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Asphalt was separated into 4 components, saturated, aromatic, resin and asphaltene, according to its polarity. The effect of the 4 components on the vulcanization process and vulcanization effect of cis-1,4-polybutadiene rubber (BR) were investigated. The results showed that the saturated and aromatic components in asphalt could prolong the scorch time of BR and improve the processing safety. Resin and asphaltene could effectively increase the maximum torque of compound and accelerate the curing rate. Asphalt prolonged the scorch time and accelerated the curing rate of the BR compound, but it could slightly reduce the maximum torque. The oxygen, nitrogen, and sulfur functional groups which were rich in resins and asphaltenes could effectively participate in the vulcanization reaction of BR.

The structure and properties of high modulus natural rubber (NR) / cis-1,4-polybutadiene rubber (BR) blends reinforced with carbon black and modified with trans-1,4-poly(butadiene-co-isoprene) rubber (TBIR) and low Mooney viscosity trans-1,4-poly(butadiene-co-isoprene) rubber (LTBIR) were investigated. The results showed that both of the TBIR and LTBIR could significantly improve the compatibility between NR and BR. Compared with NR/BR vulcanizates, the mechanical properties and resilience of high modulus NR/BR vulcanizates modified with TBIR and LTBIR with reducing 4 phr (mass) carbon black were improved, wear volume reduced by 13%, compression heat generation reduced by 10%, rolling resistance reduced by 20%, first-grade flex fatigue life improved by about 1.6 times, and sixth-grade flex fatigue life improved by about 1.1 times.

The technical requirements of electric vehicle tires, the research progress of electric vehicle tires and high-performance rubber materials for electric vehicle tires at home and abroad were summarized with 46 references, and the development of the electric vehicle tire industry was prospected.

The low cis-1,4-polybutadiene rubber material that had been filtrated and passed the homogeneity and stability tests and conformed to requirements for the reference material, was jointly determined the value by several laboratories, and the results of determination were evaluated according to the data processing procedures of fixed value, including abnormal data judgment, data normal distribution test, equal precision test and uncertainty evaluation. The results showed that at a significant level of 0.01, the fixed value data of Mooney viscosity of low cis-1,4-polybutadiene rubber reference material in each laboratory had no suspicious value, were in normal distribution, and were of equal accuracy. The nominal value of ML(1+4) 100 ℃ of the refe-rence material was 33.5±0.8. This reference material could be widely used to calibrate Mooney viscometer, providing technical support for production control, product inspection, product trade and quality arbitration in synthetic rubber industry.

Effects of liquid polybutadiene rubber activity-50 on the processability and fatigue resistance of cis-1,4-polybutadiene rubber (BR)/natural rubber (NR) blends were investigated. The fatigue resistance of vulcanizates was investigated from the perspective of fatigue crack propagation using crack growth test platform and finite element ABAQUS/CAE. The results showed that activity-50 could reduce the storage modulus and viscosity of the rubber blend, and the addition of activity-50 in the rubber blending process could improve the processability of the system. Adding 2 phr and 4 phr of active-50 could reduce the crack growth rate. When the amount of active-50 continued to increase, the crack would accelerate. Adding an appropriate amount of activity-50 could improve the processability and fatigue resistance of BR/NR blend.

The effects of amount of cis-1,4-polybutadiene rubber on curing characteristics, processing properties, physical and mechanical properties and dynamic mechanical properties of cis-1,4-polybutadiene rubber/functionalized solution polymerized styrene-butadiene rubber blends were investigated. The results showed that with increase of amount of cis-1,4-polybutadiene rubber, the networking degree of the blend was enhanced, curing process was accelerated, and dispersion of the filler was improved, but its static and dynamic mechanical properties were lost to a certain extent. When the amount of cis-1,4-polybutadiene rubber was 20 phr (mass), the wet skid resistance of functionalized solution polymerized styrene-butadiene rubber reduced by about 50%.

The effects of common cis-1,4-polybutadiene rubber （BR）, BR prepared from neodymium catalyst system and carbon black modified BR on sidewall compound properties were investigated by adding different BR to sidewall compound of passenger car radial tire. The results showed that the carbon black modified BR had higher Mooney viscosity, shorter scorch time, longer curing time, and higher minimum and maximum torque. The modulus, tensile strength and rebound resilience of the vulcanizate increased, while loss factor at 60 ℃ decreased. The rolling resistance of the finished tire was reduced.