A fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl) acrylamide oligomer/silica gel nanocomposite with no weight loss even at 800 °C equal to an original silica gel

摘要

Fluoroalkyl end-capped N-(l,l-dimethyl-3-oxo-butyl)acrylamide oligomer [R_F-(DOBAA)_n-R_F]/silica gel nanocomposite,which was prepared by reaction of the corresponding fluorinated oligomer with tetraethoxysilane and silica gel nanoparticles under alkaline conditions,exhibited no weight loss even at 800 °C equal to the original silica gel,although the corresponding parent R_F-(DOBAA)_n-R_F oligomer was completely degraded at 600 °C.Thermogravimetric analyses/mass spectra of fluorinated nanocomposite showed that this nanocomposite decomposed around 280 °C to afford CO2 and H2O as the major evolved gaseous products including some minor fluoro-and hydrocarbons.X-ray photoelectron spectroscopy analyses also showed that the contents of C,F,and Si atoms in R_F-(DOBAA)_n-R_F/SiO2 nanocomposite after the calcination at 800 °C were similar to those before the calcination.These findings suggest that the evolved gaseous products should be encapsulated quantitatively into nanometer-size-controlled silica matrices to give the fluorinated silica gel nanocomposite with no weight loss even at 800 °C equal to the original silica gel.