Crosslinking behavior and enhanced mechanical properties of acrylonitrile-butadiene rubber composites by incorporating aluminum ammonium sulfate particles

The crosslinked structure formed by the metal coordination bonding provides excellent and new properties for rubber materials. Herein, the crosslinking of acrylonitrile-butadiene rubber (NBR) is induced by introducing aluminum ammonium sulfate (NH4Al(SO4)(2)center dot 12H(2)O) particles. The crosslinking behavior, morphology, mechanical properties, and the Akron abrasion resistance of NBR/NH4Al(SO4)(2)center dot 12H(2)O composites were fully explored. The results show that the three-dimensional crosslinking structure is held together by metal-ligand coordination bonds between the nitrile group and AI(III). The coordination crosslink density exhibits a considerable increase with the addition of NH4Al(SO4)(2)center dot 12H(2)O. Thus, the mechanical properties and abrasion resistance of the obtained composites are better than that of NBR/sulfur system. Interestingly, the elongation at break for NBR/NH4Al(SO4)(2)center dot 12H(2)O composites is over 2000% due to the nature of coordination bonds. The abrasion volume loss decreases to 0.4 cm(3) for NBR/NH4Al(SO4)(2)center dot 12H(2)O composites with 20 phr NH4Al(SO4)(2)center dot 12H(2)O particles as compared to 0.75 cm(3) for NBR/sulfur system. The obtained NBR composites with facile preparation and excellent mechanical properties make the composites based on metal coordination bonding attractive for practical use. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 879-886