Preparating Organosoluble Aromatic Polyimides Based on 3,3',5,5'-Tetrabromo-2,2-Bis[4-(4-aminophenoxy)phenyl]-propane and Aromatic Dianhydrides

摘要

A new aromatic diamine, with an isopropyl.idene and bromo-substituted arylene ether structure, 3,3' ,5,5 '-tetrabromo-2,2-bis[4-(4-aminophenoxy)phenyl]pro- pane, was synthesized by the nucleophilic substitution reaction ofp-chloronitrobenzene with 3,3',5,5'-tetrabromobisphenol A, followed by a catalytic reduction of the resulting dinitro compound. Novel aromatic polyimides with inherent viscosities ranging from 0.53 to 2.1 dUg were then obtained bya one-step or two-step polymerization process with this diamine and various aromatic dianhydrides. These bromine-containing poly- imides showed typical amorphous diffraction patterns and were readily soluble at room temperature in N-methyl-2-pyrrolidone, N,N'-dimethylformamide, N,N'-dimethylacet- amide, and even in less polar solvents such as chloroform, tetrahydrofuran, and pyri- dine. They also dissolved in dimethyl sulfoxide, m-cresol, o-chlorophenol ,or concen- trated sulfuric acid with heating. Glass-transition temperatures were 272-303 °C, depending on the nature of the dianhydride moiety. Thermogravimetric analysisshowed that all the polymers were thermally stable, with 10% weight loss occurring between 465 and 499 °C in nitrogen and between 457 and 492 °C under atmospheric conditions. The bulky bromine substituents not only increased the solubility but also compensated for the loss of thermal properties caused by the flexible ether linkage.