Determination of neutral sizing agents in paper by pyrolysis–gas chromatography

Abstract

Neutral sizing agents, viz., alkylketene dimers (AKDs) and alkenylsuccinic anhydride (ASA), in paper were determined by pyrolysis–gas chromatography, including those that reacted chemically with the paper. The peaks of intact AKDs and related ketones in the pyrograms were used as the key peaks for the determination of AKDs in paper samples containing between 0.025 and 1.0% of AKDs. The results obtained suggest that almost 75% of the AKDs added are retained in all the paper samples. Further, the relationship between the AKD content and the degree of sizing is interpreted in terms of the possible paper sizing mechanisms. The ASA content in paper was also determined in essentially the same way as for the AKDs, and is discussed in relation to the degree of sizing.