3D Printable Biocomposites with Tunable Environmental Degradability

The growing environmental impacts of solid waste accumulation have resulted in an increased demand for biodegradable alternatives to conventional plastics. While several products have begun to gain popularity as biodegradable or compostable plastics, these often still negatively impact terrestrial and aquatic environments, as they frequently require precise conditions in order to fully decompose. Furthermore, standards for measuring biodegradation rates are often complex and poorly representative of real disposal sites, limiting their widespread use and applicability. In this study, we present four simple tests to assess the environmental degradability of materials without specialized equipment and demonstrate them with a series of 3D printable biotic composites composed of pectin, chitosan, and cellulose, abundant and organic biopolymers known to be degradable by common microorganisms. Five different compositions were degraded in live soil, worm burial, high humidity, and aqueous environments, and demonstrated rapid degradation with up to 100% mass loss after 21 days for a pectin-based material buried in worm-laden oil. Degradability was further found to be tunable, with decreasing degradation rate as chitosan content increased. Our results confirm that biotic composites degrade more rapidly than conventional plastics and provide accessible methods that can enable more widespread material testing for the development of sustainable material alternatives, especially to gather basic environmental degradation information representative of typical solid waste discard conditions. We anticipate that these degradation methods and the materials degraded therein will provide further impetus for reducing waste from 3D printing and for considering end of life when designing products.