I obtained cellulose from agricultural waste and synthesized its derivative, cellulose acetate. I used glycerin and PEG 400 to obtain biofilm, but I could not obtain biofilm with either method. I tried changing the glycerin and PEG 400 ratios between 5% and 20%, but my films did not dry and still remained viscous. I wonder where the problem might be, I would be very happy if you could help me. Enjoy your work.