@article{dong_turgman-cohen_roberts_kiserow_2010, title={Effect of Polymer Size on Heterogeneous Catalytic Polystyrene Hydrogenation}, volume={49}, ISSN={["0888-5885"]}, DOI={10.1021/ie1011905}, abstractNote={The effect of polymer coil size on the rate of polystyrene (PS) hydrogenation was studied in a slurry reactor with mixtures of decahydronaphthalene (DHN) and carbon dioxide (CO2) as the solvent for the polymer. The PS coil size was changed by varying the polymer molecular weight from 9300 g/mol to 357 000 g/mol and by varying the CO2 concentration. Using a 5% Pd/5% Ru/SiO2 catalyst, the rate of aromatic ring hydrogenation at 150 °C was found to be strongly dependent on the size of a polymer coil relative to the average pore diameter of the catalyst. Significant pore diffusion limitations, as indicated by values of the Weisz modulus, were observed with increasing polymer molecular weight. Increasing the concentration of CO2 resulted in increased reaction rates, with an improvement of nearly 2 orders of magnitude at the highest PS molecular weight.}, number={22}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Dong, Laura Beth and Turgman-Cohen, Salomon and Roberts, George W. and Kiserow, Douglas J.}, year={2010}, month={Nov}, pages={11280–11286} }
 @article{dong_mcvicker_kiserow_roberts_2010, title={Hydrogenation of polystyrene in CO2-expanded liquids: The effect of catalyst composition on deactivation}, volume={384}, number={1-2}, journal={Applied Catalysis. A, General}, author={Dong, L. B. and McVicker, G. B. and Kiserow, D. J. and Roberts, G. W.}, year={2010}, pages={45–50} }
 @article{kim_kim_kim_ahmed_dong_roberts_oh_2010, title={The effect of prepolymer crystallinity on solid-state polymerization of poly(bisphenol A carbonate)}, volume={51}, number={12}, journal={Polymer}, author={Kim, J. and Kim, Y. J. and Kim, J. D. and Ahmed, T. S. and Dong, L. B. and Roberts, G. W. and Oh, S. G.}, year={2010}, pages={2520–2526} }
 @article{kim_dong_kiserow_roberts_2009, title={Complex Effects of the Sweep Fluid on Solid-State Polymerization: Poly(bisphenol A carbonate) in Supercritical Carbon Dioxide}, volume={42}, ISSN={["1520-5835"]}, DOI={10.1021/ma802193q}, abstractNote={The effects of the sweep fluid on solid-state polymerization (SSP) of poly(bisphenol A carbonate) (BPA-PC) were investigated. Prepolymers with two different number-average molecular weights, PCP6C (Mn = 3800 g/mol) and PCP9C (Mn = 2400 g/mol), were synthesized using melt transesterification. Solid-state polymerization of these prepolymers was carried out at temperatures in the range of 150−190 °C with supercritical carbon dioxide (scCO2) and N2 as the sweep fluids. It was found that scCO2 at 207 bar could either increase or decrease the rate of SSP relative to the rate in atmospheric N2, depending on the prepolymer molecular weight. At 190 °C, the molecular weights of the polymers synthesized from the higher-molecular-weight prepolymer (PCP6C) were higher with scCO2 as the sweep fluid compared to those of the polymers synthesized with N2. In contrast, at the same temperature of 190 °C, the molecular weights of the polymers synthesized from the lower-molecular-weight prepolymer (PCP9C) were lower with scCO...}, number={7}, journal={MACROMOLECULES}, author={Kim, Jaehoon and Dong, Laura Beth and Kiserow, Douglas J. and Roberts, George W.}, year={2009}, month={Apr}, pages={2472–2479} }
 @article{dong_carbonell_roberts_kiserow_2009, title={Determination of polystyrene-carbon dioxide-decahydronaphthalene solution properties by high pressure dynamic light scattering}, volume={50}, ISSN={["1873-2291"]}, DOI={10.1016/j.polymer.2009.09.069}, abstractNote={The diffusion coefficients of polystyrene (PS) in decahydronaphthalene (DHN) and in solutions of carbon dioxide (CO2) and DHN were measured for dilute PS solutions over a range of temperatures and CO2–DHN ratios using high pressure dynamic light scattering. Infinite dilution diffusion coefficients (D0) of PS and dynamic second virial coefficients (kD) were determined for essentially monodisperse 308 kDa PS. At a system pressure of 20.7 MPa, PS diffusion coefficients increased by a factor of 2.5, and the activation energy of diffusion decreased by approximately 16% when DHN was “expanded” with 44 mol% CO2. However, the hydrodynamic radius of PS at a given temperature was not particularly sensitive to the CO2 concentration. Solvent quality, as measured by kD, decreased at higher CO2 concentrations. The addition of CO2 to polymer solutions may offer a way to “tune” the properties of the solution to facilitate the heterogeneous catalytic hydrogenation of polymers.}, number={24}, journal={POLYMER}, author={Dong, Laura Beth and Carbonell, Ruben G. and Roberts, George W. and Kiserow, Douglas J.}, year={2009}, month={Nov}, pages={5728–5732} }