Laccase-induced grafting on plasma-pretreated polypropylene.

A new environmentally friendly strategy for the sustainable functionalization of inert man-made polymer surfaces is mapped out for the first time using a combination of plasma pretreatment and enzymatic postgrafting. The efficiency of enzymatic covalent binding is investigated by grafting methacrylate monomers possessing different amino groups, primary, tertiary, and quaternary, onto a polypropylene surface using plasma pretreatment. Subsequent enzymatic grafting, using laccase and guaiacol sulfonic acid (GSA), is determined by surface analytical techniques, such as attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The grafting of GSA in the presence of a laccase is proven by a 10-fold increase in sulfur compared to the control. The covalent coupling between GSA and primary amine groups is determined by HPLC-MS using hexylamine as a model substrate. The advantage of technology is in the strong covalent binding of functional groups onto the synthetic polymer's surface, which could then be suitably tailored by enzymes possessing substrate specificity and regional selectivity.