1169: Ultrasonically Initiated Emulsion Copolymerization of Styrene and 2-Hydroxyethyl Methacrylate: Parameter Optimization

Ultrasonically Initiated Emulsion Copolymerization of Styrene and 2-Hydroxyethyl Methacrylate: Parameter Optimization

Emine Tomrun Güçlü, Çiğdem Taşdelen-Yücedağ*

Gebze Technical University, Chemical Engineering, Kocaeli, Turkey

^*Corresponding Author: cigdem@gtu.edu.tr

In recent years, ultrasound (US) irradiation has emerged as a powerful tool for polymerization utilizing acoustic cavitation triggered by US waves in a liquid medium [1, 2]. The radicals generated by the decomposition of solvent and solute molecules as a result of collapsing bubbles could be benefited to initiate the emulsion polymerization without the need for the chemical initiators. The replacement of chemical initiators with US, which promises a sustainable and environmentally friendly approach, leads to synthesis of high purity products [3]. The other superior properties of US assisted polymerization include higher monomer conversion, elimination of oxygen functioning as an inhibitor, and reduced reaction time [4]. To the best of our knowledge, this is the first comprehensive and systematic study on the parameter optimization of US assisted emulsion copolymerization of styrene (St) and 2-hydroxyethyl methacrylate (HEMA) conducted without an exogenous chemical initiator. 

For this purpose, the effects of St-to-HEMA molar ratio, monomer (M)-to-water (W) ratio, and sodium dodecyl sulfate (SDS)-to-M ratio, as well as the US irradiation intensity, and the reaction temperature on polymerization yield were examined to identify the critical reaction parameters. The maximum polymerization yield (~89%) was attained under the optimized conditions in terms of concentration: St/HEMA molar: 1.5, M/W ratio: 10%, and SDS/M ratio: 10%. The optimum US power and reaction temperature were determined as 34-37 W and 50^oC, respectively. The copolymer structure was confirmed via FT-IR and ¹H-NMR, while the average diameter of spherical latex particles was measured as 80 nm through SEM. 

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