Effect of SBR Rubber Particle Size Distribution on Its Thermo-Mechano-Chemical Regeneration

Abstract

Recycled Styrene-Butadiene Rubber (SBR) from ground tire rubber (GTR) was sieved into four granulometric fractions between 125 and 500 microns to determine the effect of particle size on its thermo-mechano-chemical regeneration in an internal batch mixer. Different temperatures (140-180°C) and rotor speeds (40-120 rpm) were imposed with and without the addition of a regeneration aid (aromatic oil). The results show that partial regeneration (lower crosslinking degree) is possible under specific thermo-mechanical conditions, but the addition of the aromatic oil has limited efficiency towards this regeneration.

Polystyrene/Recycled Sbr Powder Compounds Produced in An Internal Batch Mixer

“…This result shows again the importance not only of composition, but also of processing conditions on resulting mechanical properties. Introducing SBR first led to partial regeneration (thermo-mechanical) of the vulcanized molecules [15]. Then, adding SEBS (coupling agent) insures that the molecules will be located at the particle surface (and not lost in the bulk polymer matrix).…”

“…These parameters will partially determine the final compound homogeneity (particle dispersion), but other parameters are known to have a substantial effect. For example, it was shown in a previous work that SBR powder alone in an internal mixer will induce crosslink density modification (partial regeneration) [15]. In this case, the order in which the components are introduced in the internal mixer will affect the state of each component.…”

Advanced Characterization of Recycled Rubber From End-of-Life Tires

“…They use the synergism between thermal energy, high shearing forces, and elongational strain to provide enough energy to break down the sulfur cross-links formed during the vulcanization process of rubber compounds but while minimizing the rubber chain scission (mainly formed by carbon-carbon bonds). 11,24,25 Devulcanization grade and selectivity (i.e., the ratio between cross-links breakdown/chain scission) reached in thermomechanical approaches depends on diverse factors and processing parameters, 18,23,[26][27][28][29] and their optimization strongly depends on the rubber matrix. The effect of different and complex chemical processes that take place during devulcanization will be different according to the chemical structure of rubber matrices and their reactivity.…”