Study on preparation of bean gum and pretreatment of poplar in lithium salt/ionic liquid

In a novel solvent system consisting of lithium salt/ionic liquid, glycidyl methacrylate (GMA) was grafted onto the surface of soybean protein using atom transfer radical polymerization (ATRP), resulting in the preparation of a soybean protein-based graft copolymer. To establish a strong interfacial force, N-hydroxymethyl acrylamide (NMA) was introduced between the soybean protein adhesive and poplar veneer. The effects of unfolding degree of soybean protein structure on the properties of pretreated soybean protein were studied by Fourier-transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance spectroscopy ( 1 H NMR) and thermal analysis (TGA, DTG), and the results showed that the synthesis of Soybean protein macromolecular initiator (SPI-Br) and soybean protein-glycidyl methacrylate graft copolymer (SPI-g-PGMA) was successful. In addition, the pretreatment of poplar veneer with N- hydroxymethyl acrylamide improved the penetration depth of the adhesive on the veneer. The treated plywood has excellent performance and has good application prospects in construction, furniture manufacturing and other fields. • Soybean protein isolate exposed more active reactive groups after pretreatment. • Controllable grafting of epoxy group ensures the operability of adhesive. • Introducing the bonding intermediate improves the force between adhesive and board. • The reticular structure between adhesive and board prevents the water from entering.