SBR is an unsaturated hydrocarbon polymer. Physical and chemical reactions will occur under the action of light, heat, oxygen and ozone, but its oxidation is slower than natural rubber, and the aging reaction speed is slower even at higher temperatures. The aging effect of light on rubber is not obvious, but the ozone resistance is worse than natural rubber. The brittleness temperature is about minus 45℃, and the low temperature performance is slightly worse.
Compared with general rubber, it has the following advantages and disadvantages:
1. Advantages
(1) The rubber material is not easy to burn and oversulfur, and has good vulcanization flatness.
(2) Wear resistance, heat resistance, oil resistance and aging resistance are better than natural rubber. Good high temperature wear resistance, suitable for passenger tires.
(3) During processing, the molecular weight will not decrease after it drops to a certain level, so it is not easy to over-refining and the plasticity is uniform. The hardness of the vulcanizate changes little.
(4) Increase the molecular weight to achieve high filling. Oil-extended styrene butadiene rubber has good processing properties.
(5) It is easy to use with other unsaturated general-purpose rubbers, especially with natural rubber and butadiene rubber. The shortcomings of styrene butadiene rubber can be overcome by formula adjustment.
2. Disadvantages
(1) The strength of pure glue is low, and it can be used only after adding high-activity reinforcing agent. It is more difficult to add compounding agents than natural rubber, and the dispersibility of compounding agents in rubber is poor.
(2) There are many trans structures, irregular structures, and benzene rings on the side groups, so they have greater hysteresis loss, higher heat generation, lower elasticity, and slightly worse cold resistance than natural rubber. But it can reduce heat generation after oil filling.
(3) Unvulcanized rubber has large shrinkage, low strength, and adhesion performance is not as good as natural rubber.
(4) The vulcanization speed is slower than natural rubber.
(5) Vulcanized rubber has better resistance to flexural cracking than natural rubber, but the crack propagation speed is faster. Poor thermal tearing performance.
