Study On Polymerization-blending Of DCPD With EVA In Situ And Properties Of PDCPD/EVA Composite

Polydicyclopentadiene(PDCPD) is a new type of thermosetting plastic, which isobtained by ring-opening metathesis polymerization of dicyclopentadiene(DCPD).PDCPD, which has good overall performance, was attracted widely attention in thefield of polymer materials, however, its impact strength can’t meet the higherrequirements in some engineering fields. For this reason, introducing other polymer,especially elastics, to PDCPD to improve toughness is a important method. Previousstudies have always used non-polar elastomer to toughen PDCPD, but the effect is notideal. This paper used polar elastomer, ethylene-vinyl acetate copolymer(EVA) whichhas good flexibility and impact resistance to blend polymerization with DCPD in situto form a semi-interpenetrating network structure.In this paper, seven different types(different molecular weight) of EVA wereadopted to blend in situ polymerization with DCPD in the ring-opening metathesiscatalyst system.The effect of the molecular weight and the content of EVA on thepolymerization were studied, and a series of PDCPD/EVA composites were prepared.The structure of composite materials was characterized and analyzed by SEM andDSC. The thermal properties and thermal-mechanical properties of compositematerials were characterized by TG and DMA. And the mechanical properties ofcomposite materials were tested.The study found, EVA can react with the cocatalyst Et2AlCl that reduced thecatalytic activity of the polymerization. The molecular weight of EVA has no influenceon the polymerization. The addition of EVA has no effect on the conversion rate ofpolymerization. Extraction analysis, SEM and DSC showed that EVA dispersed in thematrix uniformly, forming the interpenetrating network structure of “forcedcompatible” with PDCPD.Mechanical testing results showed that the impact resistance of the materialimproved significantly after adding EVA. The impact properties of composite materials increased first and then decreased as the content of EVA increasing. Theimpact resistance achieved the highest when EVA content was5%. Among that, theimpact strength reaches to the highest which added VA600and it improved by85%than pure PDCPD. The impact section morphology of composite material was thetypical ductile fracture.The tensile strength and flexural strength decreased slightly,but the range is small, the largest decline of tensile strength and flexural was12.4%and25%. Thermal analysis showed that the thermal properties of composite materialswere higher slightly than pure PDCPD.