Materials Sciences and Applications, 2014, 5, 300-315 Published Online April 2014 in SciRes. http://www.scirp.org/journal/msa http://dx.doi.org/10.4236/msa.2014.55036 How to cite this paper: Al Safi, S.A., Al Mouamin, T.M., Al Sieadi, W.N. and Al Ani, K.E. (2014) Irradiation Effect on Photo- degradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films. Materials Sciences and Applications, 5, 300-315. http://dx.doi.org/10.4236/msa.2014.55036 Irradiation Effect on Photodegradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films Saria A. Al Safi, Thanaa M. Al Mouamin, Wadhah N. Al Sieadi, Khalid E. Al Ani * Department of Chemistry, Faculty of Science, Baghdad University, Baghdad, Iraq Email: * khalidalani44@yahoo.com , * khalid7@hu.edu.jo Received 22 January 2014; revised 3 March 2014; accepted 18 March 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract The photodegradation of irradiated thin films of poly (para-methylstyrene) with 265 nm radia- tions in the presence of airand as a function of irradiation time has been studied using UV-VIS, flu- orescence and FT-IR Spectroscopic techniques. The influence of phthalate and terephthalate plas- ticizers on stability of poly (para-methylstyrene) towards irradiations was also investigated. Blending with phthalate plasticizers was found to cause a higher efficiency of photodegradation than that obtained in doping with terephthalate plasticizers. The intensity of absorption was also found to increase with time of irradiation and in change in the shape of the spectra at longer wa- velength, thus indicating a possibility of photodegradation of polymer chains. The analysis of the FT-IR spectra of the irradiated and non-irradiated samples, shows a predominant absorption as- sociated with carbonyl compounds with 1740 cm −1 . In addition, the observed increase in the in- tensities of the carbonyl and hydroxyl regions of the FT-IR spectra, have provided an evidence for the photodegradation as well as photo-oxidation of polymeric chains. The presence of the plasti- cizer in the polymer backbone was found to accelerate the photodegradation of polymeric chains. Keywords Excimer Fluorescence, Photodegradation Kinetics, Phthalate Plasticizers, Poly (Para-Methylstyrene) 1. Introduction The effect of UV irradiation on stability of polystyrene has been studied in details by several workers [1]-[6], * Corresponding author.