Sustainable Three-dimensional Printing of Waste Paper-based Functional Materials and Constructs

3D printing is a prominent technology across various industrial sectors, and its increasing popularity urgently calls for sustainable 3D printing materials. However, the availability of such materials remains limited. Here, we present a low-cost strategy that harnesses waste papers as a feedstock for developing sustainable 3D printing inks. Our strategy offers remarkable printability and utilizes widely available biodegradable paper wastes to produce 3D printed constructs with satisfactory mechanical properties for common applications and shape stability for servicing at high temperature. Our constructs can be efficiently recycled into inks for reprinting, and our method can be applied to various types of waste papers. By employing multi-material printing, our approach can be extended to produce multi-colored constructs, security information printings and mechanically appealing designs. Our strategy offers an innovative and sustainable solution that addresses the need for repurposing paper wastes, which would otherwise end up in landfills, while concurrently reducing the reliance on virgin plastics for 3D printing.