New Techniques for Diffusion Studies of Thin Polymer Films

Abstract
A practical laboratory procedure was developed to assess the effects of a fluoro carbon elastomer processing aid on the extrusion behaviour of several linear low den sity polyethylenes (LLDPEs) that are used for tubular film manufacture. The elastomer, Dynamar* Polymer Processing Additive PPA 2231, is a copolymer of vinylidene difluoride and hexafluoropropene and appears to act as a die lubricant. Data obtained with various concentrations of PPA 2231 in three different LLDPEs showed that this additive can reduce processing problems, such as draw resonance and melt fracture. The additive also appears to improve extrusion efficiency (lbs. output/hr/hp).