利用旋转流变仪、哈克转矩流变仪以及双螺杆挤出机,研究了剪切速率对自加速效应的影响,且通过反应挤出聚合制备了聚甲基丙烯酸甲酯(PMMA)。采用多检测凝胶渗透色谱(GPC)、动态力学分析(DMA)等方法,对聚合物结构和性能进行了表征。结果表明,在反应挤出聚合过程中,改变剪切速率可有效地调控自加速效应。通过新单体补加技术充分利用自加速效应,不仅可以提高聚合速率,而且可以获得高分子量、窄分子量分布的PMMA。制备的PMMA性能优于市售PMMA。
The effect of shear rate on the Trommsdorff effect was investigated by rotational rheometer,Haake torque rheometer and twin-screw extruder.Poly(methyl methacrylate)(PMMA)was prepared via reactive extrusion in a twin-screw extruder.The structure and properties of the PMMA were characterized by multi-detector Gel Permeation Chromatography(GPC)and Dynamic Mechanical Analysis(DMA),etc.Results indicated that the Trommsdorff effect could be effectively regulated by changing the shear rate in the process of reactive extrusion.The polymerization rate was increased by taking advantage of the Trommsdorff effect through adding new monomers.Meanwhile,PMMA had high molecular weight and narrow molecular weight distribution.The performance of obtained PMMA was better than commercial PMMA.