(94c) Dissolution of Polymer Particulate Systems: Population Ensemble Modeling

The present study addresses the dissolution of cellulosic biomass particles in conditions emulating large-scale processing where the particles exhibit a distribution of size and degree of crystallinity. To this end, we have developed a model in which the behavior of a population of particles is obtained from an ensemble of individual polymer particle dissolution models. The dissolution of individual semicrystalline polymer particles is based on the relevant transport phenomena and kinetics and reveals decrystallization and disentanglement as two important and potentially rate-determinant steps in the process. [Ghasemi, M.; Singapati, A. Y.; Tsianou, M.; Alexandridis, P., Dissolution of semicrystalline polymer fibers: numerical modeling and parametric analysis. AIChE Journal 2017, 63 (4), 1368-1383. DOI: 10.1002/aic.15615] The average value or the number distribution of any intra-particle property captured by the individual particle model can be determined by simulation of a sufficient number of individual particles such that ensemble averages are independent of the particle numbers and the computed particle distributions are acceptably smooth. Using this population ensemble model, various particle size distributions and crystallinity distributions are analyzed for different dissolution parameters. The findings from this study would be useful for the rational design and optimization of biomass pretreatment processes to reduce the particle size and degree of crystallinity. [Ghasemi, M.; Tsianou, M.; Alexandridis, P., Assessment of solvents for cellulose dissolution. Bioresource Technol. 2017, 228, 330-338. DOI: 10.1016/j.biortech.2016.12.049] [Ghasemi, M.; Alexandridis, P.; Tsianou, M., Dissolution of cellulosic fibers: effect of crystallinity and fiber diameter. Biomacromolecules 2018, 19 (2), 640-651. DOI: 10.1021/acs.biomac.7b01745]