POLY(ETHYLENE OXIDE) MACROMONOMERS .10. CHARACTERIZATION AND SOLUTION PROPERTIES OF THE REGULAR COMB POLYMERS WITH POLYSTYRENE MAIN CHAINS AND POLY(ETHYLENE OXIDE) SIDE-CHAINS

A series of regular comb polymers (2) prepared by homopolymerization of p-vinylbenzyl-ended poly(ethylene oxide) (PEO) macromonomers (1) were characterized by means of light scattering (LS), gel permeation chromatography (GPC), and viscosity measurements. The molecular weights, M(w), estimated by LS, coupled with the intrinsic viscosities, both measured in tetrahydrofuran, were successfully applied to construct a universal calibration in GPC. The comb polymers, particularly those with longer, and/or a higher number of, side chains, were found to have very contracted dimensions as compared to the corresponding linear homopolymers of the same molecular weights. The exponent of the Mark-Houwink-Sakurada equation was very low (0.15) and even nearly zero (-0.06) for the comb polymers with side chains of 44 and 103 ethylene oxide units, respectively, suggesting their very densely filled, spherelike conformations. The macromonomers with longer PEO chain lengths were found to polymerize in water to much higher degrees of polymerization in the main chains than those with a tri(ethylene glycol) side chain or styrene, supporting the organized micellar polymerization mechanism of the former as previously proposed.