ChemInform Abstract: CHEMICAL AND BIOCHEMICAL REACTIONS IN LIQUID AND FROZEN SOLUTIONS. V. BROMINATION OF OLEFINS

Epoxy-Containing Porous Hydrogels of Poly(2-Hydroxyethyl Methacrylate): A Study of the Influence of the Synthesis Conditions

“…Acceleration of the reaction may be due both to increase in the polarity of the medium in the liquid microphase and to increase on account of this in the rate of the reaction. It is known that the dielectric permittivity of water increases linearly with reduction in temperature as a function of inverse temperature [9,10]. With reduction in temperature, there is also an increase in the viscosity of water by several orders of magnitude [10,11].…”

Study of cryostructuration of polymer systems. XV. Freeze-Thaw-induced formation of cryoprecipitate matter from low-concentrated aqueous solutions of poly(vinyl alcohol)

“…The major reason for such an effect has been recognized 1,15 to be cryoconcentrating phenomena, that is, increase in the solute concentration in unfrozen regions of the system's bulk. These unfrozen inclusions are termed the "unfrozen liquid microphase," 16,17 where the prefix "micro-" reflects the fact that such a phase constituted only a minor portion of the volume of a solid macrofrozen sample (for nondeeply frozen concentrated water-PVA solutions, the volume of the unfrozen liquid microphase was found to be several percent). 18,19 Due to similar cryoconcentrating effects, the entanglement and associative interactions of the PVA chains are promoted, thus favoring the intermolecular H bonding and the formation of the microcrystallinity zone.…”

UV‐Induced Cross‐Linking of Poly(ethylene oxide) in Aqueous Solution

“…[11] It was assumed that during the process of freezing, the major portion of the pure solvent was initially crystallized and all the soluble components were displaced to an ''unfrozen liquid microphase'', where the interactions of the reagents occurred in a considerably more concentrated medium than the initial one. [11][12][13][14] ''Microphase'' implies that the volume of this liquid-like phase is small compared with the total volume of the frozen sample. Lozinsky et al [11] have shown that the acceleration factors which affect the kinetic features of the photopolymerization process could be the following: formation of regions of structural and phase inhomogeneity (crystalline phase and liquid microphase), at the same time an increase in concentration of solutes in the residual unfrozen fluid, as well as an increase in its polarity with a decrease in temperature, and perhaps, increase in pressure caused by the ice crystallization.…”

“…The processes of polymerization and cross‐linking in moderately frozen solutions at temperatures not lower than 20–30 °C below the freezing point of the system have not really been studied 11. It was assumed that during the process of freezing, the major portion of the pure solvent was initially crystallized and all the soluble components were displaced to an “unfrozen liquid microphase”, where the interactions of the reagents occurred in a considerably more concentrated medium than the initial one 11–14. “Microphase” implies that the volume of this liquid‐like phase is small compared with the total volume of the frozen sample.…”