biomolecules due to its thermotropic phase change and excellent morphology. In this work, the dynamics of encapsulated water, which plays important role in stabilization and formation of reverse hexagonal mesophase, has been investigated by time dependent Stokes shift method using Coumarin-343 as a solvation probe. The formation of the reverse hexagonal mesophase (HII) and transformation to the L2 phase have been monitored using small-angle X-ray scattering and polarized light microscopy experiments. REES studies suggest the existence of different polar regions in both HII and L2 systems. The solvation dynamics study inside the reverse hexagonal (HII) phase reveals the existence of two different types of water molecules exhibiting dynamics on a 120-900 ps time scale. The estimated diffusion coefficients of both types of water molecules obtained from the observed dynamics are in good agreement with the measured diffusion coefficient collected from the NMR study. The calculated activation energy is found to be 2.05 kcal/mol, which is associated with coupled rotational-translational water relaxation dynamics upon the transition from "bound" to "quasi-free" state. The observed ∼2 ns faster dynamics of the L2 phase compared to the HII phase may be associated with both the phase transformation as well as thermotropic effect on the relaxation process. Microviscosities calculated from time-resolved anisotropy studies infer that the interface is almost ∼22 times higher viscous than the central part of the cylinder. Overall, our results reveal the unique dynamical features of water inside the cylinder of reverse hexagonal and inverse micellar phases.

New poly(ester urea) derived from L-leucine: Electrospun scaffolds loaded with antibacterial drugs and enzymes

Energy Technology Data Exchange (ETDEWEB)

Díaz, Angélica; Valle, Luis J. del [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Tugushi, David; Katsarava, Ramaz [Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, 13 km. David Aghmashenebeli Alley, Tblisi 0131, Georgia (United States); Puiggalí, Jordi, E-mail: Jordi.Puiggali@upc.edu [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain)

2015-01-01

Electrospun scaffolds from an amino acid containing poly(ester urea) (PEU) were developed as promising materials in the biomedical field and specifically in tissue engineering applications. The selected poly(ester urea) was obtained with a high yield and molecular weight by reaction of phosgene with a bis(α-aminoacyl)-α,ω-diol-diester monomer. The polymer having L-leucine, 1,6-hexanediol and carbonic acid units had a semicrystalline character and relatively high glass transition and melting temperatures. Furthermore it was highly soluble in most organic solvents, an interesting feature that facilitated the electrospinning process and the effective incorporation of drugs with bactericidal activity (e.g. biguanide derivatives such as clorhexidine and polyhexamethylenebiguanide) and enzymes (e.g. α-chymotrypsin) that accelerated the degradation process. Continuous micro/nanofibers were obtained under a wide range of processing conditions, being diameters of electrospun fibers dependent on the drug and solvent used. Poly(ester urea) samples were degradable in media containing lipases and proteinases but the degradation rate was highly dependent on the surface area, being specifically greater for scaffolds with respect to films. The high hydrophobicity of new scaffolds had repercussions on enzymatic degradability since different weight loss rates were found depending on how samples were exposed to the medium (e.g. forced or non-forced immersion). New scaffolds were biocompatible, as demonstrated by adhesion and proliferation assays performed with fibroblast and epithelial cells. - Highlights: • Electrospun scaffolds from a biodegradable poly(ester urea) have been prepared. • Scaffolds were effectively loaded with bactericide agents. • Enzymatic degradability of the L-leucine derived poly(ester urea) was demonstrated. • Enzymes that accelerate degradation were incorporated in the electrospun fibers. • Cell adhesion/proliferation assays demonstrated

The identification of cutin synthase: formation of the plant polyester cutin

DEFF Research Database (Denmark)

Yeats, Trevor H.; Martin, Laetitia B. B.; Viart, Helene Marie-France

2012-01-01

A hydrophobic cuticle consisting of waxes and the polyester cutin covers the aerial epidermis of all land plants, providing essential protection from desiccation and other stresses. We have determined the enzymatic basis of cutin polymerization through characterization of a tomato extracellular...

Synthetic scaffolds based on biodegradable, functionalized polyesters for tissue engineering applications

NARCIS (Netherlands)

Seyednejad, S.H.

2012-01-01

The aim of this thesis was to investigate the possibility of using a novel hydroxyl-functionalized polyester [poly(hydroxymethylglycolide-co-ε-caprolactone), pHMGCL] (Fig.9) to fabricate scaffolds for tissue engineering applications. Degradable polymers that are frequently used for tissue

Reduced toxicity polyester resins and microvascular pre-preg tapes for advanced composites manufacturing

Science.gov (United States)

Poillucci, Richard

Advanced composites manufacturing broadly encapsulates topics ranging from matrix chemistries to automated machines that lay-up fiber-reinforced materials. Environmental regulations are stimulating research to reduce matrix resin formulation toxicity. At present, composites fabricated with polyester resins expose workers to the risk of contact with and inhalation of styrene monomer, which is a potential carcinogen, neurotoxin, and respiratory irritant. The first primary goal of this thesis is to reduce the toxicity associated with polyester resins by: (1) identification of potential monomers to replace styrene, (2) determination of monomer solubility within the polyester, and (3) investigation of approaches to rapidly screen a large resin composition parameter space. Monomers are identified based on their ability to react with polyester and their toxicity as determined by the Globally Harmonized System (GHS) and a green screen method. Solubilities were determined by the Hoftyzer -- Van Krevelen method, Hansen solubility parameter database, and experimental mixing of monomers. A combinatorial microfluidic mixing device is designed and tested to obtain distinct resin compositions from two input chemistries. The push for safer materials is complemented by a thrust for multifunctional composites. The second primary goal of this thesis is to design and implement the manufacture of sacrificial fiber materials suitable for use in automated fiber placement of microvascaular multifunctional composites. Two key advancements are required to achieve this goal: (1) development of a roll-to-roll method to place sacrificial fibers onto carbon fiber pre-preg tape; and (2) demonstration of feasible manufacture of microvascular carbon fiber plates with automated fiber placement. An automated method for placing sacrificial fibers onto carbon fiber tapes is designed and a prototype implemented. Carbon fiber tows with manual placement of sacrificial fibers is implemented within an

High Throughput Screening of Valganciclovir in Acidic Microenvironments of Polyester Thin Films

Directory of Open Access Journals (Sweden)

Teilo Schaller

2015-04-01

Full Text Available Ganciclovir and valganciclor are antiviral agents used for the treatment of cytomegalovirus retinitis. The conventional method for administering ganciclovir in cytomegalovirus retinitis patients is repeated intravitreal injections. In order to obviate the possible detrimental effects of repeated intraocular injections, to improve compliance and to eliminate systemic side-effects, we investigated the tuning of the ganciclovir pro-drug valganciclovir and the release from thin films of poly(lactic-co-glycolic acid (PLGA, polycaprolactone (PCL, or mixtures of both, as a step towards prototyping periocular valganciclovir implants. To investigate the drug release, we established and evaluated a high throughput fluorescence-based quantification screening assay for the detection of valganciclovir. Our protocol allows quantifying as little as 20 ng of valganciclovir in 96-well polypropylene plates and a 50× faster analysis compared to traditional HPLC measurements. This improvement can hence be extrapolated to other polyester matrix thin film formulations using a high-throughput approach. The acidic microenvironment within the polyester matrix was found to protect valganciclovir from degradation with resultant increases in the half-life of the drug in the periocular implant to 100 days. Linear release profiles were obtained using the pure polyester polymers for 10 days and 60 days formulations; however, gross phase separations of PCL and acid-terminated PLGA prevented tuning within these timeframes due to the phase separation of the polymer, valganciclovir, or both.

Electro-optics of novel polymer-liquid crystalline composites

International Nuclear Information System (INIS)

Ibragimov, T.D.; Bayramov, G.M.; Imamaliyev, A.R.; Bayramov, G.M.

2014-01-01

The polymer network liquid crystals based on the liquid crystals H37 and 5CB with PMVP and PEG have been developed. Mesogene substance HOBA is served for stabilization of obtaining composites. Kinetics of network formation is investigated by methods of polarization microscopy and integrated small-angle scattering. It is shown that gel-like states of the composite H-37+PMVP+HOBA and 5CB+PEG+HOBA are formed at polymer concentration above 7 percent and 9 percent, correspondingly. The basic electro-optic parameters of the obtained composites are determined at room temperature. Experimental results are explained by phase separation of the system, diminution of a working area of electro-optical effects and influence of areas with high polymer concentration on areas with their low concentration

Crystalline and Crystalline International Disposal Activities

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-06

This report presents the results of work conducted between September 2015 and July 2016 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program. Los Alamos focused on two main activities during this period: Discrete fracture network (DFN) modeling to describe flow and radionuclide transport in complex fracture networks that are typical of crystalline rock environments, and a comprehensive interpretation of three different colloid-facilitated radionuclide transport experiments conducted in a fractured granodiorite at the Grimsel Test Site in Switzerland between 2002 and 2013. Chapter 1 presents the results of the DFN work and is divided into three main sections: (1) we show results of our recent study on the correlation between fracture size and fracture transmissivity (2) we present an analysis and visualization prototype using the concept of a flow topology graph for characterization of discrete fracture networks, and (3) we describe the Crystalline International work in support of the Swedish Task Force. Chapter 2 presents interpretation of the colloidfacilitated radionuclide transport experiments in the crystalline rock at the Grimsel Test Site.

Design of Functional Polyesters for Electronic and Biological Applications

OpenAIRE

Nelson, Ashley Marie

2015-01-01

Melt polymerization and novel monomers enabled the synthesis of polyesters for electronic and biological applications. Inspiration from nature and a passion for environmental preservation instigated an emphasis on the incorporation of renewable resources into polymeric materials. Critical analysis of current research surrounding bisphenol-A replacements and ioncontaining segmented polyurethanes aided in identifying benchmark polymers, including limitations, challenges, and future needs. Struc...

Aligned silane-treated MWCNT/liquid crystal polymer films

International Nuclear Information System (INIS)

Cervini, Raoul; Simon, George P; Ginic-Markovic, Milena; Matisons, Janis G; Huynh, Chi; Hawkins, Stephen

2008-01-01

We report on a method to preferentially align multiwall carbon nanotubes (MWCNTs) in a liquid crystalline matrix to form stable composite thin films. The liquid crystalline monomeric chains can be crosslinked to form acrylate bridges, thereby retaining the nanotube alignment. Further post-treatment by ozone etching of the composite films leads to an increase in bulk conductivity, leading to higher emission currents when examined under conducting scanning probe microscopy. The described methodology may facilitate device manufacture where electron emission from nanosized tips is important in the creation of new display devices

Isosorbide as the structural component of bio-based unsaturated polyesters for use as thermosetting resins.

