Properties of Polyurethane Modified Trifunctional Epoxy Resin

4, 4'-diphenylmethane diisocyanate (MDI) and polyethylene glycol (PEG) were used as raw materials for synthesis of isocyanate terminated polyurethane (PU) pre-polymer. Then, PU pre-polymer was used to graft trifunctional epoxy resin (TEP) which was synthesis in lab to obtain cross-link TEP-PU. Fourier Transform Infrared spectroscopic analysis (FT-IR), Scanning Electron Microscope (SEM), Thermogravimetric analysis (TG) and Dynamic Analysis of thermodynamics (DMA) were used to study post-cured of TEP-PU groups changing, morphology thermal properties and dynamic mechanical properties respectively. Results indicated that PU chain grafted onto the TEP chain successfully. When m(PU)∶m(TEP) was 5%, the Barcol hardness was 41.4 HBa, impact strength was 23.32 kJ/m2, glass transition temperature was obviously improved, section of modified TEP presented ductile fracture.