Reza Jahanmardi - Department of polymer engineering, Science and research branch, Islamic Azad University, Tehran, Iran, P.O. Box 14155-4933.
Aidaalsadat Entezari - Department of polymer engineering, Science and research branch, Islamic Azad University, Tehran, Iran, P.O. Box 14155-4933.

With the steadily expanding use of polymers and ever increasing attention being paid to environmental pollution, the use of degradable film forming polymers has become a crucialneed [1]. The problem of degradable polymers can be partially solved by rendering conventional plastics photo-degradable.Polyethylene (PE) is extensively used as packaging material due to its ideal physical properties, easy production and low cost [2]. However, it is well documented that this polymer dose not undergo biodegradation within a realistic period of time (10 years), due to its chemical inertness and its highmolecular weight. Hence, this polyolefin has received much attention for enhancement of photo-degradability [3]. In thiswork influence of stearic acid (SA) on overall photo-oxidation behavior of HDPE films has been examined and compared to the corresponding activities of benzophenone (as a conventional aromatic ketone photo-initiator).