Sustainable jute fiber-reinforced auxetic composites with both in-plane and out-of-plane auxetic behaviors

Energy-absorbing auxetic composites show flexibility in usage, yet they remain non-biodegradable, thus creating environmental challenges. Implementing sustainable auxetic materials constructed from natural fibers and biodegradable polymers remains essential for lowering environmental effects. This research involves the fabrication of eco-friendly auxetic composite using jute and jute-viscose nonwovens. Scanning electron microscopy and optical microscopy revealed the out-of-plane auxetic effect that heat compression produced at different temperatures and pressure levels. The combination of 150°C and 50 psi pressure resulted in out-of-plane Poisson's ratios (PR) of −2.6 and −3.0 for jute and jute-viscose nonwovens. The incorporation of 40% biodegradable polylactic acid (PLA) into the jute and jute-viscose nonwovens increased auxeticity to −4.5 and −5.0, respectively. Needle punching density controlled the in-plane auxetic properties, where jute/PLA composites achieved a PR of −0.45, and jute-viscose/PLA composites achieved a PR of −0.65. The unprocessed nonwoven materials displayed the highest tensile strength of 0.16 MPa for jute and 0.76 MPa for jute-viscose, but heat treatment diminished this strength level. PLA reinforcement improved composite strength. This study introduces a durable method for designing auxetic materials that can find uses in energy-absorbing systems as well as protective equipment. Highlights: Evaluating the in-plane and out-of-plane auxetic behavior in needle-punched jute and jute-viscose nonwovens. Studying the effect of various temperatures and pressures on the out-of-plane auxetic behavior of nonwovens. Fabricating a sustainable composite by reinforcing PLA and examining auxeticity. Temperature and pressure have significant effects on auxetic behavior. Optimizing PLA content further helps in improving auxetic behavior and strength properties.