A new optical set-up for on-line following up the crystallization of polymers at high cooling rates

A new experimental procedure, named « Polymer High Cooling - Optics » and whose performance has been improved, is presented. It allows us to monitor on-line the quiescent crystallization of a polymer film under high and constant cooling rates. With such a set-up, two cooling control modes are available resulting into a range of relatively moderate (from 30 to 500°C/min) and a range of high (from 500 to 1600°C/min) constant cooling rates. The crystallization experiments are observed by polarized light microscopy. Preliminary results are presented. They are obtained on the α-modification of one industrial grade of isotactic polypropylene, under relatively moderate constant cooling rates. Two relevant crystallization parameters are captured, the temperature of crystallization together with the spherulitic growth kinetics versus cooling rate. Accurate data are obtained. As well, they are in good agreement with comparable literature results compiled by Janeschitz-Kriegl [Macromolecules, 2006]. The obtained results seem to match the Hoffman and Lauritzen theory. These discussions validate our « Polymer High Cooling - Optics » set-up in relatively moderate constant cooling rates. Next step is to demonstrate the suitability of this first generation set-up for higher constant cooling rates.