3D PRINTING OF POLYMER COMPOSITES FILLED WITH BAMBOO FIBRES VIA LCD VAT PHOTOPOLYMERISATION

Additive manufacturing (AM) is one of the most promising technologies for producing complex and personalized components, offering advantages such as reduced time, costs, and material waste compared to traditional processes. Among the various techniques, liquid crystal display (LCD) vat photopolymerisation (VPP) distinguishes itself for its elevated precision and the possibility of developing new polymeric compounds and testing them in the vat. However, most of the resins used nowadays are fossil-based and show problems related to sustainability and end-of-life material handling. This work aligns with this context, aiming to develop and characterise a new bio-based thermosetting resin compound starting from Acrylate epoxidized soybean oil (AESO) as the primary matrix. The compounds were first created by adding to the AESO the Isobornyl methacrylate (IBOMA) as a reactive diluent to reduce the AESO viscosity in a 50/50 wt.% quantity, and the Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) as radical photoinitiator (2 parts for resins (phr)), compatible with the light emitting diode (LED) sources wavelengths used in LCD 3D printing (3DP) machines. To enhance the final properties of the material, different quantities of natural bamboo fibres were introduced (3, 5, and 10 phr). The choice of this reinforcement was derived from both the necessity to evaluate an effective enhancement of the properties and the desire to create a renewable, low-impact material. The obtained formulations underwent several steps, starting from the rheological tests to evaluate the processability of the resin. After defining the printing parameters for all the compounds, mechanical, thermal, and morphological characterisation tests were performed. There, the fibres showed a positive effect both on rigidity and thermal stability, confirming the potential of bamboo as a natural reinforcement in bio-based polymers. In conclusion, this work highlights how the integration of photo-curable bio-based resins and natural fibres can represent a concrete strategy for the development of innovative and sustainable materials that adapt to modern AM technologies, contributing to the progress towards a more circular and eco-compatible economy.