Polybutadiene Rubber
ARLANXEO Polybutadiene rubbers are highly elastic and have a very high degree of resistance to dynamic stress, and retain these properties even at extremely low temperatures. Blending natural rubber or styrene butadiene rubber with Buna CB improves the abrasion resistance, crack resistance and heat build-up under dynamic load.
Butadiene rubbers are produced by the solution polymerization process with the aid of organometallic catalysts. The catalyst system, which is characterized by the particular metal (neodymium, cobalt, lithium or titanium), influences the microstructure and macrostructure of the polymers and therefore the properties. ARLANXEO currently produces Nd, Co and Li grades.
The neodymium (Nd) catalyst system gives a polymer structure that cannot be obtained with other catalysts and which enables marked improvements in vulcanizate performance to be achieved. The Nd-BR grades have the highest cis-1,4 content, a relatively low molecular weight distribution and a low degree of branching.
The high-cis BR grades based on Nd, Co and Ti catalysts differ in cis-1,4 content, low-temperature crystallization behaviour and glass transition temperature. Ti-BR contains slightly less cis-1,4 than the Nd and Co grades and therefore has a higher crystallite melting temperature and slightly higher glass transition temperature. Where these microstructural properties are concerned, the Co-BR grades are intermediate between the Nd and Ti grades. The macrostructure of Co-BR is distinguished by a moderately broad molecular weight distribution and medium degree of branching.
