A new way of dissolving isotactic polypropylene (PP) in cyclohexane

by putting the samples in cyclohexane under a pressure of 3-4 atm. at 140℃ for 2-3 hrs is introduced. By using a specially designed hermetic viscomter

intrinsic viscosities [η] of PP samples were measured at 60℃ and 70℃- The data viscosity are reproducible and show that PP samples were not degraded even without antioxidant added and cyclohexane is a good solvent of PP at this measuring condition. The values of Huggin's constant are within the range of 0.36+0.02 Mark-Houwink equations [n]=1.23×10-1M0.61(60℃) and [n]=9.20×10-2M0.63(70℃) are obtained. Molar mass distributions of six PP samples are measured by GPC byusing an Apple II personal computer and iterative technique.