Thermal Features of Fe₃O₄ loaded Polytetrafluoroethylene – Polyethylene Oxide Blends

Polytetrafluoroethylene (PTFE) is a crystalline polymer, with poor processability due to its low thermal degradation temperature and high melting temperature, excellent chemical stability, and lack of (good) solvents. Polyethylene oxide (PEO) is a semicrystalline polymer, soluble both in water and some organic solvents and perceived as bio-compatible. Blends of PTFE-PEO have been obtained by mixing the water dispersion of PTFE (Polyscience) with water solutions of PEO in various ratios. PEO with an average molecular mass of 900,000 was purchased from Sigma Aldrich. After the homogenization of the final solutions, various amounts of Fe₃O₄ nanoparticles (purchased from Nanostructured & Amorphous Materials, Inc.), have been added to the PTFE water dispersion - PEO water solution mixture. The as-obtained fluid was homogenized by stirring; water was removed by heating. Complete water evaporation was confirmed by thermogravimetric analysis (TGA). The thermal features of PEO-PTFE blends and PEO-PTFE-Fe₃O₄ nanocomposites have been investigated by TGA using a Netzsch 209 F3 Tarsus instrument and by Differential Scanning Calorimetry (DSC) by using Netzsch 214 Polyma instrument. TGA data were recorded in a nitrogen atmosphere at a heating rate of 10 ^oC/min. DSC data have been recorded at various heating/cooling rates ranging from 5 ^oC/min to 50 ^oC/min. The study focused on the thermal stability of PTFE-PEO blends and on the effect of Fe₃O₄ nanoparticles on thermal stability and phase transitions.