Structural characteristics and soil degradation behavior of hybrid breathers from natural plant fibers, synthetic fibers, and lignin fibers

Three hybrid nonwoven breathers—jute/polyester, jute/lignin, and coir/polyester—were fabricated via needle-punching to improve the environmental sustainability of composite manufacturing auxiliaries, and their performance and degradation were evaluated over 90 days of soil burial. However, distinct trade-offs emerged. The jute/lignin (JL300) breather showed the highest degradation rate (17%) and best air permeability (1172 L/(m²·s)) due to uniform fiber fineness, yet it exhibited the poorest mechanical properties. In contrast, the coir/polyester (CP450) breather had the lowest degradation (2.4%). Notably, the jute/polyester (JP340) breather achieved an optimal balance, with 6.8% degradation, 3.23% moisture absorption, 1149 L/(m²·s) air permeability, and 480 N machine-direction strength. FT-IR and DSC analyses revealed a dual degradation mechanism involving C–O–C bond cleavage in natural fibers and ester bond hydrolysis in polyester, evidenced by decreased melting temperature and increased crystallinity. Overall, these findings guide the design of hybrid breathers balancing performance and degradability for green manufacturing.