Microbial desulfurization for NR ground rubber by Thiobacillus ferrooxidans

Abstract

AbstractThis study concentrated on microbial desulfurization for NR ground rubber by Thiobacillus ferrooxidans with sulfur oxidizing capacity. NR ground rubber was desulfurizated in the modified 9K medium during the cultivation of T. ferrooxidans. FTIR–ATR and XPS spectra and the increase of SO in the medium indicated that the main chains of the polymer were not broken by T. ferrooxidans, and SS linkages on the surface of ground rubber were partly oxidized to sulfoxide and sulfone, and at last partly oxidized to SO. Cumulative sulfur convention of ground rubber was 16% (w/w), which means 16% of sulfur has been fully oxidized to SO after 20 days' incubation. A sulfur oxidative scheme was proposed to explain the microbial desulfurization by T. ferrooxidans. Physical properties were determined on carbon black enforced SBR vulcanizates compounded with desulfurizated ground rubber of 40 phr loading. Preferable tensile strength and elongation at break were obtained for SBR vulcanizates filled with desulfurizated ground rubber if compared with that one obtained using ground rubber without modification. Scanning electron microscope photographs and DMA results suggested good interface coherence between desulfurizated ground rubber and SBR matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010