A FAST EMULSION POLYMERIZATION IN AN OPEN-TO-AIR ENVIRONMENT

Abstract

Radical and emulsion polymerization have long been utilized in polymer synthesis for their versatility and simplicity. However, academia and industry will prioritize open-to-air emulsion polymerization due to its potential cost and process efficiency. Glucose oxidase (GOx), an enzyme, can deplete oxygen while converting D-glucose to D-glucono-δ-lactone, generating hydrogen peroxide (H2O2). This H2O2, in turn, can produce hydroxyl radicals (•OH) via the Fenton reaction, thereby initiating polymerization. Thus, combining the Fenton chemistry and this unique nature of GOx, collectively known as the “semi bio-Fenton” polymerization, can produce polymers, even in an open-to-air environment. Here, the utility of this process for an emulsion-based system, along with the study of kinetics and the effect of surfactant, catalyst, and monomer concentration on the molecular weight and dispersity of the polymers, have been carried out primarily focusing on butyl methacrylate (BMA) monomer. The reaction rate increased significantly when the surfactant concentration was increased from 1 to 2.5 wt.%, and a full monomer conversion was achieved within 5 min of polymerization time for 5% v/v of monomer. Even when the monomer concentration was increased to 20% v/v, only about 10 min was required for complete conversion under optimized conditions. The suitability of this process for other monomers, such as methyl methacrylate (MMA) and vinyl acetate (VAc), as well as its application in copolymerization and in-situ emulsion polymerization cum coating, was also demonstrated. This approach provides an alternative pathway for emulsion polymerization application where deoxygenation or using conventional initiation is problematic or prohibited, such as coating and cosmetic products.