Studies on polyimides containing thermoplastic-thermosetting merged segments

Abstract

Polyimides (PIs) containing thermoplastic and thermosetting merged segments in a chain were developed via Diels-Alder (DA) polymerization of a bisfuran (BF), namely 2,5-bis(furan-2-ylmethylcarbamoyl)terephthalic acid and bismaleimides (BMI1 and BMI2). The intermediate DA polyadducts thus obtained, DAA1 and DAA2, were aromatized and imidized (cyclized) through carboxylic and amide groups in the presence of acetic anhydride, to afford PI1 and PI2. Synthesized DA polyadducts and PIs were characterized by elemental analysis, spectral features, number average molecular weight (Mn), degree of polymerization (Dp) and thermal analysis. Bulk polymerization was also carried out. The obtained bulk polymerization products (BPP1 and BPP2) were characterized by elemental analyses and Fourier transform infrared spectroscopy (FT-IR) analysis. The "in situ" void-free glass fiber reinforced composites GFRC1 and GFRC2 were prepared from the produced system and characterized by chemical, mechanical and electrical analysis. All of the composites depicted good mechanical and electrical properties and good resistance to organic solvents and mineral acids.