Enhanced solubility of siloxy-modified polyhedral oligomeric silsesquioxanes in supercritical carbon dioxide

Demirtas C., DİLEK HACIHABİBOĞLU Ç.

JOURNAL OF SUPERCRITICAL FLUIDS, cilt.143, ss.358-364, 2019 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 143
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.supflu.2018.09.015
  • Dergi Adı: JOURNAL OF SUPERCRITICAL FLUIDS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.358-364
  • Anahtar Kelimeler: Siloxane functionality, CO2-philicity, organic-inorganic hybrid material, density-based semi empirical models, PHASE-BEHAVIOR, POSS POLYMERS, SOLIDS, MISCIBILITY, DENSITY, POLY(DIMETHYLSILOXANE), FUNCTIONALIZATION, AMPHIPHILES, VISCOSITY, PRESSURE
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Alkyl siloxy functionalization increases the solubility of polyhedral oligomeric silsesquioxanes (POSS) in supercritical carbon dioxide over an order of magnitude compared to its counterpart with fluoroalkyl groups. The studied component, octatrimethylsiloxy POSS also exhibits higher solubility than other previously studied POSS types with various alkyl and methacryl groups. The octatrimethylsiloxy POSS-CO2 solid-vapor equilibrium curves have been constructed at temperatures between 308 and 328 K by measuring cloud points. The highest measured solubility of octatrimethylsiloxy POSS was 0.176 wt. fr., corresponding to 0.0083 mol fr., at 13.36 MPa, 328 K, and CO2 density of 0.59 g/cm(3). The solubility versus CO2 density isotherms fall on a master curve up to about 2 x 10(-3) mol fraction, while at higher concentrations, higher solubility was attained with increasing temperature. The experimental data were correlated using various semi-empirical density-based models which provided satisfactory correlations.