Science.gov (United States)

Sadler, Joshua M; Toulan, Faye R; Nguyen, Anh-Phuong T; Kayea, Ronald V; Ziaee, Saeed; Palmese, Giuseppe R; La Scala, John J

2014-01-16

In recent years, the development of renewable bio-based resins has gained interest as potential replacements for petroleum based resins. Modified carbohydrate-based derivatives have favorable structural features such as fused bicyclic rings that offer promising candidates for the development of novel renewable polymers with improved thermomechanical properties when compared to early bio-based resins. Isosorbide is one such compound and has been utilized as the stiffness component for the synthesis of novel unsaturated polyesters (UPE) resins. Resin blends of BioUPE systems with styrene were shown to possess viscosities (120-2200 cP) amenable to a variety of liquid molding techniques, and after cure had Tgs (53-107 °C) and storage moduli (430-1650 MPa) that are in the desired range for composite materials. These investigations show that BioUPEs containing isosorbide can be tailored during synthesis of the prepolymer to meet the needs of different property profiles. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tandem mass spectrometry characteristics of polyester anions and cations formed by electrospray ionization.

Science.gov (United States)

Arnould, Mark A; Buehner, Rita W; Wesdemiotis, Chrys; Vargas, Rafael

2005-01-01

Electrospray ionization of polyesters composed of isophthalic acid and neopentyl glycol produces carboxylate anions in negative mode and mainly sodium ion adducts in positive mode. A tandem mass spectrometry (MS/MS) study of these ions in a quadrupole ion trap shows that the collisionally activated dissociation pathways of the anions are simpler than those of the corresponding cations. Charge-remote fragmentations predominate in both cases, but the spectra obtained in negative mode are devoid of the complicating cation exchange observed in positive mode. MS/MS of the Na(+) adducts gives rise to a greater number of fragments but not necessarily more structural information. In either positive or negative mode, polyester oligomers with different end groups fragment by similar mechanisms. The observed fragments are consistent with rearrangements initiated by the end groups. Single-stage ESI mass spectra also are more complex in positive mode because of extensive H/Na substitutions; this is also true for matrix-assisted laser desorption ionization (MALDI) mass spectra. Hence, formation and analysis of anions might be the method of choice for determining block length, end group structure and copolymer sequence, provided the polyester contains at least one carboxylic acid end group that is ionizable to anions.

Polyurethane coating from prepolymers and Crambe oil polyesters in oxygenates and green solvents

International Nuclear Information System (INIS)

Pinto, Elaine R.P.; Messaddeq, Younes; Polito, Wagner Luiz; Matinelli, Marcia

2015-01-01

The PU coatings are extremely used in areas that require high-performance. For several applications PU resin, the solvent base is commonly used, the problem is the solvents with high content of volatile organic compounds (VCO) like: toluene, xylene, benzene, etc.. In this work, we were synthesized and characterized four kinds of prepolymers with low-VCO from renewable sources such as castor oil and crambe oil with oxygenate and green solvents. The PU prepolymers had been synthesized in the proportions NCO/OH 2:1 and 3:1. The curing process was carried out with atmospheric moisture in the films. Characterization was made from prepolymers, oligomers and polyesters and PU films by FTIR, TGA / DTA, NMR, GPC and GC-FID, besides this the coatings were applied on aluminum and glass plates and, subjected to analysis chamber saline, hardness and adhesion. The results indicated that the reaction occurred between the prepolymers with oligomers or polyesters, because disappearance of the NCO band at 2270 cm"-"1. The PU films showed good thermal stability (> 270 °C), high tensile strength and deformation. Surround the formulations, the PU films with HDI prepolymers showed the best results with polyesters from crambe oil (PEC 02 and PEC 03). (author)

Material characterization of a polyester resin system for the pultrusion process

DEFF Research Database (Denmark)

Baran, Ismet; Akkerman, Remko; Hattel, Jesper Henri

2014-01-01

In the present work, the chemo-rheology of an industrial ‘‘orthophthalic’’ polyester system specifically prepared for a pultrusion process is characterized. The curing behaviour is first characterized using the differential scanning calorimetry (DSC). Isothermal and dynamic scans are performed...

Effect of particle size and concentration on the mechanical properties of polyester/date palm seed particulate composites

Directory of Open Access Journals (Sweden)

Alewo Opuada AMEH

2015-05-01

Full Text Available The use of cellulosic materials as reinforcement in composites can greatly enhance their properties. The thrust of this study was to investigate the effect of date palm seed particle on the properties of reinforced polyester. Unsaturated polyester resin was reinforced with date palm seed particles of 0.5, 2.0 and 2.8mm particle sizes using variable particle loadings of 5, 10, 15, 20 and 25wt%. The composites obtained were subjected to various types of mechanical and physical tests in order to assess their performance. The optimum tensile strength of 16.7619N/mm2 and elastic modulus of 343.8N/mm2 were attained at 15wt% and 10wt% loading (using 0.5mm particles respectively and percent water absorption was found to be least for 0.5mm particle size. The hardness was enhanced to the maximum of 74 HRF (Rockwell Hardness Factor by 2mm particle size at 25wt% loading. Pure unsaturated polyester resin recorded tensile strength of 17.5959N/mm2, elastic modulus of 316.7N/mm2 and hardness of 33.5 HRF. The results indicated that the use of date palm seed particles as reinforcement can enhance the properties of polyester composites.

(Meth)acrylate liquid crystalline polymers for membrane applications

Czech Academy of Sciences Publication Activity Database

Rabie, F.; Sedláková, Zdeňka; Sheth, S.; Marand, E.; Martin, S. M.; Poláková, Lenka

2015-01-01

Roč. 132, č. 43 (2015), 42694_1-42694_8 ISSN 0021-8995 Institutional support: RVO:61389013 Keywords : copolymers * liquid crystals * membranes Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.866, year: 2015

Mechanical characterization of glass fiber (woven roving/chopped strand mat E-glass fiber) reinforced polyester composites

Science.gov (United States)

Bhaskar, V. Vijaya; Srinivas, Kolla

2017-07-01

Polymer reinforced composites have been replacing most of the engineering material and their applications become more and more day by day. Polymer composites have been analyzing from past thirty five years for their betterment for adapting more applications. This paper aims at the mechanical properties of polyester reinforced with glass fiber composites. The glass fiber is reinforced with polyester in two forms viz Woven Rovings (WRG) and Chopped Strand Mat (CSMG) E-glass fibers. The composites are fabricated by hand lay-up technique and the composites are cut as per ASTM Standard sizes for corresponding tests like flexural, compression and impact tests, so that flexural strength, compression strength, impact strength and inter laminar shear stress(ILSS) of polymer matrix composites are analyzed. From the tests and further calculations, the polyester composites reinforced with Chopped Strand Mat glass fiber have shown better performance against flexural load, compression load and impact load than that of Woven Roving glass fiber.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

Science.gov (United States)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting; Sun, Kaikai; Hu, Xili; Wang, Yujiao; Xu, Xiaoqi

2014-10-01

Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

CSIR Research Space (South Africa)

Boguslavsky, L

2010-10-01

Full Text Available filtration efficiency. Glass fibres are more harmful to human, compared to polypropylene and polyester fibre which are chemically inert. Hydroentanglement and chemical bonding techniques were utilised in manufacturing nonwovens for dry filtration. Acrylic...

Aza‐Michael addition reaction: Post‐polymerization modification and preparation of PEI/PEG‐based polyester hydrogels from enzymatically synthesized reactive polymers

DEFF Research Database (Denmark)

Hoffmann, Christian; Stuparu, Mihaiela C.; Daugaard, Anders Egede

2015-01-01

The utility of aza‐Michael addition chemistry for post‐polymerization functionalization of enzymatically prepared polyesters is established. For this, itaconate ester and oligoethylene glycol are selected as monomers. A Candida Antarctica lipase B catalyzed polycondensation reaction between the two...... monomers provides the polyesters, which carry an activated carbon‐carbon double bond in the polymer backbone. These electron deficient alkenes represent suitable aza‐Michael acceptors and can be engaged in a nucleophilic addition reaction with small molecular mono‐amines (aza‐Michael donors) to yield...... functionalized linear polyesters. Employing a poly‐amine as the aza‐Michael donor, on the other hand, results in the formation of hydrophilic polymer networks....

Mechanical Properties Analysis Of Composite Magnetic Base On hexa ferrite And Polyester Or Epoxy Matrix With Silane Additive Addition

International Nuclear Information System (INIS)

Sudirman; Ridwan; Mujamilah; K K, Aloma; Rembulan, Marisa; Fitriyanti

2003-01-01

Application of composite magnetic especially hexa ferrite magnet for industry and home industry in Indonesia has been used. Research purposes were making composite magnetic by mixing hexa ferrite powder with polyester or epoxy and studying the effect of coupling agent 3-aminopropyltriethoxysilane (3-APE) addition on mechanical properties of composite magnetic. The coupling agent may increase bonding properties between magnetic powder and matrix polymer, so that tensile strength of magnetic composite will increase without decreasing the magnetic properties. Magnetic powder (SrM or BaM) wich be coated by coupling agent were added to matrix polyester and mekpo or epoxy and versamid, mixed until homogen then pressing into to the dumbbell form molding. For epoxy matrix, pressing was done in hot press at 70 deg. C and 150 kg/cm 2 following by cooling in cold press, while for polyester matrix pressing was done in hydraulic press and following by curing at 70 deg. C in an oven for 1 hour. The composition of magnetic powder were varied to 30, 40 and 50% volume fraction and coupling agent were varied to 5, 10 and 15 ml for every volume fraction. The result showed that 10 ml added of coupling agent was give best mechanical properties both polyester and epoxy matrix. However generally, increasing of magnetic powder content decreased the tensile strength of magnetic composite. The properties of magnetic composite SrM was better than BaM either in polyester or epoxy matrix

A solvent induced crystallisation method to imbue bioactive ingredients of neem oil into the compact structure of poly (ethylene terephthalate) polyester

Energy Technology Data Exchange (ETDEWEB)

