PREPARATION AND CHARACTERIZATION OF END-ALKOXYSILYLATED POLYSTYRENE AND THE CRAFTING BEHAVIORS ONTO INORGANIC PIGMENTS .2. UTILIZATION OF 4-TRIETHOXYSILYL-ALPHA-METHYLSTYRENE

Novel polystyrene was prepared with triethoxysilyl (TES) groups at the end of the chain, and the grafting behaviors of the resulting polymer onto silica, alumina, and titania were studied. TES groups were intro duced by the reaction between living polystyryl anion and 4-triethoxys ilyl-alpha-methylstyrene (1) in THF at 195 K. The end-functional polym er was characterized by GPC, H-1-NMR, and TLC. It was confirmed that t he polymer had several units of 1 at the chain end and a fairly narrow molecular weight distribution. TES groups in the present polymer were found to be hydrolyzed with both acids and bases such as mono-n-butyl phosphate (MBP) and tetrabutylammonium hydroxide (TBAH), respectively. The polymer was effectively grafted onto silica and alumina in toluen e in the presence of MBP and TBAH, respectively. The amount of graft, estimated by thermogravimetry, changed with the selection of substrate s and catalysts; about 2 mg/m(2) at the highest. The change in the amo unt of graft can be explained by the amount of effective acidic- or ba sic-hydroxyl groups on the substrate surfaces. However, titania receiv ed the largest amount of graft in the absence of catalyst. This may be because the strong acidic sites on the surface of titania act as a hy drolytic catalyst. The present polymer is expected to find wide applic ation as a macromolecular dispersant for various types of inorganic pi gments. (C) 1996 John Wiley & Sons, Inc.