3D printing light-curing acrylic resins with electrical properties based on polianiline and lignin

Resumen

Advances in 3D printing, key to the new production models of Industry 4.0, require high-performance and environmentally friendly materials. Its application in sensors is especially attractive, allowing, at an affordable cost, the integration of electronics in manufacturing. The aim of this thesis is to develop new photocurable resins with electrical properties for 3D-DLP printing. Flexible resins have been designed based on acrylate monomers and nanofillers: polyaniline (PANI), PANI modified with lignin (PANI/Lignin) or with carbon nanotubes (PANI/MWCNT) and organosolv lignin. Structural characterization of the materials has been performed by TGA, FTIR, rheology, microscopy, and elemental analysis; special attention has been paid to matrix/filler compatibility, the mechanical and electrical (piezocapacitive and piezoresistive) properties. PANI has proven to be a valuable conductive filler for light-curable printable conductive resins. PANI modified with MWCNT improved the electrical conductivity of the resins, at the cost of increased heterogeneity. However, lignin, as part of the filler or additive, improved the homogeneity, surface finish and electrical properties of the composites. Finally, the obtained functional prototypes (printed sensors) validated the reproducibility and precision of the developed materials in real life conditions.