Ultraviolet spectroscopic study of the cellulose functionalization with silanes

The reaction of a cellulosic material (Whatman no. 42 filter paper) with tw o silanes was studied by Diffuse Reflectance Ultraviolet-Visible Spectrosco py and Diffuse Reflectance Fourier Transform Infrared Spectroscopy. The sil anes were 3-aminopropyltriethoxysilane (APS) and methyltrimethoxysilane (MS ), a silane with a non-reactive organofunctional group. The use of organic peroxides was required in order to achieve an efficient cellulose modificat ion with the silanes. The Diffuse Reflectance UV-VIS Spectroscopy can provi de valuable information about the mechanism of the reactions between silane s and cellulose. The reaction between APS and cellulose involves not only t he silanol groups of the silane, but also the amino groups. The spectra of APS-treated celluloses show an absorption band at 325 nm. This band was ass igned to imines produced in the reaction of the amino groups of APS with th e cellulose. This absorption band increased when APS-treated cellulose was cured at 120 degrees C. The amino groups, attached to the cellulose dissapp eared in this process.