Study On The Reinforcing Property Of Carbon Black To Nature Rubber

The reinforcing performance of carbon black on rubber products has been studied continuously at home and abroad since its discovery.Previous researches on the reinforcement of carbon black are based on the traditional mechanical method,and the reinforcement and reinforcement mechanism of carbon black are estimated through the performance research of vulcanizates.The advantages of this research method are mature technology and stable results.However,the disadvantage is that the sample preparation process is complicated and introduces large experimental errors.In this paper,the blend of carbon black and natural latex was prepared by ultrasonic method,and then the blend film was prepared by emulsion copolymerization and drying process.The tensile properties,SEM,TGA and other performance tests of the blend were carried out to study the reinforcement performance at low carbon black content.Then,the compound and vulcanizate with high carbon black content were prepared by the traditional mechanical method.The processing characteristics of the compound,the physical and mechanical characteristics of the vulcanizate and the dynamic fatigue characteristics were studied.The experimental results under the two research schemes were comprehensively analyzed,and the reinforcement of carbon black to natural rubber under different content was studied.According to the above two schemes,the reinforcement of carbon black with the same particle size structure and different surface energy was studied.The results show that the surface energy of N234 carbon black increases after being treated at different temperatures for different times,but the surface energy increases little after being treated for 1h,and the surface energy difference is obvious after being treated for 6 h.With the increase of surface energy of carbon black,the reinforcing effect of carbon black becomes worse,and the adsorption force to rubber macromolecules decreases.The dispersity difference caused by different surface energies of carbon black is small.However,thesurface energy of carbon black has a great influence on the tensile properties of vulcanizates,mainly manifested in elongation and constant elongation stress,in which elongation obviously increases,constant elongation stress decreases,abrasion resistance also decreases,compression heat generation and dynamic compression permanent deformation also have a great influence,while other physical and mechanical properties have little difference.The same method was used to study the influence of different structural degrees on the reinforcement of carbon black.The results show that when the particle size is the same,carbon black with lower structure degree is easier to adsorb and agglomerate in natural latex,and its dispersibility becomes worse.The elongation of natural rubber film is higher,the constant elongation stress is smaller,but the difference in tensile strength is smaller.In addition,for carbon black samples with lower structural degree,ML and MH in the rubber compound decreased first and then increased,MH-ML decreased and crosslinking degree decreased.The scorch time tends to be extended first and then shortened,and the process vulcanization time tends to be shortened first and then extended.The change trend is not obvious when the specific surface area of carbon black is small,but obvious when the specific surface area of carbon black is large.When the specific surface area and the amount of carbon black are the same,the tensile strength of NR vulcanizates does not change much with the decrease of carbon black structure,while the tear strength tends to increase but does not change much.The constant tensile stress is obviously reduced and the elongation is obviously increased.Hardness and resilience tend to decrease,abrasion resistance becomes worse,compression permanent deformation increases,compression heat generation and dynamic compression permanent deformation increase.In addition,the structure of carbon black has little effect on wet skid resistance and rolling resistance of NR vulcanizates.It was found in the research experiment on the influence of particle size on the reinforcement of carbon black.When the amount and structure of carbon black are the same,carbon black with high specific surface area is easier to adsorb and agglomerate in natural latex and has poor dispersibility.The adhesive film containing carbon black with high specific surface area has low tensile strength,large elongation and small constant tensile stress.When the amount and structure of carbon black are the same,the carbon black compound with high specific surface area has high ML,small MH,fast curing speed and short curing time.The specific surface area has little influence on the tensile strength and hardness of vulcanizates.The specific surface area increases,the elongationof vulcanizates increases,and the constant elongation stress decreases,but the change values are all small.Wear resistance tends to be better,impact elasticity tends to be lower,while compression permanent deformation gradually becomes larger and the difference is obvious.In addition,the particle size of carbon black has little effect on wet skid resistance and rolling resistance of NR vulcanizates.