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Studying the Relationship between Gradient Energy Coefficient with Occupied Site Fraction, Temperature, Density and Surface Tension for Liquid Cyclohexane

Authors: Saygın Muhamad Nuri --- Shanay Rajab Hasan
Journal: Diyala Journal For Pure Science مجلة ديالى للعلوم الصرفة ISSN: 83732222 25189255 Year: 2018 Volume: 14 Issue: 02 Pages: 187-202
Publisher: Diyala University جامعة ديالى

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Abstract

The Gradient energy coefficient ( ) in polymers and oligomers (a few segments) play an important role in polymer blending, wetting, coating, adhesion process, foaming and a comprehensive role in the description as well as understanding of many processes especially in innovation of new polymer with classification of materials. As a result, the main reason in this study appear which has how the gradient energy coefficient changes from bulk to surface, has been establishing the new equation that helped us to extract the correlation between gradient energy coefficient and different parameters. The gradient energy coefficient has been related with hole fractions, temperature and density. The relationships between the above-mentioned parameters are then drawn according to our model. Both Simha-Somcynsky (SS) and Cahn-Hilliard (CH) models are employed together to calculate the thermodynamic properties of cyclohexane, namely, the hole fraction in temperature range at 313-473 K various presures up to 150 Mpa. Our values for the average and maximum percentage deviation of the specific volume of cyclohexane are calculated as 0.0196% and 0.0678% respectively


Article
Extracting the Density Gradient Profile of Polyethylene Glycol from Bulk to Surface
حساب كثافة الشد السطحي لبولي اثيلين كلايكول من العمق الى السطح

Author: S. M. NURİ S. M. NURİ
Journal: kirkuk university journal for scientific studies مجلة جامعة كركوك - الدراسات العلمية ISSN: 19920849 / 26166801 Year: 2017 Volume: 12 Issue: 4 Pages: 337-352
Publisher: Kirkuk University جامعة كركوك

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Abstract

In this work the Simha and Somcynsky (SS) lattice hole theory in conjunction with Cahn-Hilliard(CH) model have been used, (SS) theory describes the thermodynamic properties of both low and high molecular weight in terms of hole fraction, On the other hand (CH) describes the free energy profile of polymer surfaces or interfaces as an inhomogeneous mixture. CH consider the energy density to be two fold. The first is the constant free energy density for a homogeneous region of the system and the second is the density gradient contribution to the free energy. Have employed the mentioned theories in derive the new equations to extract in surface tension and surface depth profile in terms of chemical potential by means of SS theory. Starting form the atmospheric pressure to 150Mpa and for temperature range from 313 to 473 K, Then ıt is found the density profile of polyethylene glycol decrease as it is approached to the surfase. PVT characteristic parameters of the SS theory are calculated using the data of polyethylene glycol. the average and maximum value (at polyethylene glycol in different molecular weight

) ونظرية (SS تضمن الجزئيات ذات الاوزان الجزئية الواطئة والعالية , ومن ناحية اخرى يصف نظرية كاهن هيليارد الطاقة الحرة في السطح البوليمرات أو الطاقة الحرة في الوصلة ما بين عمق والسطح في الجزء المتجانس والغير المتجانس في المادة , يعتبر CH كثافة الطاقة الناتجة عن مساهمة اولهما كثافة الطاقة المتجانسة والثانيهما هي ميل الطاقة من المنطقة الغير المتجانسة الى الطاقة الحرة , وقد استخدمنا النظريات المذكورة في اشتقاق المعادلات الجديدة ولأول المرة (بولي أثيلين كلايكول) للاتتزاع في الشد السطحي ولمحة عن العمق الكيميائي للبوليمر تحت الدراسة ابتدآ من الضغط الجوي الى 150Mpa ودرجة الحرارة من 313K الى 473K وكانت نسبة الخطأ الحد الادنى والأقصى للحجم النوعي او الانحراف عن نسب الحقيقي لبوليمر بولي اثيلين كلايكول المستخرجة هي 0.03 و 0.28 على التوالي

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