Graft polymerization of N-tert-butylacrylamide onto polypropylene during melt extrusion and biocidal properties of its products

Abstract

Functionalization of polypropylene (PP) by radical graft polymerization with N-tert-butylacrylamide (NTBA) was successfully conducted during melt extrusion, and the grafted products were employed as precursors of biocidal N-halamine polymers. Graft polymerization conditions, including monomer and initiator concentrations, addition of a comonomer styrene (St), were studied. Fourier transformed spectroscopy (FTIR) results and nitrogen analysis confirmed the graft polymerization on PP backbone during the reactive extrusion. The results also indicated that increase in initiator concentration led to more PP chain scission and reduction in mixing torque or polymer chain length. As the monomer concentration rose, grafted monomer content in the products improved, revealing increased grafting copolymerization in the system. Addition of St as a comonomer adversely affected grafting of NTBA, but significantly prevented polymer chain scission. This may be due to lower tendency of NTBA for copolymerization. The halogenated products exhibited potent antimicrobial properties against Escherichia coli, and the antimicrobial properties were durable and regenerable. © 2008 Society of Plastics Engineers.