A solvent free process for the generation of strong, conducting carbon spheres by the thermal degradation of waste polyethylene terephthalate

An efficient, solvent-free, catalyst-free approach is reported for the synthesis of strong, paramagnetic, conducting carbon microspheres from used polyethylene terephthalate (PET). The thermal decomposition of used PET polymer at 700 °C for 3 h in a closed reactor under autogenic [self generating] pressure yielded exceptionally hard spherical (2 to 10 μm diameters) solid carbon bodies, with the average tensile strength for a single [∼6 μm diameter] carbon sphere calculated to be 8.30 ± 0.69 GPa.