Synthesis of copper-poly tetrafluoro-ethylene composites by supercritical impregnation process

摘要

This study attempted to develop a copper-PTFE composite consisting of copper nano-particles homogeneously distributed into PTFE using scCO_2. The overall synthesis process consisted of impregnation of copper precursor and thermolytic reduction. The impregnation process was performed over a range of temperature from 40 to 160 ℃ and pressure from 120 to 200 bar. The reduction process was performed at 230 ℃ and 250 bar for 2 hours consecutively after impregnation. The changes in appearance, mass, and morphology of the PTFE composite were examined by precision balance, SEM, TEM, and EDS. The impregnation ratio increased with temperature up to 120 ℃, but decreased above 120 ℃. The impregnation ratio increased with the pressure. These results could be explained by dehydration reaction of Cu(hfa)_2H_2O and thermodynamical affinity difference of copper precursors for PTFE or scCO_2. Copper nano-particles impregnated into the PTFE were identified from SEM, TEM and EDS analysis.