P. Jannasch et B. Wesslen, PREPARATION AND PROPERTIES OF ALKYLATED POLY(STYRENE-GRAFT-ETHYLENE OXIDE), Journal of polymer science. Part A, Polymer chemistry, 33(9), 1995, pp. 1465-1474
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.