Morphologies and Mechanical Properties of Unsaturated Polyester Resin Modified with TDI

The morphology,mechanical properties of unsaturated polyester(UP)resin modified with TDI were studied via dynamic FT-IR spectra,SEM,DMA and mechanical property testing.Results show that companying with the cured cross-linking reaction of UP resin,TDI can firstly react with UP and produce polyurethane(PU),and then UP and PU form the cross-linking nets together.The impact fracture section morphology of modified UP resin manifested the typical sea-islands structure.Testing of mechanical properties showes that for introducing of PU,the TDI has an obvious effect on the toughness and strength of UP resin. When the ratio of TDI/UP(w/w)was 7.5%,the modified UP resin exhibited the best mechanical properties with flexural strength of 125 MPa,impact strength of 18 kJ·m-2 and tensile strength of 72 MPa.