147 The Application of Electron Beam Processing to Reduce Time-Dependent Creep Properties of HDPE-Based Composites
Jennifer K. Lynch, Thomas J. Nosker, William Crilley*: Rutgers, The State University of New Jersey, Materials Science and Engineering Department, 607 Taylor Road, Piscataway, NJ 08823 USA:
*E-Beam Services, 118 Melrich Road Cranbury, NJ 08512 USA
E-Mail: jklynch@rci.rutgers.edu
Abstract
Electron beam processing is used to reduce time-dependent creep properties of HDPE and filled HDPE composites. Three materials systems are investigated, including neat HDPE, 30/70 % Magnesium Hydroxide/HDPE, and 30/70 % Polypropylene coated fiberglass/HDPE, and are processed using injection molding methods. The composites are dry-blended prior to injection molding. The tensile specimens of each materials system is subject to electron beam radiation processing, including 0, 1.5, 2.0, and 2.5 kGy of radiation, followed by mechanical property testing. Uniaxial tensile experiments are performed for each materials system and radiation level at a fast and slow rate. Utilizing the Non-Linear Strain Energy Equivalence Theory (SEET), the long-term creep behavior is predicted for each materials system and at each level of electron beam radiation from these short-term tensile stress-strain experiments conducted at different strain rates. SEET is a correlative method in which data from two short-term stress-strain experiments conducted at different strain rates are used to predict long-term creep strain, the creep exponent, and stress-strain data at any strain rate. The benefit of electron beam processing on the long-term creep behaviour of plastics is investigated.
Keywords: Creep, Electron Beam Processing, Plastics