POLYESTERIMIDE-MODIFIED BISMALEIMIDE RESINS. I. EFFECT OF POLYESTERIMI DE CONTENT

Abstract

ABSTRACT A novel polyesterimide (PEsI-M) was used to improve toughness of bismaleimide (BMI) resin composed of bis(4-maleimidediphenyl) methane (BDM) and O,O′-diallyl bisphenol A (DBA). Morphologies of modified resins changed from spherical particles to inverted phase structures, depending on PEsI-M's content based on the observation of scanning electronic microscopy (SEM). PEsI-M was an effective morphology modifier so that loading of 12 pbw resulted in a diverted phase structure. Dynamic mechanical analysis (DMA), rheometrics mechanical spectroscopy (RMS) and differential scanning calorimetry (DSC) were respectively used to investigate the dynamic mechanical behavior, and the gelation time and the curing extent of unmodified and modified BMI resins. The fairly uniform morphology in 15 pbw PEsI-M modified system cured at 180°C suggests that the phase separation might take place via a spinodal decomposition mechanism. The fracture energy (G IC ) increased with the increase of PEsI-M content in the modified system. G IC of 15 pbw PEsI-M modified system was 0.63 times larger than that of the unmodified BMI resin.