Analysis of Crosslinked Styrene‐Butadiene Rubbers by Liquid Chromatography and FT‐IR Spectroscopy, 1

Abstract

Abstract Crosslinked styrene‐butadiene and butadiene rubbers can efficiently be analyzed by liquid chromatography and FT‐IR spectroscopy. In a first step the vulcanizate is pyrolyzed under mild conditions. The resulting high molar mass fragments are extracted from the bulk material and analyzed by size exclusion chromatography. The molar masses of the extractables are in the range of 3 000 to 25 000 g/mol. The chemical composition as a function of molar mass is visualized by coupled SEC‐FT‐IR spectroscopy. By quantitative analysis of the FT‐IR spectra the concentrations of the different structural units, including styrene, 1,4‐ trans ‐butadiene, 1,2‐vinylbutadiene, and 1,4‐ cis ‐butadiene, are determined. It is shown that the chemical composition of the original non‐crosslinked rubbers and the chemical composition of the extractables are rather identical. Therefore, this technique can be used to obtain structural information on rubber formulations even in the case when the material is already vulcanized. SEC chromatograms of SBR 1712 and the extractables after pyrolysis, stationary phase: SDV linear, mobile phase: THF, detector: ELSD. magnified image SEC chromatograms of SBR 1712 and the extractables after pyrolysis, stationary phase: SDV linear, mobile phase: THF, detector: ELSD.