Polyethylene/graphene‐nanoplatelets nanocomposites with improved thermochemical stability: The role of surface polarity of graphene‐nanoplatelets

Abstract

Recent studies have shown that graphene nanoplatelets (GNP) absorb free radicals and slow polymer degradation. A study has been conducted to investigate the effects of GNP polarity and concentration on polyethylene stability in ClO2‐containing water. The addition of graphene nanoplatelets SG: high polarity and CG: low polarity improved the thermo‐oxidative stability of bimodal high‐density polyethylene (PE100). As a result of the application of traditional primary and secondary antioxidants, as well as the addition of 0.1% CG, the thermo‐oxidative stability of PE100 was significantly increased, according to the oxidative induction time (OIT). The synergistic thermal stabilization effect of GNP is derived from the free radical scavenging and tortuous path effect of CG. Rheological measurements showed that the appropriate nanofiller and antioxidant combined prevent polymer thermo‐oxidation degradation during melt processing. As a result of 3 weeks of aging in chlorine dioxide‐containing water, the neat sample (PE100) demonstrates only 50% elongation at break, whereas the sample with 0.6 wt% of CG shows 200% elongation at break after 3 weeks, due to the formation of a tortuous barrier and radical scavenging of the CG structures.Highlights DPPH assay test confirms the antioxidant scavenging capability of the GNPs. The appropriate nanofiller and antioxidant combined to prevent polymer thermo‐oxidation degradation during melt processing. Low polarity GNP can be dispersed more uniformly in the nanocomposite matrix. Nanocomposite containing lower polarity GNP shows more resistance against thermochemical degradation.