Influence of poly(p‐phenyleneterephalamide) pulp by surface modification with dopamine to nitrile butadiene rubber

Nitrile butadiene rubber (NBR) is widely used in the production of oil and fuel‐resistant rubber parts. Poly(p‐phenyleneterephalamide) (PPTA) pulp is used as a reinforcing fabric in NBR composites to improve its mechanical properties despite the weak bonding between NBR and PPTA pulp. In this work, PPTA pulp was modified by interfacial polymerization of dopamine (DOPA). A surface‐adherent poly(dopamine) (PDA) film was formed on the surface of the PPTA pulp, which improved bonding to NBR and mechanical properties of the prepared composites. The surface of the modified PPTA pulp was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The results demonstrate that PDA was successfully functionalized on the PPTA pulp and that the surface of the composite was rougher after modification. The effects of treatment conditions on the mechanical properties of NBR/pulp composites were also investigated. The tensile strength markedly improved with treating time of 30 h at a DOPA concentration of 2 g/L. Strong interactions, including hydrogen bonding and adsorption, play an important role in the tensile strength of the material. Our results demonstrate that surface modification by PDA is beneficial for improving the strength of the NBR matrix. POLYM. COMPOS., 40:E476–E483, 2019. © 2018 Society of Plastics Engineers