Characterization of graphene nanoplatelets reinforced sustainable thermoplastic elastomers

Abstract

Abstract Elastomer nanocomposites have attracted tremendous attention in recent years owing to their exceptional mechanical, electrical, thermal barrier and flame-retardant properties. Graphene has become a prevalent constituent in elastomer nanocomposites thanks to its superior stiffness and strength, as well as its potential to enhance multifunctional properties. In this study, sustainable thermoplastic elastomers based on recycled polypropylene (RPP) and renewable guayule latex, which has recently entered the commercial arena as an alternative natural rubber, were prepared with polypropylene-grafted-maleic anhydride as a coupling agent. Graphene nanoplatelets (GnP) (2.5–10% by wt.) were added to enhance the mechanical (strength and modulus), thermal and flame retardant properties. With the addition of 10% GnP, the flexural modulus increased by a factor of 1.24, whereas tensile modulus increased by 76%. Scanning electron microscopy of the fractured surface of GnP reinforced nanocomposites showed a good correlation with the improvements in impact properties. Thermogravimetric analysis of composites with 10% GnP showed an increase in carbon residue at 600°C by a factor of 3.4 indicating improved thermal stability. Incorporation of GnP did not have a significant effect on the glass transition temperature range, however, the magnitude of storage modulus increased significantly. As expected, incorporation of GnP increased the shear viscosity, which decreased with shear rate exhibiting non-Newtonian behavior. These results indicate that GnP reinforced composites could be used in the next generation of automotive thermoplastic elastomer products such as cowl vent grills, wheel lips, rear bumper fascia, rocker panels and side moldings with certain improvements in mechanical, thermal and physical properties.