Etude du Comportement Thermique de la Cellulose par Spectroscopie Infra Rouge II. Analyse in situ des évolutions spectrales entre 25 et 450°C

Abstract

The part I of this work discusses the potentialities and limits of the in situ spectroscopic analysis of cellulose by Diffuse Reflectance Infrared Fourier Transform in an environment device. In this paper, we describe: the in situ evolutions of cellulose from 25 to 270°C under N₂ or air; the evolution of a partially thermolyzed cellulose residue during thermal treatment from 25 to 450°C and finally the oxidation in air of a cellulose char at 300°C. We observe a limited evolution of the cellulose below 270°C. Only some carbonyle groups issued from rearrangement of cellulose chains are formed. The thermal treatment of the thermolyzed residue leads to a progressive aromatization of the solid between 270 and 450°C. The oxidation in air induces the formation of oxygenated groups (carbonyles, carboxylic acids, lactones) and proceeds by reaction on both aliphatic and aromatic sites. Some dehydration of carboxylic groups to anhydrides are observed.