Phase Behavior of a Carbon Dioxide/Methyl Trimethoxy Silane/Polystyrene Ternary System

Abstract

Recently, polymeric foams filled with a silica aerogel have been developed. The phase behavior of CO2/silicon alkoxide binary systems and CO2/silicon alkoxide/polymer ternary systems is an important factor that affects the design of novel processes. The phase behavior of a carbon dioxide (CO2)/methyl trimethoxy silane (MTMS)/polystyrene (PS) ternary system was measured using a synthetic method involving the observation of the bubble and cloud point. The phase boundaries were measured at temperatures ranging from 313.2 to 393.2 K and CO2 weight fractions between 0.01 and 0.08. The CO2/MTMS/PS system showed a similar CO2 mass fraction dependence of the phase behavior to that observed for the CO2/tetramethyl orthosilicate (TMOS)/PS system. When the phase boundaries of these systems were compared, the vapor-liquid (VL) and vapor-liquid-liquid (VLL) lines were found to be nearly identical, while the liquid-liquid (LL) lines were different. These results indicate that the affinity between the silicon alkoxide and polymer greatly influences the liquid-liquid phase separation.

Phenylglyoxaldehyde-Functionalized Polymeric Sorbents for Urea Removal from Aqueous Solutions

“…This solubility parameter can be determined experimentally or calculated based on the molecular structure, i.e., by the method reported by Fedors . ShellSolTD is a mixture of alkanes, and therefore, ShellSolTD was replaced by heptane, for which δ = 15.2 J 1/2 m –3/2 , and the heptane/toluene ratio was adjusted to vary the δ value between 15.2 and 18.2 J 1/2 m –3/2 (i.e., the δ value of toluene). , The calculated δ values of VPE (δ = 19.0 J 1/2 m –3/2 ) and of pVPE (δ = 21.1 J 1/2 m –3/2 ) are higher than those of styrene (17.8 J 1/2 m –3/2 ) and PS (δ = 17.4–19.0 J 1/2 m –3/2 ); , thus, the δ of a suitable porogen mixture (δ mix ) is also expected to be higher than the δ mix of the porogen used for the suspension polymerization of PS. Volumetric mixtures of 75:25 and 50:50 heptane and toluene with δ mix values of 15.6 and 16.9 J 1/2 m –3/2 , respectively, did dissolve VPE and resulted in the formation polymeric beads (Table , entries 1 and 2).…”

A Ninhydrin‐Type Urea Sorbent for the Development of a Wearable Artificial Kidney

“…[30,31] For the preparation of porous particles using a non-solvent, a porogen is needed with a δ-value close to that of the monomer to ensure its dissolution, and different (preferable lower) than that of the resulting polymer, resulting in its precipitation. The δ-values of vinylindanone and poly-vinylindanone (pVI), as calculated based on the method reported by Fedors, [31] are much larger that the δ-values of styrene and polystyrene (20.5 and 22.9 vs 17.8 and 17.4-19.0 J 1/2 m −3/2 , respectively see supporting information section 3 [30,32] ). The porogen mixture used for the preparation of porous polystyrene particles has a delta-value (δ mix ) of 15.2 J 1/2 m −3/2 , which is lower than the δ-values of both styrene and polystyrene (lower by 2.6 and 2.2-3.8 J 1/2 m −3/2 , respectively).…”