Synthesis and Characteristics of Poly(macromonomers) and Graft Copolymers Composed of Poly(phenylacetylene) Main Chain and Poly(ethylene oxide) Side Chains

Abstract

New amphiphilic water-soluble poly(macromonomers), poly(1) and poly(2), consisting of a poly(phenylacetylene) [poly(3)] main chain and poly(ethylene oxide) (PEO) side chains, were synthesized by the homopolymerization of PEO macromonomers, while poly(3)-based graft copolymers, poly(1-co-3) and poly(2-co-3), with PEO side chains were prepared by the copolymerization of the PEO macromonomers with phenylacetylene (3). Two PEO macromonomers 1 (DPPEO ∼ 16) and 2 (DPPEO ∼ 45) possessing 3 as an end group were prepared by the esterfication of p-ethynylbenzoic acid with commercial PEO monomethyl ethers. The macromonomers 1 and 2 homopolymerized in the presence of a binary Rh catalyst to yield poly(1) (DPs up to 55) and poly(2) (DPs up to 18), respectively. They also copolymerized with 3 to give graft copolymers poly(1-co-3) (Mn 37 500−93 800, 1 0.3−22 mol %) and poly(2-co-3) (Mn 44 900−177 800, 2 0.5−13 mol %). Poly(1) and poly(2) were a brown liquid and solid, respectively, while poly(1-co-3) and poly(2-co-3) were yellow solids. These polymers were soluble not only in relatively nonpolar solvents such as toluene and CHCl3 but also in polar solvents such as DMSO and MeOH. The side-chain crystallinity was observed in the solid state in poly(2-co-3) with PEO contents above 9 mol % according to DSC analysis.