Crystallization kinetics based on the isoconversional approach in nanoclay-reinforced HDPE/PP blends

The present study investigates the influence of nanoclay (NC) incorporation on the thermal and sorption properties of high-density polyethylene (HDPE) and polypropylene (PP) blends, which are compatibilised with polyethylene-grafted maleic anhydride (pEMAH). Different weight percentages of NC were dispersed in HDPE/PP/pEMAH in a melt blender. The differential scanning calorimetry results indicate that the relative crystallinity increases with a higher NC content. The Avrami model analysis of relative crystallinity exhibits that a higher NC content facilitates the nucleation rate during crystallization. The Ozawa exponent increases with temperature, thereby increasing the crystallization rate of the process. According to the Mo model, higher cooling rates result in better relative crystallinity. The fold surface free energy evaluated is 1.84 × 10−5 J/m2, 4.41× 10−6 J/m2, and 3.45× 10−6 J/m2 for HDPE/PP, 1.5% NC, and 3% NC, respectively. The polymer chain segments of the nanocomposites with NC are more readily folded onto the nucleus surface as they require less energy. The NC content significantly influences solvent diffusion in the polymer matrix and the dispersion of the clay, thus determining the diffusion coefficient. SEM micrographs reveal a continuous distribution of NC within the HDPE/PP, while the incorporation of pEMAH enhances interfacial adhesion, thereby improving blend compatibility.