Novel Acetylene-Terminated Polyisoimides with Excellent Processability and Properties Comparison with Corresponding Polyimides

Two novel acetylene-terminated isoimide oligomers and their corresponding imide oligomers have been synthesized by using trifluoroacetic anhydride or acetic anhydride as dehydrating agent, respectively. Their main structure was confirmed by Fourier transform infrared spectroscopy (FTIR). The isoimide oligomers were amorphous and showed excellent solublility in many common solvents, such as acetone and tetrahydeofuran, whereas the imide oligomers cannot dissolve in them. Differential scanning calorimetry and rheometer were used to study crosslinking behavior and processability of these oligomers. The isoimide oligomers exhibited considerably wider processing window and lower viscosity compared with imide ones. As expected, the isoimide form could be converted to imide form through thermal treatment, which could be demonstrated by FTIR. After the oligomers were cured, the polyisoimides showed similar properties compared with corresponding polyimides. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 3493-3503, 2011