PMMA/mesoporous silica nanocomposites: effect of framework structure and pore size on thermomechanical properties
PMMA/mesoporous silica nanocomposites: effect of framework structure and pore size on thermomechanical properties
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DOI：
10.1039/b9py00232d
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发表时间：
2010-02
影响因子：
4.6
通讯作者：
Faai Zhang;Dong-Keun Lee;T. Pinnavaia
中科院分区：
文献类型：
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作者：
Faai Zhang;Dong-Keun Lee;T. Pinnavaia
研究了六方MCM-41 （2.4 nm）、立方MCM-48 （1.9 nm）、六方SBA-15 （7.0 nm）和介孔硅泡沫MSU-F （24.8 nm）等具有不同骨架结构和孔径的介孔二氧化硅（MS）作为功能添加剂，通过原位乳液聚合和压缩模压法制备聚甲基丙烯酸甲酯(PMMA)/介孔二氧化硅纳米复合材料。与原始聚合物相比，所有的复合材料在5 wt%的MS负载下，表现出更好的热稳定性，更高的玻璃化转变温度和增强的存储模量。MSU-F二氧化硅具有最大的骨架孔径，为复合材料提供了最佳的热力学性能改善。总的来说，热稳定性和模量的改善随着骨架孔径的减小而减小。对于由相似孔径的MCM-41和MCM-48二氧化硅制成的复合材料，3D MCM-48结构提供了优越的优势。复合材料的热机械性能的改善归功于聚合物在大孔道中的限制，特别是具有3D结构的孔道。
Mesoporous forms of silica (MS) with different framework structures and pore sizes, including hexagonal MCM-41 (2.4 nm), cubic MCM-48 (1.9 nm), hexagonal SBA-15 (7.0 nm) and mesocellular silicafoam MSU-F (24.8 nm), were examined as functional additives in the preparation of poly(methyl methacrylate) (PMMA)/mesoporous silica nanocomposites made by in situemulsion polymerization and compression molding. All of the composites at 5 wt% loadings of MS, exhibit improved thermal stability, an elevated glass transition temperature, and an enhanced storage modulus in comparison to the pristine polymer. MSU-F silica with the largest framework pore size provides the composite with the best improvement in thermomechanical properties. In general, the improvements in thermal stability and modulus diminish with decreasing framework pore size of the silica additive. For composites made from MCM-41 and MCM-48 silicas with similar pore sizes, the 3D MCM-48 structure provided superior benefits. The improvements in thermomechanical properties for the composite are attributed to the confinement of polymer in large pore channels, especially those with a 3D structure.