The characteristic properties of chitosan irradiated by gamma rays

The Characteristics Properties of Chitosan Irradiated by Gamma Rays. Chitosan is an abundant natural biopolymer after cellulose derived from the deacetylation of chitin and widely used in many applications. The purpose of this research is to determine the characteristics of the physical, chemical, and mechanical properties of oligochitosan which are irradiated by gamma-rays in various irradiation doses. Two types of chitin derived from shrimp shells were used as raw materials. The first type was the whole parts of shrimp shells (I type) and the second type was the body part only without the head and tail of shrimp shells (M type). The chitosan was produced through demineralization, deproteination, and deacetylation of chitin. The chitosan was then irradiated by gamma rays of Co-60 at various doses. The characterizations of products were conducted to determine the molecular weight, degree of deacetylation (DDA), solubility in acetic acid, color changes, tensile strength, and elongation at break. The results showed that after irradiation of 150 kGy, the all characteristics have changed. The characteristics of I type chitosan such as the molecular weight decreased from 560,943 to 54,825 Da, DDA of 81.55% to 84.85%, solubility of 81.60% to 85.63%, and degree of whiteness of 80.65% to 59.92 %. The tensile strength and elongation at break were 53.53 kg/cm2 and 50% to 10.91 kg/cm2 and 0% consecutively. Furthermore, the characterizations of M type chitosan revealed that molecular weight was found as 403,547 Da with DDA of 82.65%. The solubility was 87.64%, and the degree of whiteness was 82.54%. The tensile strength and elongation at break were 77.78 kg / cm2 and 60% consecutively. After irradiated to 150 kGy, the characteristics of M type chitosan has changed such as decreasing the molecular weight to 48,929 Da, increasing the DDA to 90.57%, increasing the solubility to 92.97%, decreasing the whiteness degree to 56.49%, and decreasing the tensile strength and elongation at break to 39.41 kg/cm2 and 0% respectively.