PECTIN COPOLYMERS WITH ORGANOSILOXANE GRAFTS AS CORROSION-PROTECTIVE COATINGS FOR ALUMINUM

When polygalacturonic acid methyl ester (pectin, PE), selected from am ong the natural polymers, is used as environmentally benign water-base d coating material to protect aluminum (Al) alloys against corrosion, it is necessary to incorporate an antimicrobial agent into its aqueous solution to prevent the growth of microorganisms. in this study, N-[3 -(triethoxysilyl)propyl]-4,5-dihydroimidazole (TSPI) was used as the a ntimicrobial agent. However, TSPI also played an important role in ens uring that TSPI-modified PE coatings adequately protect Al; this funct ion was due to a combination of the following three factors: (1) the r emoval of hydrophilic groups from PE by a chemical reaction between OH or COOH groups in PE, and silanol hydrolysate in TSPI, (2) the grafti ng of polyorganosiloxane (POS) into the PE polymer chains, and (3) the interfacial covalentoxane bonds formed by interactions between the si lanol end groups in the POS graft and Al2O3 at the surface of Al subst rates.