Degradation of β-chitosan by solution plasma process (SPP)

In this work, the solution plasma process (SPP) is used to treat β-chitosan solutions in order to induce the degradation of chitosan. The effects of solution plasma on the properties of chitosan solutions are investigated. The treatment time was varied from 0 to 300 min. The plasma-treated chitosan was characterized by the following methods; molecular weight by GPC, viscosity, crystal structure by XRD, chemical characteristics by FT-IR, solubility by UV-vis spectrophotometer, and fractional analysis. The results showed that after treatment with plasma for 15-120 min, the viscosity of the chitosan solution and apparent molecular weight of chitosans decreased remarkably, when compared to those of untreated sample. Longer treatment times had less effect on both viscosity and molecular weight of the samples. This suggested that the degradation process of chitosan occurred during plasma treatment. The XRD analysis showed that the crystallinity of chitosan was destroyed, resulting in amorphous structure. FT-IR analysis revealed that chemical structure of chitosan was not affected by solution plasma treatment. The %yield of water-soluble chitosan was increased with increasing plasma treatment time. These results implied that solution plasma process is able to induce the degradation of chitosan solutions.