From Spontaneously Tubulate Cornhusk to Cheap, Scalable, Degradable Biomass Straws via Adhesion of In Situ Regenerated Lignocellulose

Abstract Biomass with 2D structures has been exploited to produce degradable straws via the top-down strategy to alleviate environmental pollution of plastic straws. Two critical issues remain to be solved: inherent brittleness that leads to cracking during the tubulation process, and weak interfacial bonding that makes it difficult to firmly join the overlapped edges. Conventional methods usually increase tubulation performance through delignification/chitosan infiltration and realize the bonding of overlapped edges via mould-assisted hot pressing or additional adhesives. Herein, cornhusk with inherent spontaneous tubulation properties was utilized to produce straws via a green, scalable, low-carbon-footprint top-down method. The entire process includes spontaneous tubulation, NaOH/urea treatment, and drying procedures and requires no chitosan infiltration, extra adhesives, or mould-assisted hot pressing. The lignocellulose dissolved in the reaction solution acts as a binder, which can firmly join the overlapped edges only through a simple drying treatment. The bending strength of the as-prepared cornhusk straw reaches 7.1 MPa, which is comparable to that of commercial plastic straw (7.0 MPa). The production price is 0.15 cents per straw, lower than those of paper straw (4.00 cents), PLA straw (2.00 cents), and even plastic straw (0.20 cents). Theoretically, a total of 1.2 million straws can be produced per hectare of cornfield. The proposed cornhusk straw, which integrates biodegradability, scalability, cheapness, and sustainability, is a promising alternative to commercially available single-used paper and plastic-based straws.