Ultrastrong, Hydrostable, and Degradable Straws Derived from Microplastic-Free Thermoset Films for Sustainable Development

Abstract

Single-use plastics such as straws have caused intricate environmental challenges since they are not readily assimilated into nature at the end of life. Paper straws, on the contrary, become soggy and collapse in drinks resulting in an obnoxious user experience. Here, all-natural, biocompatible, degradable straws and thermoset films are engineered by integrating economical natural resources─lignin and citric acid─into edible starch and poly(vinyl alcohol), making them the casting slurry. The slurries were cast on a glass substrate, partially dried, and rolled on a Teflon rod to fabricate the straws. The straws are perfectly adhered at the edges by the strong hydrogen bonds from the crosslinker─citric acid─during drying, thus eliminating the need for adhesives and binders. Further, curing the straws and films in a vacuum oven at 180 °C results in enhanced hydrostability and endows the films with excellent tensile strength, toughness, and ultraviolet radiation shielding. The functionality of the straws and films surpassed paper and plastic straws, making them quintessential candidates for all-natural sustainable development.