Cellulose From Aloe Vera Plant Waste as Crosslinker for Vat 3D Printable Vitrimers: Toward a Circular Economy Approach in Additive Manufacturing

The reduction of the environmental impact of photocurable resins, commonly used in vat 3D printing, is an urgent request. In order to truly enable vat additive manufacturing (AM) to adopt a circular economy approach, this can be done by both selecting non-fossil carbon feedstocks and considering the end-of-life and reprocessability of the resulting thermosets. Pursuing this goal, we present the study of a 3D printing-compatible vitrimeric resin capable of dynamically reorganizing the polymeric network and exhibiting self-repair properties following heat treatment at 160°C. For the development of the resin, microcrystalline cellulose (MCC) is extracted from aloe vera peel, the main waste from the cultivation of this plant. MCC is then functionalized and used as an added-value crosslinker for the monofunctional monomer 2-hydroxy-3-phenoxypropyl acrylate (HPPA), which is considered green as it can be obtained from renewable resources. The material studied possesses excellent printing resolution, remodeling, and self-healing ability, leading to a significant recovery of mechanical properties after breakage. This work highlights the possibility of combining renewable raw materials, waste utilization, and vitrimeric chemistry to create sustainable, easily recyclable resins.