Study On SBR/CM Blends And It's Applications In Pcr Tire Tread

Chlorinated polyethylene rubber(CM)is a new kind of special rubber.Its molecular structure determines that it has good heat resistance,oxygen aging resistance,oil resistance,ozone resistance and flame retardant.It has been widely used in rubber products such as wire and cable,rubber hose and conveyor belt.However,styrenebutadiene rubber(SBR)is widely used in the production of tires,rubber shoes and other fields due to its excellent wear resistance,good wet skid resistance.In this paper,the formula of PCR tire tread is taken as the research object,and the production cost is reduced and the aging resistance is improved under the requirement of ensuring that the rubber material meets certain physical and mechanical properties.The chlorinated polyethylene rubber(CM)is partly substituted for styrene butadiene rubber(SBR)in the tread compound of PCR tire.The effects of compatibility,curing system and reinforcing filling system of SBR and CM blends on mechanical properties and dynamic properties were studied.The compatibility of SBR/CM blends was studied by thermodynamic calculation formula,DSC,DMA and other analytical test methods.The results showed that the compatibility of SBR/CM blends was better when the dosage of CM was less than 20 phr,and the compatibility of SBR/CM blends was worse when the dosage of CM was more than 20 phr.In the SBR/CM blend ratio,with the increase of the CM content,the scorch time and the process curing time of the mixture decreased,the minimum torque increased,and the crosslinking degree decreased.The tensile strength and tear strength of vulcanized rubber increased gradually,the modulus at 100% changed little,and the elastic energy decreased.Vulcanized rubber at 0 ? when the tan? increased gradually,show that blending rubber wet resistance variation;When the amount of CM added was less than 30 phr vulcanized rubber under 60 ? the tan? of the change is not obvious,This indicates that the roll resistance of the blend is less affected by the addition of CM.The effects of different curing systems on the properties of CM adhesive were studied.The results showed that the curing of CM adhesive using peroxide curing system had high crosslinking degree,fast curing speed and good tensile strength,but not high tearing strength.Using thiadiazole /DCP vulcanization system,the tear strength of the compound was improved.The S/DCP/TAIC curing system was used in SBR/CM blends.Compared with the sulfur curing system,it was found that the scorch time was short,the curing speed was fast,the crosslinking degree was high,vulcanized rubber had good elasticity and excellent wear resistance.In addition,the CM was applied to the formula of PCR tire tread adhesive and it was found that when 10 phr CM was added,the performance of SBR/CM blend adhesive was better than that of the original formula in heat resistance,wear resistance,tensile strength and hardness increased gradually,but the elastic resilience of the blend adhesive decreased.The tan? at 0? did not change,illustrates the add 10 phr of CM has no effect on the wet resistance of the rubber.The tan? at 60? was increased,but the amplitude is small.When added to 20 phr CM,the tensile strength and tear strength of the blend decreased obviously,and the stress,hardness and permanent tensile deformation of the blend became gradually increasing.The effects of different vulcanization systems on CM mixing rubber were studied.It was found that the peroxide vulcanization system has high crosslinking degree,fast vulcanization speed and good tensile strength,but the tearing performance is not good.Therefore,the use of thiadiazole/DCP vulcanization system increases the tear properties of the compound.Due to the different molecular structure of rubber,the vulcanization system is also different.Therefore,a compound vulcanization system was adopted to vulcanize the two blends,that is,S/DCP/TAIC vulcanization system.Compared with S vulcanization system,S/DCP/TAIC vulcanization system has better mechanical properties.When the addition amount of CM is less than 20 phr,it is feasible to apply it to the formula of the tread compound of PCR tires,and the performance of the compound is better.Different grades of carbon black were used to fill SBR/CM blends.RPA data showed that the smaller the particle size and higher the structure of carbon black,the more complete the packing network structure formed in SBR/CM blends and the stronger Payne effect.In addition to the comprehensive mechanical properties,it is also necessary to consider that the rubber should have the appropriate coke burning time,low Mooney viscosity,so choose the new process carbon black N234 with smaller particle size and higher structure as the best carbon black.The effect of carbon black N234 on the properties of SBR/CM blends was also studied.The data showed that when the amount of carbon black N234 was 50 phr,the tensile strength and tear performance of SBR/CM blend were better,and the elasticity and wear resistance were excellent.In the fatigue temperature rise experiment of SBR/CM blends,the heat generation was higher and the permanent deformation rate of compression was higher.In order to reduce the problem of heat generation and permanent deformation of compression,the composite filler of carbon black and silica was adopted.The experimental data showed that with the increase of the amount of silica,the heat generation of rubber decreased,the permanent deformation of compression decreased,the tensile strength and tearing strength of vulcanized rubber decreased,and the elasticity became better.When the ratio of carbon black and silica is 20/30,the wet slip resistance of rubber is better.