Preparation of glucose-based resin adhesive under ambient conditions with excellent bonding and water resistance for plywood bonding

Plywood is an important and widely used material for construction and furniture, and its properties are directly affected by the adhesives used. In order to develop an environmentally friendly adhesive with excellent bonding performance for the safe and healthy plywood production. Glucose as one of most reserves and widely distributed monosaccharide in nature, which was oxidized by sodium periodate (NaIO 4 ), then reacted with hexamethylenediamine via Schiff base reaction under ambient conditions to obtain oxidized glucose-hexamethylenediamine (OGH) resin wood adhesive. The whole preparation process was performed at ambient conditions and normal atmospheric pressure. The influence of the proportions of raw materials has been investigated, and the plywood was used to measure OGH resins bonding performance. Fourier transform infrared spectroscopy (FTIR) and liquid chromatography-tandem mass spectrometry (LC-MS) were used to characterize structures of OGH resin to investigate mechanism of the preparation reaction. The results show that when NaIO 4 addition was 9 % (w/w based on glucose), and the hexamethylenediamine with the same molar mass as glucose can yields the best bonding effect. The dry shear strength, 24 h cold water soaking wet strength, 3 h hot water(63℃) soaking wet strength, and 3 h boiled water wet strength of plywood bonded with this resin are as high as 1.76 MPa, 1.73 MPa, 1.11 MPa, 0.86 MPa respectively. This outstanding bonding performance and water resistance exceeds the GB/T 9846–2015 standard level (≥0.7 MPa), thus it has good potential as an industrial adhesive for wood bonding.