Crystallization kinetics of polymer-solvent systems .2. Experimental verification of the model

A theoretical model for the description of crystallization kinetics of a polymer from solution was suggested in a previous paper [1]. In this work, this model was verified using a polyphenylene sulfide-tetramethylbiphenyl system (PPS-TMBP) as an example. The theoretically predicted particle number density was compared with that resulting from the Avrami equation by analyzing the experimental data obtained by isothermal differential scanning calorimetry. Optical and scanning electron microscopies was also applied to obtain the values of the particle number density. Size particle distribution was calculated in accordance with the proposed model to study the number of particles with sizes exceeding the resolving power of the optical microscope. For the given experimental conditions (the dissolution temperature range is 543-563 K, the polymer concentration in a solution is 40 wt %), the theory proposed in [1] predicts the formation of particles that cannot be observed in an optical microscope. This agrees with our observations, whereas the Avrami equation predicts the presence of particles that are visible in an optical microscope. The density of particle number, obtained by scanning electron microscopy at a dissolution temperature T-d = 573 K, is in the range (0.7-1.4) x 10(9) cm(-3). The model suggested in [1] predicts the value of the particle number density just in this range, whereas the Avrami equation yields a much smaller value. Thus, the model proposed in [1] describes the crystallization kinetics in the polymer-solvent system much better than the Avrami equation.