82 Pathway for High-Quality Reclaim by Thermal Treatment of Sulphur-Vulcanized SBR

Thursday, October 13, 2011: 9:00 AM
Meeting Room #16 (The I-X Center)
Sitisaiyidah Saiwari, Wilma K. Dierkes and Jacques W.M. Noordermeer, Engineering Technology, University of Twente, Enschede, Netherlands
Reclaiming of SBR (Styrene Butadiene Rubber) is a challenge, as the broken polymer chains tend to re-arrangement and cyclisation. This influences the properties of the reclaimed and re-vulcanized rubber, and reduces the quality of the recycled material.   

Within this study, the breakdown of sulphur-cured SBR in a thermal reclaiming process was investigated under various conditions: The temperature range for the experiments was from 180ºC to 300ºC, and the treatments were done in air and under nitrogen. Depending on the parameters used, some of the reclaimed materials showed unique properties: while sol fraction increased as expected, crosslink density first decreased, but increased again above a certain temperature threshold. The reasons for this increase in crosslink density are complicated intra-molecular rearrangements of chain fragments due to uncontrolled degradation and oxidation. This was confirmed by FT-IR and TGA measurements. Preventing oxidation during thermal treatments reduces the degree of rearrangements and results in significantly improved SBR reclaim properties.