PMMA／蒙脱土纳米复合材料的结构及热性能

Structure and Thermal Properties of PMMA/Montmorillonite Nanocomposites

以甲基丙烯酸二甲胺基乙酯和1-溴正十六烷为原料合成了1种新型的带双键长碳链季铵盐甲基丙烯酰氧乙基十六烷基二甲基溴化铵（MHAB）。用MHAB对钠基蒙脱土进行改性得到有机蒙脱土（OMMT）。通过本体原位插层聚合制备了的聚甲基丙烯酸甲酯／蒙脱土纳米复合材料。MHAB的结构通过核磁共振氢谱（^1H—NMR）表征。X射线衍射（XRD）测得OMMT的001面层间距（d001）从1.25nm扩大到2．72nm。XRD和透射电镜（TEM）测试证明蒙脱土质量分数为5％，8％时完全以剥离片层形式存在于复合材料中。差示扫描量热仪（DSC）和热失重仪（TG）测试表明复合材料的玻璃化转变温度和外推起始热失重温度都随着蒙脱土的含量增加而提高。

A novel quaternary ammonium salt with a vinyl group, 2-methacryloyloxyeth- ylhexadecyldimethylammonium bromide （MHAB） was synthesized from 2-（dimethylamino） ethyl methacrylate and 1-bromohexadecane. MHAB was used to modify the Na montmorillonite （MMT） surface to prepare organic montmorillonite （OMMT）. Poly（methyl methacrylate） （PMMA）/montmorillonite nanocomposites were prepared by in-situ bulk polymerization. Structure of MHAB was characterized by proton nuclear magnetic resonance （^1H- NMR）. X-ray diffraction （XRD） reveals that the d001 of OMMT increases from 1.25 nm to 2.72 nm. XRD and transmission electron mici＇oscopy indicate the montmorillonite exists as complete exfoliation in PMMA/montmorillonite nanocomposite when mass fraction of OM- MT is 5 % and 8%. Differential scanning calorimeter and thermal gravimetric analysis show that glass transition temperature and extrapolated initial weight loss temperature increase with the increase of OMMT content in nanocomposites.