Pressure polymer miscibility

CED) of a polymer, closer to that of CO2, increased the solubility (lowered the miscibility pressures) in CO2. O Neill theorized that solubility is thus not controlled by polymer-C02-specilic interactions, but mainly by poor polymer-polymer interactions, and that a low cohesive energy density (reflected by a low surface tension) of a polymer primarily determines its solubility in CO2. In a U.S. patent issued in 1998, Johnston et al. demonstrated that surfactants based on poly(propylene oxide) and poly(butylene oxide) were also quite soluble in CO2 (39). The invention was significant for demonstrating that nonfluorinated surfactants can exhibit appreciable solubility in CO2. 

E. Kiran, Polymer miscibility and kinetics of pressure-induced phase separation in near-critical and supercritical fluids. Chapter 6 in Supercritical Fluids. Fundamentals and Applications, E. Kiran, P. G. Debenedetti and C. J. Peters, Eds., Kluwer Academic Publishers, Dordrecht, The Netherlands (2000). 

In general, a miscible blend of two polymers is likely to have properties somewhere between those of the two unblended polymers. The relative miscibility of polymers controls their phase behavior, which is of crucial importance for final properties. Polymer-polymer miscibility depends on a variety of independent variables, viz., composition, molecular weight, temperature, pressure, etc. 

POLYMER MISCIBILITY AND KINETICS OF PRESSURE -INDUCED PHASE SEPARATION IN NEAR-CRITICAL AND SUPERCRITICAL FLUIDS... 

In this work we will discuss some further aspects of the thermodynamics of polymer mixtures such as the effect of pure component properties on polymer-polymer miscibility, the influence of pressure on the LOST, and the influence of polydispersi-ty on the phase behavior of polymer mixtures. 

White RP, Lipson JEG (2014) Free volume, cohesive energy density, and internal pressure as predictors of polymer miscibility. Macromolecules 47(12) 3959-3968... 

Polymer blends are mixtures of at least two macromolecular species, polymers and/or copolymers. They are either miscible or immiscible — the latter prevailing. The polymei/polymer miscibility is limited to a "miscibility window," a range of independent variables, such as composition, molecular weight, temperature, pressure, etc. More than 1600 of these "miscibility windows" have been identified [1]. 

Range of copolymer compositions in a polymer mixture, at least one component substance of which is a copolymer, that gives miscibility over a range of temperatures and pressures. Note 1 Outside the miscibility window immiscible mixtures are formed. 

Numerous methods have been explored to recover at least some of this vast resource. Injection of oil-miscible fluids, gases under high pressure, and steam —either separately or in combination — have all been tried with various degrees of success. This is where microemulsions enter the picture. Under optimum conditions an aqueous surfactant solution — which may also contain cosurfactants, electrolytes, polymers, and so on —injected into an oil reservoir has the potential to solubilize the oil, effectively dispersing it as a microemulsion. 

For the mixture of diamine (43) with diester (44) miscibility is necessary for a successful polycondensation. Miscibility was demonstrated by showing that the mixed monolayer obeyed Crisp s rule53 (see 4.2.1). For a 1 1 molar mixture of diamine (43) and diester (44) only a slight area change during monolayer polycondensation could be observed. The compression isotherm of the polymer film exhibits a diminished collapse area and pressure (Fig. 14). The structure of the final polymer is shown in Scheme 3. 

---