Assessing the Impact of Chitosan on Tensile Strength, Biodegradability, and Water Resistance of Bioplastic 

The objective of this project is to enhance the water resistance of bio fiber plastic from last year’s science fair project so that it can be a sustainable and environment friendly replacement to conventional plastic.

Based on the research it’s found that chitosan a derivative of chitin can be used to increase the water resistance of bio-fiber plastic.  Chitin is the structural component in the shells of crustaceans like crabs, shrimp, lobsters. Chitin can be obtained from sea food industry, which produces 6-8 million tons of crab, shrimp and lobster waste each year.

First half of this project is to prepare bio plastic film by combining bio fiber plastic and Chitosan in different ratios. The second half is to calculate tensile strength, biodegradability, water resistance and flexibility of the bioplastic sample. Tensile strength is calculated using the Maximum force (measured using digital force gauge) and thickness (using Vernier caliper). Water resistance is tested by performing a water absorption test, which measures the weight of water absorbed by the bioplastic sample when immersed in water for a specific period. Biodegradability is measured by calculating the "loss of weight" of the bioplastic sample over a specific period when buried in compost soil at room temperature. Flexibility is tested by folding the bioplastic samples at 180 degrees and placing a weight (100 grams) repeatedly until it shows signs of a crease.

Results show that the tensile strength and water resistance of bioplastic sample increases as the ratio of Chitosan increases. The tensile strength of bioplastic is increased by 50% compared to the control sample. Water resistance of bio plastic is increased by 40% compared to the control sample.  Flexibility of bio plastic shows inverse relationship with Tensile strength. Biodegradability shows inverse relationship with water resistance. Hence by Varying the Chitosan ratio, bioplastic of different tensile strength and flexibility can be produced to meet different needs.

Further research can be conducted to reduce the use of potential food sources (starch) by identifying non-food sources to produce second-generation bioplastics