TRITIUM EXCHANGE BETWEEN CELLULOSE AND WATER: ACCESSIBILITY MEASUREMENTS AND EFFECTS OF CYCLIC DRYING

Tritium exchange between cellulose and water vapor was used to measure the accessibilities of amylopectin, amylose, regenerated cellulose, wood pulp, bacterial and Valonia cellulose, and cellulose trinitrate using both gas counting and solid counting techniques. The results compare satisfactorily with other accessibility and crystallinity measurements.The incomplete reversibility of the exchange reaction was used to study directly changes in the accessibility of regenerated cellulose which occurred during repeated wetting and drying from water. The results indicated that a partial interchange of accessible and inaccessible regions occurs during wetting and drying.