Preparation and characterization of chitosan/polyvinyl porous alcohol aerogel microspheres with stable physicochemical properties.

Chitosan/polyvinyl alcohol (CS/PVA) porous aerogel microspheres with stable physicochemical properties were obtained by gelation and freeze-drying process, and modified by adding different content of polyvinyl alcohol (PVA) into the microspheres. The physicochemical properties of porous aerogel microspheres, including porosity, swelling degree, acid-base resistance and compression performance were compared with chitosan (CS) microspheres. The microspheres were characterized by scanning electronic microscopy, Fourier transform infrared spectra, X-ray diffraction and compression test. The results showed that the structure of hybrid aerogel microspheres could be controlled by adjusting the content of PVA. The increase of PVA content reduced the pore size of CS/PVA porous aerogel microspheres, promoted the roughness of the surface and formed more orderly pore distribution. The higher PVA content was, the greater the swelling degree of the CS/PVA porous microspheres was. Adding proper amount of PVA into the CS/PVA microspheres could improve their acid resistance, but reduce their alkali resistance. Furthermore, the porosity of CS/PVA microspheres containing 33.3% PVA was the highest (78.3%) and the best compression strength (0.0505 MPa) when compression depth was 60% of the maximum height.