by Introduction
Polybutadiene or polybd is a synthetic rubber produced from butadiene. It has excellent resistance to chemicals, good flex life and good aging properties. Due to these properties, polybutadiene finds wide application in tire manufacturing. In this article, we will explore the properties and applications of polybutadiene in detail.
Chemical Structure and Properties
Polybutadiene is produced by polymerization of the monomer 1,3-butadiene. This polymerization can take place by anionic, cationic or Ziegler–Natta catalyst mechanisms. Depending on the proportion of 1,2-addition or 1,4-addition of the butadiene monomer, polybutadiene can be of following types:
– High cis content polybutadiene – Contains over 90% of cis-structure. It has high tensile strength and good flex life making it ideal for tire applications.
– High trans content polybutadiene – Contains 60-85% of trans-structure. It has lower tensile strength but better abrasion resistance than cis-polybutadiene.
– Low cis content polybutadiene – Contains 30-85% of cis structure. It has intermediate properties between high cis and high trans types.
All polybutadiene types have good resistance to oils, chemicals and weathering due to saturated carbon-carbon backbone. The double bonds impart elasticity while single bonds provide strength.
Tire Manufacturing
Around 65-70% of total Polybutadiene produced globally is consumed in tire manufacturing. Key properties of polybutadiene like flexibility, good aging resistance and high strength make it an ideal material for tire treads and carcasses. The wet traction of tires is improved by terminal bromination of polybutadiene.
In a tire, the carcass provides shape and strength while the tread provides traction. High cis-polybutadiene is used in tread areas for its tensile strength and flex-fatigue resistance required for continuous flexing. Transstructure improves wearing resistance making it suitable for tread wear areas. The sidewalls use mixtures of cis and trans structures for strength as well as good wearing properties.
Heel and Bead Areas
The bead area of tire requires high modulus for bead wire encapsulation. Here low cis-polybutadiene or blends of natural rubber and polyisoprene are used. The heel area connecting bead to sidewall undergoes repeated flexing and needs good fatigue resistance. Hence mixture of high cis-polybutadiene and polyisoprene is preferred here.
Applications other than Tires
While tires are the main application of polybutadiene, it also finds uses in:
– Conveyor belts – Used in high strength compounds for its good tensile properties and resistance to abrasion.
– Footwear – Provides cushioning in midsoles and flexibility in outsoles of shoes. Gives better wear than natural rubber.
– Industrial rubber goods – Used in hoses, vibration dampers, adhesives and sealants.
– Sports goods – Improves impact strength in balls. Used in shoe soles for rebound properties.
Global production of polybutadiene reached around 2.5 million tons in 2018 with major producers being Taiwan, China, USA, Japan and South Korea. Being commodity polymers, polybutadiene market follows business cycles. But demand is projected to grow 3-4% annually driven by increasing automobile and tire production worldwide. Asia Pacific currently dominates the market due to presence of major tire manufacturers. New applications in footwear and sports sectors are opening new markets for polybutadiene globally.
Polybutadiene’s unique combination of strength, flexibility and resistance to oils/chemicals has made it ubiquitous in rubber industry today. Especially in tire manufacturing, its vital use will ensure sustained demand growth. Its applications are also expanding to new areas due to versatility. As automobile sector continues to grow, polybutadiene will stay vital supporting higher mileage and fuel-efficient tires for greener future mobility.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
