Horseradish peroxidase (HRP) nanoflowers-mediated polymerization of vinyl monomers

Abstract

The effects of flower-shaped hybrid nano biocatalyst (hFe-NFs) from coordination between horseradish peroxidase (HRP) enzyme and Fe2+ ions on the free-radical polymerization reactions of three different vinyl monomers (styrene, methylmethacrylate and acrylamide) were investigated. Polymerizations of styrene and methylmethacrylate (MMA) were performed under emulsion conditions using three different surfactants in the presence of acetylacetone (AcAc) and hydrogen peroxide (H2O2) initiator. Polymerization of water soluble acrylamide was accomplished under surfactant-free media. According to the obtained outcomes, hFe-NFs exhibited higher catalytic activity towards polymerization of vinyl monomers compared to the free-HRP enzyme in terms of yields and the number average molecular weights (Mn) of the synthesized polymers. hFe-NFs also demonstrated very high thermal stability. While optimum polymerization of styrene was achieved at room temperature (RT), the highest polymerization yields for acrylamide and MMA were respectively accomplished at 70 and 60 degrees C in which free-HRP enzyme loses its catalytic activity. Preparation of the flower-shaped hFe-NFs, therefore, enables inexpensive and stable catalyst system for free-radical polymerization of vinyl monomers compared to free-HRP enzyme. Increasing catalytic activity and stability of hFe-NFs at higher reaction temperatures are very crucial for utilization of these types of catalysts in both scientific and industrial purposes.