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Title: Elongational viscosity of photo-oxidated LDPE

Sheets of low-density polyethylene (LDPE) were photo-oxidatively treated at room temperature, and subsequently characterized rheologically in the melt state by shear and uniaxial extensional experiments. For photo-oxidation, a xenon lamp was used to irradiate the samples for times between 1 day and 6 weeks. Linear-viscoelastic characterization was performed in a temperature range of 130 to 220°C to obtain the master curve at 170°C, the reference temperature at which the elongational viscosities were measured. Linear viscoelasticity is increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by an increasing gel fraction as determined by a solvent extraction method. The elongational measurements reveal a strong enhancement of strain hardening until a saturation level is achieved. The elongational data are analyzed in the frame work of two constitutive equations, the rubber-like liquid and the molecular stress function models. Within the experimental window, timedeformation separability is confirmed for all samples, independent of the degree of photo-oxidation.
Authors:
;  [1]
  1. Chair of Polymer Engineering and Polymer Physics, Berlin Institute of Technology-TU Berlin. Fasanenstr. 90. 10623 Berlin (Germany)
Publication Date:
OSTI Identifier:
22271001
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1593; Journal Issue: 1; Conference: PPS-29: 29. international conference of the Polymer Processing Society, Nuremberg (Germany), 15-19 Jul 2013; Other Information: (c) 2014 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CROSS-LINKING; GELS; OXIDATION; POLYETHYLENES; RUBBERS; SHEAR; SHEETS; SOLVENT EXTRACTION; STRAIN HARDENING; STRESSES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; VISCOSITY