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In this paper, in-situ polymerization method had multiphase polyurethane urea / epoxy composites . The use of tensile test , impact test, differential thermal analysis (DSC), thermogravimetry (TG), scanning electron microscopy (SEM) were used to investigate the mechanical properties of composite materials , thermal properties and impact fracture morphology , discusses molecular weight polyurethane urea and the added amount of the various properties of composite materials , and the reaction kinetics of the composite system was discussed . The results showed that: in the composite , the polyurethane urea resin formed and two mutually penetrating network structure , the soft segments form the polyurethane urea aggregates , easily lead to the base resin micro-cracks and absorb impact energy , while the impact or the drawing process the soft segment aggregates can yield strain energy absorbed by its own , prompting the matrix yielding , brittle -ductile transition . Without reducing the thermal properties of the epoxy resin in the case of polyurethane urea is preferably added to improve the mechanical properties of the epoxy resin . In this study area , TDI- polyester urethane urea resin can improve the impact strength of 114% , the tensile strength increased 44%. MDI- polyester urethane urea resin can improve the impact strength of 132% , the tensile strength increased 41%. TDI- polyether urethane urea resin can improve the tensile strength 68% , impact strength of 51%. MDI- polyether urethane urea resin can improve the tensile strength 45% , the impact strength increased 70%. In addition , the polyurethane urea added to make the curing reaction of the epoxy resin of about 22% decrease in the activation energy .
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