Preparation and properties of modified bismaleimide resins based on phthalide-containing monomer

A series of bismaleimide resins based on phthalide-containing monomer have been prepared by the copolymerization reaction of 3,3-bis[4-(4-maleimidophenoxy)phenyl]-phthalide (PPBMI), 4,4'-dimaleimido diphenylmethane (MBMI) and 2, 2'-diallyl bisphenol A (DABPA) in different feed ratios. The curing behavior, thermal, mechanical and physical properties and compatibility of all resultant resins were carefully characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), notched Izod impact test, water absorption test and scanning electron microscopy (SEM). DSC investigations showed that with an increase of the weight ratio of PPBMI, the dominating exothermic polymerization temperature (T-p) increased. The glass transitions were observed from DMA thermograms for the cured BMI resins in the temperature range from 277 degrees C to 311 degrees C and decreased with increasing PPBMI content. The TGA results indicated the thermal stability was improved as PPBMI content increased. The investigations of the mechanical properties showed a complicated trend with an increase in PPBMI content. In addition, the equilibrium water uptake of the modified resins was reduced as PPBMI content increased. (C) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1084-1091, 2013