Syntheses of Soluble Biopolyimides Using 4-Aminophenylalanine

摘要

4-Aminophenylalanine(4APhe),an exotic amino acid which is obtained as a microorganism metabolite of glucose,is polycondensed with various tetracarboxylic dianhydrides as a diamine monomer to obtain poly(amic acid)s.Subsequent thermal imidization of poly(amic acid)s is made at 220°C with stepwise heating from 100°C.Some of the obtained polyimides(PIs)exhibited good solubility in organic solvents such as N,N-dimethylformamide,N.N dimethylacetamide,and more.The progress of imidization was observed by proton nuclear magnetic resonance and infrared spectroscopy to confrm that the imidization ratio was up to 98%.Carboxylate group of the side-chains of PIs affected their solubilities despite the high imidization ratio,and the solubility was lost for any organic solvents by decarboxylation at 280。C,confirmed from mass-loss of thermogravimetric analysis.Thus,a new series of PIs were obtained with abilities of solvent-molding in PI state and thermal resistivityt enhancement by further heating after molding.