Investigation of mycelium film as the adhesive for poplar veneer bonding: insight into interfacial bonding mechanisms

The emergence of mycelium-bonded biocomposites has been stimulated in the quest for sustainable development. These biocomposites exhibit enhanced mechanical properties through hot pressing, with mycelium playing a crucial role as both the adhesive and reinforcing material in this composite system. This study aims to investigate and compare the effectiveness of different mycelium films for veneer bonding, with a specific focus on the interface between the mycelia and the substrate. Two fungal species, Pycnoporus sanguineus and Trametes versicolor, were utilized to colonize poplar veneers for 14 days. Subsequently, a wood bonding interface was successfully established between the mycelium film and the decayed veneer surface. The results revealed that bonded veneers with the mycelium film of Pycnoporus sanguineus exhibited higher adhesion strength with 1.76 ± 0.16 MPa. A series of analyses have revealed the occurrence of both mechanical and chemical bonds between mycelia and wood. The bonding interface between mycelium and wood was formed by a synergistic combination of mechanical interlocking, hydrogen bonding interaction, Schiff base reaction, and lignin repolymerization. This study provides valuable insights into the underlying mechanisms involved in the formation of interfacial bonding by fungal mycelia.为践行可持续发展理念，菌丝体(Mycelium)粘结生物复合材料应运而生。此类生物复合材料经热压工艺后力学性能显著提升，菌丝体在该复合体系中同时充当粘结剂与增强材料，发挥核心作用。本研究旨在探究并对比不同菌丝体薄膜用于木材单板粘结的效果，重点关注菌丝体与木材基底之间的界面特性。本研究选取血红密孔菌（Pycnoporus sanguineus）与彩绒革盖菌（Trametes versicolor）两个真菌菌种，将其接种至杨木单板表面并培养14天。随后，成功在菌丝体薄膜与腐朽杨木单板表面之间构建出木材粘结界面。结果表明，采用血红密孔菌菌丝体薄膜制备的粘结单板具有更高的粘结强度，可达1.76±0.16 MPa。一系列分析结果证实，菌丝体与木材之间同时存在机械结合与化学结合。菌丝体与木材的粘结界面由机械互锁、氢键相互作用、希夫碱反应以及木质素再聚合的协同作用共同形成。本研究为真菌菌丝体构建界面粘结的内在作用机制提供了极具价值的参考。