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    Demixing pressures of hydroxy-terminated poly(dimethylsiloxane)-carbon dioxide binary mixtures at 313.2 K, 323.2 K and 333.2 K
    (Elsevier Science Bv, 2014) N/A; Department of Chemical and Biological Engineering; Şanlı, Deniz; Erkey, Can; Researcher; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; College of Engineering; N/A; 29633
    The phase behavior of PDMS(OH)-CO2 binary mixtures was investigated. Two different molecular weight PDMS(OH) were utilized and the demixing pressures were determined at three temperatures for a wide composition range. Both of these polymers were found to form miscible mixtures with CO2 at all compositions at pressures lower than 31 MPa in the temperature range 313.2-333.2 K. Depending on the composition of the binary mixtures, two types of phase separation was observed during depressurization; the bubble point and the cloud point. In addition, at specific weight fractions a color change was also observed which was attributed to the mixture critical point. The demixing pressures were observed to increase with temperature and decrease with increasing polymer weight fraction. In addition, higher demixing pressures were obtained for the higher molecular weight polymer mixtures. The bubble point data were modeled by using Sanchez-Lacombe equation of state (SLEoS) and the binary interaction parameters were regressed at the studied temperatures. It was observed that the binary interaction parameters decreased with increasing temperature.
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    Novel nanostructured composites of silica aerogels with a metal organic framework
    (Elsevier, 2013) N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Ülker, Zeynep; Eruçar, İlknur; Keskin, Seda; Erkey, Can; PhD Student; PhD Student; Faculty Member; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; 262388; 260094; 40548; 29633
    Novel nanostructured composites of silica aerogel with Cu-BTC were synthesized using a slightly modified version of the conventional sol-gel method used to synthesize silica aerogels. The composite materials had monolithic structures with blue color consisting of well dispersed microporous domains of Cu-BTC in the mesoporous inorganic silica aerogel network. The Cu-BTC content in the composites ranged from 5 to 30 weight percent and the total surface area of the composites ranged from 1025 to 1138 m(2)/g. The microporosity of the composites increased with the increasing amount of Cu-BTC indicating that the micropores of Cu-BTC were accessible and functional. XRD analysis indicated that Cu-BTC retained its crystal structure in the composite despite being immersed in a solution containing water, ethanol and tetraethylorthosilicate. Additionally, it was observed that increasing Cu-BTC content caused a decrease in the average desorption pore radius with a wider pore size distribution. Nitrogen adsorption isotherms for composites could be predicted using the experimentally obtained pure component isotherm for the silica aerogel, theoretically obtained isotherm for Cu-BTC and the weight fractions of the components within the composite material.