Correlation of Material and Processing Time Scales with Structure Development in Isotactic Polypropylene Crystallization

摘要: The influence of average molar mass and shear on the crystallization isotactic polypropylene (iPP) has been studied. Weissenberg number, a dimensionless parameter consisting product rate characteristic relaxation time (γ0λr), provides criterion to locate morphological transition from spherulitic extended growth. applies polymers high low molecular weight. This is attributed importance initial nucleation process. Comparison materials different masses various histories allowed by introduction normalized τ, which ratio experimental λVvmax that needs be defined several possible choices. Rheological rheooptical experiments furnish material scales, respectively. λVvmax, with light scattering as moment at maximu...