Soluble porous polymers

Keywords. Porous polymer, Solubility parameter, Phase separation. Epoxy, Cyanurate,... 

The higher polarity and thus higher water solubility of acrolein and acrylonitrile required an elevated purge temperature (85 °C) to produce acceptable recoveries. The trap composition was initially 24 cm of the porous polymer, Poropak N. It was subsequently changed to 1 cm of 3% OV-1 on Chromosorb W and 23 cm of Tenax-GC. 

Permeability measurements were done on the porous polymers obtained by polymerization of the middle phase microemulsion containing SDS. As shown in Figure 6 and Table II, the permeability coefficients in both N2 and 02 gas are higher than in polystyrene. As expected, the diffusivity of nitrogen is higher than that of oxygen. Values of the solubility coefficient (ratio of permeability to diffusivity) are also listed in Table II. 

In size exclusion chromatography the solid support is a porous polymer with a controlled pore size, and the solute molecules are separated according to their size in solution. The larger molecules are excluded most and thus they have the shortest retention times. The size exclusion may be performed in aqueous systems (gel filtration), where water soluble macromolecules can be separated, or in non-aqueous systems (gel permeation). By proper calibration the method can also be used for determination of molecular weight or molecular weight distribution. 

In our study the butanol-soluble fraction was proved to be effective for terminating pregnancy in rats. The results agreed with literature reports and suggested the active principles should be hydrophilic components. However, some soponins we subjected to test showed not effective and the water eluent on a highly porous polymer chromatography seems much better than individual saponin in animal test. The experiments should be repeated and confirmed to make a conclusion carefully. 

The simplest model used to explain and predict gas permeation through non-porous polymers is the solution-diffusion model. In this model it is assumed that the gas at the high-pressure side of the membrane dissolves in the polymer and diffuses down a concentration gradient to the low pressure side, where the gas is desorbed. It is further assumed that sorption and desorption at the interfaces is fast compared to the diffusion rate in the polymer. The gas phase on the high- and low-pressure side is in equilibrium with the polymer interface. The combination of Henry s law (solubility) and Picks law (diffusion) leads to... 

Porous polymer templates are often soluble in common organic solvents, making them incompatible with many organic-based electrolytes. In some cases, this problem can be avoided by cross-linking the template, for example by UV-cross-linking of polystyrene. Aqueous electrol5des normally present no such solubility problem but must often contain additives such as... 

Gas-diffusion membranes Hydrophobic porous polymer membranes with air filling the membrane pores have been used successfully in the online separation of volatile and semivolatile analytes between two miscible liquid streams in flow injection analysis (FIA) systems. The corresponding technique is frequently referred to as gas-diffusion EIA. The mass transfer of an analyte across a gas-diffusion membrane is controlled by the membrane pore size and the solubility of the analyte in the feed and receiver solutions. The latter can be manipulated by appropriately modifying the chemical composition of the two solutions. In this way it is possible to enhance both the evaporation of the analyte from the feed solution into the membrane pores and its subsequent absorption into the receiver solution. 

Polymers with intrinsic microporosily, also abbreviated as PIMs, are soluble porous polymers formed from non-reversible condensation methods. These polymers cannot pack efflcientiy in the solid state due to rigid ladder-like components. Tliese polymers have a site of contortion in their stmcture and are known for their properties, including gas permeation and selective separation. 

While there are now a number of reports of soluble and dispersible CMPs, they are mainly produeed as insoluble networks and therefore the proeessability of CMPs is poor in contrast to some PIMs. Until a general method to produce a wide vary of processable CMPs is developed the use of this elass of porous polymer may be limited. 

CO2 as a byproduct during the combustion of fuels in industrial plants and automobiles is a major contributor to global warming. Hence, the selective capture of carbon dioxide requires special attention from the scientific community. The principle sources of CO2 that cause harm to the environment are contaminated natural gas, containing a mixture of methane and CO2 (known as pre-combustion), and exhaust gas generated in industiy or from automobiles (post-combustion). Separate physical conditions are needed for CO2 capture from pre- and post-combustion mixtures, and a variety of porous polymer networks, both soluble and insoluble, have been involved in CO2 capture with consideration of their pore dimensions. " ... 

Processing technique It is very difficult to process porous polymers because most of the amorphous porous polymers are in the powder form, while crystalline porous polymers are nanocrystals. Only PIMs and soluble CMPs are solution-processable. A breakthrough with regards to the processing technique will expand the applications of porous polymers. 

The book was initially eonstrueted with a historical development sequenee of porous polymers eombined with illustrations of structure-property correlations. Eaeh ehapter provides an example of a particular element of porous polymers. Chapter 1 provides a summary of porous polymers and discusses the relationship between structure and function. In Chapter 2, the design principles of porous polymers are diseussed and modification methods are introdueed, while Chapter 3 introduees the synthetic routes and reactions used in polymerization. An understanding of these reactions is essential if we are to understand the origin of the ordered or amorphous structure of porous polymers. Chapter 4 describes the first porous polymers, developed in the 1990s and named hypercrosslinked polymers or Davankov-type resins. Chapter 5 focuses on the first soluble polymer with intrinsic microporosity that was reported in 2002. Meanwhile, Chapter 6... 

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