Light scattering and viscosity measurements
were made on dilute solutions of a polymacromonomer consisting of
a polystyrene main chain and polyisoprene (PI) side chains, which
was synthesized by anionic polymerization. The second virial coefficient A
2 in 1,4-dioxane was positive at the theta temperature
for linear PI, 35.3 °C, and became zero at 31.0 °C. The
positive A
2 at 35.3 °C was ascribed
to the effect of the intermolecular interaction between the PI unit
and the main-chain unit. From analyses of the mean-square radius of
gyration, intrinsic viscosity, and A
2 obtained
as functions of molecular weight, the stiffness parameter λ–1 and the excluded-volume parameter B in cyclohexane at 25.0 °C (good solvent) and in 1,4-dioxane
at 35.3 °C were determined. The experimental λ–1 for cyclohexane solutions was close to the value predicted by the
first-order perturbation theory, but the value for 1,4-dioxane solution
was larger than the theoretical one, showing that the contribution
of the interaction between the side-chain and the main-chain units
is essential. The smoothed-density theory for B gave
a close value to the experimental one for cyclohexane solutions, while
it gave a much larger value than the experimental one for 1,4-dioxane
solutions. This was attributed to the defect of the theory ignoring
the chain connectivity.