Abstract
Traditional construction is slow, labor-intensive and wasteful. Additive manufacturing (AM) enables faster, automated and efficient buildings with less waste and more design flexibility. This study looked at the possible applications of a biobased novolac (pyrolysis oil / phenol-formaldehyde) resin and hexamethylenetetramine (HMTA) hardener with either 40 mesh and 100 mesh wood fiber (30%), and extrusion of wood composites. Wood pyrolysis oil was partially substituted (50%) for phenol in the novolac resin preparation to increase its biobased content. The materials were characterized by a combination of thermal analysis, rheology, mechanical, and water absorption properties. The flow characteristics of the uncured resin and composites were determined by dynamic rheometry. The curing behavior of the resin and composites was determined by differential scanning calorimetry (DSC). The presence of wood decreased the curing enthalpies and increased the curing peak temperature. The wood resin composite blends displayed good pseudoplastic behavior. Composites made with smaller wood particles showed more thermal stability and lower glass transition temperature (T
g
) because of the increased interaction between the fiber and the resin matrix. Extrusion experiments on the wood resin composites successfully produced a continuous rod. The extruded wood resin composite rods were cured (150℃ for 5 min) and showed good flexural properties. The successful extrusion of biobased novolac with wood demonstrates its potential for AM, making it a promising sustainable alternative for construction applications.