Polymer incompatibility

HV Alginate 2% Spermine/1% Poly-methylene-co-guanidine T Smooth, Mosaic Membrane (Polymer Incompatibility ) 7/7... 

Under certain conditions, polymer incompatibility in aqueous solutions can lead to the formation of two phases with high water content. With such a system, it is possible to separate sensitive biological molecules, such as proteins, without denaturation, which would be the case for an ordinary aqueous-organic solvent system. 

Zeman, L., Patterson, D. (1972). Effect of the solvent on polymer incompatibility in solution. Macromolecules, 5, 513-516. 

Kasapis, S., Morris, E.R., Norton, I.T., Gidley, M.J. (1993b). Phase equilibria and gelation in gelatine/maltodextrin systems. Part II. Polymer incompatibility in solution. Carbohydrate Polymers, 21, 249-259. 

The bilayer morphology of thin asymmetric films of may be unstable. A regularly corrugated surface structure of the films was ascribed to spinodal transition into a laterally phase separated structure, where the surface morphology depended on the polymer incompatibility and the interfacial interactions [347, 348]. Recently, the phase separation and dewetting of thin films of a weakly incompatible blend of deuterated PS and poly(p-methylstyrene) have been monitored by SFM [349, 350]. Starting from a bilayer structure, after 454 h at T= 154 °C the film came to the final dewetting state where mesoscopic drops of... 

Complex coacervation Polymer/polymer incompatibility Interfacial polymerization in liquid media In situ polymerization In-liquid drying... 

One of the main aims of macromolecular chemists is the synthesis of new materials whose properties are perfectly adapted to their utilization. Synthesis of new monomers cannot resolve all problems and composite materials have been the object of increasing development during the last 20 years. However, the formation of polymeric blends is generally prevented by the incompatibility of polymeric chains and it is difficult to prepare composite materials exhibiting all the desirable properties present in their components. A way of overcoming the inconveniences of the polymer incompatibility is the formation of covalent bonds between the constituents to obtain block or graft copolymers. 

Their morphology which because of polymer-polymer incompatibility causes most of these materials to display two or more distinct phases. 

Syrbe, A., Fernandes, P. B., Dannenbeig, F., Bauer, W. J., and Klostermeyer, H. 1995. Whey protein-polysaccharide mixtures polymer incompatibility and its application, in Food Macromolecules and Colloids, eds. E. Dickinson and D. Lorient, pp. 328-339, The Royal Society of Chemistry, London. 

When two dissimilar plastic foams are to be joined, which is rarely done, adhesive bonding is generally preferable because of solvent and polymer incompatibility problems. Solvents used to cement plastics should be chosen with approximately the same solubility parameter (5) as the plastic to be bonded. The solubility parameter is the square root of the cohesive energy density (CED) of the liquid solvent or polymer. CEDs of organic chemicals are primarily derived from the heat of vaporization and molecular volume of the molecules, and are expressed as calories per cubic centimeter (cal/cm ). Literature sources provide data on 6 s of a number of plastics and resins (2) (3) (4). 

It was observed that the formulations consisting of ethoxylated sulfonates and petroleum sulfonates are relatively insensitive to divalent cations. The results show that a minimum in coalescence rate, interfacial tension, surfactant loss, apparent viscosity and a maximum in oil recovery are observed at the optimal salinity of the system. The flattening rate of an oil drop in a surfactant formulation increases strikingly in the presence of alcohol. It appears that the addition of alcohol promotes the mass transfer of surfactant from the aqueous phase to the interface. The addition of alcohol also promotes the coalescence of oil drops, presumably due to a decrease in the interfacial viscosity. Some novel concepts such as surfactant-polymer incompatibility, injection of an oil bank and demulsification to promote oil recovery have been discussed for surfactant flooding processes. 

The mixing of surfactant and polymer in the porous medium occurs due to both dispersion and the excluded volume effect for the flow of polymer molecules in porous media, which in turn could lead to the phase separation. Figure 16 illustrates the schematic explanation of the surfactant-polymer incompatibility and concomittant phase separation. We propose that around each micelle there is a region of solvent that is excluded to polymer molecules. However, when these micelles approach each other, there is overlapping of this excluded region. Therefore, if all micelles separate out then the excluded region diminishes due to the overlap of the shell and more solvent becomes available for the polymer molecules. This effect is very similar to the polymer depletion stabilization (55). Therefore, this is similar to osmotic effect where the polymer molecule tends to maximize the solvent for all possible configurations. ... 

Figure 16. Schematic illustration of surfactant-polymer incompatibility leading to phase separation in mixed surfactant-polymer systems.

