Synthesis and Properties of Low-Thermal-Expansion Polyamic Esters

Abstract

Polyamic acid esters (PAE) were synthesized from biphenyltetracarboxylic dialkylester dichlorides (alkyl group: methyl, ethyl, n-propyl, and n-butyl) and p-phenylenediamine (PDA). The weight-average molecular weights (M_w) ranged from 51000 to 60000. Solution viscosities of the polyamic esters were lower than that of the polyamic acid (PAA) synthesized from biphenyltetracarboxylic dianhydride (BPDA) and PDA. The values of elongation at breakwere 16-20% for all the films, and thermal expansion coefficients of the films ranged from 1.8×10^-5/K to 2.2×10^-5/K. The values were larger than that of the polyimide film (0.5×10^-5/K) formed from the corresponding PAA.