Water Uptake Properties of Pectin/Chitosan Thin Films Naznin Sultana and Louisa OzeTexas Undergraduate Medical Academy, College of Arts and Sciences
Louisa Oze Mentor: Naznin Sultana Chemistry Department Introduction: The water absorption properties of biodegradable polymers are of importance as the primary mechanism of the polymer degradation is hydrolysis. The ingress of water into polymer-based substance can have both adverse and beneficial effects on their properties. Hydrolysis and microcrack can be formed due to water exposure [1,2]. On the other hand, breakdown of polymer substrates can occur due to excessive water uptake. The water uptake and diffusion characteristics of polymeric composite substrates have been rarely assessed and reported. The hypothesis of the specific research is that the classical diffusion theories can be applied to solvent-cast Chitosan and pectin-based substrates [3,4]. Objectives/Goals (1) To produce solvent cast thin films based on biodegradable and natural polymer chitosan. (2) To add another natural product Pectin at different compositions. (3) To determine the water uptake and diffusion characteristics. (4) To investigate the effect of incorporation of pectin, porosity, and microstructures of the thin films on the diffusion coefficient, equilibrium uptake, and temperature dependence.
Materials and Methods: Initially, an aqua acidic solution of 2% (w/v) acetic acid will be prepared as a solvent of which 20 ml will be added to each specimen in a Schott bottle, for making a solution with the desired concentration of chitosan (C.S.). In this case, chitosan powder will be weighed and dissolved in 20 ml acetic acid 2%, at variable concentrations of 1.5% (w/v) (0.3 g CS), 2.0% (w/v) (0.4 g CS), 2.5% (w/v) (0.5 g CS) and 3.0% (w/v) (0.6 g CS). The solution will be stirred in a 25 ml Schott bottle with a magnetic stirrer until completely dissolved. Pectin at different compositions will be added to the solution. Then the solutions will be transferred in glass petri dishes and left at the fume hood until the solvent evaporates completely. The initial weight of the specimens will be taken and then placed into 100mL of distilled water at 37∘C. During the first day of immersion, the specimens will be removed at intervals of 2, 5, 10, 15min, and so forth, blotted dry on filter paper to remove excess water, weighed, and returned to the water. Following the first day, the samples will be weighed daily, until the uptake slowed. Until there was no significant change in weight, the uptake of water was recorded. Results and Discussion: Figure 1 shows the thin films prepared from different compositions of pectin and Chitosan using solvent casting method. It took approximately 7days for the complete evaporation of solvents under a chemical fume hood. The films were transparent, and the dispersion of pectin was clearly observable in pectin/chitosan thin films. Incorporation of higher content of pectin made the film unstable.
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