Circular economy is one of the solutions to solve environmental issues and resource limitations. In the field of lignocellulosic materials, utilizing agricultural waste streams to fabricate renewable and sustainable materials can be a promising approach for closed-loop manufacturing. Polyhydroxyalkanoates (PHA), which is a rapidly developing material from lignocellulosic resources, showed great potential for sustainable applications but was limited by its poor mechanical and thermal performance. In this work, lignin was used as a functional filler to prepare PHA composites through 3D printing. Lignin was proven to reinforce the PHA/lignin composites and bring anti-aging performance at the same time, maintaining the sustainability of the resultant products. By using micro- and nano-lignin particles, the interactions between lignin and the polymer matrix could be adjusted, resulting in the change of mechanical properties, which also illustrates the structure-property relationship in preparing PHA/lignin composites. Given lignin another bio-renewable components from lignocellulosic resources and the advantages of 3D printing, this method make it possible for a circular economy in terms of sustainable materials from agricultural waste.
