Oxidation and crosslinking processes during thermal aging of low‐density polyethylene films

• DOI: 10.1002/app.34080
• Publication Date: 2011-12-14T19:06:27Z
• Authors: Salem F. Chabira; Mohamed Sebaa; Christian G'sell
• Keywords: Thermal oxidation; Chain scission; Ductility (Earth science); Polystyrene

Abstract This work analyzes the influence of thermal degradation on microstructure and mechanical properties low‐density polyethylene subjected to aging at 70°C in dark for times up 21 months. It is found that polymer shows a gradual increase its elastic modulus dramatic reduction ductility, due secondary crystallization. Infrared spectroscopy (FTIR) reveals autoaccelerated oxidation after 5 months aging. observed unsaturated vinylidene groups initially present material are gradually overridden by vinyl and, eventually, t‐vinylene groups. Nuclear magnetic resonance ( 13 C NMR) initial butyl chain branches progressively completed shorter ramifications, namely ethyl branches. These results discussed term macromolecular mechanisms: (i) oxidation, (ii) scission, (iii) crosslinking. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci,