Slow Crack Growth Resistance of HDPE Nanocomposites with Modified Graphenes: A Comparative Study with Carbon Black Masterbatch

High density polyethylene is susceptible to Slow Crack Growth (SCG), which may cause premature failures. In this work, masterbatches of chemically reduced graphene oxide (CRGO), amino‐functionalized CRGO (FCRGO), and carbon black (CB) were used. Polyethylene grafted maleic anhydride (PE‐g‐MA) was used as a compatibilizer. RGO Masterbatches were prepared using solvent‐mixing and compared with the CB industrial masterbatch. Final nanocomposites produced by melt‐mixing (upon 2 wt.% of nanoparticles). Tensile modulus of all composites increased up to 17%. Elongation at break decreased 90% for CRGO composite, but slightly by CB and FCRGO composites (20%) loading. Tensile strength remained almost constant by adding FCRGO and CB, but decreased 60% with CRGO loading. Notched constant tensile loading (NCTL) test results showed improvement in the SCG resistance by adding 1.5 wt.% of FCRGO for more than 50%, but dis‐improvement in the SCG resistance of CB and CRGO composites. Strain hardening modulus (SHM) of FCRGO composites were 7% higher than HDPE, supporting the NCTL results. OLM and SEM macroscopic images showed that FCRGO nanocomposite has better dispersion than the non‐functionalized ones. All tests revealed a strong interaction between FCRGO nanoparticles and the matrix. Thus, FCRGO has a high potential to enhance long‐term properties of HDPE particularly for pipe grade PE.