Plastic-coated paper straws are insufficient to solve the plastic pollution problem because microplastics are formed during their degradation. In this study, upgraded paper straws were prepared by coating with biodegradable sodium alginate/cellulose nanofiber/stearic acid (SA/CNF/STA) on the surface of paper without additional adhesives. The tensile strength of the paper was enhanced synergistically by the coated SA and CNF after cross-linking with Ca ions, reaching a maximum (26.46 MPa) when the mass ratio of SA to CNF was 4:1. The straws were prepared by spirally winding coated paper into tubes. Subsequent STA modification with different concentration (1–40%) improved the water stability of the paper straws. The paper straws exhibited excellent mechanical properties (including 13.45 MPa of flexural strength, 13.30 MPa of compressive strength) and hydrophobicity (103.67° of maximum water contact angle). After 130 days of soil burial, the paper straws were completely degraded. The comprehensive performance of prepared straws exceeds that of commercially available products in the same category, and they are safe and biodegradable. Paper straw in the work is in line with the concept of green and low-carbon development.

中文翻译：

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基于可生物降解复合涂层的全天然、疏水性、坚固的纸吸管

涂塑纸吸管不足以解决塑料污染问题，因为在降解过程中会形成微塑料。本研究通过在纸表面涂覆可生物降解的海藻酸钠/纤维素纳米纤维/硬脂酸（SA/CNF/STA）制备了升级版纸吸管，无需额外的粘合剂。涂覆的SA和CNF经Ca离子交联后，纸张的拉伸强度协同增强，当SA与CNF的质量比为4:1时，拉伸强度达到最大值（26.46 MPa）。通过将涂层纸螺旋缠绕成管来制备吸管。随后不同浓度（1-40%）的 STA 改性提高了纸吸管的水稳定性。纸吸管表现出优异的机械性能（弯曲强度13.45 MPa，压缩强度13.30 MPa）和疏水性（最大水接触角103.67°）。土埋130天后，纸秸秆完全降解。制备好的秸秆综合性能超过市售同类产品，且安全、可生物降解。纸吸管的工作符合绿色低碳发展理念。