Mechanochemical Treatment in High-Shear Thermokinetic Mixer as an Alternative for Tire Recycling

This publication highlights the use of a high-speed thermokinetic mixer as an alternative to recycling ground tire rubber (GTR) using mechanochemical treatment. The GTR initially had a gelled fraction of 80% and presented a reduction of up to 50% of gel fraction in the most intensive condition (5145 rpm, n(2)). The processing condition at the lowest speed (2564 rpm, n(1)) resulted in greater selectivity in chain scission (K similar to 1). However, in the most intense processing condition (10 min to n(2)), more significant degradation was observed via random scission, reduction in the glass transition temperature, T-g (11 degrees C), increase in the soluble polymeric fraction, and a more significant reduction in the density of bonds occurs. The artificial neural network could describe and correlate the thermal degradation profile with the processing conditions and the physicochemical characteristics of the GTR. The n(2) velocity resulted in the formation of particles with a smoother and more continuous surface, which is related to the increase in the amount of soluble phase. The approach presented here represents an alternative to the mechanochemical treatment since it can reduce the crosslink density with selectivity and in short times (1-3 min).

Automated summary

This study explores the use of a high-speed thermokinetic mixer for recycling ground tire rubber (GTR) through mechanochemical treatment. Different processing conditions are found to reduce the gel fraction and result in various degradation effects and physicochemical changes. An artificial neural network is utilized to describe and correlate the thermal degradation profile with the processing conditions and characteristics of the GTR.