A review of recent developments for applicational performances in soybean protein-bonded wood composites

Abstract

Developing sustainable adhesives has garnered increasing attention in the wood industry due to problems such as hazardous substance emissions and dependence on fossil energy in the synthesis of resins. Benefiting from its abundant sources, easy processing and various functional sites, soybean protein is considered as a potential material to prepare eco-friendly wood adhesives. As a result, a series of strategies such as molecular modification, cross-linking modification, organic–inorganic hybrid system construction and biomimetic design have been reported for improving the bonding properties and functionalising soybean protein adhesives. Herein, we report on recent developments in the production of soybean protein adhesives for wood bonding with various application requirements, such as water resistance, low viscosity, desired pre-pressing bonding properties, fast curing, strong yet tough bonding, anti-bacterial properties, flame resistance, cost-effectiveness and satisfactory electromagnetic shielding performance. The structural properties of soybean protein molecules, bonding mechanisms of soybean protein adhesives in wood composites, and challenges in the field of soybean protein adhesive development are also discussed. Thus, this review provides insights into the frontier study of soybean protein–based wood adhesives and assist in further research and fabrication of high-value bio-based composites.