Influence of melamine formaldehyde microsphere on the vulcanization kinetics and mechanical properties of nitrile butadiene rubber

The melamine formaldehyde (MF) microsphere/nitrile butadiene rubber (NBR) vulcanizates were prepared by adding MF into NBR through mechanical mixing, followed by a vulcanization process. The influences of MF on the vulcanization characteristics, vulcanization kinetics, and mechanical properties were investigated. The results showed that MF interacted with NBR through hydrogen bonds. In addition, parameter b calculated by the ratio of modulus and strains also demonstrated the strong interaction between MF and NBR. Adding MF into NBR would reduce the curing time of NBR compounds, and increase the curing rate, as well as the cross-linked density. The vulcanization kinetics of MF/NBR compounds could be simulated accurately by Ghoreishy’s model. The mechanical properties of MF/NBR increased with the incorporation of MF. The modulus at 100%, modulus at 300%, and tensile strength of NBR vulcanizates with 20 parts per hundred rubber MF had 155, 90, and 110% increment, respectively, compared with those of neat NBR. The MF also enhanced the tear strength of NBR by 80% with a rough tear-fractured surface of NBR recorded by scanning electron microscope