Thermal degradation of nanoporous Si-containing hybrid terpolymer

Abstract

In this work development of structural and chemical properties of four nanoporous hybrid carbons has been presented. The carbons were synthesized by direct carbonization at 450, 600, 750 and 900 °C of the terpolymeric hybrid precursor composed of methacrylamide, divinylbenzene and trimethoxyvinylsilane and impregnated with sulfanilic acid (SA) as the surface modifier. The conditions of the carbonization process were set on the basis of the thermogravimetric analysis combined with FTIR analysis of the evolved gases (TGA-EGA). The use of SA contributed to the reduction of the carbonization temperature by about 100 °C and resulted in carbons with very uniform and bimodal porosity with the width range of about 1 and 14–28 nm. Spectral (ATR, Raman, XPS) and X-ray diffraction methods used to characterize the resulting carbon products allowed to define the gradual changes taking place in the morphological and chemical structure of the prepared materials. Cyclic and symmetrical structures of silicates species were gradually replaced by amorphous arrangements. At the same time, the increase in the sp2/sp3 carbon ratio from 1 to 65% proved progressive ordering and aromatization of the carbonized polymeric hybrid precursor. Some functional groups (e.g., N-containing) were built into carbon clusters forming pyridinic, pyrrolic and N-graphitic like structures, while others (e.g., carbonyls) were removed from the surface.