Enhanced electrorheological activity of porous chitosan particles.

Novel porous filler for electrorheological fluids was fabricated from chitosan via freeze drying technique. An exceptional electrorheological effect was discovered in suspensions of polydimethylsiloxane (silicone oil) filled by highly porous chitosan particles. The electrorheological activity was studied by rotational rheometry and visualized by optical microscopy. High porosity of the filler allows preparing highly efficient electrorheological fluids at rather low (< 1 wt%) concentration of dispersed phase. The mechanism of chain-like structure formation was considered. The electrorheological behavior of suspensions and the filler structural organization at different concentration were comprehended in terms of dielectric properties. The rheological data were approximated by Bingham and Cho-Choi-Jhon equations. The sedimentation stability of chitosan suspensions in polydimethylsiloxane was significantly affected by particles porosity.

[The prospects of hydrogels usage as a basis for curable osteoplastic materials]. / Perspektivy ispol'zovaniia gidrogelei v kachestve osnovy dlia otverzhdaemykh kostno-plasticheskikh materialov.

The article deals with the main types of the polymers used in hydrogel preparation. Their biological, physical and chemical properties was compared. Ways of polymers hardening and prospects of medical application were considered. The prospect of use of chitosan hydrogels activated by osteoinductors as a material for bone augmentation were concluded.