45D-17 |
Mechanical property, permeability and biodegradability of PHB/chitosan films |
M. KIM, Food Science & Nutrition, Kyungpook National University, 1370 Sankyuk-dong, Puk-gu, Daegu, 702-701, South Korea and H. Kim, Family & Consumer Sciences, Inje University, 692 Sambang-dong, Kimhae-city, 621-749, South Korea. JUSTIFICATION Biodegradable films have been developed to alleviate the environmental pollution caused by synthetic polymers. Poly(3-hydroxy butyric acid) (PHB) is a natural biodegradable plastic with biocompatibility. However, PHB is brittle and stiff, which restricts its application. Because PHB has a poor site for chemical modification, the blends of PHB with flexible polymers can overcome these undesirable properties. OBJECTIVE The objective was to prepare the blend films of PHB with chitosan, analyze the mechanical properties and barrier properties, and monitor biodegradability of PHB/chitosan films. METHODS PHB/chitosan films were prepared by casting and measured the tensile strength and elongation using a rheometer. The permeabilities of water vapor, oxygen, and lipid of the films were analyzed. Biodegradability of the films was evaluated by measuring the consumed oxygen during incubation with microorganisms. RESULTS The degree of crystallinity of PHB/chitosan films by X-ray diffraction decreased with increasing chitosan concentration. The granular sizes of the films were reduced with the addition of chitosan to the film in the microstructural observation by a scanning electron microscope. Tensile strength and percent elongation of the blend films increased with increasing chitosan ratio in the films. The water vapor permeability (WVP) of the PHB film was the highest and WVP was decreased by the addition of chitosan. Oxygen permeability of the films decreased as chitosan amount increased. The film had very good barrier property against lipid. The consumed oxygen of PHB film was greater than that of chitosan film for incubation on the biodegradability determination of the films. SIGNIFICANCE These results demonstrated that mechanical properties of the films were improved by the addition of chitosan and barrier properties of the film were very good. Additionally, the blend films could be expected to increase the rate of degradation in natural environments.
Session 45D, Food Packaging: General
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