SOLUTION BEHAVIOR OF A RANDOM COPOLYMER OF POLY(ISOBUTYL METHACRYLATE-TERT-BUTYLAMINOETHYL METHACRYLATE) .2. VISCOSITY AND LIGHT-SCATTERING INTENSITY STUDIES

Random copolymers of poly(isobutyl methacrylate-t-butylaminoethyl methacrylate) with Mw ∼ 2.4 × 106 g mol-1 could be shown to form more expanded coils in the very dilute solution regime (≲ 10-5 g ml-1) due to intramolecular repulsion, to associate in most solvents in the dilute solution regime (∼ 10-4 g ml-1) where inter- and intramolecular interactions are present, and to aggregate further in semidilute/concentrated solution regimes where intermolecular interactions dominate. The formation of larger aggregates in semidilute/concentrated solutions is responsible for its effectiveness as a polymer additive. At the same time, the rheological properties, such as the shear-rate dependence of the viscosity, tend to become more sensitive to concentration and temperature variations. © 1990.