Promoter in rubber o-rings, rubber seal, rubber seals and other rubber products plays a very important role in curing process.Because of the existence of the accelerator, reducing the sulfur ring fracture activation energy.Promoter of pyrolysis, increased the system of free radicals or ion concentration, to accelerate the curing of chain reaction and chain extension reaction, improves the vulcanization reaction speed, at the same time, also improved the structure and properties of vulcanized rubber.
Class 1 times sulfonamide promoter without the presence of zinc oxide first react with sulfur to generate the aggregation of the accelerator sulfide, sulfur can be vulcanization of macromolecular radicals are produced by crosslinking with rubber molecules.It need more than one sulfur free radicals at the same time have the effect of mutual inhibition, which extended the charred.For most times sulfonamide classes promoter, its dosage the more the longer scorch.In the process of decomposition reaction of accelerator M, M form DM and react with times sulfonamide, DM and react with sulfur generated M, promoter M generated in the reaction of times sulfonamide happened automatically catalysis.Accelerated the decomposition of sulfonamide, accelerate the crosslinking reaction, induction period shorten, this is disadvantageous for delayed sex, antiscorching agent principle is to make reaction with antiscorching agent promoter M part its consumption, to extend the scorch time.Time yellow amides promoter has certain scorch time it is the main cause of 1. In decomposition on the accelerator DM, M and its three promoter of health can be different, under the same curing condition to split out the speed of free radicals in turn, show some delayed.Sulfonyl group 2. The separating time stability of free radicals and stability, the higher the more delay the sulfuration.
2 mercaptobenzothiazole or promoter M itself can occur in the process of sulfide reduction reaction, when the presence of peroxide, consumes peroxide.So peroxide vulcanization is can't use M or can break down the acid promoter M.Promoter M to participate in the curing reaction will break out of free radicals.Presence of sulfur, HS compounds are generated from the integrated reaction and more S free radicals can cause sulfur vulcanization of chain growth.Under the condition of the existence of stearic acid and zinc oxide are produced by ionic reaction, generate more sulphur ligand complex, this complex is a kind of strong vulcanizing agent it is rubber molecules grafted compounds, prompting rubber crosslinking macromolecules.
3. The accelerator DM diphenyl sulfide and thiazole occurred without the presence of ZNO splitting decomposition of symmetric structure and benzene thiazole free radicals and sulfur radicals and accelerator M they can participate in the curing reaction.The survival of the M played a M promote sulfide function.In the presence of active zinc oxide with stearic acid its role under the condition of the same as the M, DM with sulfur curing, also break down the double-base active sulphur or more base active sulphur crosslinking can make the rubber molecules.