Green and scalable transformation of bamboo into high-performance structural materials

Developing high-performance structural materials from fast-renewable biomass is an effective strategy to reduce dependence on fossil resources and mitigate CO 2 emissions. Here, we report a scalable, water-only process that transforms fast-growing bamboo into robust structural materials through hydrothermal-assisted disintegration followed by thermal self-bonding. Subcritical water treatment softens cell walls and enables the controlled separation of high-aspect-ratio (>3000) macrofibers, while inducing the selective lignin migration and surface enrichment. During subsequent hot-pressing, this mobilized lignin undergoes in-situ condensation and interfacial crosslinking, forming a continuous, load-bearing network that reinforces a densely hydrogen-bonded cellulose microfiber framework. Reducing the macrofiber diameter to 100 μm significantly increases the specific interfacial area and promotes microfiber alignment, yielding fully adhesive-free structural materials with exceptional mechanical performance, including a tensile strength of 580 MPa, a flexural strength of 228 MPa, and a toughness of 4.35 MJ/m 3 , surpassing conventional adhesive-bonded fiberboard by 3–5 times. Life-cycle assessment reveals more than a 60% reduction in fossil carbon input and CO 2 emissions relative to petroleum-based plastics. This work demonstrates a green and generalizable strategy for lignocellulosic biomass valorization through programmed lignin activation and chemical-free consolidation, providing sustainable production of high-performance bio-based structural materials with a minimized environmental footprint.