Thermal and Chemical Characterization of Digital Light Processing (DLP)-Manufactured Polymer Composites Reinforced with Jute Fibers

The growing demand for sustainable materials with tunable thermal and structural properties has driven the development of composites reinforced with natural fibers in additive manufacturing (AM) technologies. This study investigates the thermal and chemical behavior of polymer composites produced via Digital Light Processing (DLP), an AM technique based on vat photopolymerization that stands out for its high resolution, dimensional control, and superior speed compared to methods such as FDM and SLA. Samples were manufactured with a UV-curable acrylate resin reinforced with jute fibers (<i>Corchorus capsularis</i>) in mass fractions of 0%, 2%, 2.5%, and 3% in solid geometries (CS-). TGA indicated a 4% reduction in the initial degradation temperature with increasing fiber content, from 326.3 °C (CS-0) to 313.2 °C (CS-3.0). TMA revealed a reduction of up to 19% in the coefficients of thermal expansion, indicating greater dimensional stability. The DMA indicated a 16.9% decrease in the storage modulus with 3% fibers, evidencing changes in the viscoelastic response. FTIR detected additional bands at 3340 cm^-1 and 1030 cm^-1, related to O-H and polysaccharides, confirming a fiber-matrix chemical interaction. These results demonstrate the potential of jute as a sustainable reinforcement in photopolymerizable resins, paving the way for ecological and functional applications in 3D-printed composites.