Ali, Wazed [Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Sultana, Parveen [Department of Physics, Jadavpur University, Kolkata 700032 (India); Joshi, Mangala [Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Rajendran, Subbiyan, E-mail: sr2@bolton.ac.uk [Institute for Materials Research and Innovation, The University of Bolton, Bolton BL3 5AB (United Kingdom)

2016-07-01

Neem oil, a natural antibacterial agent from neem tree (Azadarichtaindica) has been used to impart antibacterial activity to polyester fabrics. Solvent induced polymer modification method was used and that facilitated the easy entry of neem molecules into the compact structure of polyethylene terephthalate (PET) polyester. The polyester fabric was treated with trichloroacetic acid-methylene chloride (TCAMC) solvent system at room temperature prior to treatment with neem oil. The concentration of TCAMC and the treatment time were optimised. XRD and SEM results showed that the TCAMC treatment causes polymer modification and morphological changes in the PET polyester. Antibacterial activity of TCAMC pre-treated and neem-oil-treated polyester fabric was tested using AATCC qualitative and quantitative methods. Both Gram-positive and Gram-negative organisms were used to determine the antimicrobial activity. It was observed that the treated fabric registers substantial antimicrobial activity against both the Staphylococcus aureus (Gram-positive) and the Escherichia coli (Gram-negative) and the effect increases with the increase in concentration of TCAMC treatment. The antibacterial effect remains substantial even after 25 launderings. A kinetic growth study involving the effect of antibacterial activity at various incubation times was carried out. - Highlights: • A novel technique whereby the antibacterial components of neem oil are imbued into the compact structure of PET polyester • Trichloroacetic acid-Methylene Chloride treatment facilitated the easy entry of neem ingredients into the PET structure • Neem oil treated PET registered substantial antibacterial efficacy • Antibacterial effect is retained even after multiple use-wash cycles.

Homogeneous alignment of liquid crystalline dendrimers confined in a slit-pore. A simulation study.

Science.gov (United States)

Workineh, Zerihun G; Vanakaras, Alexandros G

2016-03-23

In this work we present results from isobaric-isothermal (NPT) Monte Carlo simulation studies of model liquid crystalline dendrimer (LCDr) systems confined in a slit-pore made of two parallel flat walls. The dendrimers are modelled as a collection of spherical and ellipsoidal particles corresponding to the junction points of the dendritic core and to the mesogenic units respectively. Assuming planar uniform (unidirectional) soft anchoring of the mesogenic units on the substrates we investigate the conformational and alignment properties of the LCDr system at different thermodynamic state points. Tractable coarse grained force fields have been used from our previous work. At low pressures the interior of the pore is almost empty, since almost all LCDrs are anchored to the substrates forming two-dimensional smectic-like structures with the mesogens aligned along the aligning direction of the substrates. As the pressure grows the LCDrs occupy the whole pore. However, even at low temperatures, the smectic organization does not transmit in the interior of the pore and is preserved for distances of 2-3 mesogenic diameters from the walls. For this reason, the global orientational order decreases with increasing pressure (density). In the vicinity (2-3 mesogenic diameters) of the pore walls, mesogenic units preserve the smectic structure whose layers are separated by layers of spherical beads. In this region individual LCDrs possess a rod like shape.

Mesophase and size manipulation of itraconazole liquid crystalline nanoparticles produced via quasi nanoemulsion precipitation.

Science.gov (United States)

Mugheirbi, Naila A; Tajber, Lidia

2015-10-01

The fabrication of drug nanoparticles (NPs) with process-mediated tunable properties and performances continues to grow rapidly during the last decades. This study investigates the synthesis and phase tuning of nanoparticulate itraconazole (ITR) mesophases using quasi nanoemulsion precipitation from acetone/water systems to seek out an alternative pathway to the nucleation-based NP formation. ITR liquid crystalline (LC) phases were formed and nematic-smectic mesomorphism was achieved via controlling solvent:antisolvent temperature difference (ΔTS:AS). The use of ΔTS:AS=49.5°C was associated with a nematic assembly, while intercalated smectic A layering was observed at ΔTS:AS=0°C, with both phases confined in the nanospheres at room temperature. The quasi emulsion system has not been investigated at the nanoscale to date and in contrary to the microscale, quasi nanoemulsion was observed over the solvent:antisolvent viscosity ratios of 1:7-1:1.4. Poly(acrylic acid) in the solvent phase exhibited a concentration dependent interaction when ITR formed NPs. This nanodroplet-based approach enabled the preparation of a stable ITR nanodispersion using Poloxamer 407 at 80°C, which was unachievable before using precipitation via nucleation. Findings of this work lay groundwork in terms of rationalised molecular assembly as a tool in designing pharmaceutical LC NPs with tailored properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Homogeneous alignment of liquid crystalline dendrimers confined in a slit-pore. A simulation study

Science.gov (United States)

Workineh, Zerihun G.; Vanakaras, Alexandros G.

2016-03-01

In this work we present results from isobaric-isothermal (NPT) Monte Carlo simulation studies of model liquid crystalline dendrimer (LCDr) systems confined in a slit-pore made of two parallel flat walls. The dendrimers are modelled as a collection of spherical and ellipsoidal particles corresponding to the junction points of the dendritic core and to the mesogenic units respectively. Assuming planar uniform (unidirectional) soft anchoring of the mesogenic units on the substrates we investigate the conformational and alignment properties of the LCDr system at different thermodynamic state points. Tractable coarse grained force fields have been used from our previous work. At low pressures the interior of the pore is almost empty, since almost all LCDrs are anchored to the substrates forming two-dimensional smectic-like structures with the mesogens aligned along the aligning direction of the substrates. As the pressure grows the LCDrs occupy the whole pore. However, even at low temperatures, the smectic organization does not transmit in the interior of the pore and is preserved for distances of 2-3 mesogenic diameters from the walls. For this reason, the global orientational order decreases with increasing pressure (density). In the vicinity (2-3 mesogenic diameters) of the pore walls, mesogenic units preserve the smectic structure whose layers are separated by layers of spherical beads. In this region individual LCDrs possess a rod like shape.

Homogeneous alignment of liquid crystalline dendrimers confined in a slit-pore. A simulation study

International Nuclear Information System (INIS)

Workineh, Zerihun G; Vanakaras, Alexandros G

2016-01-01

In this work we present results from isobaric-isothermal (NPT) Monte Carlo simulation studies of model liquid crystalline dendrimer (LCDr) systems confined in a slit-pore made of two parallel flat walls. The dendrimers are modelled as a collection of spherical and ellipsoidal particles corresponding to the junction points of the dendritic core and to the mesogenic units respectively. Assuming planar uniform (unidirectional) soft anchoring of the mesogenic units on the substrates we investigate the conformational and alignment properties of the LCDr system at different thermodynamic state points. Tractable coarse grained force fields have been used from our previous work. At low pressures the interior of the pore is almost empty, since almost all LCDrs are anchored to the substrates forming two-dimensional smectic-like structures with the mesogens aligned along the aligning direction of the substrates. As the pressure grows the LCDrs occupy the whole pore. However, even at low temperatures, the smectic organization does not transmit in the interior of the pore and is preserved for distances of 2–3 mesogenic diameters from the walls. For this reason, the global orientational order decreases with increasing pressure (density). In the vicinity (2–3 mesogenic diameters) of the pore walls, mesogenic units preserve the smectic structure whose layers are separated by layers of spherical beads. In this region individual LCDrs possess a rod like shape. (paper)

Crystalline and Crystalline International Disposal Activities

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-12-21

This report presents the results of work conducted between September 2014 and July 2015 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program.

Study of the properties of poly(ester urethanes) following ionizing irradiation

International Nuclear Information System (INIS)

Kornacka, A.M.; Przybytniak, G.

2006-01-01

Copolymers of polyurethanes and polyesters were found unsuitable for long-term implants because of fast hydrolysis of the ester soft segments. On the other hand, such properties make them valuable as gradually degradable biomaterial that might be used as scaffolds for tissue engineering. The elastomeric polyurethanes are known to be radiation stable materials in sterilizing dose. Nevertheless, if additional components appear in the system, e.g. segments of polyesters, then the influence of irradiation is poorly recognized. In presented paper it has been shown that ionizing radiation induces solid state reorganization of the segmented domains, leading to migration of soft segments towards the surface and to grow of hydrophobic properties. Obtained results confirmed that the urethane segments were more resistant towards ionizing irradiation and the presence of ester units facilitated generation of free radicals. It was also found that in poly(ε-caprolactane)diol (PCL) segments ionizing radiation induces radicals that are able to introduce cross-linking in macromolecules, and consequently reduce ability to biodegradation

Azobenzene Polyesters Used as Gate‐Like Scaffolds in Nanoscopic Hybrid Systems

DEFF Research Database (Denmark)

Bernardos, Andrea; Mondragón, Laura; Javakhishvili, Irakli

2012-01-01

inside the mesopores. Two solid materials, Rh‐PAzo8‐S and Rh‐PAzo6‐S, containing two closely related polymers, PAzo8 and PAzo6, in the pore outlets have been prepared. Materials Rh‐PAzo8‐S and Rh‐PAzo6‐S showed an almost zero release in water due to steric hindrance imposed by the presence of anchored...... bulky polyesters, whereas a large delivery of the cargo was observed in the presence of an esterase enzyme due to the progressive hydrolysis of polyester chains. Moreover, nanoparticles Rh‐PAzo8‐S and Rh‐PAzo6‐S were used to study the controlled release of the dye in intracellular media. Nanoparticles...... were not toxic for HeLa cells and endocytosis‐mediated cell internalisation was confirmed by confocal microscopy. Furthermore, the possible use of capped materials as a drug‐delivery system was demonstrated by the preparation of a new mesoporous silica nanoparticle functionalised with PAzo6 and loaded...

Direct Visualisation of the Structural Transformation between the Lyotropic Liquid Crystalline Lamellar and Bicontinuous Cubic Mesophase.

Science.gov (United States)

Tran, Nhiem; Zhai, Jiali; Conn, Charlotte E; Mulet, Xavier; Waddington, Lynne J; Drummond, Calum J

2018-05-29

The transition between the lyotropic liquid crystalline lamellar and the bicontinuous cubic mesophase drives multiple fundamental cellular processes involving changes in cell membrane topology including endocytosis and membrane budding. While several theoretical models have been proposed to explain this dynamic transformation, experimental validation of these models has been challenging due to the short lived nature of the intermediates present during the phase transition. Herein, we report the direct observation of a lamellar to bicontinuous cubic phase transition in nanoscale dispersions using a combination of cryogenic transmission electron microscopy and static small angle X-ray scattering. The results represent the first experimental confirmation of a theoretical model which proposed that the bicontinuous cubic phase originates from the centre of a lamellar vesicle, then propagates outward via the formation of inter-lamellar attachments and stalks. The observation was possible due to the precise control of the lipid composition to place the dispersion systems at the phase boundary of a lamellar and a cubic phase, allowing for the creation of long-lived structural intermediates. By surveying the nanoparticles using cryogenic transmission electron microscopy, a complete phase transition sequence was established.

