Properties and Materials'Science of LLDPE and MDPE Blown Films of Metallocene,Ziegler and Enhanced Polyethylene Commercial Resins

摘要

A number of single site,metallocene and constrained geometry catalyst (CGCT),resins are now commercially available and used in a wide range of blown film applications.In many cases,these new resins compete with traditional Ziegler-Natta catalyst based resins.This paper summarizes a comparison of the key blown film properties of resins (density range 0.915 -0.935 g/cc)made using metallocene catalysis,Ziegler catalysis,and constrained geometry catalysis,and discusses some of the material science concepts regarding the molecular architecture that results in these film properties.The development of different single site catalysts (SSC)with different capabilities in terms of molecular architecture and comonomer integration,together with novel process/catalyst combinations for the manufacture of polyethylene resins now offer the material scientist greater range of options in resin design.This paper demonstrates some of the wide ranges of possibilities now open to the resin designer and discusses the trade-offs associated with the structure-property-processing relationships.