Thermotropic homopolyesters. IV. Study of fiber formation

摘要: We report a melt spinning and viscosity study of two semiflexible homopolyesters containing both rigid flexible segments in the repeating unit. Single filaments polyesters formed from 4,4′-diacetoxybiphenyl azelaic acid (PB7) sebacic (PB8), 4′-hydroxyphenyl-4-hydroxycinnamate (C7), were spun at temperatures between 205 255°C. The temperature dependence Newtonian PB7 C7 was investigated, range molecular weights studied for PB7. parameters, fiber characteristics, viscosity-temperature behavior are related to type mesophase formed. mechanical properties fibers nematic smectic phases these chain polymers poor. Increasing polymer weight or extrusion rate only afforded modest improvement properties. Most could not be corresponding existence single mesophase. Hence low typical is necessarily an advantage formation melt. It appears results that this polyester does possess adequate extension develop ultrahigh-modulus director, which describes local orientation molecules within mesophase, may undergo more frequent variations than case polyesters. Mechanisms relevant contribute development class nematogenic melts.