Chemical grafting of metallocene-catalyzed functional polypropylene copolymer on glass substrates through surface modification

This work deals with surface modification of soda-lime glass slides which, by itself, does not have hydroxyl groups at the surface. So, a glass surface pretreatment is needed, to create hydroxyl groups onto it, before carrying out the polypropylene (PP) grafting reaction. Different acid/base pretreatments were performed to develop an adequate concentration of superficial hydroxyl groups. Subsequently, a metallocenic polymerization (propylene-alpha olefin graft reaction, catalyzed by EtInd(2)ZrCl(2)/methylaluminoxane), was carried out to provide graft-PP chains chemically linked to the glass surface. The surface so modified can be further functionalized and tailored for different applications, including polymer composites. The pretreatment conditions that best preserved homogeneity and caused less damage to the glass surface resulted from a step of contact with dilute HF/NH(4)F buffer, a washing step with distilled water, and a final exposure to KOH. After the propylene copolymerization was performed, part of the graft copolymer formed remained chemically bonded to the glass slide surface. The presence of grafted PP at the surface was confirmed by SEM, FTIR, and EDAX characterization, even after the physically adsorbed polymer was excluded by a severe solvent extraction treatment. From these results, the copolymerization of a hydroxy a-olefin, grafted on a MAO-pretreated glass slide, is foreseen as a possible way to graft polymers onto inorganic solids. (C) 2008 Wiley Periodicals, Inc.