Lm. Zhu et al., AN AMPHIPHILIC GRAFT COPOLYMER AS A SURFACE-MODIFYING ADDITIVE FOR POLY(METHYL METHACRYLATE), Journal of polymer science. Part A, Polymer chemistry, 33(8), 1995, pp. 1257-1265
An amphiphilic graft copolymer was prepared by transesterification of
poly(2-ethylhexyl acrylate-co-methyl methacrylate) with poly(ethylene
glycol) monomethyl ether (MPEG2000). The grafting reaction was perform
ed in melt at 155 degrees C. The purified graft copolymer was blended
into poly(methyl methacrylate) in concentrations of 1.5-30 wt %, eithe
r by mixing in chloroform solution or by melt mixing by means of a twi
n-screw extruder or a Brabender blender. Films of the blends were prep
ared by solution casting onto glass plates or by hot pressing between
polished Al plates. At concentrations up to 20% of the graft copolymer
homogeneous blends were obtained. At higher concentrations the blends
were heterogeneous, and side-chain crystallinity was detectable by DS
C analysis. The surface properties of the films were studied by measur
ements of water contact angles. The surface accumulation of the graft
copolymer was demonstrated as a large increase in the wetting angle hy
steresis, and found to depend on the procedure for film preparation as
well as the casting substrate. (C) 1995 John Wiley and Sons, Inc.