Transparent Poly(Amide-Imide)s Containing Trifluoromethyl Groups with High Glass Transition Temperature

Abstract

Soluble and transparent poly(amide-imide)s (PAIs) with a glass transition temperature over 300 °C were synthesized from the alicyclic diacid monomers containing a biphenyl unit with two trifluoromethyl (CF3) groups. Combination of two isomeric biphenyl units with CF3 groups significantly improves the glass transition temperature of the corresponding PAIs. The increase of unsymmetrical biphenyl units increased the glass transition temperature of the polymers by reducing the average chain packing distance.