Optimization of processing parameters for the synthesis of low-density polyethylene/organically modified montmorillonite nanocomposites using X-ray diffraction with experimental design

The influence of the processing parameters on the synthesis of low-density polyethylene (LDPE)/organically modified montmorillonite (OMM) nanocomposite films was studied using experimental design. Intercalation in the nanocomposites was analysed using X-ray diffraction and verified using atomic force microscopy. Four direct melt processing parameters were studied to obtain surface maps of intercalation in the nanocomposites: concentration of OMM (clay-%), concentration of Polybond^® 3149 (compatibilizer-%), mixing temperature (T_mix) and mixing time. An ANOVA validated the polynomial function, and intercalation maps from response surface methodology (RSM) were obtained. The clay-% parameter had the most significant effect, and T_mix showed no significant effect on intercalation (p<0.05). A strong synergic interaction between clay-% and compatibilizer-% was observed, which is not possible to detect using univariate experiments. RSM provides a powerful tool for choosing the best processing conditions that lead to formulations with the highest intercalations by considering the main factors and their interactions.