Studies on the photo-oxidative degradation of LDPE films in the presence of oxidised polyethylene

• Published in: Polymer degradation and stability Vol. 92; no. 6; pp. 1151 - 1160
• Main Authors: Roy, P.K., Surekha, P., Rajagopal, C., Chatterjee, S.N., Choudhary, V.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2007; Elsevier Science
• Subjects: Ageing; Applied sciences; Cobalt stearate; Compounding ingredients; Exact sciences and technology; Low-density polyethylene; Mechanical properties; Miscellaneous; Physical properties; Polymer industry, paints, wood; Prooxidant; Properties and testing; Technology of polymers; Mechanical properties; Prooxidant; Cobalt stearate; Low-density polyethylene; Polymer blends; Olefin copolymer; Composition effect; Crystallinity; Experimental study; Tensile strength; Low density ethylene polymer; Morphology; Ethylene copolymer; Reaction mechanism; Photochemical stability; Artificial ageing; Olefin polymer; Kinetics; Exposure time; Photochemical degradation
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2007.01.010

This paper reports the results of photo-oxidative degradation studies of LDPE in the presence of varying amounts of oxidised polyethylene (OPE), which was prepared by heating LDPE films containing 0.1% cobalt stearate in oxygen atmosphere at 100 °C. OPE, with a CI of 12 was used as an additive for LDPE. Varying amounts of OPE (0.5–5%) were blended with polyethylene in an extruder and films of 70 μm thickness were prepared by film blowing process. The physico-chemical properties of the films were evaluated and these were found to be proportional to the amount of OPE. The films thus obtained were subjected to UV-B exposure at 30 °C for extended time periods. The chemical and physical changes induced by UV exposure were followed by monitoring the changes in mechanical properties (tensile strength and elongation at break), carbonyl index (CI), morphology, molecular weight, MFI and DSC crystallinity. Incorporation of OPE was found to be effective in initiating the photo-degradation of LDPE in relatively short span of time and the degradation was found to be proportional to the amount of OPE in the formulation.