TY  - JOUR
ID  - pittir20557
UR  - http://d-scholarship-dev.library.pitt.edu/20557/
IS  - 3
A1  - Shi, C
A1  - Huang, Z
A1  - Beckman, EJ
A1  - Enick, RM
A1  - Kim, SY
A1  - Curran, DP
Y1  - 2001/01/01/
N2  - Direct thickeners for dense carbon dioxide were designed and synthesized. Each thickener contained "CO2-philic" fluorinated groups to impart solubility in carbon dioxide and "CO2-phobic" functionalities to promote intermolecular associations for viscosity enhancement. Semifluorinated trialkyltin fluorides and fluorinated telechelic ionomers were soluble to at least several weight percent in dense liquid carbon dioxide without the use of a cosolvent. Increases in solution viscosity at 297 K were measured using falling cylinder viscometry. The viscosity of liquid carbon dioxide was increased by a factor of 2-3 at thickener concentrations of 2-4 wt %. These results demonstrate that carbon dioxide viscosity enhancement is possible without the need for a cosolvent through the design of compounds with the appropriate balance of CO2-philic groups for solubility and CO2-phobic associating groups for macromolecular, viscosity-enhancing interactions. Neither compound, however, was as effective as the (29% styrene-71% fluoroacrylate) copolymer we recently developed. More substantial increases in solution viscosity were not attained with the semi-fluorinated trialkyltin fluoride because the fluorinated alkyl chains disrupted the associations that formed viscosity-enhancing, weakly associating, linear polymers. The viscosity increases obtained with the telechelic ionomer were also less than expected because of the relatively low molecular weight of the carbon-dioxide-soluble ionomers. Higher-molecularweight ionomers would not be CO2-soluble, however.
JF  - Industrial and Engineering Chemistry Research
VL  - 40
SN  - 0888-5885
TI  - Semi-fluorinated trialkyltin fluorides and fluorinated telechelic ionomers as viscosity-enhancing agents for carbon dioxide
SP  - 908 
AV  - public
EP  -  913
ER  -