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

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 the results 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 the processing conditions of studied materials. Poly(ε‐caprolactone) (PCL) based nanocomposites including clay modified with soy lecithin are interesting materials to be used in food contact applications. Kinetic parameters, obtained by using classical models, were able to partially describe the non‐isothermal crystallization process of such materials, whereas CCT plots allow to estimate the global behavior. Non‐isothermal crystallization from the molten state is of increasing technological importance because real industrial processes, such as extrusion and film forming, usually proceed under dynamic non‐isothermal conditions. The developed work contributes to design the processing stages.