Thermo-optical analysis as a complementary method in the study of phase transitions of thermotropic liquid crystalline polymer and its blends with polycarbonate

Mucha, Maria

doi:10.1007/bf01410335

Cited by 6 publications

References 10 publications

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Blends of a chlorinated poly(vinyl chloride) compound and a thermotropic liquid crystalline copolyester: Mechanical properties of squeezed flow films

Lee¹

1992

Polymer Engineering & Sci

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The mechanical properties of squeezed flow films were measured on blends of a chlorinated poly(viny1 chloride) (CPVC) compound and a thermotropic liquid crystalline copolyester of p-hydroxybenzoic acid/poly(ethylene terephthalatel (60/40), hereafter referred to as LCC. CPVC is immiscible with LCC. The most serious and unique problem of liquid crystalline polymers is their tendency to fibrillate when fabricated into films and injection molded parts, primarily because of a high degree of mechanical anisotropy. It has been found that the mechanical anisotropy of LCC and blends could be lessened using nonisother-ma1 squeezing equibiaxial extension flow. The maximum tensile properties of LCC are achieved when processed in the vicinity of 260°C. For blends of CPVC containing LCC, the mechanical properties are dependent on the processing temperature and compositions. Blends with no more than 20 wt% of LCC exhibit significant increases in tensile properties. This is due to the possibility of frozen-in macroscopic biaxial orientation of LCC in the blends during the nonisothermal squeezing flow. Within the range of processable temperatures, the reinforcement of CPVC due to the incorporation of LCC can be achieved at a temperature below the optimum processing temperature of LCC, although the thermal history of blends never reaches that temperature.

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Blends of a chlorinated poly(vinyl chloride) compound and a thermotropic liquid crystalline copolyester: Mechanical properties of squeezed flow films

Lee¹

1992

Polymer Engineering & Sci

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Thermal and mechanical properties of injection molded liquid crystalline polymer/amorphous polymer blends

Engberg

Strömberg

Martinsson

et al. 1994

Polymer Engineering & Sci

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Injection molded samples of binary blends of Vectra (LCP) and the three amorphous polymers polyethersulfone (PES), polycarbonate (PC), and aromatic poly(ester carbonate) (APEC) have been subjected to morphological and rheological characterization, and coefficients of linear thermal expansion and Young's moduli have been determined. The Young's modulus of the PES/LCP blends exhibited a near lower‐bound behavior that could be predicted by the one‐adjustable‐parameter equations of Halpin‐Tsai (ζ = 0.18) and Takayanaga (b = 0.23), whereas the coefficients of linear thermal expansion followed the Takayanaga equation with a value of b = 0.50. The chain orientation of the LCP component was essentially constant in all PES/LCP blends with a Herman's orientation parameter of 0.39 ± 0.03. Transesterification reactions led to randomization of the constituents of the PC/LCP and APEC/LCP blends. The effect was more pronounced in the PC/LCP blends. The introduction of the LCP into the PC/LCP blends led to no reduction in melt viscosity and no self‐reinforcement. APEC/LCP exhibited self‐reinforcement in blends with a content greater than 27 vol% LCP, and especially the blend with 67 vol% LCP. The self‐reinforcement was caused by the presence of an oriented LCP phase, confirmed by X‐ray diffraction, and by improved interfacial bonding, presumably resulting from the transesterification reactions occurring at the phase boundaries.

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An Introduction to Liquid Crystallinity

Brostow

1992

Liquid Crystal Polymers: From Structures to Applications

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Thermo-optical analysis as a complementary method in the study of phase transitions of thermotropic liquid crystalline polymer and its blends with polycarbonate

Cited by 6 publications

References 10 publications

Blends of a chlorinated poly(vinyl chloride) compound and a thermotropic liquid crystalline copolyester: Mechanical properties of squeezed flow films

Blends of a chlorinated poly(vinyl chloride) compound and a thermotropic liquid crystalline copolyester: Mechanical properties of squeezed flow films

Thermal and mechanical properties of injection molded liquid crystalline polymer/amorphous polymer blends

An Introduction to Liquid Crystallinity

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