Liu Jin-gang

Synthesis and Properties of PMR Matrix Resins of Poly(Pyrrolone-Benzimidazole)s

PMR type of poly(pyrrolone-benzimidazole) copolymers (PPBI) were synthesized by the polycondensation of monoethyl ester of cis-5-norbornene-endo-2,3-dicarboxylic acid (NE), diphenyl-isophthalate (DPIP), diethyl ester of 4,4′-oxydiphthalic acid (ODPE) and 3,3′-diaminobenzidine (DAB) or 3,3′,4,4′-tetraamindiphenyl ether(TAD) in a mixing solution of anhydrous ethyl alcohol and N -methylpyrrolidone (NMP) under different temperature and pressure procedures. The resulting resin solution showed an excellent solubility in polar organic solvents and good stability at room temperature, while the corresponding PPBI molded powder and molded plate could be prepared by undergoing amidation, imidization, cyclization and crosslinking reactions when the reaction temperature would be increased from 150 to 350°C, especially, the crosslinking structure formed by the reverse Dials-Alder reaction at 270-290°C under 2.5-3.5 MPa pressure displayed by the pressure meter. The chemical reactions and properties of the resulting PPBI molded powders and molded plates were studied by means of FT-IR, TGA, DMA methods, and the results indicate that the PPBI materials obtained hold excellent thermal stability and processability, the initial decomposition temperature > 600°C and its T g defined by the peak temperature in tan δ curve from the DMA method is 448°C (DAB) or 423°C (TAD) for PPBI-20 molded plate.