CRYSTALLIZATION KINETICS IN RELATION TO POLYMER PROCESSING

Phase distribution of quenched samples has been determined by a deconvolution procedure of WAXS spectra in a wide range of cooling rates. The informations collected together with isothermal and DSC results provide a very wide set of data on the crystallization kinetics of polymers relevant which covers conditions encountered in most polymer processing operations. They have been compared with predictions of a non-isothermal crystallization model assuming two independent and parallel crystallization processes competing during solidification. The case of a nucleated Polyamide 6 is described in this work. While amorphous phase increases slowly with cooling rate, alpha-monoclinic phase starts to decrease significantly above cooling rates of a few degrees-C/s whereas gamma-pseudohexagonal phase starts to grow; above cooling rates of 200-degrees-C/s only traces of alpha-form are observed and gamma-phase seems to have reached a plateau. All these features are satisfactorily described by the crystallization kinetics model adopted.