Intrinsic viscosity and molecular weight of isotactic polypropylene

Two samples of highly isotactic polypropylene prepared by a NATTA's catalysis, have been fractionated by a column fractionation technique. Fractions having M̄w/M̄n ratio very small (1.14 – 1.27) have been obtained and used for the determination of [η]−M̄n and [η]−M̄w relations. Because of the small values of M̄w/M̄n ratio, the [η]−M̄w relation may be assumed also valuable as [η]−M relation. This relation is for molecular weight range of 40,000–650,000, where [η] is measured in tetralin at 135°C. Moreover values of {article}{empty}{document}√ rz² ̄{document} and of second virial coefficients A2 are given in function of molecular weight.