Preparation of high water-retention biodegradable kidney tray from rice straw pulp

A biomedical pulp product, a hydrogel-coated high water-retention biodegradable kidney tray from rice straw pulp, was successfully prepared in a simple and environmentally friendly process. Response surface methodology (RSM) was applied to optimize the rice straw pulping condition. The optimum condition was investigated using influential parameters and the results were 17% active alkali, 21.15% sulfidity, and 120 -min pulping time, resulting in a pulp yield of 38.56% and a delignification selectivity of 25.91%. This pulping condition effectively increased the cellulose proportion and the crystallinity of the pulp, while the lignin portion was decreased. The hydrogel was prepared by mixing acid-soluble chitosan solution and rice straw pulp suspension. Introducing the hydrogel into the kidney tray led to water retention for 5 h with no leak and swelling degree up to 500%. The kidney tray also showed a good level of biodegradation, indicated by changes in surface morphology and weight loss of the sample and also high tensile strength. Therefore, this research suggests that rice straw pulp has promising application in the development of biodegradable and high-strength biomedical pulp products such as pulp-based kidney trays.