Study Of Vulcanization Mechanism Of EPDM Composite Curing System

EPDM with a high saturation, non-polar molecule structure was cured by sulfur vulcanization system and peroxide vulcanization system, advantages and disadvantages both existed. Redox system has been successfully used in cross-linking of latex with a better vulcanization performance than other vulcanization system. Ingredient in sulfur system has a negative effect on peroxide, but the mechanism is seldom studied. Sulfur, as an assistant cross-linker, is usually added to peroxide in a way of sulfur system, its aid cross-linking characteristic and mechanism is not studied in detail and positively.This article reveals the vulcanization properties of EPDM with three redox systems-BPO/Na2S2O3、BPO/DMA、BPO/S, and the effect of accelerator M、TMTD、CZ on the vulcanization performance of individual peroxide, and analysis the mechanism. The aid cross-linking properties of sulfur and TAIC on BPO and DCP are studied through vulcanization characteristic, mechanical performance and FTIR spectrum.Experimental results show that:when redox system used for rubber cross-linking, compared with individual peroxide, the cross-linking ability of different reducing agents have quite difference. Reducing agent DMA and Na2S2O3 can weaken the curing efficiency but sulfur is different. Redox system can react in rubber medium with the order:BPO/DMA>BPO/Na2S2O3 >BPO/S. During the mixing stage (40-50℃), redox reaction can occur in BPO/DMA system and BPO/Na2S2O3 system,the redox is inappropriate for rubber vulcanization system.However, the BPO/S system can be as the effective redox system. It was found that the typical accelerator for sulfur vulcanization:M、TMTD、CZ can significantly reduce the curing capacity of individual peroxide. This paper expounds the causes and put forward the possible mechanism. The experiment also found that when using BPO/S system, S has a great help on the cross-linking of BPO, and the comprehensive performances of vulcanized rubber are the best when BPO/S reaches to the mole ratio of 2:1. However S can restrain the curing capacity of DCP when using the DCP/S system. TAIC can help the cross-linking of both BPO and DCP. The causes are analyzed in this paper.