The role of m-phenylenebismaleimide (BMI) in reactive processing of poly(propylene)/magnesium hydroxide composites, 3 - Analysis of interphase structure development

In the first and second parts of this series, the effect of m-phenylenebism aleimide. (BMI), processing temperature and a lubricant (a fatty acid ester /amide blend) on the mechanical and rheological properties of poly(propylen e) (PP)/magnesium hydroxide composites was investigated. The third part foc uses on interactions between BMI and the magnesium hydroxide and between th e BMI and PP matrix. It has been shown that interaction between BMI and the filler is via an amide carboxylate together with possible polymerisation a t the filler surface. Interaction of BMI with the PP matrix is via addition of PP macro-radicals, produced via thermo-mechanical degradation to the ma leimide alkenes of BMI. Greater crosslink density in the interphase region than in the bulk matrix is considered to result in a reduction of crystalli nity within this region. This is manifested as a significant improvement in composite toughness relative to the equivalent unmodified composite.