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使用2种硅烷偶联剂(KH550和KH792)对介孔分子筛MCM-41进行表面改性,采取氮气吸附-脱附、FTIR和TGA等进行表征,并采用原位聚合法制备了MCM-41/环氧树脂复合材料,研究了偶联剂种类和MCM-41用量等对复合材料固化过程及性能的影响。结果表明:硅烷偶联剂可与MCM-41表面的硅羟基反应,在分子筛内外表面接枝上功能化基团。经表面修饰的MCM-41比表面积下降为原来的1/5,KH550在MCM-41表面接枝率仅为KH792的一半。KH550与MCM-41外表面反应得更充分,KH792对MCM-41孔道内壁的修饰效果更强。固化动力学结果表明:KH792的功能化基团有伯胺和仲胺,与环氧树脂具有更高的反应活性,但不利于环氧大分子进入孔道,仅以球形粒子的形式添加在环氧树脂中;KH550表面修饰的MCM-41可使环氧大分子进入孔道内形成互穿结构。KH550表面修饰体系更多体现出MCM-41多孔的特征,形成了有机-无机互穿结构的复合体系,大幅度提高了储能模量和玻璃化转变温度。KH792表面修饰体系则呈常规球形纳米粒子的特征,其储能模量和玻璃化转变温度较纯环氧树脂有所提高但幅度不大。
The mesoporous molecular sieve MCM-41 was modified by two kinds of silane coupling agents (KH550 and KH792) and characterized by N2 adsorption-desorption, FTIR and TGA. The MCM-41 / Epoxy resin composites, the effects of coupling agent type and amount of MCM-41 on the curing process and properties of the composites were studied. The results show that the silane coupling agent can react with the silanol groups on the surface of MCM-41 to graft functional groups on the inner and outer surfaces of the molecular sieve. Surface modification of MCM-41 reduced the specific surface area of the original 1/5, KH550 MCM-41 surface grafting rate of only half of KH792. KH550 and MCM-41 outer surface reaction more fully, KH792 MCM-41 pore wall modification effect more. Curing kinetics results show that: KH792 functional groups with primary and secondary amines, and epoxy resin has higher reactivity, but is not conducive to epoxy macromolecules into the pore, only in the form of spherical particles added in the epoxy Resin; KH550 surface modified MCM-41 allows epoxy macromolecules into the pore to form interpenetrating structure. KH550 surface modification system more reflects the porous nature of MCM-41, forming a composite system of organic-inorganic interpenetrating structure, greatly improving the storage modulus and glass transition temperature. KH792 surface modification system showed the characteristics of the conventional spherical nanoparticles, the storage modulus and glass transition temperature of the pure epoxy resin has increased but not significant.