Liquid-crystalline polymer blend fibers

Blends of polypropylene (PP) and liquid crystalline polymer (LCP) processed without melting the LCP were compared with conventional melt processed blends. In a first stage, PP was blended with 20 wt% of LCP in a twin-screw extruder with the take-up speed varied to achieve blends with different LCP fiber dimensions. In the second stage, these blends were processed both below and above the Tm of the LCP by extrusion and injection molding. 

Crystallization and Morphology of Fibers Prepared from Compatibilized Blends of Polyethylene with a Liquid Crystalline Polymer... 

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). 

Fiber Drafting from Blends of Polypropylene and Liquid-Crystalline Polymers... 

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]. 

The approaches to the new polymer developments cover a multitude of areas such as new polymer systems such as the liquid crystalline polymers, new applications of old polymers such as carbon fibers which were used in Edison s light bulbs in the 1800 s to their use today and in the future as advanced composites in aerospace structures and the exploding field of polymer blends and alloys. 

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). 

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