STAR-CRAFT COPOLYMERS - SYNTHESIS OF AMPHIPHILIC GRAFT-COPOLYMERS WITH STAR-BRANCHED POLY(OXYETHYLENE) SIDE-CHAINS

The synthesis of novel amphiphilic star-graft (SG) copolymers containi ng hydrophilic poly(oxyethylene) (PEG) side chains attached to a hydro phobic backbone by multifunctional entity is reported. In a first step poly(phthalimidoacrylate-co-styrene) was converted into polymers cont aining different number of multifunctional branching cites distributed along the main chain by partial aminolysis of the phthalimidoacrylate units with tris (hydroxymethyl)aminomethane. In the second step, thes e reactive copolymers yielded SG copolymers with different number of s tar-shaped PEO side groups by reaction with isocyanato terminated meth oxy-PEO. The copolymers were characterized by size-exclusion chromatog raphy, IR-, and NMR-spectroscopy. Their thermal properties were examin ed by thermal gravimetric analysis and differential scanning calorimet ry. The studies indicate that the grafting degree and hydrogen bonding determine to a great extent the behavior of the SG copolymers in soli d state and in solution. (C) 1997 John Wiley & Sons, Inc.