PARTICLE ANALYSIS OF MICROCRYSTALLINE CELLULOSE - DIFFERENTIATION BETWEEN INDIVIDUAL PARTICLES AND THEIR AGGLOMERATES

The presence of two types of particles, the individual particles and t heir agglomerates, complicates the characterization of the particle si ze and the external surface area in the microcrystalline cellulose pow ders. During characterization, different degrees of de-agglomerations may be applied with varying size and surface areas as a result. The cr ystallinity of the cellulose particles were characterized by a crystal linity index, using the solid state NMR technique. Methods for the cha racterization of particle size, surface, shape of individual particles and their agglomerates were examined and recommendations of suitable methods are given. Individual particles were separated from agglomerat es by ultrasonic treatment of a water suspension of agglomerates. Phot oextinction measurements on sonicated water suspensions were used in t he characterization of size and surface area of individual particles. The size of the agglomerates were estimated by dry sieving and the ext ernal surface area of the agglomerates with photoextinction measuremen ts on cyclohexane suspensions not treated with ultrasonic energy.