Mass-production of oligo chitosan in the liquid phase by irradiation technique

Chitosan is a natural product of chitin deacetylation, and low molecular weight chitosan (oligo chitosan) can be produced in the liquid phase by irradiation technique. Due to the long molecular chain and high molecular weight, the application of chitosan is limited. This study aimed to prepare oligo chitosan by irradiation technique in liquid phase at a capacity of 1000 L. Irradiation was carried out with gamma rays from a C0-60 source. The first stage of this study was to standardize chitosan properties (viscosity and molecular weight) to be pumped and flowed to the irradiation tank. In large-scale liquid phase chitosan irradiation, the chitosan solids must be standardized to lower the viscosity and enable flow by pumping or gravity. The experimental results show that for the chitosan liquid to flow from the mixing tank to the irradiation tank, the initial chitosan must have a molecular weight of 12-15 kDa to obtain a viscosity of 100-200 cps. The irradiation method was very effective in reducing molecular weight and viscosity. Irradiated chitosan had a low decrease in thermal properties and a molecular weight of 9.2 kDa. Functional group analysis shows that there were still functional groups of chitosan in irradiated chitosan.