Thermal stability of poly(N-vinylpyrrolidone) immobilized on the surface of silica in the presence of noble metals in an atmosphere of hydrogen and oxygen

Thermogravimetric analysis in combination with FTIR spectroscopy were used to assess the thermal stability and mechanism of degradation of poly(N-vinylpyrrolidone) (PVP) grafted on the surface of silica under oxidizing and reducing conditions before and after impregnation of noble metals. The structure of PVP immobilized on the silica surface is stable up to 175 degrees C regardless of the atmosphere of the process. The presence of a noble metal shifts the degradation of the polymer towards a lower temperature under reducing conditions while under oxidative conditions the degradation of the polymer occurs at a temperature close to bare PVP/SiO2. The lower thermal stability of Me/PVP/SiO2 (where Me = Pd, Ru, Rh, Pt) complexes compared to based PVP/SiO2 under reducing conditions is due to the high reactivity of the hydrogen molecule on the surface of impregnated metals.

Automated summary

Thermogravimetric analysis in combination with FTIR spectroscopy was used to assess the thermal stability and mechanism of degradation of poly(N-vinylpyrrolidone) (PVP) grafted on the surface of silica under oxidizing and reducing conditions before and after impregnation of noble metals. The presence of noble metals decreases the thermal stability of the polymer under reducing conditions, while under oxidative conditions, the degradation temperature is similar to bare PVP/SiO2.