An improved, less erroneous protocol for the classical “cuen”, “cuoxam” or “cadoxen” viscosity measurements of pulps

Abstract Correctness and reliability of molar mass data by viscometry in organometallic solvents (cuen, cuoxam, cadoxen) are compromised the alkalinity these which causes immediate depolymerization especially case pulps with higher carbonyl content (oxidative damage). The viscosity values thus correspond to after beta-elimination reactions that underly degradative processes, is sometimes significantly smaller than determined gel permeation chromatography (GPC) non-degrading solvent system DMAc/LiCl. Despite this well-known drawback, measurements have become a standard approach for due their ease fastness, pulp paper industries. A potential way reduce inherent error determinations via reductive treatment prior dissolution solvents, converts labile, alkali-sensitive structures back respective alcohols. Using sodium borohydride (NaBH 4 ) on different types cellulosic pulps, we demonstrate beneficial effects such reduction step degree polymerization (DP) all three common solvents: cuen, cuoxam cadoxen. Molar distributions profiles groups were GPC selective fluorescence labeling (“CCOA method”). Such was valuable hemicellulose-containing pulps. While decreased measurement according new protocol beyond doubt, an acceptance industries at least questionable, because new, more correct would not agree old – wrong, but consistent numbers accumulated over years decades. In long run, however, improved will prevail here as well its lower rate.