Liquid-crystalline polymer blend fibers properties

Drazic PS (1995) Liquid crystal dispersions. World Scientific, Singapore Dufresne A (2006) Comparing the mechanical properties of high performances polymer nanocomposites from biological sources. J Nanosci Nanotechnol 6 322-330 Dutta D, Weiss RA, Kristal K (1992) Blends containing liquid crystalline polymers preparation and properties of melt drawn fibers, unidirectional prepregs and composite laminates. Polym Compos 13 394-401... 

Ternary blends from a thermotropic liquid crystalline polymer, PEN, and PET were prepared by melt blending and melt spinning to fibers. The mechanical properties of ternary blend fibers could be significantly improved by annealing at 180°C for 2 h. This is attributed to the development of more ordered crystallites and to the formation of more perfect crystalline structures. The interfacial adhesion between PEN and liquid crystalline polymer phases is enhanced when the blends are processed with dibutyl-tindilaurate as a reactive catalyst to promote transesterification. 

W. Chinsirikul, T. C. Hsu, and I. R. Harrison, Liquid crystalline polymer (LCP) reinforced polyethylene blend blown film Effects of counter-rotating die on fiber orientation and film properties, Polym. Engr. and Sci., vol. 36, No. 22, 2708-2717, November (1996). 

Electrical properties have been reported on numerous carbon fiber-reinforced polymers, including carbon nanoflber-modified thermotropic liquid crystalline polymers [53], low-density polyethylene [54], ethylene vinyl acetate [55], wire coating varnishes [56], polydimethyl siloxane polypyrrole composites [50], polyacrylonitrile [59], polycarbonate [58], polyacrylonitrile-polycarbonate composites [58], modified chrome polymers [59], lithium trifluoromethane sulfonamide-doped polystyrene-block copolymer [60], boron-containing polyvinyl alcohols [71], lanthanum tetrafluoride complexed ethylene oxide [151, 72, 73], polycarbonate-acrylonitrile diene [44], polyethylene deoxythiophe-nel, blends of polystyrene sulfonate, polyvinyl chloride and polyethylene oxide [43], poly-pyrrole [61], polypyrrole-polypropylene-montmorillonite composites [62], polydimethyl siloxane-polypyrrole composites [63], polyaniline [46], epoxy resin-polyaniline dodecyl benzene sulfonic acid blends [64], and polyaniline-polyamide 6 composites [49]. 

Carfagna, C., Amendola, E., Nicolais, L., Acierno, D., Francescangeli, O., Yang, B., and Rustichelli, F., Blends of a polyetherimide and a liquid crystalline polymer Fiber orientation and mechanical properties, J. Appl. Polym. Sci. 43 839 (1991). 

Carfagna C, Amendola E, Nicolais L, Aciemo D, Francescangeli O, Yang B, Rustichelli F (1991) Blends of a polyetherimide and a liquid crystalline polymer fiber oiicmtatimi and mechanical properties. J Appl Polym Sci 43 839-844... 

Skin/core morphologies are common in blends of LCP s and thermoplastic polymers and they play a significant role in defining the properties of both extruded and injection molded samples. Usually, LCP s in the skin have a higher degree of orientation than in the core when the blends are extruded or injection molded (Husman et al. 1980 Hedmark et al. 1989 Lee 1988). Baird et al. (Baird and Mehta 1989 Baird and Sukhadia 1993) observed a skin/core morphology in blends of PA 66 with HBA/HNA and 40 PET/60 PHB and 20 PET/80 HBA copolyesters. More LCP fibers were present in the skin than in the core for both systems. Isayev and Swaninathan (1994) also reported shell-core structure in the fracture surfaces of injection molded blends of HNA/HBA liquid crystalline copolyesters and poly (etherimide). 

Description of the mechanical properties of polymer composites are also made by considering the properties of particulate-long fiber and laminate composites through the different models generated in the literature. It is shown that, many advantages can be derived by use of liquid crystalline compounds as reinforcing fillers to produce blends with engineering thermoplastics. 

Meng YZ, Tjong SC, Hay AS. Morphology, rheological and thermal properties of the melt blends of poly(phthalazinone ether ketone sulfone) with liquid crystalline copolyester. Polymer 1998 39 1845-50. Kim JY, Kang SW, Kim SH. Thermotropic liquid crystal polymer reinforced poly(butylene terephthalate) composites to improve heat distortion temperature and mechanical properties. Fibers Polym 2006 7 358-66. Kim JY, Kim SH. Structure and property relationship of thermotropic liquid crystal polymer and polyester composite fibers. J Appl Polym Sci 2006 99 2211-9. 

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