原位乳液聚合法制备PVAc-OMMT纳米复合材料的性能研究

通过乳液聚合技术引发醋酸乙烯酯（VAc）在有机插层剂改性的蒙脱土（OMMT）中原位插层聚合，制备了一种新型聚合物-黏土纳米复合材料PVAc-OMMT。利用X射线衍射、透射电子显微镜和红外光谱研究了复合材料的结构和微观形态；利用热失重分析、差示扫描量热法研究了不同OMMT用量的复合材料的热稳定性；同时探讨了OMMT用量对材料力学性能的影响。结果表明，采用该方法得到了插层型纳米复合材料，且该纳米复合材料与相同条件下制备的纯聚醋酸乙烯酯（PVAc）相比，具有较高的玻璃化转变温度、优良的热稳定性和较好的力学性能；随着OMMT用量的增加，材料的起始热分解温度逐渐向高温方向移动，热稳定性提高；材料的拉伸强度随OMMT用量的增加出现先增加后减小的趋势，当OMMT用量为10 %（质量分数，下同）时，材料的拉伸强度达到最大值7.87 MPa。

Preparation and Property of Poly(vinyl acetate)-Organophilic Montmorillonite Nanocomposites Initiated by Emulsion Polymerization

Nanocomposites of poly(vinyl acetate)/organophilic montmorillonite (PVAc/OMMT) were prepared via emulsion polymerization. The structure and morphology of the nanocomposites were characterized using X-ray diffraction(XRD)，transmission electron microscopy (TEM), and FT-IR spectrum. The thermal stability of the nanocomposites was investigated using thermogravimetric analysis and DSC. Intercalated structures were found in the nanocomposites. Based on neat PVAc, the glass transition temperature (Tg) of the nanocomposite was increased, the thermal stability and mechanical properties were also enhanced. The initial decomposition temperature of the nanocomposites increased with increasing contents of OMMT. The tensile strength of the nanocomposites were first increased and then decreased with increasing contents of OMMT. When the content of OMMT was 10 wt %, the maximum value of 7.87 MPa was obtained.