Non-isothermal crystallization of poly(ε-caprolactone) nanocomposites with soy lecithin-modified bentonite

Abstract

Non-isothermal crystallization behavior of poly(ε-caprolactone)/bentonite (natural and soy lecithin-modified) nanocomposites was studied by means of differential scanning calorimetry (DSC). In addition, a microscopic analysis of cryofracture surface was performed by scanning electron microscopy (SEM). Experimental data show that pure bentonite (Bent) acts as retarding agent and that soy lecithin partially counteracts this effect because it accelerates the crystallization process. The soy lecithin was used as natural and cheap clay modifier that can be used in food contact applications, which is the thought application for the studied materials. Kinetic parameters, obtained by using classical methods such as Avrami and Mo models, were able to partially describe the non-isothermal crystallization behavior of the studied materials and theresults are further supported by the effective activation energy calculations by iso-conversional method of Friedman. The full models, which take into account the different parameters during cooling under non-isothermal conditions, were used to construct continuous cooling transformations (CCTs) diagrams that confirm all previous results and that will be used to determine theprocessing conditions of studied materials.