Abstract
Thermal insulation materials reduce heat transfer and are typically made from materials like fiberglass, foam, or mineral wool, which are engineered to trap air and hinder heat conduction and convection. The traditional manufacturing processes of thermal insulation materials are often energy-intensive and result in significant greenhouse gas emissions. In the current global drive for sustainability, these energy-intensive manufacturing processes raise environmental concerns and need to be addressed. In this work, with the objective of addressing both material sustainability and manufacturing sustainability, we present an additive manufacturing strategy to fabricate biomass materials for thermal insulation applications. Firstly, we propose to use biomass materials, such as wheat straw, as the primary feedstock materials for manufacturing. Such biomass materials offer the unique capacity to sequester carbon dioxide during their growth, and when incorporated into thermal insulation structures, they effectively capture and store carbon inside the structure. Concurrently, our pursuit of manufacturing process sustainability is driven by using a cost-effective additive manufacturing technology to fabricate durable thermal insulation structures. In the presented work, we first demonstrate the formulation of a 3D-printable ink using chopped straw fibers. We conduct comprehensive rheological characterizations to reveal the shear-thinning properties and the printability of the straw fiber ink. Utilizing the direct ink writing (DIW) process, the straw fiber material is deposited into 3D structures. Following bulk material characterization tests, including microstructure, mechanical, and thermal tests. We unveil the low thermal conductivity and robust mechanical properties.
