Recent Progress on the Application of Hyperbranched Polymers in Biomass-Based Adhesives for Sustainable Wood Bonding

Biomass-based adhesives have emerged as promising alternatives to fossil-based counterparts for the wood industry. However, their practical application is hindered by the high hydrophilicity, low reactivity, and complex molecular structures of biomass, leading to inadequate bonding strength and water resistance. Recently, hyperbranched polymers (HBPs) have attracted increasing attention as effective modifiers due to their unique three-dimensional and highly branched molecular architecture. Although considerable progress has been made in employing HBPs for wood bonding and biomass-based adhesives enhancement, a systematic understanding of the interaction mechanisms and structure-performance relationships remains lacking. Moreover, the diversity of biomass substrates and HBPs complicates the establishment of universal design principles. Therefore, a systematic overview of the current advances, modification strategies, and structure-performance relationships of HBP-modified biomass-based adhesives is urgently needed. This review provides a concise overview of the fundamental characteristics of HBPs and recent advances in their application in wood bonding and biomass-based adhesives. The underlying enhancement mechanisms, current challenges and future research directions are highlighted, aiming to guide the development of sustainable, high-performance wood adhesives.