Electrostatic Effects in Phase Transitions of Biomembranes between Cubic Phases and Lamellar Liquid-Crystalline (Lα) phase

Science.gov (United States)

Masum, Shah Md.; Li, Shu Jie; Tamba, Yukihiro; Yamashita, Yuko; Yamazaki, Masahito

2004-04-01

Elucidation of the mechanisms of transitions between cubic phase and liquid-crystalline (Lα) phase, and between different IPMS cubic phases, are essential for understanding of dynamics of biomembranes and topological transformation of lipid membranes. Recently, we found that electrostatic interactions due to surface charges of lipid membranes induce transition between cubic phase and Lα phase, and between different IPMS cubic phases. As electrostatic interactions increase, the most stable phase of a monoolein (MO) membrane changes: Q224 ⇒ Q229 ⇒ Lα. We also found that a de novo designed peptide partitioning into electrically neutral lipid membrane changed the phase stability of the MO membranes. As peptide-1 concentration increased, the most stable phase of a MO membrane changes: Q224 ⇒ Q229 ⇒Lα. In both cases, the increase in the electrostatic repulsive interaction greatly reduced the absolute value of spontaneous curvature of the MO monolayer membrane. We also investigated factors such as poly (L-lysine) and osmotic stress to control structure and phase stability of DOPA/MO membranes. Based on these results, we discuss the mechanism of the effect of electrostatic interactions on the stability of cubic phase.

Ultrasound enhanced plasma treatment of glass-fibre-reinforced polyester in atmospheric pressure air for adhesion improvement

DEFF Research Database (Denmark)

Kusano, Yukihiro; Singh, Shailendra Vikram; Norrman, Kion

2011-01-01

A glass-fibre-reinforced polyester (GFRP) plate was treated with dielectric barrier discharge (DBD) at atmospheric pressure in air for adhesion improvement. The effects of ultrasonic irradiation using a high-power gas-jet generator during the treatment were investigated. The optical emission...... damage of the GFRP plates. The polar component of the surface energy of the polyester plate was 21 mJ/m2 before the treatment, increased markedly to 52 mJ/m2 after 2-s plasma treatment without ultrasonic irradiation, and further increased slightly after longer treatments. In addition, the polar component...

Alignment control of columnar liquid crystals with wavelength tunable CO2 laser irradiation

International Nuclear Information System (INIS)

Monobe, Hirosato; Awazu, Kunio; Shimizu, Yo

2008-01-01

Infrared-induced alignment change with wavelength tunable CO 2 laser irradiation for columnar liquid crystal domains was investigated for a liquid crystalline triphenylene derivative. A uniformly aligned alignment change of domains was observed when a chopped linearly polarized infrared laser light corresponding to the wavelength of the aromatic C-O-C stretching vibration band (9.65 μm) was irradiated. The results strongly imply that the infrared irradiation is a possible technique for device fabrication by use of columnar mesophase as a liquid crystalline semiconductor

Biodegradable polyesters reinforced with triclosan loaded polylactide micro/nanofibers: Properties, release and biocompatibility

Directory of Open Access Journals (Sweden)

L. J. del Valle

2012-04-01

Full Text Available Mechanical properties and drug release behavior were studied for three biodegradable polyester matrices (polycaprolactone, poly(nonamethylene azelate and the copolymer derived from 1,9-nonanediol and an equimolar mixture of azelaic and pimelic acids reinforced with polylactide (PLA fibers. Electrospinning was used to produce suitable mats constituted by fibers of different diameters (i.e. from micro- to nanoscale and a homogeneous dispersion of a representative hydrophobic drug (i.e. triclosan. Fabrics were prepared by a molding process, which allowed cold crystallization of PLA micro/nanofibers and hot crystallization of the polyester matrices. The orientation of PLA molecules during electrospinning favored the crystallization process, which was slightly enhanced when the diameter decreased. Incorporation of PLA micro/nanofibers led to a significant increase in the elastic modulus and tensile strength, and in general to a decrease in the strain at break. The brittle fracture was clearer when high molecular weight samples with high plastic deformation were employed. Large differences in the release behavior were detected depending on the loading process, fiber diameter size and hydrophobicity of the polyester matrix. The release of samples with the drug only loaded into the reinforcing fibers was initially fast and then became slow and sustained, resulting in longer lasting antimicrobial activity. Biocompatibility of all samples studied was demonstrated by adhesion and proliferation assays using HEp-2 cell cultures.

Liquid Crystals in Decorative and Visual Arts

Science.gov (United States)

Makow, David

The following sections are included: * INTRODUCTION * PIGMENT AND STRUCTURAL COLOURS AND THEIR RELEVANCE TO LIQUID CRYSTALS * LIQUID CRYSTAL MATERIALS AND TECHNIQUES FOR DECORATIVE AND VISUAL ARTS * Free cholesteric liquid crystals (FCLC's) * Encapsulated liquid crystals (ECLC's) * Nonsteroid Chiral nematics * Polymers with liquid crystalline properties (PLCs) * COLOUR PROPERTIES OF CHOLESTERIC LIQUID CRYSTALS (CLC's) * Molecular structure and the mechanism of colour production * Dependence of perceived colours on the angle of illumination and viewing * Dependence of perceived colours on temperature * Additive colour properties * Methods of doubling the peak reflectance of cholesteric liquid crystals * Colour gamut * Colours of superimposed and pigmented coatings * Colours in transmission * ACKNOWLEDGEMENTS * REFERENCES

Liquid crystals in biotribology synovial joint treatment

CERN Document Server

Ermakov, Sergey; Eismont, Oleg; Nikolaev, Vladimir

2016-01-01

This book summarizes the theoretical and experimental studies confirming the concept of the liquid-crystalline nature of boundary lubrication in synovial joints. It is shown that cholesteric liquid crystals in the synovial liquid play a significant role in the mechanism of intra-articular friction reduction. The results of structural, rheological and tribological research of the creation of artificial synovial liquids - containing cholesteric liquid crystals in natural synovial liquids - are described. These liquid crystals reproduce the lubrication properties of natural synovia and provide a high chondroprotective efficiency. They were tested in osteoarthritis models and in clinical practice.

Filler Fraction Effect on Creep Response of Crosslinked Polyester Matrix with Mineral Filler

Czech Academy of Sciences Publication Activity Database

Hristova, J.; Minster, Jiří

Vol. 89, - (2003), s. 3329-3335 ISSN 0021-8995 Institutional research plan: CEZ:AV0Z2071913 Keywords : polyester composites * creep * ageing Subject RIV: JI - Composite Materials Impact factor: 1.017, year: 2003

Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

DEFF Research Database (Denmark)

Nguyen, Hiep Dinh; Löf, David; Hvilsted, Søren

2016-01-01

A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA)...... stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition....

The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

International Nuclear Information System (INIS)

Jegdic, B.V.; Bajat, J.B.; Popic, J.P.; Stevanovic, S.I.; Miskovic-Stankovic, V.B.

2011-01-01

Highlights: → The effect of NaNO 2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO 2 . → EIS results and microscopic examinations correlate well with adhesion measurements. - Abstract: The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO 2 as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM). The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO 2 -free bath.

Synthesis and Characterization of Liquid Crystalline Copolymethacrylates, Copolyacrylates and Copolysiloxanes Containing 4-Methoxy-4’-Hydroxy-alpha-Methylstilbene and 4-Hydroxy-4’-Methoxy-alpha-Methylstilbene Constitutional Isomers as Side Groups.

Science.gov (United States)

1987-01-01

10*C, concentrated sulfuric acid (31.0 g, 0.32 mole ) was added dropwise during 1.5 hr. The reaction mixture was stirred at this temperature for 2...characterization of the polymethacrylates . Indifferent of the thermal history and - ., .. _%,, n -x,, ; *> ;.. ’ . ,..... *p.****, * . - _. .. ... .~ • ’ -18...followed by a liquid crystalline mesophase, and the isotropization transition. Only the polymethacrylate containing eleven methylenic units in the

Effect of polyester fiber reinforcement on the mechanical properties of interim fixed partial dentures

Directory of Open Access Journals (Sweden)

N. Gopichander

2015-10-01

Conclusion: Within the limitations of this study, polyester fiber reinforcements improved the mechanical properties of heat-polymerized PMMA, cold-polymerized PMMA, and bis-acrylic provisional FPD materials.

Purification and Properties of a Polyester Polyurethane-Degrading Enzyme from Comamonas acidovorans TB-35.

Science.gov (United States)

Akutsu, Y; Nakajima-Kambe, T; Nomura, N; Nakahara, T

1998-01-01

A polyester polyurethane (PUR)-degrading enzyme, PUR esterase, derived from Comamonas acidovorans TB-35, a bacterium that utilizes polyester PUR as the sole carbon source, was purified until it showed a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This enzyme was bound to the cell surface and was extracted by addition of 0.2% N,N-bis(3-d-gluconamidopropyl)deoxycholamide (deoxy-BIGCHAP). The results of gel filtration and SDS-PAGE showed that the PUR esterase was a monomer with a molecular mass of about 62,000 Da. This enzyme, which is a kind of esterase, degraded solid polyester PUR, with diethylene glycol and adipic acid released as the degradation products. The optimum pH for this enzyme was 6.5, and the optimum temperature was 45 degrees C. PUR degradation by the PUR esterase was strongly inhibited by the addition of 0.04% deoxy-BIGCHAP. On the other hand, deoxy-BIGCHAP did not inhibit the activity when p-nitrophenyl acetate, a water-soluble compound, was used as a substrate. These observations indicated that this enzyme degrades PUR in a two-step reaction: hydrophobic adsorption to the PUR surface and hydrolysis of the ester bond of PUR.

