Thermal analysis of ground tire rubber devulcanized by microwaves

Ground tire rubber (GTR) was treated by microwaves at the same power and at different times of exposure, in order to improve their recycling characteristics. The resulting materials were characterized by thermogravimetric analysis (TG/DTG) and differential scanning calorimetry (DSC). DSC analysis showed that the microwaves treatment, specially for longer exposure times, changes the thermal behavior at low temperatures, that is to say, changing its glass transition (T-g), probably due to the modification in the chemical structure of the rubber. The TG/DTG analysis showed that the thermo-oxidation behavior of the sample after the microwaves treatment is different from the sample before the treatment. The thermo-oxidation temperature of the devulcanized rubber is shifted to lower temperatures, even for the rubber treated in short times.