Freeze-drying polyethylene glycol

That none of the above methods is completely satisfactory as a conservation procedure is generally agreed. One interesting recent development involves the application of freeze-drying technology (24,25) combined with polyethylene glycol impregnation. 

From ZrOCl2 and Y(NOj)j Nanosized synthetic Y-modified zirconia, 8 mol% Y O, ZrOCl2 SHjO, and YfNO,), 6HiO were dissolved in a water-ethanol 1 5 (volume ratio) mixture. Polyethylene glycol was added, and the mixture was heated at 75°C for 2 h. Then the pH was adjusted to 9 with ammonia. The gel was washed with water and freeze-dried. Einally, it was calcined under different conditions. 

A 20.7 cm portion of each of the metal salt solutions described in Examples 1 and 4 is added a 323 g portion of the just described silica sol in a 20 min period while agitating the sols in a Waring blender. The mixtures are agitated for one hour after the addition of the respective metal solutions. A total of 43 g of solid polyethylene glycol of Example 1 is then added to each of the mixtures and stirring is continued for 15 min. The sols are freeze-dried as described and the resulting powders are pressed into bars as described in Example 1. 

Figure 14.16 Scanning electron microscopy of a freeze-dried hydrogel made by polyacrylic acid and polyethylene glycol (a and c) compared to the same type of gel functionalized with arginine-glycine-aspartic acid (b and d).

Daruvala ST. The eificacy of polylysine, lysine monomer uid polyethylene glycol as excipients for the controlled release of nerve growth factor from freeze dry silk scaffolds. Department of Biology Tufts University 2013. 

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