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In this study, the effect of photoinitiator concentration on the gelation time of different resins were studied in the absence of oxygen in the reaction volume by using passive microrheology technique. Four different monomers which are ethoxylated pentaerythritol tetraacrylate (SR494), trimethylolpropane triacrylate (SR351), triethylene glycol diacrylate (SR272), and 2(2‐ethoxyetoxy) ethyl acrylate (SR256) were used in these experiments. Resins were prepared from these four different monomers by mixing them with various amount of 2,2‐dimethoxy 1,2‐diphenylethanone photoinitiator molecule with high absorption coefficient at the frequency of UV light used in these experiment. The simulations of the results obtained from microrheology experiments were carried out with the new model based on the stochastic Monte Carlo approach in order to account for the inherently random and discrete nature of the photopolymerization reactions. The model captures the nonlinear decrease of gelation time with increasing photoinitator concentration and number of acrylate fragments on each monomer. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

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The effect of different magnesium salts such as MgO, MgSO(4).7H2O and Mg(OH)2 on the total sulphation capacities of limestone slurries prepared from five different limestone samples was investigated. Sulphation reactions of slurries were conducted at a constant temperature of 323 K in a gaseous mixture consisting of 5% O2, 10% CO2, 0.5% SO2 and a balance of nitrogene by volume. It was found that the total sulphation capacities of limestone slurries increased with the addition of MgO and Mg(OH)2 salts and decreased with the addition of MgSO4.7H2O salt. Depending on the chemical composition of the limestone samples the total sulphation capacities of limestone slurries were increased between 22.30% and 75.00% by MgO addition and between 23.70% and 69.00% by Mg(OH)2 addition.