Application Research Of Liquid Polybutadiene In Green Tire Tread

Treated Distilled Aromatic Extracts(TDAE)are widely used in tread compounds.However,the polycyclic aromatic hydrocarbons(PAHs)contained in TDAE are very harmful to the environment and human beings.Therefore,it is of great significance to select non-toxic and harmless new plasticizers to replace TDAE.Liquid poly-butadiene(LPB)is a good choice,which is fluid at room temperature.LPB is a low-molecular polymer with a number-average molecular weight(M_n)of about 500-10,000.In this paper,solution-polymerized styrene-butadiene rubber(SSBR)and cis-butadiene rubber(BR)were selected as the tread base rubber.In the first stage of the experiment,LPB of AL brand was selected to replace TDAE to plasticize different proportions of SSBR/BR(60/40,70/30,80/20),high and low sulfur dosages were set in each ratio system.The results showed that when SSBR/BR(80/20),the substitution effect of LPB(AL)was the best.The comprehensive results of the LPB plasticized system and the TDAE plasticized system in the high-sulfur group were not significantly different from those in the low-sulfur group.In the second stage of the experiment,the LPB of AV brand with higher 1,2-vinyl content was added,and LPB(AL,AV)was used to gradually replace the amount of TDAE in the system(until it was completely replaced,and the period was a mixed system of TDAE and LPB).LPB(AL)and LPB(AV)with high 1,2-vinyl content completely replace TDAE in SSBR/BR(80/20)system when the amount of sulfur was the same,and have no adverse effect on the physical and mechanical properties and dynamic mechanical properties of the material.In the third stage,after the ratio of SSBR/BR and the amount of LPB were clarified,four kinds of LPB(AL,PM4,AV,N4)with different1,2-vinyl content,T_g,M_n and viscosity(25?)were used to completely replace TDAE plasticized SSBR/BR(80/20),and selected LPB(AL,AV)with high 1,2-vinyl content to gradually increase the amount of sulfur,and conducted a comprehensive study on the application value of LPB.The results showed that,at the same sulfur content,when LPB(AL,PM4,AV,N4)was used as plasticizer to plasticize SSBR/BR,compared with TDAE as plasticizer,the critical strain amplitude of the Payne effect of SSBR/BR compounds was effectively reduced,the Mooney viscosity was slightly increased,the T_g of SSBR/BR vulcanizates was further reduced,the difference in thermal conductivity between 60?and 100?was small,the difference in physical and mechanical properties was small,the reduction of material strength during heating was smaller,the dynamic fatigue resistance was better(effectively increasing the service life of the material),the degree of crosslinking was slightly reduced,and the difference of rolling resistance as well as wet skid resistance was very small,low-temperature grip of the tread improved.When LPB(AL,AV)was selected to plasticize SSBR/BR and the sulfur content was gradually increased,the decrease in hardness and the increase in heat generation from dynamic fatigue were solved,and the tensile strength and wet skid resistance of the tread compound were further improved.LPB can be used as a new type of environmentally friendly plasticizer to effectively replace TDAE in tread tires.And the LPB(AL)and LPB(AV)plasticized systems can achieve the best substitution effect when the sulfur content is increased by 30%and 75%respectively compared with the TDAE plasticized system.