PMMA–mesocellular foam silica nanocomposites prepared through batch emulsion polymerization and compression molding
PMMA–mesocellular foam silica nanocomposites prepared through batch emulsion polymerization and compression molding
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DOI：
10.1016/j.polymer.2009.08.007
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发表时间：
2009-09
期刊：
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
首次在具有介孔泡沫结构(平均空腔尺寸为24.8 nm)的大孔MSU-F二氧化硅存在下，通过甲基丙烯酸甲酯的原位间歇乳液聚合和随后的聚合物-二氧化硅纳米混合物的模压成型制备了PMMA-介孔二氧化硅纳米复合材料。对于含5.0wt%二氧化硅的复合材料，其起始分解温度和10%失重温度分别比纯PMMA提高了41℃和50℃。差示扫描量热法测定，纳米复合材料的玻璃化转变温度提高了9.3℃。在50℃和100℃下，动态力学分析测得的储能模数分别提高了17%和80%。当纳米粒子含量为10wt%时，拉伸强度(+50%)和定伸应力(+72%)均有显著提高。由PMMA和MSU-F二氧化硅粉末物理混合物模压成型的复合材料在热稳定性、玻璃化转变温度和力学性能方面的改善比原位间歇乳液聚合制备的复合材料略有改善。与以前报道的由纳米粘土制成的复合材料不同，这里报道的二氧化硅复合材料在热稳定性和机械增强方面都有所改善。
PMMA–mesoporous silica nanocomposites were prepared for the first time through in situ batch emulsion polymerization of methyl methacrylate in the presence of large pore MSU-F silica with a mesocellular foam structure (24.8nm average cavity size) and subsequent compression molding of the polymer–silica nanoparticle mixtures. For composites containing 5.0wt % silica, the onset decomposition temperature and the temperature at 10% weight loss for the nanocomposite increased 41°C and 50°C, respectively, in comparison to pure PMMA. The glass transition temperature of the nanocomposite increased 9.3°C, as determined by differential scanning calorimetry. In addition, the storage modulus determined by dynamic mechanical analysis increased 17% and 80% at 50°C and 100°C, respectively. Substantial improvements in tensile strength (+50%) and modulus (+72%), were achieve at 10wt % nanoparticle loading. Composites made by compression molding of physical mixtures of PMMA and MSU-F silica powders provide less improvement in thermal stability, glass transition temperature and mechanical properties in comparison to the composites made through in situ batch emulsion polymerization. Unlike previously reported composites made from nanoclays, the silica composites reported here show improvements in both thermal stability and mechanical reinforcement.