As far as I can understand, the most cited researches at that field declare casting method to be the mainstream one. Here is the basic procedure:
"500 mg chitosan powders was dissolved in 25 mL 2% (v/v) acetic acid aqueous solution upon stirring at 200rpm for 3 h. After that, the chitosan suspension was poured into a plastic dish that was placed in a fume hood at room temperature to evaporate water and acetic acid. The as-prepared composite film was dried under vacuum at 40°C until their weight was equilibrated." Apart from methodology, given here, I suppose prolonged stirring to positively affect composite structure (homogeneity).
Procedure cited from:
Article Fabrication of biocompatible and mechanically reinforced gra...
Best of luck in your research!
Yours sincerely,
M. Sc. Vadym Chibrikov
Department of Microstructure and Mechanics of Biomaterials
Institute of Agrophysics, Polish Academy of Sciences