INVESTIGATION ON BISMALEIMIDE BEARING POLYSILOXANE (BPS) TOUGHENING OF 4,4'-BISMALEIMIDO DIPHENYLMETHANE (BMI) MATRIX-SYNTHESIS, CHARACTERIZATION AND TOUGHNESS

N-(4-Hydroxyphenyl) maleimide was synthesized via two synthesizing pro cedures, and a new bismaleimide bearing polysiloxane (BPS) was prepare d by reacting N-(4-hydroxyphenyl) maleimide with dichlorodimethyl sila ne at first, then the adduct was reacted with polysiloxane terminated by hydroxyl groups. The products were characterized by i.r., n.m.r. an d elemental analysis, respectively. The molecular weight of BPS was de termined by g.p.c. and its curing behaviour and cured resin thermal st ability were investigated by d.s.c. and t.g.a. The toughening effect o f BPS was investigated by introducing it into 4,4'-bismaleimido diphen ylmethane (BMI) cured matrix. The results indicated that adding 20 wt% BPS into the BMI matrix could increase the impact strength 3.7 times as much as that of the pure BMI matrix. The toughening mechanism of th e matrix was elucidated by the glass transition temperature, determine d by d.s.c., and the fracture surface morphology was observed by s.e.m . Copyright (C) 1996 Elsevier Science Ltd.