Medium vinyl polybutadiene is one of the polybutadiene rubbers developed in the 1970s. It was originally developed by the British International Synthetic Rubber Company (ISR) and officially put into production in 1973 under the trade name Intollene50.
The vinyl polybutadiene rubber produced in the industry was also successfully developed by Yanshan Petrochemical Company in the 1980s. It has undergone small tests and pilot tests. It is well known that the product is classified into three polybutadienes such as cis-1, 4, trans-1, 4 and -1, 2, depending on the content of vinyl in the polybutadiene chain structure. Among them, the vinyl content of 35%~55% is called medium ethylene polybutadiene to distinguish it from low cis polybutadiene (vinyl content <10%) and high vinyl polybutadiene (ethylene). Base content > 55%) The amount of vinyl is regulated by a regulator.
The basic properties of medium vinyl polybutadiene rubber are similar to those of butadiene rubber, and are excellent in elasticity and low temperature resistance, and have wet skid resistance and heat aging resistance which are not comparable to those of butadiene rubber. These characteristics make it highly valued by the tires, rubber shoes and other industries. For example, the tread rubber used for tires can improve the wet skid resistance and facilitate safe driving; if it is used as the main material of the rubber sole, it can prevent slipping when walking on wet ground.
However, due to the presence of more vinyl groups in the main chain and a narrow molecular weight distribution, it has disadvantages such as high heat generation, high wear loss, and poor cold flow resistance. In order to expand the application of medium vinyl rubber, these disadvantages must be overcome. The reason why the domestic vinyl rubber has not been promoted is because of this. In order to solve this problem, some rubber companies adopt the process of multi-functional organolithium as initiator, tetrahydrofuran as solvent, reaction temperature of 50 °C, 80 °C later, reaction time of 1.5~2h, and the star structure is obtained. Vinyl polybutadiene rubber (S-MVBR), which has good wet skid resistance, low rolling resistance and better processing properties, is an ideal low heat tread rubber.