摘要
正电子湮灭研究结果发现,常温下超高分子量聚乙烯和低乙烯含量嵌段聚丙烯熔融共混体系自由体积含量随组分呈非单调变化,与线性加和关系相比发生了正偏离,意味着界面相区域堆砌密度较低,导致了过量的自由体积.在此基础上建立了非相溶二元共混体系自由体积分布的一般模型,提出界面自由体积的概念,解释了导致自由体积发生偏离的原因,并得出了界面自由体积与分散相半径(球形近似)和界面空隙厚度的关系.模型与实验结果吻和.
The Positron annihilation technique has been applied to study the blends of ultra-high molecular weight polyethylene and polypropylene. A positive deviation of free volume content in the blends has been found compared to the linear addition relationship. The phenomenon means a low density in the interface domain, which leads to the excess of free volume. A free-volume distribution model for incompatible blends was built and the concept of interface free volume was proposed to explain the positive deviation of free volume. The relationship between interface free volume and interface density and scattering phase average size was obtained. The model agrees with the experimental results quite well.
基金
国家自然科学基金资助课题