Diffraction from polarization holographic gratings with surface relief in side-chain azobenzene polyesters

DEFF Research Database (Denmark)

Naydenova, I; Nikolova, L; Todorov, T

1998-01-01

We investigate the polarization properties of holographic gratings in side-chain azobenzene polyesters in which an anisotropic grating that is due to photoinduced linear and circular birefringence is recorded in the volume of the material and a relief grating appears on the surface. A theoretical...... model is proposed to explain the experimental results, making it possible to understand the influence of the different photoinduced effects. It is shown that at low intensity the polarization properties of the diffraction at these gratings are determined by the interaction of the linear and circular...... photobirefringences, and at larger intensity the influence of the surface relief dominates the effect of the circular anisotropy. Owing to the high recording efficiency of the polyesters, the +/-1-order diffracted waves change the polarization interference pattern during the holographic recording, resulting...

Preferential Incorporation of Azelaic Acid Units into the Crystalline Phase of the Copoly(Alkylene Dicarboxylate Derived from 1,9-Nonanediol and an Equimolar Mixture of Pimelic and Azelaic Acids

Directory of Open Access Journals (Sweden)

Angélica Díaz

2015-09-01

Full Text Available The crystalline structure of two biodegradable odd-odd polyesters (i.e., poly(nonamethylene pimelate (PES 9,7 and poly(nonamethylene azelate (PES 9,9 was investigated by means of electron and X-ray diffraction of single crystals and oriented fibers, respectively. Truncated rhombic crystals were obtained with an aspect ratio that was strongly depended on the supercooling degree. The crystalline structure of both homopolyesters was defined by an orthorhombic P21ab space group and a large unit cell containing four molecular segments with an all-trans conformation. Nevertheless, the structure in the chain axis projection was equivalent to a simpler cell containing only two segments. Crystalline lamellae were effectively degraded by lipases, starting the enzymatic attack on the lamellar surfaces. The random copolymer constituted by an equimolar amount of pimelate and azelate units (COPES 9,7/9 crystallized according to regular lamellae with a similar molecular arrangement in the chain axis projection. The structure of this copolymer was preferably conditioned by the azelate component as could be deduced from both, diffraction and spectroscopic data. Analysis of small angle X-ray scattering patterns pointed out that less crystalline lamellae with higher amorphous thickness had developed in the copolymer. This feature was interpreted as a consequence of the preferential incorporation of pimelate comonomer units in the folding surface.

Polyester synthesis for application in PEMFC type fuel cells; Sintese de poliester para aplicacao em celulas a combustivel do tipo PEM

Energy Technology Data Exchange (ETDEWEB)

Fiuza, R.P.; Souza, D.R. de; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: raigenis@gmail.com

2006-07-01

The PEMFC (Proton Exchange Membrane Fuel Cell), along the SOFC (Solid Oxide Fuel Cell), is the most important technology, among the various types of fuels cell. The PEMFC shows a large versatility of applications, both for stationary and mobile use. However the PEMFC presents high manufacture cost, directly impacting in the cost of the produced energy. This work contemplates the previews sulfonation of phtalic acid and its subsequent polymerization with glycerol, using as catalytic tin dibutyl-dilaurate. The obtained material has been characterized by DSC, TGA, FTIR, MEV, DRX and XRF. The gotten results indicated that phtalic acid was sulfonated and the increase of the sulfonation degree significantly increased the crystallinity of the sulfonated ftalico acid. Furthermore, the polymer produced from the sulfonated monomer presented adequate thermal resistance and a high content of conducting groups, necessary conditions for application as electrolyte in PEMFC. All these characteristics, particularly the low cost of the reagents and the ease of production process, make the sulfonated polyester membrane a promising candidate as fuel cell electrolyte. (author)

Transient molecular orientation and rheology in flow aligning thermotropic liquid crystalline polymers

International Nuclear Information System (INIS)

Ugaz, Victor M.; Burghardt, Wesley R.; Zhou, Weijun; Kornfield, Julia A.

2001-01-01

Quantitative measurements of molecular orientation and rheology are reported for various transient shear flows of a nematic semiflexible copolyether. Unlike the case of lyotropic liquid crystalline polymers (LCPs), whose structure and rheology in shear are dominated by director tumbling, this material exhibits flow aligning behavior. The observed behavior is quite similar to that seen in a copolyester that we have recently studied [Ugaz and Burghardt (1998)], suggesting that flow aligning dynamics may predominate in main-chain thermotropes that incorporate significant chain flexibility. Since the flow aligning regime has received little attention in previous attempts to model the rheology of textured, polydomain LCPs, we attempt to determine whether available models are capable of predicting the orientation and stress response of this class of LCP. We first examine the predictions of the polydomain Ericksen model, an adaptation of Ericksen's transversely isotropic fluid model which accounts for the polydomain distribution of director orientation while neglecting distortional elasticity. This simple model captures a number of qualitative and quantitative features associated with the evolution of orientation and stress during shear flow inception, but cannot cope with reversing flows. To consider the possible role of distortional elasticity in the re-orientation dynamics upon reversal, we evaluate the mesoscopically averaged domain theory of Larson and Doi [Larson and Doi (1991)], which incorporates a phenomenological description of distortional elastic effects. To date, their approach to account for polydomain structure has only been applied to describe tumbling LCPs. We find that it captures the qualitative transient orientation response to flow reversals, but is less successful in describing the evolution of stresses. This is linked to the decoupling approximation adopted during the model's development. Finally, a modified polydomain Ericksen model is introduced

Parallel gastric emptying of nonhydrolyzable fat and water after a solid-liquid meal in humans

International Nuclear Information System (INIS)

Cortot, A.; Phillips, S.F.; Malagelada, J.R.

1982-01-01

Our aim was to examine the control of gastric emptying of the oil phase of a mixed solid and liquid meal. Previous studies had shown that liquid dietary fats normally leave the stomach at a slower rate than does water. We wished to determine whether the slower emptying of fats was due to the physical characteristics of food (lower density and greater viscosity than water), to retardation by duodenal feedback mechanisms, or whether both factors contributed. Thus, we quantified the emptying rates of water and sucrose polyester (a nonabsorbable analog of dietary fat) ingested by healthy volunteers as a mixed solid and liquid meal. Gastric emptying was quantified by an intubation-perfusion method incorporating an occlusive jejunal balloon to facilitate recovery. Four phase-specific, nonabsorbable markers were used. [14C[Sucrose octaoleate and polyethylene glycol were incorporated in the meal and traced the lipid and water phases, respectively; [3H]glycerol triether and phenolsulfonphthalein were used as duodenal recovery markers. Sucrose polyester (substituting for dietary fat) was emptied very rapidly, and at about the same rate as was water, in contrast to natural fat, which empties very slowly. Emptying of water was rapid and comparable to that observed after mixed meals containing natural fat. These results imply that gastric emptying of the oil phase is controlled by receptors sensitive to the hydrolytic products of fat digestion and that the slow emptying of dietary fat is not simply due to its lower density

Crystalline Silica Primer

Science.gov (United States)

,

1992-01-01

Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a threedimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHAregulated businesses that use materials containing 0.1% or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHAregulated

Absorbable Polydioxanone (PDS) suture provides fewer wound complications than polyester (ethibond) suture in acute Tendo-Achilles rupture repair

LENUS (Irish Health Repository)

Baig, M N

2017-05-01

We prospectively studied acute Achilles tendon rupture in patients over a two 2-year period and reviewed the causes, outcome and complications. There were 53 patients included with acute Achilles rupture with minimum follow up period of 6 months. We compared the outcomes including infection rate and Boyden score between the two groups repaired by Polydioxanone and Polyester respectively. All infected cases had a suture repair using the polyester suture. The difference in the infection rate was highly significant between the 2 groups (p=0.001). All 34 patients (100%) in the PDS group had good \\/ excellent results based on the Boyden clinical assessment. Conversely, only 16 patients 9(68.4%) had good or excellent results IN Polyester repair group. Patients treated with a non- absorbable suture (ethibond) material for repair had a higher incidence infection and worse Boyden scores than the absorbable PDS group.

UV-irradiation effects on polyester nuclear track detector

International Nuclear Information System (INIS)

Agarwal, Chhavi; Kalsi, P.C.

2010-01-01

The effects of UV irradiation (λ=254 nm) on polyester nuclear track detector have been investigated employing bulk-etch technique, UV-visible spectrophotometry and infra-red spectrometry (FTIR). The activation energy values for bulk-etching were found to decrease with the UV-irradiation time indicating the scission of the polymer. Not much shift in the absorption edge due to UV irradiation was seen in the UV-visible spectra. FTIR studies also indicate the scission of the chemical bonds, thereby further validating the bulk-etch rate results.

Plasma Surface Modification of Glass-Fibre-Reinforced Polyester Enhanced by Ultrasonic Irradiation

DEFF Research Database (Denmark)

Kusano, Yukihiro; Singh, Shailendra Vikram; Bardenshtein, Alexander

2010-01-01

treatment can be highly enhanced by simultaneous high-power ultrasonic irradiation of the treating surface, because the delivered acoustic energy can reduce the thickness of the boundary gas layer. Here surfaces of glass-fibre-reinforced polyester (GFRP) plates were treated using an atmospheric pressure...

Thermoplastic poly(urethane urea)s from novel, bio-based amorphous polyester diols

NARCIS (Netherlands)

Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

2012-01-01

In this study, two novel, bio-based, amorphous polyester diols, namely poly(1,2-dimethylethylene adipate) (PDMEA) and poly(1,2-dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and

Fully Biobased Unsaturated Aliphatic Polyesters from Renewable Resources : Enzymatic Synthesis, Characterization, and Properties

NARCIS (Netherlands)

Jiang, Yi; Alberda van Ekenstein, Gerhard; Woortman, Albert J. J.; Loos, Katja

2014-01-01

Fully biobased saturated and unsaturated aliphatic polyesters and oligoesters are successfully prepared by Candida antarctica lipase B (CALB)-catalyzed polycondensations of succinate, itaconate, and 1,4-butanediol. The effects of monomer substrates and polymerization methods on enzymatic

Experimental Investigation on Mechanical Properties of Hemp/E-Glass Fabric Reinforced Polyester Hybrid Composites

Directory of Open Access Journals (Sweden)

M R SANJAY

2016-09-01

Full Text Available This research work has been focusing on Hemp fibers has an alternative reinforcement for fiber reinforced polymer composites due to its eco-friendly and biodegradable characteristics. This work has been carried out to evaluate the mechanical properties of hemp/E-glass fabrics reinforced polyester hybrid composites. Vacuum bagging method was used for the preparation of six different kinds of hemp/glass fabrics reinforced polyester composite laminates as per layering sequences. The tensile, flexural, impact and water absorption tests of these hybrid composites were carried out experimentally according to ASTM standards. It reveals that an addition of E-glass fabrics with hemp fabrics can increase the mechanical properties of composites and decrease the water absorption of the hybrid composites.

