Several novel thermotropic liquid-crystalline polymers (TLCPs) were blended with poly(ethylene terephthalate) (PET) and spun into fibres in an effort to improve fibre performance and processability. The TLCPs were screened to determine the optimal molecular architecture for fibre enhancement and compatibilty. At concentrations up to 20 wt%, blends of the block copolymers PME-b-PET and PME-b-PBT (PME=poly(ethoxy 1,4-phenylene terephthalate), PBT=poly(butylene terephthalate)) with PET showed minor improvements in modulus. Another TLCP, PBEM (poly(butoxyethoxy 1,4-phenylene terephthalate)), proved to be an excellent processing aid for PET, since it reduced the melt viscosity of PET by approximately 75 % at a concentration of only 2.5 wt%. The third class of TLCP investigated was a 'Random Copolymer' system. At a concentration of only 5 wt%, this blend exhibited a 50% modulus improvement (25 GPa) and an equivalent ultimate strength (ll00MPa) compared to neat PET fibres. SEM experiments exposed TLCP fibrils uniformly dispersed within the PET matrix with aspect ratios ranging between 20 and 200. The thermal stability of these fibres was similar to the PET control.
Посилання на статтю:
Thermotropic liquid-crystalline polymers with flexible moieties blended with poly(ethylene terephthalate) / Scott L. Joslin*, Reiner Giesat and Richard J. Farris // Polymer. – 1994. – Vol 35. – P. 4303-4312.