SYNTHESIS AND PROPERTIES OF POLY(DIPHENYLACETYLENES) HAVING ALIPHATICPARA-SUBSTITUENTS

1-(p-t-Butylphenyl)-2-phenylacetylene and 1-(p-n-butylphenyl) -2-pheny lacetylene were polymerized in catalytic systems based on TaCl5 to giv e new polymers in high yields. These monomers were more reactive than diphenylacetylene (DPA) in copolymerization. Unlike poly(DPA), the pre sent polymers were soluble in toluene, CHCl3, etc. owing to the high c onfigurational entropy induced by the para-substituents. Their relativ e weight-average molecular weights determined by GPC were in the range of 6 X 10(5)-36 X 10(5), and films could be obtained by solution cast ing. These polymers were fairly thermally stable, as seen from their h igh onset temperatures (320-380 degrees C) of weight loss in TGA in ai r. The oxygen permeability coefficient of the polymer with t-Bu group was 1100 barrers, the highest among those of all the hydrocarbon polym ers. (C) 1994 John Wiley & Sons, Inc.