PREPARATION OF POLYPYROMELLITIMIDES WITH CROWN-ETHER SEGMENTS

Crown ether containing polypyromellitimides as cast films were prepare d by reacting cis-or trans-diamino dibenzo 18-crown-6 with pyromelliti c dianhydride. Binary mixtures of crown ether diamines with some aroma tic diamines (p-phenylene diamine, benzidine and 4,4'-diamino diphenyl methane) were also used to obtain copolyimides. Our observations shaw that incorporation of crown ether segments imparts little solubility in N-methyl 2-pyrrolidone and N,N-dimethyl formanide, but reduce the t hermal stability of polymides.