Volumetric determination of alpha-, beta-, and gamma-cellulose in pulps and in papers containing sizing, filler, and other materials

Abstract

The volumetric method for the determination of alpha-, beta-, and gamma-cellulose, previously described in Bureau Research Paper RP979 is shown to be applicable to papers containing rosin, glue, starch, oxidizable fillers and lignin, and to pulps containing natural resins in any amount. As the method depends upon the estimation of each cellulose fraction by oxidation with dichromate, and as the sizing ma terials are all oxidizable, the manner of making corrections for these materials is described in detail. The alpha-cellulose values so obtained are shown to be in good agreement with those of a gravimetric method for a wide range of pulps and papers. The relative shortness of the volumetric procedure is especially apparent when the pa pers contain mineral fillers or lignin, as these are removed when necessary rather than estimated and corrected for. CONTENTS r. Introduction ________ _____ ___ ______ ______ _______ ______ ____ ___ _ _ II. Analytical procedure _____ ____ _________ __ _______ __ _________ ____ _ III. Comparison of the volumetric and gravimetric results for alpha-cellulose _________ ___ __ _______ __ ___ __ _________ _____ _________ _ I V. Corrections for the sizing materials __ ____ _______ _____ ___ _______ _ _ 1. Dichromate equivalents of the sizing materials-___ _____ ___ _ 2. Distribution of the sizing materials among the three cellulose fractions and the method of applying the corrections ___ __ _ (a) Alpha fraction ________ ________ ____ ________ ____ _ _ (b) Gamma fraction ___________ ___ ___ _______ __ ____ _ _ V. Dichromate equivalents for cellulose and lignin ______ __ _____ __ ___ _ VI. Summary _____ ____ _____ _____ _________ ___________ ___ ________ _ _