PYROLYSIS PRODUCTS AS MARKERS IN THE CHEMICAL CHARACTERIZATION OF PAPERBOARDS FROM WASTE PAPER AND WHEAT-STRAW PULPS

Analytical pyrolysis was used to characterize paperboard prepared with wheat straw subjected either to semichemical or biomechanical pulping (the latter including solid-state fermentation with the ligninolytic fungi Pleurotus ostreatus and P. floridanus) and variable proportions of waste paper Pyrolysis products were also quantified and selected in attempt to match the industrial and laboratory parameters used in the assessment of pulp quality. Although the pyrolytic compounds from str aw pulp and from waste paper pulp (mainly derived from wood fibres) we re essentially the same, significant quantitative differences were fou nd. The yields of up to 14 pyrolytic compounds were related to the per centage of waste paper in the pulps: typical cinnamyl- and syringyl-ph enolics being the most diagnostic for straw whereas the methoxyphenols with an oxidized n-chain (aldehyde-ketone) were diagnostic for waste paper Only the yields of six pyrolysis products (mainly anhydrosugar m olecules) were significantly different as regards the pulping method, suggesting different hemicellulose removal patterns. (C) 1997 Elsevier Science Ltd.