It is widely known that PTFE(polytetrafluoroethylene) produces harmful gases, for example, C3F6, C2F4, and HF by pyrolysis. In this study, CaCO3 or Ca(OH)2 were added to PTFE to prevent from producing harmful gases and to fixate F in the residue as CaF2 by acid-base reaction between PTFE and CaCO3 or Ca(OH)2. In a series of pyrolysis experiments, F in PTFE was fixated in the residue as CaF2. The yields of F as a CaF2 were about 20-40wt% in the case of CaCO3 addition and 50-60wt% in the case of Ca(OH)2 addition. To raise the yield of F as CaF2, Ca(OH)2, PE(polyethylene) and zeolite were added to PTFE. About 80wt% was obtained for the yield of F as CaF2. It is revealed that simultaneous pyrolysis of PTFE and PE promotes the formation of HF and is effective in the fixation F as a CaF2.
