Synthesis of high performance epoxy/silica hybrids by using the sol-gel reaction

在这项研究中，环氧树脂/二氧化硅杂化物的合成和表征，以改善固化的环氧树脂的热机械性能。在碱性催化剂存在下，以液态环氧树脂为溶剂和有机单体，通过原位溶胶-凝胶聚合法制备了SiO2/环氧杂化材料，SiO2以纳米尺寸的团簇均匀分散在环氧树脂网络中。控制环氧树脂和二氧化硅网络之间的相互作用（如共价键和氢键的形成）是制备环氧树脂/二氧化硅杂化物的最重要因素，环氧树脂/二氧化硅杂化物的玻璃-橡胶转变随着环氧树脂和二氧化硅网络的杂化过程而迅速消失。这是由于二氧化硅网络的杂化抑制了环氧网络的微布朗运动。因此，很明显，固化的环氧树脂的耐热性通过与二氧化硅网络的杂化而显著改善。由环氧/二氧化硅杂化物制成的涂层显示出高的硬度和刚性，而在玻璃态区的韧性和弯曲强度略低。

In this study, the epoxy/silica hybrids were synthesized and characterized for improving the thermo-mechanical properties of the cured epoxy resin. The hybrids were prepared by the in-situ sol-gel polymerization of the silane alkoxide in the presence of a basic catalyst in the liquid epoxy resin which was used as both the organic monomer and solvent for the sol-gel reaction.In this hybrid, the silica networks were uniformly dispersed in the epoxy networks as the nano-meter size of clusters. The control of the interaction (e.g. the formation of the covalent and hydrogen bondings) between the epoxy and silica networks was the most important factor for preparing the epoxy/silica hybrids in which both the networks is dissolved in the molecular order.The glass-rubber transition of the epoxy/silica hybrids was rapidly disappeared with the progress of the hybrization in the epoxy and silica networks. This was due to the suppression of the Micro-Brownian motion of the epoxy networks with the hybrization of the silica networks. Thus, it is clear that the heat resistance of the cured epoxy resin is considerably improved by the hybrization with the silica networks. The coatings made from the epoxy/silica hybrids showed the high hardness and rigidity, and the slightly low toughness and flexural strength in the glassy region.