title: Supercritical fluid assisted production of chitosan oligomers micrometric powders.
abstract: Chitosan oligomers (O-chitosan) micrometric particles were produced from aqueous solution using a novel process, i.e. supercritical fluid assisted atomization introduced by hydrodynamic cavitation mixer (SAA-HCM). Hydrodynamic cavitation was introduced to enhance mass transfer and facilitate the mixing between SC-CO2 and liquid solution for fine particles formation. Well defined, separated and spherical microparticles were obtained, and the particles size could be well controlled with narrow distribution ranging from 0.5 μm to 3 μm. XRD patterns showed amorphous structure of O-chitosan microparticles. FTIR, TGA and DSC analyses confirmed that no change in molecular structure and thermal stability after SAA-HCM processing, while the water content was between 5.8% and 8.4%. Finally, tap densities were determined to be below 0.45 g/cm(3) indicating hollow or porous structures of microparticles. By tuning process parameters, theoretical mass median aerodynamic sizes lied inside respirable range of 1-2 μm, which presented the potential of the O-chitosan microparticles in application as inhaled dry powders. SAA-HCM was demonstrated to be very useful in particle size engineering.
authors: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors: Zhe
authors: Z
authors: Du
authors: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors: Yu-Bin
authors: YB
authors: Shen
authors: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors: Chuan
authors: C
authors: Tang
authors: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: guanyx@zju.edu.cn.
authors: Yi-Xin
authors: YX
authors: Guan
authors: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors: Shan-Jing
authors: SJ
authors: Yao
authors: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors: Zi-Qiang
authors: ZQ
authors: Zhu
keywords: Chitosan oligomers; Hydrodynamic cavitation mixer; Micronization; Supercritical fluid assisted atomization