Epoxy Resin Composite Toughening Modification Research

Epoxy resin has been widely applied in many field due to its excellent properties. However, the brittleness and the low impact resistance limit its application in the circumstances which need high impact resistance and great rigidity. So the research of strenghened and toughened epoxy resin has very practical value.The studying bases on two aspects. Firstly, we synthesize a new sort of epoxy resin curing agent. We change the property of tradition curing agent by regulating the addition of the self-made curing agent. Secondly, we adopt the method of in-situ polymerization by using hydroquinone et. as raw material, after reaction a new composite of polyurethane/epoxy resin was got. Then the excellent epoxy resin matrix material is got through a best mixture ratio of the two substances.The properties were investigated by IR and SEM, the toughening mechanism is studied also. The results are as follows:1,When addition of new-synthesized curing agent reaches 50% of the total curing agent,the mechanical properties of the composite is best.The impact resistance can be improved as high as 346.5%,the tensile strength improved 73.0%,the flexural strength improved 31.1%, and the flexural modulus improved 21.7%.2,The intermediate product Mesogenic diol is synthesized by the hydroquinone.When the volume ratio of Mesogenic diol: epoxy resin is 6% and the molar rate of Mesogenic diol:TDI is 1:2,after the reaction for 2.5h the impact resistance of the composite is improved 187.9%, the flexural strength improved 4.7%, and the tensile strength improved 73.0%. Polyurethane/ epoxy resin system is a homogeneous system and its thermal performance can be significantly improved.3,The epoxy resin matrix composites was investigated by scanning electron microscopy (SEM). The result shows that the polyurethane / epoxy system prepared by the method of in-situ polymerization has good compatibility. The toughening mechanism is the interaction among the microcracks and the sheer zone, the migration of microcracks path bran and the branch of microcracks.