Novel application of Zn‐containing Zeolitic Imidazolate Frameworks in promoting the vulcanization and mechanical properties of natural rubber composites

Abstract

AbstractThree kinds of Zn‐containing Zeolitic Imidazolate Frameworks (Zn‐ZIFs, including ZIF‐8, ZIF‐11 and ZIF‐14) based on the zinc ions coordinating with different imidazolate ligands were added into the natural rubber (NR) using the DM and TMTD binary accelerators system, respectively. The influences of Zn‐ZIFs on the sulfur vulcanization behaviors and mechanical properties of NR matrix were evaluated. The results indicated that the addition of ZIF‐8 or ZIF‐14 could realize the fast vulcanization of NR at 130°C (the ordinary vulcanization temperature of NR is above 150°C), while ZIF‐11 did not show the obvious accelerating performance. Amongst the three Zn‐ZIFs, ZIF‐8 benefited NR matrix for the acquirement of the highest tensile strength and the largest crosslinking density. As an optimal additive, ZIF‐8 with 0.6 phr distinctly improved the physical‐mechanical, thermo‐oxidative aging resistance and dynamic mechanical properties of NR composites. It proved that Zn atom and its coordination porous network in Zn‐ZIFs played synergistic effects in accelerating vulcanization and enhancing mechanical properties of NR matrix besides its role of reinforcement filler. Then the above ZIF‐8/DM/TMTD vulcanization system was used to prepare the UHMWPE fibers/NR composites. The mechanical properties of the UHMWPE/NR composites were significantly improved in contrast to the pure NR matrix.