Modelling the Kinetics of Migration of Stabilisers from Polypropylene

Modelling the Kinetics of Desorption of a Mixture of Flame Retardants from Rubber

“…With the desorption kinetics of an ingredient depending on its diffusion within the rubber compound, for prediction of the rate of the process an empirical model is proposed, the equation of which has the form [1][2][3][4]:…”

Modelling the Kinetics of Desorption of Ingredients from Polymers

“…To this end, the coefficient of distribution is introduced into the models, which is calculated as the ratio of the equilibrium concentration of the ingredient in the surrounding medium to its concentration in the polymer. The coefficient of distribution determines the influence of the change in the concentration gradient at the polymer/medium surface on the rate of transfer of the ingredient in the bulk of the polymer and from its surface [50][51][52][53][54][55][56][57][58][59][60][61].…”

“…Broadening of the limits of application of the models is connected with determination of the temperature dependences of the empirical coefficients of diffusion and the solubility of the ingredients. The temperature dependences of the empirical coefficients were obtained for desorption of stabilisers from polyolefins [13,17,18,20,21] and plasticisers from polyvinyl chloride [19]. Determination of the dependence of the empirical coefficients on the chemical nature of the ingredients under different desorption process conditions has proved to be less successful, which explains the small volume of experimental data.…”

“…The influence of the extraction conditions on modelling the kinetics of the process has been analysed in previous studies [53][54][55][56]. The accuracy of prediction depends on the mixing of the liquid, the solubility of the ingredient in the liquid, and the ratio between the content of the ingredient in the liquid and its equilibrium solubility.…”

“…Checking of the model [24] during the sorption of stabilisers [41,46,47,56] and plasticisers [11,12,58] showed that, to increase the reliability of prediction, it is necessary to adjust the values of coefficient a i . The general results of correcting coefficient a i during evaporation and extraction of stabilisers, obtained under process conditions with retention of the polymer/medium boundary, are presented in Tables 2 and 3, and Table 2 also presents calculated values of coefficient a i obtained for specified values of M τ /M 0 .…”