Gelation internal

Akkermans, A. J., Van der Grexjt, P., Venema, P., van der Linelen, E., Bexmi, R. (2008). Properties of protein fibrils in whey protein isolate solutions MitTostruemre, flow behaviom and gelation. International Dairy Journal, 18, 1034—1042. 

The most important role of UO3 is in the production of UF4 [10049-14-6] and UF [7783-81-5], which are used in the isotopic enrichment of uranium for use in nuclear fuels (119—121). The trioxide also plays a part in the production of UO2 for fuel peUets (122). In addition to these important synthetic appHcations, microspheres of UO3 can themselves be used as nuclear fuel. Fabrication of UO3 microspheres has been accompHshed using sol-gel or internal gelation processes (19,123—125). FinaHy, UO3 is also a support for destmctive oxidation catalysts of organics (126,127). 

Uranium and mixed uranium—plutonium nitrides have a potential use as nuclear fuels for lead cooled fast reactors (136—139). Reactors of this type have been proposed for use ia deep-sea research vehicles (136). However, similar to the oxides, ia order for these materials to be useful as fuels, the nitrides must have an appropriate size and shape, ie, spheres. Microspheres of uranium nitrides have been fabricated by internal gelation and carbothermic reduction (140,141). Another use for uranium nitrides is as a catalyst for the cracking of NH at 550°C, which results ia high yields of H2 (142). 

Chatterjee S., Bohidar H.B. 2005. Effect of cationic size on gelation temperature and properties of gelatin hydrogels. International Journal of Biological Macromolecules 35, 81-88. 

With large single crystals of polyethylene, the gelation dose is some 10 times greater than for the same polymer grown under conventional conditions (14). This is not caused by any inherent difference in the effect of radiation since both the radical concentration (deduced from ESR measurements) and hydrogen production are similar. We must therefore assume that most of the links produced in the single crystal are internal links which do not influence solubility. This is understandable in a crystal where each molecule folds backward on itself. 

At lower concentrations the gelation dose increases sharply until no network is formed, even at the highest doses. This competing effect is ascribed to internal linking—links occur between different monomers in the same chain but are ineffective for network formation. 

Eliot, C., Dickinson, E. (2003). Thermoreversible gelation of caseinate stabilized emulsions at around body temperature. International Dairy Journal, 13, 679- 684. 

We have seen earlier in this chapter how the self-assembly of casein systems is sensitively affected by temperature. Another thermodynamic variable that can affect protein-protein interactions in aqueous media is the hydrostatic pressure. Static high-pressure treatment causes the disintegration of casein micelles due to the dismption of internal hydro-phobic interactions and the dissociation of colloidal calcium phosphate. This phenomenon has been used to modify the gelation ability of casein without acidification as a consequence of exposure of hydrophobic parts of the casein molecules into the aqueous medium from the interior of the native casein micelles (Dickinson, 2006). High-pressure treatment leads to a reduction in the casein concentration required for gelation under neutral conditions, especially in the presence of cosolutes such as sucrose (Abbasi and Dickinson, 2001, 2002, 2004 Keenan et al., 2001). 

Flow imparts both extension and rotation to fluid elements. Thus, polymer molecules will be oriented and stretched under these circumstances and this may result in flow-induced phenomena observed in polymer systems which include phase-changes, crystallization, gelation or fiber formation. More generally, the Gibbs free energy of polymer blends or solutions depends under non-equilibrium conditions not only on temperature, pressure and concentration but also on the conformation of the macromolecules (as an internal variable) and hence, it is sensitive to external forces. 

Reis, C. P, Neufeld, R. J., Vile la, S., Ribeiro, A. J., and Veiga, F. (2006), Review and current status of emulsion/dispersion technology using an internal gelation process for the design of alginate particles, /. Microencapsul., 23(3), 245-257. 

E. Forslind. Proc. 2nd Intern. Congr. Rheol. 1953, 50-63. Water association, gelation and hydrogels. 

Poncelet, D. Lencki, R. Beaulieu, C. Halle, J.P. Neufeld, R.J. Fournier, A. Production of alginate beads by emulsifi-cation/internal gelation. 1. methodology. Appl. Microbiol. Biotechnol. 1992, 38 (1), 39 5. 

Sharma, P.K. Bhatia, S.R. Effect of anti-inflammatories on Pluroinc FI27 micellar assembly gelation and partitioning. International Journal of Pharmaceutics 2004, 278, 361-377. 

Chan LW, Lee HY, Heng PW. Production of alginate microspheres by internal gelation using an emulsification method. Int J Pharm 2002 242(1-2) 259-262. 

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