Example 2
209.14 g of N-methylpyrrolidone, 11.41 g or 0.05 mol of 4-Aminobenzoic acid 4-aminophenyl ester were added into a container and stirred to be dissolved. 7.76 g or 0.025 mol of bis-(3-phthalyl anhydride) ether and 13.01 g or 0.025 mol of 4,4′-(4,4′-Isopropylidenediphenoxybis(phthalic anhydride)(BPADA) were added into the container and stirred for 1 hour to react. 14.62 g or 0.05 mol of 1,3-Bis(3-aminophenoxy)benzene was added into the container and stirred until dissolved. 22.93 g or 0.05 mol of p-Phenylene bis(trimellitate) dianhydride was added into the container and stirred for 48 hours to react thereby obtaining a block copolymer of polyamide acid.
227.29 g of N-methylpyrrolidone, 11.41 g or 0.05 mol of 4-Aminobenzoic acid 4-aminophenyl ester were added into a container and stirred until dissolved. 22.93 g or 0.05 mol of p-Phenylene bis(trimellitate) dianhydride was added into the container and stirred for 1 hour to react. 25.92 g or 0.05 mol of 2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane was added into the container and stirred until dissolved. 15.51 g or 0.05 mol of bis-(3-phthalyl anhydride) ether was added into the container and stirred for 48 hours to react, thereby obtaining a block copolymer of polyamide acid.
