Styrene Butadiene Rubber, or SBR for short, is the abbreviation for Polymerized Styrene Butadiene Rubber. Styrene Butadiene Rubber is the backbone of the rubber industry, is the largest general-purpose synthetic rubber varieties, but also one of the earliest industrialized production of synthetic rubber varieties.
According to the polymerization process, SBR is divided into emulsion styrene butadiene rubber (ESBR) and solution styrene butadiene rubber (SSBR). Compared with the solubilized SBR process, the emulsion SBR process is more advantageous in terms of cost savings, and about 75% of the global SBR plant capacity is based on the emulsion SBR process.
1. Advantages
(1) The rubber is not easy to scorch and oversulfurization, good vulcanization flatness.
(2) Abrasion resistance, heat resistance, oil resistance and aging resistance are better than natural rubber. High temperature abrasion resistance is good, suitable for passenger tires.
(3)The molecular weight will not be lowered after a certain degree in processing, so it is not easy to be over-refined, and the plasticity is uniform. The hardness of vulcanized rubber changes little.
(4)High filling can be achieved by increasing molecular weight. Oil-filled styrene butadiene rubber has good processing performance.
(5) It is easy to be used with other unsaturated general-purpose rubber, especially with natural rubber and cis-butadiene rubber, and can overcome the shortcomings of styrene-butadiene rubber after formula adjustment.
Disadvantages
(1) The strength of pure rubber is low, need to add highly active reinforcing agent can be used. It is more difficult to add reinforcing agent than natural rubber, and the dispersion of reinforcing agent in rubber is poor.
(2)Trans structure, irregular structure, benzene ring on the side base, so it is larger than natural rubber, high heat generation, low elasticity, cold resistance is also a little worse than the hysteresis loss. However, it can reduce heat generation after oil filling.
(3) Unvulcanized rubber material shrinkage, low strength, adhesion performance is not as good as natural rubber.
(4)The vulcanization speed is slower than natural rubber.
(5) Vulcanized rubber is better than natural rubber in flex-cracking resistance, but the crack expansion rate is fast. Thermal tearing performance is poor.