Chemometric methods for studying the effects of chemicals on cellulose pyrolysis by thermogravimetry–mass spectrometry

Abstract

Chemometric methods were used for extracting information out of the mixture mass spectra recorded in a thermogravimetric–mass spectrometric (TG–MS) analysis. Principal Component Analysis (PCA) and Discriminant Rotation (DR) were applied for studying the effects of fire retardants on the gases evolved during thermal degradation of cellulose. The chemicals (NH 4) 2SO 4, (NH 4) 2HPO 4 and a commercial retardant (Fire Trol) were used as fire retardants. PCA and DR resulted in four factors discriminating between untreated cellulose and cellulose treated with fire retardants. For the interpretation of the factors the rotated discriminant spectra were used. For estimating the effects of the fire retardants, the score plot in the first two discriminants space was used. It was shown that in all cases the retardation action was based on various factors such as: the increase of CO 2 evolution produced by dehydration of cellulose, the relative decrease of very flammable volatile products (carbonyl compounds, reduced furans and pyranone derivatives) and the increase of levoglucosenone produced by dehydration of levoglucosan. A differentiation between the effects of (NH 4) 2SO 4 and the other two retardants was also observed and it concerned mainly the production of phenol derivatives and acetic acid.