An Exploratory Study on the Development of Sargassum Algae-Based Biodegradable Polymer Composites Via Selective Laser Sintering

As a direct effect of climate change and agricultural runoff seeping into the Amazon River, tons of brown macroalgae known as Sargassum, have been accumulating on shores throughout the South Coast of North America and the Caribbean region since 2011. This phenomenon has had severe repercussions for marine ecosystems, human health, and the economies of coastal communities in some U.S. territories and states. Despite its negative impacts, Sargassum holds potential as a resource for various industries, such as cosmetics, fertilizers, and construction materials. However, its potential as a biomaterial for additive manufacturing (AM), a transformative field in the production of goods, remains largely unexplored. AM is expected to play a crucial role in America's future economy and national security. Hence, the primary objective of this research project is to investigate the use of Sargassum/biopolymer composite micro-powders for selective laser sintering (SLS) 3D printing, a highly promising technology in the AM sector. If successful, this research could diversify the range of materials compatible with SLS, which is currently dominated by polyamide 12 (nylon PA12).

To achieve the project goal, the team has established three main objectives: (1) fabricate Sargassum/biopolymer composite micro-powders having algal biomass contents ≥ 30wt%, and excellent flowability for SLS, (2) fabricate Sargassum/biopolymer composite specimens via SLS using the obtained powders, and (3) study the effects of Sargassum content and key SLS printing parameters on the microstructure and mechanical properties of the specimens.

Regarding the first objective, Sargassum/biopolymer composite micro-powders are fabricated via wet granulation as follows: Firstly, a suitable amount of dried Sargassum is pulverized via ball milling and then incorporated into an aqueous biopolymer/binder dispersion using a planetary mixer. The resulting brown paste is then dried in an oven overnight to obtain a cake. This dried cake is cut into pieces, which are then fed into an oscillating granulator to obtain a fine powder. Lastly, the fine powders are characterized via optical microscopy, and angle of repose.

To fabricate the 3D printed specimens, the powders are fed into a SLS machine from Sintratec®, where the printing process takes place under controlled conditions. In addition, the team plans to evaluate the effect of some key parameters on the mechanical properties and microstructure of the specimens. The printing parameters to be changed are the laser scan speed, layer thickness, and hatching spacing. In the case of the specimens’ properties, these will be evaluated via tensile and flexural tests.