| Organic silicone modified epoxy resin can reduce the internal stress and improve the flexibility and heat resistance of epoxy resin. The main chains of organic silicone resin are composed of Si-O bond with good flexibility and larger bond energy than C-C bond and C-O bond, therefore organic silicone have excellent heat resistance and weather resistance. When organic silicone resin was introduced into the epoxy resin through many appropriate methods, we can get the organic siliconized epoxy resin with good heat resistance, and the modified resin can be applied to the areas that have high requirements of heat resistance.The organic siliconized epoxy resin was prepared by direct condensation of diphenylsilandiol and epoxy resin. We studied the effect of reaction conditions and the molar ratio of reagents on the heat resistance of modified products in detail. The results revealed stannous octanoate was the effective catalyst for the direct condensation of diphenylsilandiol and epoxy resin, and diphenylsilandiol significantly improved the heat resistance of epoxy resin. When the molar ratio of reagents was 3:1, the glass transition temperature of modified epoxy resin was 147.45℃, and the decomposition temperature at 50% weight loss was 490.5℃. The decomposition temperature at 50% weight loss increased by 24℃than pure epoxy resin.Nano-silica was used to further improve the heat resistance of organic siliconized epoxy resin. Coupling agentγ-glycidyloxypropyltrimethoxy silane (KH-560) was used to modify the surface of nano-silica, which improved the dispersion of nano-silica in the organic siliconized epoxy resin and improved the compatibility of nano-silica and organic siliconized epoxy resin. The results revealed nano-silica significantly improved the crosslinking density of organic siliconized epoxy resin, and improved the heat resistance and impact toughness and reduced the glass transition temperature. When the amount of nano-silica was 3%, the composites got the best heat resistance and impact strength.Ladder-type oligomeric silsesquioxane with phenyl and epoxy group was prepared by condensation of phenyl triethoxy silane andγ-glycidyloxypropyl trimethoxy silane (KH-560), and the ladder-type oligomeric silsesquioxane had good compatibility with epoxy resin. The results of the study revealed the composites of ladder-type oligomeric silsesquioxane modified epoxy resin had higher initial decomposition temperature and impact strength than pure epoxy resin, but had lower glass transition temperature.We first used stannous octanoate as catalyst in the experiment of diphenylsilandiol modifying epoxy resin, and it proved that stannous octanoate was the effective catalyst for the modified reaction. The optimal reaction conditions and reagent molar ratio obtained from the experiment provided reference for the modification study and actual production and application of epoxy resin. We also prepared ladder-type oligomeric silsesquioxane with phenyl and epoxy group, and used it to improve the heat resistance of epoxy resin, which provided a guidance for the deeply investigation of organic silicone modified epoxy resin. |
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