茂金属聚乙烯与低密度聚乙烯共混的结晶形态和空间电荷效应

Space Charge Distribution and Crystalline Structure in Low-Density Polyethylene Modified by Metallocene Catalyzed Polyethylene

将少量茂金属聚乙烯(MPE)作为成核剂与普通低密度聚乙烯(LDPE)共混,用电声脉冲法(PEA)测量了其空间电荷分布;以差示扫描量热法(DSC)研究了共混物的非等温结晶行为;通过小角激光散射(SALS)和广角X衍射(WAXD)实验研究了共混物的球晶尺寸和结晶形态的变化。测试结果表明,1%wt的MPE与LDPE共混,能有效减小球晶尺寸,提高结晶速率和晶体成核能力,有利于电荷的输运,从而降低了空间电荷的聚集。

A small amount of metallocene catalyzed polyethylene（MPE）, acting as a nucleator, is blended into low-density polyethylene（LDPE） in this paper. Then the space charge profile in the blends is measured by pulsed electro-acoustic （PEA） method. At the same time the crystallization of the blends was studied by differential scanning calorimerty （DSC） method. In addition, the tests of small-angle light scattering （SALS） and wide-angle X-ray diffraction （WAXD） experiments research the changes of the size of spherulite and crystalline form. The test results show that the decrease of space charge in the blends especially in the LDPE by blending 1 wt% MPE can probably be attributed to the improvement of the nucleation, and the decrease of the size of spherulite and the dissipation of charges through boundary regions of smaller spherulites.