styrene butadiene rubber
1. Advantages
(1) The rubber material is not prone to scorching and excessive sulfur, and has good vulcanization flatness.
(2) Wear resistance, heat resistance, oil resistance, and aging resistance are all better than natural rubber. Good high-temperature wear resistance, suitable for passenger tires.
(3) After the molecular weight is reduced to a certain extent during processing, it no longer decreases, making it difficult to over refine and with uniform plasticity. The hardness change of vulcanized rubber is small.
(4) Increasing molecular weight can achieve high filling. The processing performance of oil-extended styrene butadiene rubber is good.
(5) It is easy to mix with other unsaturated general-purpose rubbers, especially with natural rubber and cis-1,4-polybutadiene rubber, and can overcome the shortcomings of styrene butadiene rubber through formula adjustment.
2. Disadvantages
(1) Pure rubber has low strength and requires the addition of highly active reinforcing agents before use. The difficulty of adding a blending agent is greater than that of natural rubber, and the dispersion of the blending agent in rubber is poor.
(2) There are many trans structures with irregular structures and benzene rings on the side groups, resulting in greater hysteresis loss, higher heat generation, lower elasticity, and slightly poorer cold resistance compared to natural rubber. But filling with oil can reduce heat generation.
(3) Unvulcanized rubber has large shrinkage, low strength, and inferior adhesion performance to natural rubber.
(4) The vulcanization speed is slower than natural rubber.
(5) Vulcanized rubber has better resistance to bending and cracking than natural rubber, but its crack propagation speed is fast. Poor thermal tearing performance.