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International Journal of Polymer Science
Volume 2015, Article ID 510390, 10 pages
http://dx.doi.org/10.1155/2015/510390
Research Article

Synthesis of New Thiophene Derivatives and Their Use as Photostabilizers for Rigid Poly(vinyl chloride)

1College of Pharmacy, Babylon University, Babylon, Iraq
2Department of Chemistry, College of Science, Al-Nahrain University, Baghdad, Iraq
3Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia
4School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK

Received 23 September 2014; Revised 16 December 2014; Accepted 19 December 2014

Academic Editor: Qinglin Wu

Copyright © 2015 Asim A. Balakit et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Five new thiophenes, namely, N-[(3-bromo-2-methylthiophen-5-yl)methylene]-4-methoxyaniline (4a), N-[(3-bromo-2-methylthiophen-5-yl)methylene]-3,4-dimethoxyaniline (4b), N-[(3-bromo-2-methylthiophen-5-yl)methylene]-3,4-dimethylaniline (4c), 3-[(3-bromo-2-methylthiophen-5-yl)methyleneamino]-2-methylquinazolin-4(3H)-one (4d), and 3-[(3-bromo-2-methylthiophen-5-yl)methyleneamino]-2-isopropylquinazolin-4(3H)-one (4e), have been synthesized. All of these materials brought about a reduction in the level of photodegradation of poly(vinyl chloride) (PVC) films containing the synthesized thiophenes (0.5%; by weight). The results obtained showed that the extent of photostabilization of PVC in the presence of an additive was in the order 4e > 4d > 4b > 4a > 4c. For the most favorable additive (4e), the rate of appearance of infrared absorption bands of degradation products was reduced by around two-thirds, while the quantum yield of chain scission was calculated to be reduced by a factor of more than one thousand. It is suggested that the additives may help stabilize PVC by direct absorption of UV radiation and dissipation of the energy as heat or that electrostatic attraction between the additives and PVC may assist transfer of energy from excited state PVC to the additive, from where it can be dissipated.