Synthesis of sodium alginate composite bioplastic films

Abstract

In recent years, plastic pollution has reached high levels; eight million metric tons of plastic waste leaked into the oceans in 2010, with estimates predicting 53 million metric tons of emissions annually by 2030. The increasing use of single-use plastics accounts for much of this mismanaged plastic. Aside from harming marine ecosystems, burning plastic waste in landfills may release toxic chemicals that cause illnesses. Bioplastic, a plastic derived from biological sources, has emerged as a sustainable alternative to mitigate this issue. However, their lack of biodegradability and high costs restrict widespread adoption. We investigated the development of alginate-based bioplastic films as a sustainable plastic alternative. We hypothesized a sodium alginate-based bioplastic film synthesized in ambient conditions would demonstrate higher biodegradability, higher tensile strength, higher solubility in water, lower oxygen permeability, and lower water vapor permeability compared to PET plastic packaging films. We synthesized the films in ambient conditions with glycerol and calcium chloride as an added plasticizer. The material displayed transparency and flexibility. Additionally, the film was able to dissolve in water after 180 minutes and biodegrade in microbial conditions (i.e., environments that can sustain microbes and other decomposers) within seven days. Ultimately, our research supports sodium alginate composite films as a biodegradable bioplastic film that exhibits higher solubility in water, and greater biodegradability compared to PET plastic films. However, contrary to our hypothesis, sodium alginate composite films also demonstrated lower tensile strength and higher water vapor permeability. This suggests sodium alginate composite films are not ready to replace PET packaging films in the industry.