| Epoxy resin is widely used in different fields. This kind of resin has excellent thermalstability, electrical insulation and mechanical properties, but the crosslinking density ofepoxy resin is high, which leads to high brittleness and low impact strength. As a new kindof material, fluorine-containing silicone has the characteristics of both organic silicon andfluorine, such as excellent weather resistance, high and low temperature resistance,hydrophobicity and hatred of oil. In order to improve the mechanical properties, heatresistant properties and surface properties of epoxy resin, a kind of fluoride silicon modifier(FSM) was synthesized with diphenyl silanediol, toluene diisocyanate and octafluoropentylalcohol as the main raw materials in this article. The modifier contains reactive groups, canreact with epoxy resin to form a cross-linked polymer. Isophorone diamine (IPDA)compound with FSM was utilized to cure epoxy resin, thus solved the compatibilityproblems of organic fluorin, silicone and epoxy resin by the way of chemical reaction.For the synthesized FSM, the change of the–NCO group in the process of the reactionwas characterized by infrared spectroscopy(FT-IR), the structure of FSM was characterizedby infrared spectroscopy(FT-IR) and nuclear magnetic resonance (NMR). The resultsshowed that the structure of the product is consistent with the expected molecular design.The reaction kinetic parameters of the EP/FSM system and the EP/IPDA/FSM systemwere carried out with non-isothermal DSC method, then obtained that the apparent activationenergy were respectively50.632k·Jmol-1and71.58k·Jmol-1. Though the analysis of thedynamic parameters, we can know that the reaction rate of the EP/FSM system is very low atlow temperature, so a high reaction temperature is need to cure epoxy resin. The curingtemperature of the EP/FSM system and the EP/IPDA/FSM system was got by theextrapolating method of linear fitting. Combining with the react characteristics of the EP/FSM system, the curing process of the EP/IPDA/FSM system was determined as follows:60℃/2hâ†'80℃/2hâ†'130℃/6h.How the content of FSM influenced the mechanics perforance of the EP/IPDA/FSMsystem was studied, the results showed that the tensile strength and impact strength of epoxyresin both increased with the additive amount of FSM, when the additive amount of FSMreached10phr, the tensile strength reached a maximum,68.29Mpa; when the additiveamount of FSM reached15phr, the impact strength reached a maximum,23.12kJ/m2, thenboth tend to fall. The bending strength is always decreased with the increase of FSM, and thedownward trend is more and more small. The SEM test results showed that theEP/IPDA/FSM system presented the characteristics of ductile fracture, the fracture surfacewas more and more rough with the additive of FSM, the two phase structure is more andmore obvious in the area of the break crackle. The microstructure and the macro mechanicalproperties reached a basic consistent.The DSC analysis results showed that the addition of FSM had little effect on the glasstransition temperature of the EP/IPDA/FSM system, it maintained at about135℃. TheTGA analysis results showed that the thermal stability of the modified epoxy resin has beenimproved.The surface performance of the EP/IPDA/FSM system was studied by measuring thecontact angle. Results showed that the surface contact angle with water increased with theadditive amount of FSM, when the additive amount was20phr, the contact angle reach to120°, but the increasing trend of the contact angle weakened accordingly. The surfacefluoride content of the EP/IPDA/FSM system was analyzed by the X-ray spectrometer. Theresults showed that the content of the surface fluoride were higher than the matrix theoreticalfluoride, and the increasing trend of the surface fluorine is consistent with change of thesurface contact angle. |
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