Isothermal crystallization of polycaprolactone/modified clay biodegradable nanocomposites

Abstract

In this paper, the isothermal crystallization of polycaprolactone (PCL)/modified clay nanocomposites, at several temperatures, was studied. The effects of clay type (organo-modified bentonite B-TBHP and organo-modified montmorillonite C20A) and also the clay content were analysed. Bulk crystallization was studied by differential scanning calorimetry and modelled by the Avrami equation. Special effort was made to correlate the crystallization parameters with the clay dispersion degree inside the polymer matrix. The lowest induction time and fastest overall crystallization rate were obtained with the B-TBHP nanocomposites, which showed the lowest clay dispersion degree. In contrast, C20A nanocomposites showed higher clay dispersion degree inside the PCL matrix and higher induction times and lower overall crystallization rate than B-TBHP ones, even retarding the formation of the equilibrium nucleus with critical dimensions in comparison with neat PCL.