Effect of chitin nanowhiskers on mechanical and swelling properties of Gum Arabic hydrogels nanocomposites.

ABSTRACT

Hydrogels based on biopolymers like Gum Arabic (GA) usually show low applicability due to weak mechanical properties. To overcome this issue, (nano)fillers are utilized as reinforcing agents. Here, GA hydrogels were reinforced by chitin nanowhiskers (CtNWs, aspect ratio of 14) isolated from the biopolymer chitin through acid hydrolysis. Firstly, GA was chemically modified with glycidyl methacrylate (GMA), which allowed its crosslinking by free radical reactions. Next, hydrogel samples containing different concentrations of CtNWs (0-10 wt%) were prepared and fully characterized. Mechanical characterization revealed that 10 wt% of CtNWs promoted an increase of 44% in the Young's modulus and 96% the rupture force values compared to the pristine hydrogel. Overall, all nanocomposites were stiffer and more resistant to elastic deformation. Due to this feature, the swelling capacity of the nanocomposites decreased. GA hydrogel without CtNWs exhibited a swelling degree of 975%, whereas nanocomposites containing CtNWs exhibited swelling degrees under 725%.