No abstract

In this study, aluminum sulfate 18-hydrate [Al 2 (SO 4 ) 3 Á18H 2 O] particles of different sizes, which were obtained via high-energy ball-milling technology, were successfully compounded with acrylonitrile-butadiene rubber (NBR) to fabricate crosslinked rubber composites. The results suggest that high-energy ball milling had no significant change on the crystal structure of Al 2 (SO 4 ) 3 Á18H 2 O, but it significantly reduced the particle size. The effects of the particles size on the coordination crosslinking behaviors and mechanical properties of the NBR-Al 2 (SO 4 ) 3 Á18H 2 O composites were fully explored. The coordination crosslinking reaction was demonstrated to occur between the nitrile group (─CN) and Al(III). Moreover, with the decreasing particle size, the composites achieved a better interfacial adhesion and more crosslinking points, and this led to significant increases in the crosslinking density and the mechanical properties.

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)2·12H2O) particles. The crosslinking behavior, morphology, mechanical properties, and the Akron abrasion resistance of NBR/NH4Al(SO4)2·12H2O 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)2·12H2O. 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)2·12H2O composites is over 2000% due to the nature of coordination bonds. The abrasion volume loss decreases to 0.4 cm3 for NBR/NH4Al(SO4)2·12H2O composites with 20 phr NH4Al(SO4)2·12H2O particles as compared to 0.75 cm3 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. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 879–886