The influence of the formed polytetrafluoroethylene (PTFE) grain size on the thermal degradation mechanism under nitrogen atmosphere and in air was studied by the TG-FTIR technique. The possibility of the monomer recovering from the PTFE waste was followed since the fluorinated polymers are rather expensive if their obtaining and the monomer synthesis are taken into account. The characteristic amounts from TG-DTG-DTA afforded some information on the influence of the formed PTFE grain size on the degradation mechanism in air and in nitrogen that is similar to the PTFE from synthesis degradation mechanism. The TG-FTIR analysis of the gas species evolved by thermal degradation of the samples provides information on the monomer (C2F4) recovery from the waste resulting in the machining of the formed PTFE. Our results suggest optimal conditions for an advantageous recovery of monomer from the formed PTFE waste: heating rate of 10 K/min, inert atmosphere, and a higher grain size of the formed PTFE. (C) 2014 Elsevier B.V. All rights reserved.