Study On Nano-silica Toughening Modification For Epoxy Resin

Epoxy resin is important thermosetting resin, holding excellent adhesive, abrasiveresistance, mechanical, electrical insulating and anticorrosion property, furthermore,having low shrinkage rate, easy machine-shaping, low cost, was extensive usedin many fields, such as adhesive, heavy-duty coating, electronic and electricalinsulation material, reinforced material, advanced composite etc. But the solidifiedfilm, specially for low molecular weight epoxy resin, held high crosslink density andbrittle, poor flexibility and resistance to impact, low peel strength, influencing theadhesive power and barrier property of epoxy resin film, limiting the application of itin high and new technology fields. So how to toughen modification epoxy resin,premising keeping the excellent performance of it, was very hot research subject fordomestic and foreign researcher, also the key point of expanding application fieldabout epoxy resin.Using nano-silica to modify epoxy resin, the silicon hydroxyl group (Si-OH) at thesurface silica particle, can react with epoxy group in epoxy resin at the condition ofheating and adding accelerator. Through testing the stability and viscosity of modifiedresin, and evaluating the adhesion, resistance to impact, flexibility, crosslink densityand salt-fog corrosion resistance of coating using modified resin to form film, thereaction technological conditions was confirmed: reactive temperature should becontrolled about 150℃, reactive time should be controlled 2～3h, the addition ofaccelerator A is in the rang from 0.10%～0.30% and the addition of nano-silica L20 isin the rang from 5%～15%.The paper tested the mechanical property of modified resin by tensile test, usinguniversal test machine controlled by computer, such as tensile strength, rate ofelongation at break, modulus of elasticity etc. Analyzed the surface pattern of coatingimpact fracture plane through Scanning Electron Microscopy(SEM), discussed thetoughening mechanism and testing other property of coating, the result showed thatthe flexibility of modified resin is better than pure-epoxy resin, that the key factor oftoughening is grafting rate of modified resin, and other property was held aftertoughening modification.Finally, using infra-red spectrum (IR) to attribute microstructure of modifiedepoxy resin, researching the representative macroscopic properties about it, and themodified reaction mechanism was tentatively discussed. The result showed that thenew Si-O-C was generated in modified epoxy resin, and forming inorganic-organicstructure...