PREPARATION AND PROPERTIES OF ALKYLATED POLY(STYRENE-GRAFT-ETHYLENE OXIDE)

Poly(styrene-graft-ethylene oxide), having alkyl chains (C-12 or C-18) on the polystyrene main chain or on the poly(ethylene oxide) (PEO) si de chains, were synthesized. The main chain was alkylated by first ion izing amide groups in a styrene/acrylamide copolymer with tert-butoxid e, and then using the amide anions as sites for reactions with 1-bromo alkanes. An excess of amide anions was used in the reaction, and the r emaining anions were subsequently utilized as initiator sites for the anionic polymerization of ethylene oxide (EO). Synthesis of poly(styre ne-graft-ethylene oxide) with alkylated side chains was accomplished b y polymerization of EO onto the ionized styrene/acrylamide copolymer, followed by an alkylation of the terminal alkoxide anions with 1-bromo alkanes. The alkylated graft copolymers were structurally characterize d by using elemental analysis, H-1 NMR, GPC, and IR spectroscopy. DSC analysis showed that only graft copolymers with PEO contents exceeding about 50 wt % had side chain crystallinities comparable to those of h omo-PEO. Main chain alkylated graft copolymers generally had higher cr ystallinities, as compared to nonalkylated and side chain alkylated sa mples. The graft copolymers absorbed water corresponding to one water molecule per EO unit at low PEO contents. The water absorption increas ed progressively at PEO contents above 30 wt % for main chain alkylate d samples and above 50 wt % for non-alkylated samples. (C) 1995 John W iley & Sons, Inc.