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 (H2S) by flexible reinforced thermoplastic pipes can cause safety problems due to diffusion of H2S 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 H2S at 0.1 MPa for 7 days, the diffusion distance of H2S in the composite is 659 ± 17 μm, demonstrating a high barrier ability on H2S via absorption. This study provides a feasible method for preparation of polymer composites with suitable mechanical properties for inhibiting H2S permeation in reinforced thermoplastic pipes.