Direct vulcanization adhesion of nickel platings to NBR compounded with the softener using 1, 3, 5-triazine-2, 4, 6-trithiol monosodium salt (TTN) has been investigated. The softener was using aromatic hydrocarbon formaldehyde resin (AHF) and di-octyl-phthalate (DOP). It was found that TTN accelerated vulcanization reactions of NBR compounded with the softener. The tensile strength of NBR compounded with more than 50phr AHF was showed constant value of 7.5MPa, and the elongation at break decreased with increasing the amount of AHF. On the other hand, the tensile strength of NBR/DOP decreased with increasing the amount of DOP.
The peel strength of adhesion was influenced by the amount of TTN, curing temperature, curing time and the amount of softener. The adhesion interface of nickel platings to NBR/AHF left standing for more than 48 hours in air became the cohesive failure. The concentration of sulfur in the interfacial layer of nickel plating NBR compounded with the softener were observed to increase from EDS analysis. The above results suggest that TTN works as a binder which bonds between nickel platings and NBR compounded with the softener.
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