A dual modification approach for high-strength, and waterproof 3D printed fish gelatin-alginate tableware.

The pervasive use of disposable plastic tableware, often ending up in landfills or natural environments after consumption, poses significant ecological and human health risks. To address this challenge, we developed an environmentally friendly, food-safe composite material with robust mechanical strength and water resistance to replace conventional plastics. This study utilizes fish processing byproducts to fabricate a gelatin‑sodium alginate (FG-SA) composite, which was shaped into tableware precursors via 3D printing. A two-step modification strategy was employed: First, ethanol treatment at ambient temperature dramatically enhanced mechanical properties, increasing Young's modulus by 22,591.8-fold (from 57.5 kPa to 1.29 GPa) and tensile strength by 557.0-fold (from 78.7 kPa to 43.8 MPa). Second, paraffin coating conferred hydrophobicity, achieving a water contact angle of 113.2 ± 0.4°. The FG-SA gel exhibited excellent printing adaptability, enabling the fabrication of diverse utensil geometries (e.g., forks and knives) while maintaining structural integrity. Comprehensive performance evaluations revealed that the fish gelatin-based tableware surpasses commercial plastics in mechanical durability, water resistance, and usability, while complying with food contact safety standards. This work establishes a sustainable paradigm for upcycling fishery waste into high-performance green tableware, offering a scalable solution to mitigate plastic pollution.