Improvement of mechanical properties of highly ZnO‐filled polyethylene composites by dual‐compatibilizer for hydrogen sulfide permeation inhibition

Abstract Transportation of acidic fluids containing hydrogen sulfide (H 2 S) by flexible reinforced thermoplastic pipes can cause safety problems due to diffusion of H 2 S in the pipe. Herein, high‐density polyethylene (HDPE) composites are prepared with a large amount of zinc oxide (ZnO) particles as absorbent fillers by melt‐mixing via introducing maleic anhydride‐grafted polyethylene (PE‐ g ‐MAH) and maleic anhydride‐grafted poly(ethylene‐ co ‐octene) (POE‐ g ‐MAH) as dual‐compatibilizer. By controlling the mass ratio of the two compatibilizers, ZnO particles can be encapsulated by PE‐ g ‐MAH and POE‐ g ‐MAH so that mechanical properties of the prepared HDPE/ZnO composites are improved owing to enhanced compatibility between the filler and the resin. By adding PE‐ g ‐MAH and POE‐ g ‐MAH with total 10 wt% in a mass ratio of 1/3, the HDPE/ZnO composite containing 50 wt% ZnO exhibits 37.3 ± 3.8 MPa of yield strength, 576 ± 16 MPa of flexural modulus, and 84.4 ± 1.4 kJ m −2 of notched Izod impact strength corrected to 311 ± 24.9 kJ m −2 . After exposure in H 2 S at 0.1 MPa for 7 days, the diffusion distance of H 2 S in the composite is 659 ± 17 μm, demonstrating a high barrier ability on H 2 S via absorption. This study provides a feasible method for preparation of polymer composites with suitable mechanical properties for inhibiting H 2 S permeation in reinforced thermoplastic pipes.