Using fractal dimension and shape factors to characterize the microcrystalline cellulose (MCC) particle morphology and powder flowability

Abstract

The flowability of microcrystalline cellulose is related to its particle morphology and structure, but this relation is difficult to characterize quantitatively, due to irregularity in particle shape. This study uses fractal dimension combined with shape factors (circularity, elongation, compactness, solidity) for characterization of six microcrystalline cellulose (MCC) powder samples of different particle morphology. Fractal dimension was shown to be the main factor affecting the powder flowability. The K-means clustering method and box plot were used to analyze the morphological differences of three types of MCC particles with large flowability differences as well as small flowability differences with large size differences. Among the four shape factors, circularity was shown to exert the greatest influence on powder flowability. Validating these results, a thorough statistical multivariate regression analysis was conducted. This treatment eliminated the other shape factors, to yield a two-parameter equation characterizing the quantitative relationship between the MCC powder flowability and morphology.