LPE growth and scintillation properties of (Zn,Mg)O single crystalline film

Czech Academy of Sciences Publication Activity Database

Yoshikawa, A.; Yanagida, T.; Fujimoto, Y.; Kurosawa, S.; Yokota, Y.; Yamaji, A.; Sugiyama, M.; Wakahara, S.; Futami, Y.; Kikuchi, M.; Miyamoto, M.; Sekiwa, H.; Nikl, Martin

2012-01-01

Roč. 59, č. 5 (2012), 2286-2289 ISSN 0018-9499 R&D Projects: GA MŠk LH12150 Institutional research plan: CEZ:AV0Z10100521 Keywords : crystalline materials * epitaxial layers * liquid phase epitaxy * scintillator * semiconductor films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.219, year: 2012

Radiation-induced changes affecting polyester based polyurethane binder

Science.gov (United States)

Pierpoint, Sujita Basi

The application of thermoplastic polyurethane elastomers as binders in the high energy explosives particularly when used in weapons presents a significantly complex and challenging problem due to the impact of the aging of this polymer on the useful service life of the explosive. In this work, the effects of radiation on the aging of the polyester based polyurethane were investigated using both electron beam and gamma irradiation at various dose rates in the presence and absence of oxygen. It was found by means of GPC that, in the presence and absence of oxygen, the poly (ester urethane) primarily undergoes cross-linking, by means of a carbon-centered secondary alkyl radical. It was also concluded that the polymer partially undergoes scission of the backbone of the main chain at C-O, N-C, and C-C bonds. Substantial changes in the conditions of irradiation and in dose levels did not affect the cross-linking and scission yields. Experiments were also performed with EPR spectroscopy for the purpose of identifying the initial carbon-centered free radicals and for studying the decay mechanisms of these radicals. It was found that the carbon-centered radical which is produced via C-C scission (primary alkyl radical) is rapidly converted to a long-lived allylic species at higher temperatures; more than 80% radicals are converted to allyl species in 2.5 hours. In the presence of oxygen, the allyl radical undergoes a fast reaction to produce a peroxyl radical; this radical decays with a 1.7 hour half-life by pseudo first-order kinetics to negligible levels in 13 hours. FTIR measurements were conducted to identify the radiation-induced changes to the functional groups in the polyester polyurethane. These measurements show an increase in carbonyl, amine and carboxylic groups as a result of reaction of H atoms with R-C-O·, ·NH-R and R-COO·. The FTIR results also demonstrate the production of the unsaturation resulting from hydrogen atom transfer during intrachain conversion

Experimental evidence of a liquid-liquid transition in interfacial water

Science.gov (United States)

Zanotti, J.-M.; Bellissent-Funel, M.-C.; Chen, S.-H.

2005-07-01

At ambient pressure, bulk liquid water shows an anomalous increase of thermodynamic quantities and apparent divergences of dynamic properties on approaching a temperature Ts of 228 K. At normal pressure, supercooled water spontaneously freezes below the homogeneous nucleation temperature, TH = 235 K. Upon heating, the two forms of Amorphous Solid Water (ASW), LDA (Low Density Amorphous Ice) and HDA (High Density Amorphous Ice), crystallise above TX = 150 K. As a consequence, up to now no experiment has been able to explore the properties of liquid water in this very interesting temperature range between 150 and 235 K. We present nanosecond-time-scale measurements of local rotational and translational dynamics of interfacial, non-crystalline, water from 77 to 280 K. These experimental dynamic results are combined with calorimetric and diffraction data to show that after exhibiting a glass transition at 165 K, interfacial water experiences a first-order liquid-liquid transition at 240 K from a low-density to a high-density liquid. This is the first direct evidence of the existence of a liquid-liquid transition involving water.

Unsaturated polyester resin composition curable with ionizing radiations

International Nuclear Information System (INIS)

Maruyama, Tsutomu; Murata, Koichiro.

1971-01-01

An unsaturated polyester resin composition curable with ionizing radiations and excellent in weather resistance is provided. The composition is obtained by reacting 10-12 moles of a polyhydric alcohol (e.g. ethylene glycol) with 10 moles of an acid mixture (25.45% by mole of endo-cis-bicyclo (2,2,1)-5-heptene-2-3-dicarboxylic acid (A), 20-40% of unsaturated dibasic acid and 15-55% of saturated dibasic acid) so that the acid value reaches 4-11. The composition is useful as coating, laminating and molding materials. As a coating material it is excellent in surface hardening property. The ionizing radiation used is preferably β-, α-rays or electron beams. In one example, and unsaturated polyester was prepared by reacting 3 moles of fumaric acid, 2 moles of phthalic anhydride, 3 moles of adipic acid 3, moles of (A), 10 moles of neopentyl glycol and 1 mole of trimethylolpropane. The resin was dissolved into a mixture of styrene, methyl methacrylate and butyl acrylate (50:8:42) and incorporated with titanium white. An ABS plate was coated with the enamel thus obtained and irradiated with electron beams (12 Mrad). In exposure test at 60 0 C, luster of the film was 92 before exposure and 83 after 30 months. In a comparative run in which (A) was not used, luster of the film decreased from 90 to 45 in 30 months. (Sakaichi, S.)

Modelling of polyester fabric dyeing in the presence of ultrasonic waves

Directory of Open Access Journals (Sweden)

Kodrić Marija

2017-01-01

Full Text Available In this paper, modelling of dyeing, i.e. adsorptive behaviour of disperse dyes on polyester fibres (dyeing, under the influence of ultrasound has been considered with the aim of getting the data about mechanisms of binding the dyes and defining the conditions of dyeing process of this synthetic fibres along with additional energy source without the use of carriers, compounds that increase permeability of the fibres and help dyeing. Dyeing - adsorption is conducted under different conditions, and the concentration of dyes, mass of the substrate, recipes and time of dyeing were being varied. It has been established that ultrasound allows dyeing without carriers and the efficiency of dyeing depends on the time of contact, initial concentration of the dye and the amount of absorbent - material. There is the continuity of growth of the amount of bound dye to the mass of the absorbent. Characteristic graphs, obtained from Langmuir isotherm, have confirmed that this model ensures precise description of polyester dyeing by disperse dye. Kinetic of dyeing has been remarkably interpreted by pseudo second-order in regards to the high functionality.

Ericksen number and Deborah number cascade predictions of a model for liquid crystalline polymers for simple shear flow

Science.gov (United States)

Klein, D. Harley; Leal, L. Gary; García-Cervera, Carlos J.; Ceniceros, Hector D.

2007-02-01

We consider the behavior of the Doi-Marrucci-Greco (DMG) model for nematic liquid crystalline polymers in planar shear flow. We found the DMG model to exhibit dynamics in both qualitative and quantitative agreement with experimental observations reported by Larson and Mead [Liq. Cryst. 15, 151 (1993)] for the Ericksen number and Deborah number cascades. For increasing shear rates within the Ericksen number cascade, the DMG model displays three distinct regimes: stable simple shear, stable roll cells, and irregular structure accompanied by disclination formation. In accordance with experimental observations, the model predicts both ±1 and ±1/2 disclinations. Although ±1 defects form via the ridge-splitting mechanism first identified by Feng, Tao, and Leal [J. Fluid Mech. 449, 179 (2001)], a new mechanism is identified for the formation of ±1/2 defects. Within the Deborah number cascade, with increasing Deborah number, the DMG model exhibits a streamwise banded texture, in the absence of disclinations and roll cells, followed by a monodomain wherein the mean orientation lies within the shear plane throughout the domain.

Structural and Functional Studies of A. oryzae Cutinase: Enhanced Thermostability and Hydrolytic Activity of Synthetic Ester and Polyester Degradation

OpenAIRE

Liu, Zhiqiang; Gosser, Yuying; Baker, Peter James; Ravee, Yaniv; Lu, Ziying; Alemu, Girum; Li, Huiguang; Butterfoss, Glenn L.; Kong, Xiang-Peng; Gross, Richard; Montclare, Jin Kim

2009-01-01

Cutinases are responsible for hydrolysis of the protective cutin lipid polyester matrix in plants and thus have been exploited for hydrolysis of small molecule esters and polyesters. Here we explore the reactivity, stability, and structure of Aspergillus oryzae cutinase and compare it to the well-studied enzyme from Fusarium solani. Two critical differences are highlighted in the crystallographic analysis of the A. oryzae structure: (i) an additional disulfide bond and (ii) a topologically fa...

Quality by Design approach to spray drying processing of crystalline nanosuspensions.

Science.gov (United States)

Kumar, Sumit; Gokhale, Rajeev; Burgess, Diane J

2014-04-10

Quality by Design (QbD) principles were explored to understand spray drying process for the conversion of liquid nanosuspensions into solid nano-crystalline dry powders using indomethacin as a model drug. The effects of critical process variables: inlet temperature, flow and aspiration rates on critical quality attributes (CQAs): particle size, moisture content, percent yield and crystallinity were investigated employing a full factorial design. A central cubic design was employed to generate the response surface for particle size and percent yield. Multiple linear regression analysis and ANOVA were employed to identify and estimate the effect of critical parameters, establish their relationship with CQAs, create design space and model the spray drying process. Inlet temperature was identified as the only significant factor (p value dried nano-crystalline powders. Aspiration and flow rates were identified as significant factors affecting yield (p value dried at higher inlet temperatures had lower moisture compared to those dried at lower inlet temperatures. Published by Elsevier B.V.

