Dynamically vulcanized CNC‐reinforced thermoplastic elastomer based on PP/EPDM: Morphology and mechanical properties control via interfacial compatibilization

Abstract

AbstractIn this study, dynamically vulcanized thermoplastic elastomer nanocomposites consisting of polypropylene (PP) as the thermoplastic matrix, ethylene propylene diene monomer (EPDM) rubber as the dispersed phase, and needle‐like cellulose nanocrystals (CNC) were investigated. The two polymers were melt blended in a ratio of 70/30 (PP/EPDM) and 60/40% w/w (PP/EPDM) together with CNC (2, 3, and 5 phr) and sulfur‐curing system. The potential of EPDM‐g‐MA and PP‐g‐MA's as interfacial compatibilizers for enhancing interfacial interactions between components and partitioning of CNC between the two polymer phases was examined by measuring the decrease in the size of EPDM particles. The resulting thermoplastic vulcanizates (TPV) were characterized using a melt rheometric mechanical spectrometer (RMS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and tensile tests. The inclusion of any type of interfacial compatibilizers led to enhanced tensile properties when compared to the samples lacking compatibilizers in both TPVs and TPEs in different ratios. EPDM‐g‐MA was found to be more effective for 60/40% w/w (PP/EPDM) TPVs, while PP‐g‐MA showed higher potential for 70/30% w/w TPVs. The CNC‐reinforced TPVs displayed higher melt elasticity than their unloaded counterparts. These nanocomposites also showed reduced EPDM particle size, enhanced Young modulus, and a higher degree of crystallinity.Highlights Nanocomposite thermoplastic vulcanizates (TPVs): polypropylene (PP)/ethylene propylene diene monomer (EPDM)/cellulose nanocrystals (CNC) with matrix‐dispersed morphology. Interfacial enhancement: Compared EPDM grafted maleic anhydride (EPDM‐g‐MA) and PP‐g‐MA potentials. Tensile properties: EPDM‐g‐MA is more effective in higher rubber content TPVs. Mechanical enhancements: Improved properties and Young's modulus in CNC‐filled TPVs. Diverse applications: PP/EPDM/CNC nanocomposites in auto, electrical, electronic, and packaging industries.