Microbial desulfurization of SBR ground rubber by Sphingomonas sp. and its utilization as filler in NR compounds
(2344–2351)Polymers for Advanced Technologies 22 #12 (2011)
Jiang et al of Beijing University of Chemical Technology, China, studied microbial desulfurization of waste tyre rubber because waste rubber has created serious ecological and environmental problems. A microbial desulfurization technique for SBR ground rubber has been developed by a novel sulfur-oxidizing bacterium Sphingomonas sp.  The oxidation of crosslinked SS and SC bonds and the rupture of CC double bonds had happened to SBR vulcanizates during microbial desulfurization. NR vulcanizates filled with desulfurized SBR ground rubber had lower crosslink density and hardness, higher tensile strength and elongation at break, compared with those filled with SBR ground rubber of the same amount. (RDC 11/25/2011)

Accelerated aging of elastomeric composites with vulcanized ground scraps
(280–285)Journal of Applied Polymer  Science 123 #1 (2012)
Carli et al, Brazil, showed that accelerated aging led to a decrease in the mechanical properties as a result of an increase in the stiffness of the material, related to an increase in the crosslink density.  However, these properties were not affected by the addition of rubber scraps up to 50 phr, either before or after aging.  The increase in the glass transition temperature of the composites after aging, measured using dynamic mechanical analysis, confirmed the occurrence of a postcrosslinking process. (RDC 10/12/2011)

Sustainable acoustic and thermal insulation materials from elastomeric waste residues
( 4157-4171) Chemical Engineering Science 66  #18 (2011)
Benkreira, Khan and Horoshenkov of the University of Bradford, United Kingdom, developed a new processing route to transform elastomeric waste residue (particulates) into acoustic and thermal insulation materials that can compete with commercial products.  Grain and fibre particulates are bound with a foaming polyurethane or a similar polymer, the chemistry of which can be manipulated to control the structure stiffness and the evolution of the foaming gas into open or closed cells.  Here the study uses two examples of such residues, tyre and carpet shreds both composed of fibres trapping grains of either rubber or PVC.  Compounds were made from these systems with different PU binders and the structural properties (density, porosity, air flow resistivity, tortuosity and stiffness) and performance properties (sound absorption, sound transmission, impact sound insulation and thermal conductivity) were measured as a function of binder loading and chemistry. The data obtained show clearly that performance can be tailored by tailoring structural properties resulting with materials that match or even outperform commercial products. The data set obtained here can be usefully exploited with available acoustic and thermal insulation materials model to take the approach further and extended to other waste systems.  (RDC 7/12/2011)