Magneto-responsive liquid crystalline elastomer nanocomposites as potential candidates for dynamic cell culture substrates

Energy Technology Data Exchange (ETDEWEB)

Herrera-Posada, Stephany; Mora-Navarro, Camilo; Ortiz-Bermudez, Patricia; Torres-Lugo, Madeline [Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico); McElhinny, Kyle M.; Evans, Paul G. [Department of Materials Science and Engineering, 1509 University Avenue, University of Wisconsin-Madison, WI 53706 (United States); Calcagno, Barbara O. [Department of General Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico); Acevedo, Aldo, E-mail: aldo.acevedo@upr.edu [Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico)

2016-08-01

Recently, liquid crystalline elastomers (LCEs) have been proposed as active substrates for cell culture due to their potential to attach and orient cells, and impose dynamic mechanical signals through the application of external stimuli. In this report, the preparation of anisotropic and oriented nematic magnetic-sensitized LCEs with iron oxide nanoparticles, and the evaluation of the effect of particle addition at low concentrations on the resultant structural, thermal, thermo-mechanical, and mechanical properties is presented. Phase transformations produced by heating in alternating magnetic fields were investigated in LCEs in contact with air, water, and a common liquid cell culture medium was also evaluated. The inclusion of nanoparticles into the elastomers displaced the nematic-to-isotropic phase transition, without affecting the nematic structure as evidenced by similar values of the order parameter, while reducing the maximum thermomechanical deformations. Remote and reversible deformations of the magnetic LCEs were achieved through the application of alternating magnetic fields, which induces the nematic–isotropic phase transition through nanoparticle heat generation. Formulation parameters can be modified to allow for remote actuation at values closer to the human physiological temperature range and within the range of deformations that can affect the cellular behavior of fibroblasts. Finally, a collagen surface treatment was performed to improve compatibility with NIH-3T3 fibroblast cultures, which enabled the attachment and proliferation of fibroblasts on substrates with and without magnetic particles under quiescent conditions. The LCEs developed in this work, which are able to deform and experience stress changes by remote contact-less magnetic stimulation, may allow for further studies on the effect of substrate morphology changes and dynamic mechanical properties during in vitro cell culture. - Highlights: • Magnetic LCE nanocomposites were

Magneto-responsive liquid crystalline elastomer nanocomposites as potential candidates for dynamic cell culture substrates

International Nuclear Information System (INIS)

Herrera-Posada, Stephany; Mora-Navarro, Camilo; Ortiz-Bermudez, Patricia; Torres-Lugo, Madeline; McElhinny, Kyle M.; Evans, Paul G.; Calcagno, Barbara O.; Acevedo, Aldo

2016-01-01

Recently, liquid crystalline elastomers (LCEs) have been proposed as active substrates for cell culture due to their potential to attach and orient cells, and impose dynamic mechanical signals through the application of external stimuli. In this report, the preparation of anisotropic and oriented nematic magnetic-sensitized LCEs with iron oxide nanoparticles, and the evaluation of the effect of particle addition at low concentrations on the resultant structural, thermal, thermo-mechanical, and mechanical properties is presented. Phase transformations produced by heating in alternating magnetic fields were investigated in LCEs in contact with air, water, and a common liquid cell culture medium was also evaluated. The inclusion of nanoparticles into the elastomers displaced the nematic-to-isotropic phase transition, without affecting the nematic structure as evidenced by similar values of the order parameter, while reducing the maximum thermomechanical deformations. Remote and reversible deformations of the magnetic LCEs were achieved through the application of alternating magnetic fields, which induces the nematic–isotropic phase transition through nanoparticle heat generation. Formulation parameters can be modified to allow for remote actuation at values closer to the human physiological temperature range and within the range of deformations that can affect the cellular behavior of fibroblasts. Finally, a collagen surface treatment was performed to improve compatibility with NIH-3T3 fibroblast cultures, which enabled the attachment and proliferation of fibroblasts on substrates with and without magnetic particles under quiescent conditions. The LCEs developed in this work, which are able to deform and experience stress changes by remote contact-less magnetic stimulation, may allow for further studies on the effect of substrate morphology changes and dynamic mechanical properties during in vitro cell culture. - Highlights: • Magnetic LCE nanocomposites were

Design of multi materials combining crystalline and amorphous metallic alloys

International Nuclear Information System (INIS)

Volland, A.; Ragani, J.; Liu, Y.; Gravier, S.; Suéry, M.; Blandin, J.J.

2012-01-01

Highlights: ► Elaboration of multi materials associating metallic glasses and conventional crystalline alloys by co-deformation performed at temperatures close to the glass transition temperature of the metallic glasses. ► Elaboration of filamentary metal matrix composites with a core in metallic glass by co extrusion. ► Sandwich structures produced by co-pressing. ► Detection of atomic diffusion from the glass to the crystalline alloys during the processes. ► Good interfaces between the metallic glasses and the crystalline alloys, as confirmed by mechanical characterisation. - Abstract: Multi materials, associating zirconium based bulk metallic glasses and crystalline metallic alloys like magnesium alloys or copper are elaborated by co-deformation processing performed in the supercooled liquid regions (SLR) of the bulk metallic glasses. Two processes are investigated: co-extrusion and co-pressing. In the first case, filamentary composites with various designs can be produced whereas in the second case sandwich structures are obtained. The experimental window (temperature, time) in which processing can be carried out is directly related to the crystallisation resistance of the glass which requires getting information about the crystallisation conditions in the selected metallic glasses. Thermoforming windows are identified for the studied BMGs by thermal analysis and compression tests in their SLR. The mechanical properties of the produced multi materials are investigated thanks to specifically developed mechanical devices and the interfaces between the amorphous and the crystalline alloys are characterised.

A study on influence of borax to polyester insulators

OpenAIRE

ERSOY, Aysel; KUNTMAN, Ayten

2014-01-01

In this study the effect of borax on polyester insulators is investigated by evaluating the tracking and erosion resistance using the inclined plane test. The test procedure follows the ASTM D2303 standard. During the test, 50 Hz current was acquired from the ground electrode allowing a sampling rate of 48000 samples per second. The effect of borax concentration on the glass transition and the degradation temperature is studied by employing differential scanning calorimetry (DSC) an...

Competitive concurrence of surface wrinkling and dewetting of liquid crystalline polymer films on non-wettable substrates.

Science.gov (United States)

Song, Sung E; Choi, Gwan H; Yi, Gi-Ra; Yoo, Pil J

2017-11-01

Polymeric thin films coated on non-wettable substrates undergo film-instabilities, which are usually manifested as surface deformation in the form of dewetting or wrinkling. The former takes place in fluidic films, whereas the latter occurs in solid films. Therefore, there have rarely been reports of systems involving simultaneous deformations of dewetting and wrinkling. In this study, we propose polymeric thin films of liquid crystalline (LC) mesogens prepared on a non-wettable Si substrate and apply a treatment of plasma irradiation to form a thin polymerized layer at the surface. The resulting compressive stress generated in the surface region drives the formation of wrinkles, while at the same time, dipolar attraction between LC molecules induces competitive cohesive dewetting. Intriguing surface structures were obtained whereby dewetting-like hole arrays are nested inside the randomly propagated wrinkles. The structural features are readily controlled by the degree of surface cross-linking, hydrophilicity of the substrates, and the LC film thickness. In particular, dewetting of LC mesogens is observed to be restricted to occur at the trough regions of wrinkles, exhibiting the typical behavior of geometrically confined dewetting. Finally, wrinkling-dewetting mixed structures are separated from the substrate in the form of free standing films to demonstrate the potential applicability as membranes.

Liquid crystalline phase as a probe for crystal engineering of lactose: carrier for pulmonary drug delivery.

Science.gov (United States)

Patil, Sharvil S; Mahadik, Kakasaheb R; Paradkar, Anant R

2015-02-20

The current work was undertaken to assess suitability of liquid crystalline phase for engineering of lactose crystals and their utility as a carrier in dry powder inhalation formulations. Saturated lactose solution was poured in molten glyceryl monooleate which subsequently transformed into gel. The gel microstructure was analyzed by PPL microscopy and SAXS. Lactose particles recovered from gels after 48 h were analyzed for polymorphism using techniques such as FTIR, XRD, DSC and TGA. Particle size, morphology and aerosolisation properties of prepared lactose were analyzed using Anderson cascade impactor. In situ seeding followed by growth of lactose crystals took place in gels with cubic microstructure as revealed by PPL microscopy and SAXS. Elongated (size ∼ 71 μm) lactose particles with smooth surface containing mixture of α and β-lactose was recovered from gel, however percentage of α-lactose was more as compared to β-lactose. The aerosolisation parameters such as RD, ED, %FPF and % recovery of lactose recovered from gel (LPL) were found to be comparable to Respitose® ML001. Thus LC phase (cubic) can be used for engineering of lactose crystals so as to obtain particles with smooth surface, high elongation ratio and further they can be used as carrier in DPI formulations. Copyright © 2014 Elsevier B.V. All rights reserved.

Lyotropic Liquid Crystalline Nanoparticles of Amphotericin B: Implication of Phytantriol and Glyceryl Monooleate on Bioavailability Enhancement.

Science.gov (United States)

Jain, Sanyog; Yadav, Pooja; Swami, Rajan; Swarnakar, Nitin Kumar; Kushwah, Varun; Katiyar, Sameer S

2018-05-01

Implication of different dietary specific lipids such as phytantriol (PT) and glyceryl monooleate (GMO) on enhancing the oral bioavailability of amphotericin B (AmB) was examined. Liquid crystalline nanoparticles (LCNPs) were prepared using hydrotrope method, followed by in vitro characterization, Caco-2 cell monolayer uptake, and in vivo pharmacokinetic and toxicity evaluation. Optimized AmB-LCNPs displayed small particle size (< 210 nm) with a narrow distribution (~ 0.2), sustained drug release and high gastrointestinal stability, and reduced hemolytic toxicity. PLCNPs presented slower release, i.e., ~ 80% as compared to ~ 90% release in case of GLCNPs after 120 h. Significantly higher uptake in Caco-2 monolayer substantiated the role of LCNPs in increasing the intestinal permeability followed by increased drug titer in plasma. Pharmacokinetic studies demonstrated potential of PT in enhancing the bioavailability (approximately sixfold) w.r.t. of its native counterpart with reduced nephrotoxicity as presented by reduced nephrotoxicity biomarkers and histology studies. These studies established usefulness of PLCNPs over GLCNPs and plain drug. It can be concluded that acid-resistant lipid, PT, can be utilized efficiently as an alternate lipid for the preparation of LCNPs to enhance bioavailability and to reduce nephrotoxicity of the drug as compared to other frequently used lipid, i.e., GMO.

Preparation and characterization of metal complex hydrogels crosslinked with hyperbranched polyester

Czech Academy of Sciences Publication Activity Database

Haroun, A. A.; Hakeim, O. A.; Trhlíková, Olga; Šlouf, Miroslav; Netopilík, Miloš

2017-01-01

Roč. 60, č. 5 (2017), s. 849-856 ISSN 0449-2285 R&D Projects: GA ČR(CZ) GC17-04258J Grant - others:AV ČR(CZ) ASRT-16-02 Program:Bilaterální spolupráce Institutional support: RVO:61389013 Keywords : hyperbranched polyester * chitosan * miniemulsion Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science

Gliding arc discharge — Application for adhesion improvement of fibre reinforced polyester composites

DEFF Research Database (Denmark)

Kusano, Yukihiro; Teodoru, Steluta; Leipold, Frank

2008-01-01

production, and surface treatment. However, the application for adhesion improvement of structural materials has been rarely reported. In the present work, glass fibre reinforced polyester plates were treated using atmospheric pressure gliding arcs with high speed air flow for adhesion improvement...

