Vulcanisation semi-efficient

Conventional Vulcanisation, Semi-Efficient Vulcanisation and Efficient Vulcanisation... 

NR (ISNR 5 grade) was modified with 10 phr each of phosphorylated cashew nut shell liquid(PCNSL) prepolymer and an aromatic oil plasticiser (spindle oil) in a typical semi-efficient vulcanisation system. Despite the lower chemical crosslink density, the PCNSL modified NR vulcanisates showed higher TS, EB, thermal stability and resistances to fatigue failure and thermooxidative decomposition, as compared with the vulcanisate containing the same dosage of spindle. 12 refs. 

Benzothiazole sulphenamide accelerators are suitable for semi-efficient and efficient vulcanisation systems. 

The chemical microstructures of cis-polyisoprene (HR) vulcanised with sulfur and N-t-butyl-2-benzothiazole sulfenamide (TBBS) accelerator were studied as a function of extent of cure and accelerator to sulfur ratio in the formulations by solid-state 13C NMR spectroscopy at 75.5 MHz [29]. Conventional (TBBS/Sulfur=0.75/2.38), semi-efficient (SEV=1.50/1.50) and efficient (EV=3.00/1.08) vulcanisation formulations were prepared, which were cured to different cure states according to the magnitude of increase in rheometer torque. The order and types of the sulfurisation products formed are constant in all the formulation systems with different accelerator to sulfur ratios. However, the amount of sulfurisation has been found to vary directly with the concentration of elemental sulfur. 

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