Effect of solvent Extractions on a linear Combination fitting in sulfur K-edge X-ray Absorption near edge structure Spectroscopy for Sulfur cross-linked Rubber

Necessity of solvent extractions in the linear combination fitting method of sulfur K-edge X-ray absorption near edge structure (S-XANES) spectroscopy is described for evaluation of a sulfidic structure of isoprene rubber (IR) vulcanizate prepared using N-(1,3-benzothiazol-2-ylsulfanyl)cyclohexanamine as an accelerator, and zinc oxide and stearic acid as activators. The solvent extractions using chloroform/acetone and tetrahydrofuran are useful for removing the un-reacted reagents from the vulcanizate. A majority of the sulfur cross-linked segments is found to be a disulfidic type in the vulcanizate. Oxidation reactions of sulfur are also recommended to be taken into account for characterization of sulfidic linkages in the vulcanizate by the S-XANES analysis.