Chitosan-polylactic acid composites: from seafood waste to advanced functional materials for 3D printing

Abstract The development of functional and sustainable materials for additive manufacturing is a rapidly expanding area of interest. In this context, composite blends of chitosan—including commercial low and medium molecular weight variants, as well as laboratory-extracted chitosan from shrimp head and shell waste—and polylactic acid (PLA) were prepared using extrusion molding. Filament characterization was conducted to explore the effects of chitosan molecular weight and content on the filament properties using melt flow index, tensile testing, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). The morphology of the extruded filaments was analyzed using scanning electron microscopy (SEM). Additionally, the possibility of incorporating a high ratio of metal into the composite filaments without compromising their printability and structural integrity was investigated. The results indicated that certain compositions of chitosan-PLA composite filaments enable the effective incorporation of nickel, highlighting their potential as innovative catalyst supports. The filaments were 3D printed in a molten state, and the resulting specimens were subsequently examined using micro-CT. This approach seeks to create an innovative material from food waste, offering a sustainable and circular solution for transforming seafood waste into advanced functional materials. The successful integration of shrimp waste-derived chitosan into PLA filaments not only enhances the material properties, but also demonstrates the potential for creating high-value products from bio-waste, contributing to environmental sustainability and advancing the field of eco-friendly additive manufacturing. This work highlights the promising application of composite filaments in various industrial sectors, emphasizing their role in promoting a circular economy.