Apparent Decrease in the Critical Concentration of Gelation

8 (a) Crosslinking reaction of polystyrene using xylylene dichloride as a crosslinkcT in nitrobenzene, (b) Gel-fraction 5deld plotted against the initial polymta- concentiatirai expressed in molarity of styrene (St) units. Relative temperature AT) was —19 °C curve 2) and 28 C curve I). (Plotted based on the data from [26]) 

In this connection, we should note that for such wide-pore gel matrices, the swelling capacity of the gel phase is an essential indicator of the polymer content in this phase and of the crosslinking extent. By contrast, the total volume occupied by such swollen gel materials is a less informative indicator for the properties of the polymeric network. This is due to the fact that the volume occupied by free solvent inside the capillary-sized pores accounts for the greater part of the liquid absorbed by these wide-pore sponges. In turn, the fraction of tightly bound solvate fiquid 

Precursor Precursor concentration in the feed (wt%) Solvent Temperature of the gelation process (°C) Appearance of the samples after the gel formation process References 

Potato starch 2.5 Water -t-18 Rather weak starch [147] 

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Due to concentrating of solutes in the unfrozen liquid microphase, an apparent decrease in the critical concentration of gelation is observed in cryotropic gel formation as compared to gelation at positive temperatures... 

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