An Infrared Spectroscopic Study of Chemically Modified Chemithermomechanical Pulp

Abstract

Abstract FT-IR spectroscopy was used to characterize chemically modified wood pulp and to judge the efficiency of different pulp modification processes. Treatment of wood pulp with aliphatic anhydrides was shown to be more effective in a polar solvent such as DMF compared to a non-polar one typified by xylene. The esterification of hydroxyl group associated with the cellulosic material was indicated by the characteristic absorption bands of the resulting cellulosic esters; the degree of hydroxyl conversion was determined by the ratio of peak intensity of hydroxyl and carbonyl stretching vibrations. The so-called “Infrared Acetyl Index” was shown to give a linear correlation with the gravimetrically determined anhydride uptake. Isocyanate modification of wood pulp yielded more complex infrared spectra, because of various secondary reactions of the reactive isocyanate component. Various aromatic isocyanates, used for chemical treatment of the wood pulp, led mainly to urethane formation, as evidenced by the ...