Crystal morphology and crystallization kinetics of polyamide-11/clay nanocomposites

Abstract

Polyamide-11 (PA11)/clay nanocomposites were prepared by in situ intercalative polymerization. The crystal morphology and crystallization kinetics of these nanocomposites, were investigated via polarized light microscopy (PLM), small-angle laser scattering (SALS) and differential scanning calorimetry (DSC). PA-11 can crystallize into well-formed spherulites, while only very tiny crystallites were observed by PLM and SALS for the nanocomposites. Both isothermal and non-isothermal crystallization methods were employed to investigate the crystallization kinetics by DSC. Both techniques showed an increased crystallization rate with the addition of clay. However, the Avrami exponent decreased with the addition of clay in isothermal crystallization but showed a wide range of values depending on the cooling rate in the non-isothermal crystallization. The changes in crystal morphology and crystallization kinetics can be understood as being due to the 'supernucleating' effect of the nanodispersed clay layers. © 2004 Society of Chemical Industry.