Soluting-In and Soluting-Out of Water-Soluble Polymers in Aqueous Carbohydrate Solutions Studied by Vapor Pressure Osmometry
کد مقاله : 1226-PHYSCHEM20
نویسندگان:
1نوسیبه ابراهیمی *، 2رحمت صادقی
1سنندج، بلوار پاسداران، دانشگاه کردستان، دانشکده علوم پایه، گروه شیمی
2عضو هیأت علمی دانشگاه کردستان. (استاد گروه شیمی فیزیک)
چکیده مقاله:
Precise vapor pressure osmometry (VPO) measurements at 308.15 K have been performed for ternary systems of carbohydrate in aqueous 0.2 w/w polymer solutions. The polymers are polyethylene glycol 400 (PEG400), polyethylene glycol 10000 (PEG10000) and polypropylene glycol 400 (PPG400), and the carbohydrates are xylose, xylitol, glucose, fructose, sucrose and raffinose. In order to study the soluting-out and soluting-in effects occurring in the polymer-carbohydrate aqueous systems, deviations of vapor-liquid equilibria behavior of these systems from the semi-ideal state have been evaluated. The VPO data obtained for PEG-carbohydrate aqueous systems, which are completely miscible, generally show positive deviations (soluting-in effect) from the semi-ideal behaviour that become more positive by increasing hydrophobic nature of PEG and carbohydrates. However, in the case of PPG + carbohydrates aqueous systems that can undergo phase separation, the VPO data in the monophasic and biphasic regions, respectively show negative (soluting-out effect) and positive deviations from the semi-ideal behaviour. In these systems, because of unfavorable PPG-carbohydrate interactions, the solutes exclude themselves from the vicinity of each other and therefore aqueous biphasic systems are entropically formed above a critical concentration.
کلیدواژه ها:
Vapor pressure osmometry, Water-soluble polymer, Carbohydrate, Semi-ideal behavior, Soluting effects
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