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Advances in Physical Chemistry
Volume 2013 (2013), Article ID 838402, 6 pages
http://dx.doi.org/10.1155/2013/838402
Research Article

Solvent Effect on Photoinitiator Reactivity in the Polymerization of 2-Hydroxyethyl Methacrylate

1Baqai Institute of Pharmaceutical Sciences, Baqai Medical University, 51 Deh Tor, Toll Plaza, Super Highway, Gadap Road, Karachi 74600, Pakistan
2Department of Dental Material Sciences, Baqai Dental College, Baqai Medical University, 51 Deh Tor, Toll Plaza, Super Highway, Gadap Road, Karachi 74600, Pakistan
3H.E.J. Research Institute of Chemistry, University of Karachi, Karachi 75270, Pakistan

Received 26 September 2013; Revised 22 November 2013; Accepted 23 November 2013

Academic Editor: Francesco Paolucci

Copyright © 2013 Iqbal Ahmad 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

Efficacy of photoinitiators such as riboflavin (RF), camphorquinone (CQ), and safranin T (ST) and triethanolamine as a coinitiator has been compared in carrying out the polymerization of 2-hydroxyethyl methacrylate (HEMA) in aqueous and organic solvents. HEMA solutions were polymerized in the presence of RF, CQ, and ST using a low intensity visible radiation source. HEMA was assayed by a UV spectrophotometric method during the initial stages of the reactions (i.e., ~5% change). A comparison of the efficacy of photoinitiators in causing HEMA polymerization showed that RF is more efficient than CQ and ST. The rate of polymerization is directly related to solvent dielectric constant and inversely related to the solvent viscosity. RF is the most efficient photoinitiator in the polymerization of HEMA and the highest rate of reaction occurs in aqueous solutions. A general scheme for the polymerization of HEMA in the presence of photoinitiators is presented.