Sustainable thermal insulation panels from lignocellulosic agricultural residues for green building applications

Abstract The urgent need to decarbonize the construction sector has increased interest in circular approaches that convert biomass waste into high‐performance building materials. Unmanaged agricultural residues pose environmental risks, highlighting the importance of valorizing such waste through sustainable material innovations. This study explores the characterization and fabrication of composite thermal insulation panels using two lignocellulosic wastes: empty fruit bunch (EFB) fibers and spent mushroom substrate (SMS) fibers. Empty fruit bunch fibers were physically treated using a refining process at disk gap settings of 1.75 mm, 1.50 mm, and 1.25 mm. Panels were fabricated using a hot‐pressing technique with a 60% SMS and 40% EFB fiber blend. Morphological analysis, flexural strength, thermal diffusivity, atomic force microscopy (AFM), and heat flux simulations were conducted. Refining improved EFB fiber morphology by increasing fibrillation, which enhanced interfiber bonding and distribution. The panel that used EFB refined at 1.50 mm showed optimal performance, combining thermal properties with adequate mechanical strength. It achieved a specific flexural strength of 21.00 MPa, thermal conductivity of 0.246 W m −1 K −1 , and thermal diffusivity of 0.235 mm 2 s −1 . A peak specific heat capacity of 1.049 J kg −1 K −1 indicated effective thermal buffering. Atomic force microscopy confirmed fewer voids and better surface uniformity. Heat flux simulation revealed a reduction from 287 to 68.88 W m −2 as panel thickness increased from 6 mm to 25 mm. This study demonstrates a viable pathway to convert biomass waste into sustainable insulation materials, offering a low‐carbon alternative that supports energy efficiency and sustainable building practices.