Filler–polymer interactions in filled polybutadiene compounds

Bound rubber in a filled rubber compound is formed by physical adsorption and chemisorption between the rubber and filler. Polybutadiene (PB) is composed of three components of 1,2-, cis-1,4-, and trans-1,4-units. Filler–polymer interactions in PB compounds filled with carbon black or silica were studied by analyzing microstructures of the bound rubbers with pyrolysis-gas chromatography. Differences in the filler–polymer interactions of the 1,2-, cis-1,4-, and trans-1,4-units were investigated. The filler–polymer interaction of the 1,2-unit is stronger than those of the cis-1,4- and trans-1,4-units. The interaction of the 1,2-unit with silica is stronger than with carbon black. Bound rubber content is decreased by treatment with ammonia. Change of the bound rubber composition after the ammonia treatment was also studied.