Structural analysis of embedding polyethylene glycol in silica aerogel

Embedding of the functional materials into aerogel powders was realized via the filtration method. In this work, the effect of aerogel on the molecule structure of the embedded polyethylene glycol (PEG) was investigated by dispersing aerogel powders in 20 wt% PEG aqueous solution with subsequent filtration method. The encapsulation of the PEG in the aerogel was characterized by isothermal nitrogen (N2) adsorption/desorption. The structure of the embedded PEG in the aerogel powders was investigated via SEM-EDS, FE-SEM, FT-IR, XRD. TG-DTA, DSC, and leakage test. It was found that the only physical capillary force worked to adsorb PEG molecules from its solution by the aerogel powders. The BET surface area and the DFT pore volume of the PEG/aerogel powders were reduced obviously when compared with pure aerogel powders. The ability of the pores in the aerogel powders ranging from 14 nm to 16 nm to adsorbing the PEG molecules from the water system was weak. The crystallinity of the PEG was significantly reduced because of the limited space for crystal growth, and the decomposed temperature and thermal capacity decreased correspondingly.