RANDOM THERMOTROPIC ELASTOMERS .1. EFFECTS OF SUBSTITUTION AND HARD SOFT SEGMENT LENGTHS ON PROPERTIES/

Syntheses of segmented copoly(ether-ester)s with xy-2-methyl-1,4-pheny leneoxycarbonyl-1,4-phenylene carbonyl)/(oxy-2-chloro-1,4-phenyleneoxy carbonyl) (methyl-/chloro-substituted) hard segments and poly(oxytetr amethylene) soft segments, are reported. The methodology consisted of staged addition melt condensation of terephthaloyl chloride, poly(oxyt etramethylene)glycol (POTMG; (M) over bar(n) = 250, 650, 1000, 2000) a nd methyl-/chloro-hydroquinone. Lengths of hard and soft segments were varied while the weight ratio of hard to soft segment was maintained constant. Copolymers were characterised for solubility behavior, and b y infrared spectroscopy, x-ray diffraction, DSC, and polarizing micros copy. Thermal properties were found to be dependent on length of soft segment as well as on the type of substituent in the mesogenic core. I n both methyl- as well as chloro-substituted copoly(ether-ester)s soft segment glass transition temperature (T-gs) was obtained between -40 and -50 degrees C. All copoly(ether-ester)s are elastomeric at room te mperature (25 degrees C). These polymers exhibit thermotropic liquid c rystalline behavior and were easily sheared and aligned in liquid crys talline state. (C) 1994 John Wiley and Sons, Inc.