Control of chitosan molecular weight with cyclotron ion beam irradiation Original Research Article

Control of water-soluble chitosan molecular weight was performed by irradiation of cyclotron proton ion beams by changing treatment conditions such as beam irradiation time for upto 10 min, beam energies as well as beam distances between the sample surface and beam after pre-calculating the sample positions with Stopping and Range of Ions in Matter software. Irradiation of high energy cyclotron ion beam induced significant reduction of molecular weights of water-soluble chitosan as observed by changes in both relative viscosity and molecular weights measured by gel permeation chromatography. The molecular weights of the beam-treated chitosan were reduced to 55–20% compared to that of the untreated one, depending on the beam irradiation conditions such as treatment time and beam energy. Polydispersity index indicated that the reduced chitosan molecular weights were wider distributed compared to that of the untreated chitosan samples.