Dynamic mechanical and dielectric behavior of banana–glass hybrid fiber reinforced polyester composites.

CSIR Research Space (South Africa)

Pothan, LA

2009-01-01

Full Text Available Hybrid composites of glass and banana fiber (obtained from the pseudo stem of Musa sapientum) in polyester matrix, are subjected to dynamic mechanical analysis over a range of temperature and three different frequencies. The effect of temperature...

Transport behavior of n-alkane penetrants into castor oil based polyurethane-polyester nonwoven fabric composites

International Nuclear Information System (INIS)

Satheesh Kumar, M.N.; Manjula, K.S.; Siddaramaiah

2007-01-01

Castor oil based polyurethane (PU)-polyester nonwoven fabric composites were fabricated by impregnating the polyester nonwoven fabric in a composition containing castor oil and diisocyanate. Composites were fabricated with two different isocyanates such as toluene-2,4-diisocyanate (TDI) and hexamethylene diisocyanate (HMDI). Transport behavior of n-alkane penetrants (pentane, hexane and heptane) into both PUs and PU-polyester nonwoven fabric composites were studied. Sorption studies were carried out at different temperatures. From the sorption results, the diffusion (D) and permeation (P) coefficients of penetrants have been calculated. Significant increase in the diffusion and permeation coefficients was observed with increase in the temperature of sorption experiments. Drastical reduction in diffusion and permeation coefficients was noticed in the composites compared to neat PUs. Attempts were made to estimate the empirical parameters like n, which suggests the mode of transport and K is a constant depends on the structural characteristics of the composite in addition to its interaction with penetrants. The temperature dependence of the transport coefficients has been used to estimate the activation energy parameter for diffusion (E D ) and permeation (E P ) processes from Arrhenius plots. Furthermore, the sorption results have been interpreted in terms of the thermodynamic parameters such as enthalpy (ΔH) and entropy (ΔS)

Effect of organoclay on the orientation and thermal properties of liquid-crystalline polymers

CSIR Research Space (South Africa)

Bandyopadhyay, J

2007-08-01

Full Text Available in the pure LCP; in the nanocomposites, the polymer chains tended to orient in the direction of the dispersed clay layers. According to the DSC results, during first heating, the first melting peak represents the crystalline to nematic transition and, after...

Obtaining polyester from glycerin for synthesis of polyurethanes; Obtencao de poliester a partir da glicerina para sintese de poliuretanas

Energy Technology Data Exchange (ETDEWEB)

Breves, Rodolfo A.; Ghesti, Grace F.; Sales, Maria J.A., E-mail: eu_sou_o_rodolfo@hotmail.com [Universidade de Brasilia (LabPol/UnB), DF (Brazil). Laboratorio de Pesquisa em Polimeros; Silva, Jessica S.; Coelho, Paulo V.M.; Lopes, Roseany V.V. [Universidade de Brasilia (UnB), DF (Brazil). Faculdade do Gama; Brioude, Michel M. [Freiburg University (Germany)

2014-07-01

The use of renewable resources has been increasing, due to the development of materials that have viable applications that are environmentally friendly. In this paper, a polyester was synthesized from glycerin, with the addition of adipic acid in a molar ratio of 1: 1.5, with dilauryl tin catalyst, which was added in proportions of 1 to 3% obtained PUs from castor oil (Ricinus communis) and MDI (diphenyl methane diisocyanate). The materials were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance {sup 1}H NMR, thermogravimetry (TG) and derivative thermogravimetry (DTG). The reaction for obtaining the polyester was confirmed by FTIR, the absorption band between 1708-1730 cm{sup -1} and {sup 1}H NMR, in the region 1.4 to 1.8 ppm and 2.2 to 2.6 ppm. The thermal decomposition of polyester occurred with temperature above 300 ° C. PUs showed similar thermal stability. (author)

Improvement of interaction between pre-dispersed multi-walled carbon nanotubes and unsaturated polyester resin

Energy Technology Data Exchange (ETDEWEB)

Beg, M. D. H., E-mail: dhbeg@yahoo.com; Moshiul Alam, A. K. M., E-mail: akmmalam@gmail.com; Yunus, R. M. [Universiti Malaysia Pahang, Faculty of Chemical and Natural Resources Engineering (Malaysia); Mina, M. F. [Bangladesh University of Engineering and Technology, Department of Physics (Bangladesh)

2015-01-15

Efforts are being given to the development of well-dispersed nanoparticle-reinforced polymer nanocomposites in order to tailor the material properties. In this perspective, well dispersion of multi-walled carbon nanotubes (MWCNTs) in unsaturated polyester resin (UPR) was prepared using pre-dispersed MWCNTs in tetrahydrofuran solvent with ultrasonication method. Then the well-dispersed MWCNTs reinforced UPR nanocomposites were fabricated through solvent evaporation. Fourier-transform infrared spectroscopy indicates a good interaction between matrix and MWCNTs. This along with homogeneous dispersion of nanotubes in matrix has been confirmed by the field emission scanning electron microscopy. At low shear rate, the value of viscosity of UPR is 8,593 mPa s and that of pre-dispersed MWCNT–UPR suspension is 43,491 mPa s, showing implicitly a good dispersion of nanotubes. A notable improvement in the crystallinity of UPR from 14 to 21 % after MWCNTs inclusion was observed by X-ray diffractometry. The mechanical properties, such as tensile strength, tensile modulus, impact strength, and elongation-at-break, of nanocomposite were found to be increased to 22, 20, 28, and 87 %, respectively. The estimated melting enthalpy per gram for composites as analyzed by differential scanning calorimetry is higher than that of UPR. The onset temperature of thermal decomposition in the nanocomposites as monitored by thermogravimetric analysis is found higher than that of UPR. Correlations among MWCNTs dispersion, nucleation, fracture morphology, and various properties were measured and reported.

Synthesis of a novel polyester building block from pentoses by tin-containing silicates

DEFF Research Database (Denmark)

Elliot, Samuel Gilbert; Andersen, Christian; Tolborg, Søren

2017-01-01

a product containing functional groups originating from trans-2,5-dihydroxy-3-pentenoic acid methyl ester in the polyester backbone. The reactivity of the incorporated olefin and hydroxyl moieties was investigated using trifluoroacetic anhydride and thiol-ene chemisitry, thus illustrating the potential...

Development of a model for the synthesis of unsaturated polyester by reactive distillation

NARCIS (Netherlands)

Shah, M.R.; Zondervan, E.; Oudshoorn, M.L.; Haan, de A.B.; Haan, de A.B.; Kooijman, H.; Górak, A.

2010-01-01

Traditionally polyester production is done in a batch reactor equipped with a separation column for batch distillation. A promising alternative for the intensification of this process is reactive distillation. In this paper, a reactive distillation model is developed for the synthesis of an

Polyester composites reinforced with corona-treated fibers from pine, eucalyptus and sugarcane bagasse

Science.gov (United States)

This study aims to evaluate plant fibers that were surface activated with NaOH and corona discharge before incorporating in ortho unsaturated polyester-based fiber composites. It demonstrates the potential use of lignocellulosic particles, especially eucalyptus that presented the higher values for a...

Reduction in the body content of DDE in the Mongolian gerbil treated with sucrose polyester and caloric restriction

International Nuclear Information System (INIS)

Mutter, L.C.; Blanke, R.V.; Jandacek, R.J.; Guzelian, P.S.

1988-01-01

It has previously been shown that oral administration to rats of sucrose polyester (SPE4), a nonabsorbable lipophilic binding agent, greatly stimulates the fecal excretion of coorally administered DDT5. To determine whether this agent would stimulate the excretion of persistent metabolites of DDT stored in body tissues, we treated a group of gerbils with [ 14 C]-DDT and monitored the fecal excretion of radioactivity for several months until a terminal, log-linear phase of excretion was observed. At this point, when greater than 75% of the fecal radioactivity was identified as [ 14 C]DDE, we fed the animals diets containing up to 10% sucrose polyester and found that the rate of excretion of radioactivity in the stool promptly increased two to three times as compared to the rate in the preceding control period. Some rats were subjected to a 25-50% restriction in total food allotment, but this produced no significant change in fecal excretion of total radioactivity. However, when food restriction was combined with administration of sucrose polyester, there was a dramatic, eightfold average increase in excretion of fecal radioactivity. This synergistic effect was reversed (within 24 hr) when the animals were transferred to a normal diet. Measurement of total body radioactivity confirmed that food restriction plus sucrose polyester treatment reduced the body content of the pesticide. We conclude that stimulation of intestinal excretion may offer a new approach to treatment of patients exposed to lipophilic environmental contaminants

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

Energy Technology Data Exchange (ETDEWEB)

Magaryan, K.A., E-mail: xmagaros@gmail.com [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Mikhailov, M.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Karimullin, K.R. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); E.K. Zavoyski Kazan Physical-Technical Institute of RAS, 10/7 Sibirski trakt Str., Kazan 420029 (Russian Federation); Knyazev, M.V.; Eremchev, I.Y. [Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Naumov, A.V. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Vasilieva, I.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Klimusheva, G.V. [Institute of Physics, NAS of Ukraine, 46 Prospect Nauki, Kiev 03028 (Ukraine)

2016-01-15

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm{sup 2}. Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

International Nuclear Information System (INIS)

Magaryan, K.A.; Mikhailov, M.A.; Karimullin, K.R.; Knyazev, M.V.; Eremchev, I.Y.; Naumov, A.V.; Vasilieva, I.A.; Klimusheva, G.V.

2016-01-01

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm 2 . Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

Light scattering from crystals, glasses and liquids

International Nuclear Information System (INIS)

Subbaswamy, K.R.

1984-09-01

The theory of inelastic light scattering from a model system in the crystalline, disordered and liquid phases is analyzed. The roles of disorder induced first order scattering and second order scattering are clarified in the context of the classical liquid. The correlation functions appropriate for the various contributions are identified and useful ways of processing experimental data are pointed out. (author)