Study On Polysiloxane Copolymerization Modified Epoxy Resin Capability

With the development of aerospace and electric industry, high performance has been demanded more and more to the organic silicon encapsulating material. It is the important research topic in the field that exploring new method of preparing organic silicon encapsulating materials and finding effective approach to improve the applying performance. Epoxy resin possesses many excellent properties of materials; however, as the kind of thermosetting material is with a high cross-link density, the behavior of its crack growth shows that it is of typical brittleness, which leads to some weak points, such as the great brittleness in the curing state, low heat-resistance, low impact strength, easy crack ness. So it difficult to satisfy the requirements of the developing engineering technology.Polysilicone has been widely used in hotness resistance ,weather resistance, solution resistance, high and low temperature resistance, high hydrophobicity property and high air permeability property. So epoxy resins was modified by silicone,epoxy resin's properties can be improved.There are two way一copolymerization and direct blend—is employed to make the epoxy resin/silicone composed material. Organic silicone modified epoxy resin with copolymerization by Organic silicone react with epoxy resin Organic silicone modified epoxy resin with direct blend by epoxy resin physical blend with organic silicone Molecular structure of copolymerization and direct blend modified resin was characterized by means of Fourier transform infrared (IR) spectrum analysis in the paper. The results showed that, copolymerization modified resin of 3500cm-1 free aroma components hydroxy greatly become reduce than those of the pure epoxy resin. But direct blend modified resin have no change. Microstructure of synthesized copolymerization and direct blend modified resins was measured and analyzed by means of scanning electron microscope (SEM). The result shows that the toughed fracture characters of copolymerization modified resins are appeared. but the fracture surface of direct blend modified resin is Smooth and straight After modification with diphenyldichlorosilane of 5.9phr, the materials exhibited impact strength (20.65kJ/m2), Tensile strength(67.85MPa),elongation(7.59%),bend strength(72.65MPa),Tg(146.5℃) breakdown voltage(23.98KV/mm),which all were higher than those of the pure epoxy resin, the impact strength increased about 54.3%,the tensile strength increased about 38.6%, the elongation increased about 90.2%,the bend strength increased about 30.6%,the Tg increased about 23.6%,the breakdown voltage increased about 7.4%.Respectively.for materials modified by the mixture of 1.2phr diphenyldichlorosilane and 10 phrα,ω-chloro-polydimethylsiloxane, the properties were further improved especially, the impact strength reached 22.18kJ/m2,and the elongation reached 15.65%, which all were higher than those of the pure epoxy resin, the impact strength increased about 65.7%, the elongation increased about 292%.They were8.8 kJ/m2,11.66%.and which all were higher than those of the epoxy resins modified by diphenyldichlorosilane , the impact strength increased about7.4%, the elongation increased about106%,the toughening effect is very remarkable...