Effect of molecular weight on microsphere production from chitosan emulsion.

In this work, the effect of chitosan molecular weight on microsphere production from chitosan emulsion was studied. The emulsion was produced by the mixing of a water phase (chitosan solution) and oil phase (sunflower and castor oil) to develop mixes of three molecular weights. The morphological and rheological properties of the emulsion were then characterised using digital and optical microscopy and a cone-plate viscometer. The density, surface tension and thermal conductivity of the emulsion were thus tested. The results showed that the viscosity changed according to the change in the molecular weight of the chitosan emulsion, with the diameter, number, and shape of microspheres being strongly related to their rheological behaviours. As the diameter increases, the number of microspheres decreases, and their shapes are less uniform as the molecular weight increases. The formation of microspheres was then numerically simulated utilising a fluent ANSYS 15 program based on the two-phase flow phenomena, with rheological properties used as input data. In terms of the shape, size, and timing of microsphere creation, good agreement thus emerged between the experimental and numerical studies. [ABSTRACT FROM AUTHOR]