Preparation and Determination of the Characteristics of Hydrogel Membrane of Poly-Vinyl Alchol, Starch and Chitosan

In this study, a new kind of crosslinking film of polyvinyl alcohol, starch, and chitosan was obtained by alternating freeze-thaw cycles, and its various properties such as swelling rate, water vapor transmission rate, mechanical properties, and morphology were checked using electron microscopy. The results of this study showed that the hydrogel, made by providing a damp environment and the ability to pass water vapor in the range ۷۲۰-۱۶۸۰ g/m۲, has acceptable mechanical properties so that the fracture stress in polyvinyl alcohol was equal to ۰.۶۴۲ kgf/ mm۲, which reached ۰.۳۷۲ kgf/ mm۲ with the introduction of starch and ۰.۲۴۷۵ kgf/ mm۲ with the addition of chitosan. When we add starch and chitosan to polyvinyl alcohol at the same time, the fracture stress reaches ۰.۲۶۱ kgf/ mm۲. In the sample containing pure polyvinyl alcohol, the elastic strain is equal to ۶.۱۵۷ and with the addition of starch, this value reaches ۴.۶۲۵ and with the addition of chitosan, this value reaches ۵.۷۰. Adding starch and chitosan to polyvinyl alcohol increases the modulus and toughness and decreases the flexibility of the polyvinyl alcohol hydrogel membrane. Images of SEM from a cross-section of hydrogel membrane fracture show that hydrogel membranes containing polyvinyl alcohol are very smooth and monotonous; however, when starch and chitosan are added to polyvinyl alcohol, the porosity will increase.

کلیدواژه ها:

Chitosan ، hydrogel ، Polyvinyl Alcohol ، starch