聚乙烯/聚丙烃反应器合金的制备

Polyethylene/Polypropylene in-reactor alloys synthesized by a spherical supported Ziegler-Natta catalyst

采用负载型球形催化剂催化乙烯、丙烯两段淤浆聚合,得到了高孔隙率的球形PE/PP反应器合金.用光学显微镜、扫描电镜(SEM)和红外光谱(FTIR)等方法对所得聚合物的颗粒形貌、孔隙率、粒径分布和组成等进行了表征.实验表明,合金粒子的粒径分布较窄、形貌规则、孔隙率高.第二段聚合生成的聚丙烯有部分填充入聚乙烯粒子的细孔隙内,合金粒子的孔隙率低于聚乙烯粒子.DSC分析合金热行为和偏光显微镜观察结晶形貌表明,PE与PP两相部分相容.力学性能测试表明,PE/PP合金兼有高韧性和高刚性.材料的冲击断面具有韧性断裂特征,PE与PP两相间有较强的相互作用.

Spherical Polyethylene （PE）/Polypropylene （PP） in-reactor alloy granules of high porosity were synthesized by two-stage sequential polymerization of ethylene and propylene using a spherical supported Ziegler-Natta catalyst. The morphology, particle size distribution, porosity and composition of the alloy granules were studied by optical microscope, scanning electron microscope, FT-IR and other means. The granules obtained have excellent spherical morphology, high porosity and a narrow size distribution. Many tiny cavities in the granules are filled up by PP in the alloy, resulting in lower porosity than that of the PE granules. As disclosed by the DSC thermal behaviors and the crystalline morphology of the alloy, the PE and PP phases are partially compatible with each other. The PE/PP alloy has excellent impact strength and flexural modulus. The morphology of the impact fracture surface shows some characteristics of a ductile material, and implies a strong interaction between the PE and PP components.