茂金属聚乙烯的流变性与加工性

研究了丁烯 １ 共聚的茂金属聚乙烯（ｍＰＥ） 的流变性，发现茂金属聚乙烯的窄分子量分布导致它在挤出加工剪切速率范围里熔体粘度高、对剪切敏感性差以及熔体从牛顿型转为非牛顿型所需的剪切速率、转变应力高，在挤出加工条件下流动性差，加工困难．对茂金属聚乙烯（ｍＰＥ） 进行改性制得ＭｍＰＥ，ＭｍＰＥ 熔体对温度、剪切速率的敏感性提高，在加工温度、加工剪切速率范围里的表观粘度降低，加工流动性得到了显著的改进，可在普通聚乙烯加工设备上，制备性能优良的茂金属聚乙烯薄膜制品．

RHEOLOGY AND PROCESSABILITY OF METALLOCENE POLYETHYLENE

The rheological property of metallocene polyethylene MPE(ethylene and 1\|butene copolymer) and conventional LDPE has been studied in detail by using a Rheometrics Scientifics DSR\|200 rheometer with parallel plate geometry. Measurements include steady\|state viscosity, dynamic viscoelasticity, followed by linear fitted with the modified cross model.MPE has poor processability due to its narrow MWD. Compared with conventional LDPE,MPE has higher apparent viscosity in middle shear rate range,low sensitivity to shearing,and higher values of shear rate and shear stress in the transition region from Newtonian to power\|law behavior. In order to improve its processability,MMPE modified from MPE has been produced.MMPE has all the advantages of metallocene polyethylene, and also has good processability:lower apparent viscosity,higher sensitivity to shearing,and lower values of shear rate and shear stress in the transition region from Newtonian to power\|law behavior.The blown film with good mechanical properties has been made from MMPE.