Non-isothermal crystallization kinetics of poly(propylene)-based graphene nanocomposites for injection moulding

Abstract

This work reports the preparation and the studies on the non-isothermal crystallization kinetics of poly(propylene) (PP)-based graphene nanoplatelets (GnPs) nanocomposites. The PP-based GnPs nanocomposites were prepared by melt blending technique. The structural characterization of these nanocomposites was performed through Raman spectroscopy and X-ray diffraction (XRD) measurements. The non-isothermal experiments were performed using a differential scanning calorimeter (DSC). The effect of GnPs and compatibilizer presence on the PP non-isothermal crystallization behaviour was analysed. Maleic anhydride (MA) was selected as a compatibilizer agent. A shift in the G band of the Raman spectra was observed for all nanocomposites. The XRD measurements suggest the formation of β-PP crystals in GnPs free sample. The DSC analysis showed a reduction of nanocomposites melt temperature (Tm) compared to neat PP. Based on the cooling curves, that showed an increase in the crystallization temperature (Tc) of the nanocomposites compared to neat PP, it is suggested that GnPs actas a nucleating agent. A slight increase in the degree of crystallinity (Xc) of the nanocomposites was also observed. The non-isothermal crystallization kinetics were evaluated through Ozawa, Liu, Kissinger, Tahkor, and Augis–Bennett methods. Overall, these results indicated that the type of nucleation, growth, and morphology of PP crystals change in the presence of GnPs and compatibilizer, which is also confirmed by optical microscopy analysis.