From Brown Tides to 3D Printers: Additive Manufacturing of Novel Algae-Based Polymer Composites

Abstract

As a direct effect of ocean warming and nutrient enrichment, tones of a brown macroalgae known as Sargassum, have been accumulating on shores throughout the Caribbean region since 2011. These unprecedented annual events have been detrimental to marine ecosystems, human health, and economy of coastal communities. In the search for new applications of Sargassum biomass, the present work aimed to explore the use of this seaweed as a raw material for the fabrication of renewable powder that was incorporated into polylactic acid (PLA) composite filaments to 3D print different specimens. The mechanical properties of the resulting structures were evaluated via tensile tests, while studies of biodegradability were performed using burial tests. The results indicate that it is possible to fabricate filaments with Sargassum powder contents up to 30 wt%. However, the required extrusion temperatures and the brittleness of the filaments increase with the Sargassum content. Also, 3D printing of these composite materials required nozzles with sizes ≥1 mm to avoid clogging. Regarding the mechanical properties of the specimens, both the elastic modulus and yield strength exhibit a declining trend as the Sargassum content into the PLA polymer matrix increase. As expected, preliminary studies of biodegradability suggest that the composite degradation increases significantly with the Sargassum content. Samples having 30 wt% of Sargassum exhibited weight loss % of 25.6, after 60 days of being buried into a compost at ambient temperature. Additional experiments are required to gain evidence of accelerated biodegradation at ambient conditions of the PLA conforming the 3D printed structures.