In the case of DNA collapse in a solution of neutral polymer incompatible with DNA molecules, two main effects have to be taken into account. The first effect is the osmotic pressure of the counterions on the DNA coil. The second effect is connected with the difference in polymer concentration inside and outside the DNA coil. It was found that the concentration of neutral polymer within the effective volume of DNA is always lower than that in external solution. This difference could be negligible in the case of good compatibility observed at low polymer concentration. In this case the polymer molecules practically freely penetrate inside the DNA coil, so that the water/polymer composition inside the DNA coil is the same as the composition in the external solution. The second regime is the regime of practically perfect segregation between the DNA chain and the polymer. The polymer segregates from the DNA coil and imposes additional osmotic pressure,... 

A variety of methods have been reported for producing microspheres including phase separation by polymer/polymer incompatibility and coacerva-tion [81] solvent evaporation or solvent removal [82] hot-melt microencapsulation spray drying interfacial polymerization and supercritical fluidprocessing teehniques (such as the gas antisolvent spray precipitation process [83] or rapid expansion of supercritical fluids [84]). The characteristics of the most important of these methods have been reviewed [85, 86]. 

Polymer coacervation can occur in either aqueous or organic liquids. Coacervation in aqueous liquids and the related processes are mainly used to encapsulate water-immiscible liquids or water-insoluble solid particles. On the other hand, coacervation in organic liquids, or sometimes called phase separation in organic liquids, is used to encapsulate core materials that are not miscible or soluble in the organic liquids. It may be induced by the addition of a nonsolvent to the polymer solution or by the addition of an incompatible polymer based on polymer-polymer incompatibility. This chapter will only discuss the coacervation in aqueous liquids. 

Ethylene/MA copolymer compatibilizer, polymers Ethylene/MA copolymer compatibilizer, polymers Incompatible e-Caprolactone homopolymer compatibilizer, PP/FVOH Polybond 3002 Polybond 3150 compatibilizer, PP/polyamIde Polybond 3002 Polybond 3150 compatibilizer, PVB Resamin HF 480 compatibilizer, PVC copolymers Resamin HF 480 compatibilizer, silicones Phenyl trimethicone compatibilizer, sidisliales Ethylene/MA copolymer compatibilizer, therirnplastic backbone coating resins Resamii HF 480... 

Polymerization of monomer II in the presence of polymer I definitely leads to increases in molecular weight, increased viscosity, and often true gel formation. This latter is actually a form of joined IPN or AB crosslinked copolymer. Using the cellular model of phase separation, we may predict that gelation, if it occurs, will be most extensive near the cell wall. In Section 3.1.1.3, we concluded that polymer II was unable to pass easily through polymer I even in the highly swollen state, because of polymer incompatibility. Obviously, this transport difficulty is augmented by a surrounding gel network. 

There also exists a need to avoid surfactant aggregate structures such as lamellar liquid crystals which exhibit high viscosity (29-32). System parameters should be such that mixing between the fluids in the surfactant, oil and polymer slugs does not occur. A dispersion of surfactant and oil would form an undesired emulsion, while a dispersion of surfactant and polymer, if incompatible, could lead to phase separation, which would decrease the effectiveness of the process. Other points to take into account are (i) the mass transfer of surfactant to the oil bank can change the interfacial tension, and (ii) surfactant-polymer incompatibility leads to a phase separation, which would reduce the efficiency of the process (30, 31). 

We have already learnt that polyelectrolytes are much more soluble than the corresponding uncharged polymer, which we attribute to the entropy of the counterion distribution confining polymer molecules to part of the system costs little entropy due to the low number of entities. On the other hand, there is a large entropy loss on confining the (much more numerous) counterions. In mixed polymer systems, we see many consequences of the electrostatic interactions due to net charges. One is the low tendency to phase separation in a mixed solution of one nonionic and one ionic polymer in the presence of added electrolyte, this inhibition of phase separation is largely eliminated and typical polymer incompatibility is observed. 

The phase separation phenomena in polymer-polymer-solvent system can be called as polymer incompatibility The relative solubility of two polymer in the common sol-... 

In addition to the factors mentioned earlier (e.g., ultralow interfacial tension and coalescence of oil ganglia), mobility control of the oil bank and surfactant slug is an important requirement for a successful oil recovery process. As shown in Figure 8, pol3rmer solutions are used as drive fluids for proper mobility control of the oil recovery process. The dispersion of surfactant, polymer, oil and brine during the flow could lead to emulsion formation and/or phase-separation due to surfactant-polymer incompatibility (7). Efforts should be made to minimize the formation of... 

Several examples of polymer-polymer incompatibility in aqueous solution are given in Reference 3, whereas de Hek and Vrij (4) recently described a phase separation in a solvent in which both polymer and colloidal spheres were dissolved. Ph se separation can be suppressed by reducing the molecular weight of the polymers. Reduction of the salinity reduces the size of the surfactant micelles and indeed also the polymer-surfactant incompatibilities (5,6). Actually, reduction of the salinity of the polymer drive, even without direct reference to polymer/surfactant incompatibilities, has recently become a favorable recipe for successful micellar floods (7-9). 

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