Crystallization of polypropylene at high cooling rates

Séverine A.E. Boyer (1, 2) , Jean-Marc Haudin (1)

1 CEMEF - Centre de Mise en Forme des Matériaux
2 TPCIM - Département Technologie des Polymères et Composites & Ingénierie Mécanique

In the context of polymer crystallization under high and constant cooling rates, a new survey is presented. The growth kinetics of spherulites from the molten state and the corresponding temperature of crystallization under similar cooling rates are considered. An industrial grade of isotactic polypropylene (iPP) is investigated in the range of slow (from 1 to 10°C/min), of relatively moderate (from 30 to 500°C/min) and of high (from 500 to 1600°C/min) constant cooling rates. The growth kinetics for the α-modification of iPP versus the temperature of crystallization is in agreement with the data published by Janeschitz-Kriegl [Macromolecules, 2006]. To understand the growth mechanism, the Hoffman equation is used and then extrapolated to lower temperatures of crystallization. Finally, to describe the non-isothermal crystallization, the equation of Ozawa is used. The benefits to use the spherulitic growth kinetics to extrapolate data from alternative methods, i.e., differential scanning calorimetry (DSC), are briefly discussed.

Mots clés: Industrial processes; Liquid to solid transition; Isotactic polypropylene; Kinetics; Polarized optical microscopy; Differential scanning calorimetry

Domaines: Matériaux

Séverine A.E. Boyer, Jean-Marc Haudin. Crystallization of polypropylene at high cooling rates. 12th ESAFORM Conference on Material Forming, Apr 2009, Enschede, Netherlands. pp.Pages 857-860, ⟨10.1007/s12289-009-0631-5⟩. ⟨hal-00509429⟩