Study on the molecular weight dependence of dilute solution properties of narrowly distributed polystyrene in toluene and in the unperturbed state

Abstract

Abstract Intrinsic viscosities [η], second and third virial coefficients A 2 and A 3 , respectively, and mean square radius of gyration 〈 R G 2 〉 of a polymer homologous series of narrow‐molecular‐weight‐distribution polystyrene samples in a molecular weight range of 2000 up to 24 · 10 6 were determined in toluene at 25°C by light scattering and viscometry measurements. The results are (3 · 10 4 < M w < 24 · 10 6 , M w / M n ≤ 1,3): These results were obtained by consideration of the limit of the dilute solution regime, the determination of zero‐shear rate intrinsic viscosities, and the molecular weight dependence of the refractive index increment d n /d c . It was found that d n /d c increases slightly up to M w = 1,8 · 10 6 . A comparison of the [η]− M w ‐relationship with literature data is given. In addition the unperturbed (theta) dimension parameters K 0 , 〈h 2 〉 0 / M , the characteristic ratio C ∞ , the steric factor σ, and the thermodynamic interaction parameter B were calculated from the modified Burchard‐Stockmayer‐Fixman procedure using polymolecularity correction and the results compared with experimental data from the literature.