Mathematical models developed describe the unfolding of polymeric crystals in the presence of a solvent followed by their subsequent disentanglement. A thermodynamic model considering the free energy changes during crystal unfolding was proposed to obtain an expression for the unfolding rate. A simplified version of this expression, assuming uniform crystal size, was incorporated into a continuum model to predict the dissolution kinetics of a semicrystalline polymer slab. The model yielded predictions of the crystalline and solvent volume fractions as a function of position within the slab, in addition to changes in the fraction of polymer dissolved as well as the degree of crystallinity of the polymer as a function of time. The degree of crystallinity of the polymer decreased with time and the plot of the fraction of the polymer dissolved as a function of time exhibited Case II behavior. The model predictions agreed will with experimental results obtained during dissolution of semicrystalline poly(vinyl alcohol) in water.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.