EFFECTS OF ENZYMATIC AND CHEMICAL DRAINAG E AIDS .1. FREENESS AND WATER-RETENTION

The paper contains further information about specific effects oi enzym atic drainage aids. After evaluating relevant published facts, some re sults oi an own comparison between an enzymatic aid (Pergalase A40) an d a polymeric one (Polymin SK) were summarised. This has been carried out by microscopic investigations and by measuring the effects on free ness and water retention of various pulps and pulp fractions. The resu lts suggest, that the enzyme cocktail reduces the mucilage components, diminishes the ''fibre fur'', shortens damaged fibres, and swells the walls oi broken fibres. A chemical drainage aid contributes predomina tely to the formation of fibre flocks and to the binding of fines and mucilage onto the fibre surface.