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Showing 1 to 20 of 31 for “"copolyesters"”.
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Effects of solvents on thermotropic liquid crystalline copolyesters
… carried our on thermotropic liquid crystalline copolyesters based on poly(ethyleneterephthalate) (PET) and para hydroxybenzoate (PHB), where PHB content varied from 0 mole percent up to 80 mole percent. The technique of chemical etching coupled with SEM and WAXS was utilized to obtain structural …
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Design of unique composites based on aromatic thermosetting copolyesters
Aromatic thermosetting copolyester (ATSP) has promise in high-temperature applications. It can be employed as a bulk polymer, as a coating and as a matrix for carbon fiber composites (ATSP/C composites). This work focuses on the applications of high performance ATSP/C composites. The morphology of …
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The synthesis of novel biodegradable polyesters and copolyesters from anhydrosulfites
… with -caprolactone. The polyesters and copolyesters synthesised are of considerable interest in medical applications and also for use as environmental friendly packaging. A range of anhydrosulfites were prepared according to an established method. Aliphatic anhydrosulfites were obtained …
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The effect of interchain transesterification reactions on the development of aromatic copolyesters
Aromatic copolyesters (LCPs) have been a subject of extensive research effort over the past 30 years. This is due primarily to their unique combination of properties and processability. They are limited, however, due to high temperatures required for processing and limitations on achievable …
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Synthesis and Characterization of Amorphous Cycloaliphatic Copolyesters with Novel Structures and Architectures
A series of random and amorphous copolyesters containing different cycloaliphatic rings within the polymer chains were prepared by melt polycondensaton of difunctional monomers (diesters and diols) in the presence of a catalyst. These polyesters were characterized by nuclear magnetic resonance …
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Thermal and Morphological Study of Segmented Multiblock Copolyesters Containing 2,2,4,4-Tetramethyl-1,3-cyclobutanediol
… studies of the segmented multiblock copolyesters containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and dimethyl-1,4-cyclohexane dicarboxylate were carried out using differential scanning calorimetry, small angle X-ray scattering, wide angle X-ray diffraction and dynamic mechanical …
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Mold filling characteristics and molecular orientation in injection molding of liquid crystalline copolyesters of poly (ethylene terephthalate)
… Instron model 3211 capillary rheometer. Two copolyesters of PET modified with 60 and 80 mole percent parahydroxy benzoate were examined. Melt viscosities were measured as a function of temperature and wall shear rates. Mold filling characteristics were investigated by introducing different …
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A study of the mechanical properties and the equilibrium nature of the blend of thermotropic liquid crystalline copolyesters
… polyethylene terephthalate) and 80/20 PHB/PET copolyesters in a 50:50 weight% ratio. Specifically, the interest was to determine as to how do the mechanical properties of the injection-molded parts from the blend compare with that of 70/30 PHB/PET composition and to find out if the melt blend …
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Design of Functional Polyesters for Electronic and Biological Applications
… issues in electronic encasings, the synthesis of copolyesters containing SDE ensued. 1,6-Hexanediol (HD) and 1,4-butanediol comonomers in varying weight ratios readily copolymerized with SDE under melt transesterification conditions to afford a systematic series of copolyesters. Differential …
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Synthesis and Structure-Property Relationships of Polyesters Containing Rigid Aromatic Structures
… to enhance thermal and mechanical properties. Copolyesters were prepared through melt polycondensation of diesters and diols in the presence of an exchange catalyst. Monomer incorporation was verified with nuclear magnetic resonance (NMR) and molecular weights were obtained by measuring …
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Advancing Step-Growth Polymers: Novel Macromolecular Design and Electrostatic Interactions in Polyesters and Polyurethanes
… synthesized high molecular weight segmented copolyesters. The cycloaliphatic monomers 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) and dimethyl-1,4-cyclohexane dicarboxylate (DMCD) afforded sterically hindered, ester carbonyls in high-Tg polyester precursors. Reaction between the polyester …
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Synthesis and Thermal Characterization of a Series of Copolyesters Synthesized from Terephthaloyl Chloride, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and Bisphenol A, AF, F, and HPF
The synthesis of copolyesters which contain both aromatic as well as aliphatic dial monomer units has been conducted The rigidity of 2,2,4,4-tetramethyl-1,3- cyclobutanediol (CBDO) makes it a viable candidate to replace or use along with rigid aromatic dials. Bisphenols A, AF, F, and HPF have also …
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In situ composites of compatibilized polypropylene/liquid crystalline polymer blends
… polymers (LCPs), two liquid crystalline (LC) copolyesters and one LC poly(ester-amide), were used. The PP/LCP blends were compatibilized with a maleic anhydride grafted polypropylene (MAP) to enhance the mechanical properties. The effect of increasing MAP content on the mechanical properties, …
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Design of Improved Polyester Dielectric Insulators for Electronic Packaging
… in melting temperature of the liquid crystalline copolyesters upon annealing near their original melting temperature to improve the dimensional stability is elucidated. Lastly, a description of a new photosensitive copolyester dielectric insulator is presented.
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The synthesis of new electro-optic polymers.
… show a high degree of electron delocalization. Copolyesters were synthesized by copolymerization of these monomers with methyl 12-hydroxydodecanoate by the standard two-stage, high-temperature polyesterification procedure. The copolyesters, incorporating dipolar units all pointing in the same …
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The design, synthesis and properties of pressure-processable biodegradable block copolymers
In this thesis, biodegradable block copolyesters were specifically designed and synthesized for their susceptibility to pressure-induced mixing. These baroplastic materials are capable of being processed and molded through the application of pressure at temperatures far below those needed in …
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Molecular order at polymer surfaces via X-ray photoelectron spectroscopy
… of crystallinity of the matrix increases. Block copolyesters unsaturated blocks present containing saturated and the saturated blocks preferentially segregated toward the surface. Crystalline ethylene/chlorotrifluoroethylene alternating copolymer shows the preferential orientation of ethylene …
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Step-Growth Polymerization Towards the Design of Polymers: Assembly and Disassembly of Macromolecules
… to synthesize polyesters and segmented block copolyesters. Triazole-containing homopolyesters exhibited a marked increase (~40 °C) in Tg, relative to structurally analogous classical polyesters synthesized in the melt. However, the triazole-containing homopolyesters exhibited insignificant …
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Studies of blends containing liquid crystalline polymers with PET and related investigations of hydroquinone/biphenol polysulfone systems
… from blends of thermotropic liquid crystalline copolyesters with polyethylene terephthalate (PET). Data were obtained which showed not only the temperature dependence of the moduli and stress-strain behavior but also the orientation effects that must be prevalent in order to explain the …
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