纳米二氧化硅填充线性低密度聚乙烯的等温结晶动力学

Kinetics of isothermal crystallization for LLDPE filled with nano-SiO_2

用DSC方法研究了纳米SiO2 含量和表面处理对填充LLDPE体系等温结晶行为的影响。结果表明 ,随着纳米SiO2 含量的增加 ,体系的结晶速率呈现先降低后增加的趋势 ,这是因为在高表面积纳米SiO2 变量范围内 ,含量较低时填料对基体结晶行为的影响以吸附作用为主 ,含量较高时则成核作用占优势。同时还发现 ,纳米SiO2 含量相同时 ,与硅烷偶联剂表面处理比较 ,偶联剂 /分散剂复配处理使纳米SiO2 粒子表面的吸附层增厚 ,基体与粒子间的相容性增加 ,填料的异相成核作用明显 。

Effect of nano SiO 2 content and surface treatmeat on the isothermal crystallization behavior of LLDPE filled was investigated by DSC method. Results show that the crystallization rate of the system firstly increases and then decreases with increase in nano SiO 2 content. The reason is that the adsorption of LLDPE chains on the filler surface plays a decisive role on the crystallization behavior when the nano SiO 2 content is lower, and the nucleation prevails when the nano SiO 2 content is higher. Simultaneously, compared to the surface treatment of coupling agents with same nano SiO 2 content, the co surface treatment of coupling agents and dispersing agent results in an increase in the thickness of surface filler adsorption layer and the compatibility between the matrix and filler, which lead to an obvious heterogeneous nucleation of filler and an increase in the crystallization rate of matrix.