Synthesis, characterization, and thermal properties of anhydride terminated and allyl terminated oligoimides

This study concerns the synthesis of anhydride terminated oligoimides (ANTO I) and allyl terminated oligoimides (ALTOI), in acetic acid medium, which a llows a very fast reaction and an easy working out. For the preparation of ALTOIs, two methods are compared: the first one consists of adding the mono functional compound (allyl amine) to the ANTOI already formed during a firs t step by reaction of a dianhydride (excess) and a diamine. The second meth od consists of a "one pot" reaction between the dianhydride, the diamine, a nd the monofunctional allyl-amine compounds, at the beginning of the reacti on. The experimental results show that the best control of the molecular we ights is obtained with the first method. If the amount of allyl amine is hi gher than the amount necessary to end cap the ANTOI, a transimidization rea ction occurs. Thermal analyses of oligoimides terminated by anhydride or al lyl groups have been performed by differential scanning calorimetry (DSC) a nd thermogravimetric analysis (TGA). Transition and thermoresistance proper ties make ANTOI and ALTOI derivatives interesting as precursors for block p olyimide copolymers. (C) 2000 John Wiley & Sons, Inc.