Development of a methodology for the production of nanostructured polymeric biocomposites with cellulose nanocrystals

The increasing utilization of polymeric composites stands out as a versatile solution across various engineering fields. To meet the demand for more sustainable and efficient materials, research has been exploring natural and biodegradable sources for the fabrication of these new materials. Among these alternatives, green polyurethane (GPU), derived from castor oil (Ricinus communis), shines due to its sustainability, low toxicity, and abundant availability. However, GPU exhibits limitations in mechanical strength, prompting studies on composites reinforced with synthetic, vegetable fibers, and particles. In this context, cellulose nanocrystals (CNC) emerge as promising due to their rigidity and mechanical strength. However, their industrial production through aqueous dispersion presents challenges in application to polymeric matrices due to resin hydrophobicity. This study proposes a new methodology to extract and incorporate CNC into composites, aiming to characterize the physical, chemical, mechanical, and morphological aspects of a composite material formed by GPU reinforced with different proportions of CNC (0%, 1%, 2%, and 3%). The results demonstrate a significant improvement in mechanical strength, with a 262% increase upon adding 3% CNC reinforcement. In terms of thermal resistance, there was a lower mass loss and alterations in the initial degradation temperature range observed. This study contributes to the understanding of composite properties and their potential in various applications.