Composite gels blending

Mohammed, Z. H., Hember, M. W. N., Richardson, R. K., and Morris, E. R. 1998. Application of polymer blending laws to composite gels of agarose and crosslinked waxy maize starch. Carbokydr. Polym. 36 27-36. 

The sol-gel blend or pre-crosslinked grades of polychloroprene such as the T Type polychloroprenes available from DuPont Dow contain a highly cross-linked network, which that acts as an internal processing aid (94,95). The hlend has many of the same characteristics as the sol component, hut different compoimd rheology properties. This composition results in faster extrusion with extrudates having smoother surfaces. Extrudates also retain their shape better with good definition until vulcanized. 

Acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, ethyl acetate, and tetrahydrofuran are solvents for vinyhdene chloride polymers used in lacquer coatings methyl ethyl ketone and tetrahydrofuran are most extensively employed. Toluene is used as a diluent for either. Lacquers prepared at 10—20 wt % polymer sohds in a solvent blend of two parts ketone and one part toluene have a viscosity of 20—1000 mPa-s (=cP). Lacquers can be prepared from polymers of very high vinyhdene chloride content in tetrahydrofuran—toluene mixtures and stored at room temperature. Methyl ethyl ketone lacquers must be prepared and maintained at 60—70°C or the lacquer forms a sohd gel. It is critical in the manufacture of polymers for a lacquer apphcation to maintain a fairly narrow compositional distribution in the polymer to achieve good dissolution properties. 

This blend is recommended as thin-gel composite membranes for bovine serum albumin ultra-filtration [114],... 

During the last two decades the sol-gel approach has been fiuther developed by material chemists to insert POMs within various inorganic matrices. Many sol-gel/POM composites have been reported [66,67,150-152] however, the number of their applications as liquid-phase oxidation catalysts is still not as large as one might have anticipated based on the advantages that POMs offer in the ease of incorporation into sol-gel matrixes and on then-unique blend of properties. One of possible reasons is the lack of information on the stability of the composite materials with respect to POM leaching in polar media. 

For example, irradiation of blends at 1.55 Mrad shows that at compositions of >7% PS, gel formation decreases with increasing PS content, but not as predicted by an additive rule (Table V, Figure 3). At compositions of <7% PS a significant decrease in gel formation is observed. 

When liquid-liquid phase separation occurs, resulting in water-in-water emulsions where the different biopolymers are concentrated in the different phases, and when one or both phases can gel, these systems can be used to produce anisotropic microgel particles and/or gel composites with anisotropic inclusions, resulting in a variety of interesting microstructures and morphologies. An interesting concept to generate alternative gel structures with basis on phase separated biopolymer blends... 

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