【作者】 林宇； 上官勇刚； 郑强；

【Author】 Yu Lin,Yonggang Shangguan,Qiang Zheng Department of Polymer Science and Engineering,Key Laboratory of Macromolecular Synthesis and Functionalization,Ministry of Education,Zhejiang University,Hangzhou 310027

【机构】 浙江大学高分子科学与工程学系高分子合成与功能构造教育部重点实验室；

【摘要】 通过溶液浇铸和熔融共混法制备了不同分子链缠结程度的PMMA/SMA共混物,发现溶液浇铸样品缠结分子量高,缠结密度较低。采用宽频介电谱仪研究了分子链缠结对PMMA/SMA共混物分子动力学的影响。结果显示,缠结对共混物α松弛有显著的影响,缠结密度越大,松弛时间越长;而缠结密度几乎不影响β松弛及其活化能。进一步考察了高温(T>Tg)热处理对共混体系缠结密度及分子动力学的影响,发现随着热处理温度升高或热处理时间延长,共混体系平台模量升高,缠结密度增大,α松弛时间变长。更多还原

【Abstract】 Different degrees of molecular entanglement in poly(methyl methacrylate)/poly(styrene-co-maleic anhydride)(PMMA/SMA) blends were prepared through solution casting and melt blending.The solution casting samples give rise to a lower entanglement densities.The effect of molecular entanglement on molecular dynamics of PMMA/SMA blends was investigated by using broadband dielectric spectroscopy.It is found that molecular entanglement has a pronounced effect on the α-relaxation dynamics.The relaxation time of the α-relaxation is lower for lower entanglement densities.However,neither the dynamics nor the distribution width of the β-relaxation is affected by entanglement density.On the other hand,annealing effects on the molecular entanglement and molecular dynamics was also investigated.The molecular entanglement and molecular dynamics are significantly in?uenced by the high temperature annealing process.更多还原