PBR stands for polybutadiene rubber - a synthetic rubber made by polymerizing 1,3-butadiene. It is valued for its outstanding abrasion resistance, high resilience, and good low-temperature flexibility, which make it a key material in tires and in tough rubber and plastic compounds.
1. Key Properties
Polybutadiene's defining properties are high wear resistance, excellent rebound, low heat build-up under dynamic loading, and good low-temperature performance. These properties are controlled by the microstructure of the polymer chain (cis-1,4, trans-1,4, and 1,2-vinyl units), which is set by the catalyst system used in polymerization.
2. Main Applications
Tires account for about 70% of PBR consumption, mainly in treads and sidewalls where abrasion resistance and rolling resistance matter. Another roughly 25% is used as an impact modifier to improve the toughness of plastics such as high-impact polystyrene (HIPS) and acrylonitrile-butadiene-styrene (ABS). Other applications include golf ball cores, shoe soles, conveyor belts, hoses, and footwear.
3. Types of Polybutadiene
PBR is classified into four main types by microstructure: high-cis, low-cis, high-vinyl, and high-trans polybutadiene. High-cis polybutadiene (cis-1,4 above 95%) offers the best elasticity and abrasion resistance; high-vinyl grades provide greater hardness and strength; high-trans grades offer rigidity and dimensional stability. The grade is selected according to the balance of resilience, abrasion resistance, and processability required.
4. PBR vs. Other Rubbers
Compared with SBR and natural rubber, PBR offers superior abrasion resistance and resilience but lower tear strength and wet grip. For this reason, it is typically blended with SBR or natural rubber in tire compounds to combine durability with grip and processability.
