مقالههای Elham Ebrahimiaqda
توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقالههای نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده میشوند.
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال ۱۳۹۰
تعداد صفحات: ۶
The new local composition model, Segmental–Wilson–NRF, based on the volume fraction is developed and a new excess Gibbs energy function for description of the binary polymer–solventsystems is obtained. This model for non–polymeric systems reduces to N–Wilson–NRF model. Theactivity coefficient of the new model consists of two parts, combinatorial and residual terms. In this work the S–Wilson–NRF are used for residual term and Flory–Huggins equations are appliedfor combinatorial term. The models with one temperature depended adjustable energy parametersare applied to correlate and predict the activity of solvent for 50 binary polymer solutions at various number–average molar mass of polymer and temperatures. In this work, the two differentapproaches are used for optimization of the solvent and segmental parameters. In the first approach, the two parameters are correlated for each binary polymer systems at the different conditions, however in the other approach we assume that the solvent and segmental interactionparameters are the same for the same binary polymer systems but they have the different numberaverage molar mass. Thus, using a temperature dependent relation for each parameter, only the two adjustable parameters for this group of systems are correlated. Using the first and secondapproaches, the overall root of mean square deviation (RMSD) are 0.018 and 0.037, respectively. The results show that the new model with the two different approaches is in good agreement with experimental data<\div>
۲A New Segmental Local Composition Model for Calculation Thermodynamic Properties of Binary Polymer Solutions
اطلاعات انتشار: Scientia Iranica، بيست و يكم،شماره۶، ۲۰۱۴، سال ۰
تعداد صفحات: ۱۱
A new local composition model, Segmental–Wilson Non–Random Factor (S–Wilson–NRF), based on volume fraction is developed. The new activity coefficient model consists of combinatorial and residual terms that the combinatorial Flory–Huggins equation and the S–Wilson–NRF function are used for the entropy and enthalpy terms, respectively. This model for non–polymeric systems reduces to Nonelectrolyte–Wilson–NRF model. The present model with two dependent adjustable energy parameters is applied to correlation of the activity of solvent for 24 binary polymer systems at various number–average molar masses of polymer and temperatures. Moreover, the results of the present model are compared with the other local composition models such as Nonrandom Two–Liquid (NRTL), NRTL–Nonrandom Factor (NRTL–NRF) models and the Flory–Hugginsmodel. Finally, the new model is applied for correlation of the excess molar enthalpy of the binary polymer solutions at the different conditions. As a conclusion, the results of the new model are in good agreement with the experiment.
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