Synthesis and Characterization of Diaminodisulfide Derivatives and
their use as Accelerator in Curing Process of Rubber Compounds
In some special cases, rubber compounds with high amounts of unsaturated elastomer are recommended with organic sulfur donors instead of mineral sulfurs. In this condition, activated sulfur is produced in situ and curing process is facilitated without accelerators. Organic sulfur donor compounds have low thermal stability and in the vulcanization temperature produce free and activated sulfurs. The advantages of these compounds are: 1. High effectiveness of curing agent in low quantities in rubber compounds manufacturing. 2. Producing activated sulfurs in controlled condition and avoiding the over curing of rubber compounds. In this report the novel synthesis of some derivatives of diamino-disulfides which can be applied as sulfur donors in vulcanization of special rubber compounds is introduced. The key process is reaction of sulfur monochloride with amines in petroleum ether as solvent in low temperature. Dithio-dimorpholine(DTDM), dithio-dipipyridyl (DTDP), dithio-bis dibutylamine (DTBDB) and dithio-bisdiisopropyl amine (DTBDI) were prepared according to this method. All products thus obtained were characterized by 1H and 13C-NMR spectroscopies. The effects of accelerating and sulfur donoring of all prepared agents were detected in rubber compounds with natural and synthetic rubber bases. All physical, chemical, reological and mechanical properties of rubber compounds based on prepared sulfur donors were characterized.