Damping and vibration properties of alginate–poloxamer hydrogels doped with sepiolite and cactus fibers

We investigated a novel class of composite hydrogels composed of alginate, poloxamer, sepiolite, and cactus fibers for vibration damping applications. Using a design of experiments methodology, we systematically correlated manufacturing parameters with mechanical and damping properties, using dynamic mechanical analysis and vibration testing. The hydrogels were characterized under controlled temperature, frequency, and humidity conditions, with results demonstrating that the storage modulus can reach up to twice that of pure hydrogel formulations using diluted dispersions with total additive concentration below 2 wt. %. Sepiolite additions below 0.3 wt. % were found to stabilize the material response to temperature variations, while cactus fibers enhanced both stiffness and damping performance in a concentration-dependent manner. Optimal performance was achieved with a formulation containing 5 wt. % alginate, 5 wt. % poloxamer, 0.1 wt. % sepiolite, and 2 wt. % cactus fibers. This composition provided a favorable balance between quasi-static mechanical integrity and dynamic damping capability, with loss factors exceeding 0.4. These findings provide a foundation for developing advanced and sustainable hydrogel materials with tailorable vibration damping characteristics.