Development of eco-friendly and robust structural materials via binder-free lamination of waste biomass with help of finite element method

To alleviate the environmental pressure, it is of great significance to develop the green and sustainable structural materials by utilization of waste biomass. In this work, an eco-friendly, high-strength, superhydrophobic, and thermally stable material was fabricated through a scalable binder-free lamination method using waste biomass (e.g., wood residues, crop straw, and waste paperboard). The waste biomass was separated and molded into fiber mats by a clean pulping process, and then laminated without adhesives. The finite element method (FEM) was adopted to visually observe fracture behaviors and detect the weakest zones. The utilization of FEM to enhance the mechanical strength is unique in productions of traditional biomass composites. The weakest zones were reinforced by the H2O2 spraying approach, and the flexural strength (FS) was improved from 80.12 to 120.35 MPa. The moisture content (MC) in the mat was used for regulating the softening of cellulosic fibers. In virtue of the water-induced plasticization, the laminated materials showed a high internal bonding strength (IBS) of 2.24 MPa and excellent FS of 134.81 MPa. Being benefitted from the silica modification, the materials exhibited a superhydrophobic surface with the high water contact angle (154.1°), good dimensional stability (a thickness swelling of 14.8%), and superior mechanical stability (remained 94.3% FS after two months of ultraviolet radiation). This work provides a new strategy to develop green and sustainable structural materials for buildings, furniture, and related applications.