Solid State Coextrusion of High Density Polyethylene. II. Effect of Molecular Weight and Molecular Weight Distribution.
Abstract
The recently developed technique of solid state coextrusion for ultradrawing semicrystalline thermoplastics has been applied in the preparation of self-reinforced high density polyethylene extrudates. The extrudates consist of definite core and sheath phases composed of different molecular weights (Mw) in the range of 60,000 - 250,000 and different molecular weight distributions (Mw/Mn = 0.3 - 20). Cocylindrical billets of two different phases were prepared for extrusion by inserting a polyethylene rod within a tubular billet of a different high density polyethylene followed by melting the two phases to obtain bonding between them. The billet was then split longitudinally to increase extrusion speed followed by extrusion at 120 C, 0.23 GPa and extrusion draw ratio 25. Thus it was possible to produce extrudates of high tensile modulus (45 GPa) and strength (0.55 GPa) at a rate near 0.7 cm./min. In general, the tensile properties of the extrudates increased with average molecular weight and were insensitive to the molecular weight distribution of the two phases. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 16, 1978
- Accession Number
- ADA060802
Entities
People
- Anagnostis E. Zachariades
- Roger S. Porter
- Tetsuo Kanamoto
Organizations
- University of Massachusetts Amherst