Study On Bonding Technology Of Larch Structural Glulam

The research and development of structural glulam plays an important role for the efficient utilization of wood and sustainable development of wood industry.This paper focuses on the research of bonding technology of Chinese Larch Glulam (glued-laminated timber) with Phenol resorcinol formaldehyde(PRF) and Aqueous polymer Isocyanate(API)adhesives.Orthogonal Experimental Method.is adopted to study the effect of pressure, glue spread and pressing time on the shear strength parallel to grain, Wood Failure Percentage(WFP)and delamination. The results indicate that shear strength of the two adhesives could meet the requirements of GB/T 50329-2002, and the relationship of shear strength and WFP meet that of ISO/DIS 12578. Water soak, water boiling and Vacuum-Pressure delamination testing methods are conducted according to JAS1152 and ISO/DIS 12580. It shows that PRF and API should be used for service class 3 as typeâ… and for service class 2 as typeâ…¡adhesive respectively based on EN301 and JAS1152 standard. Besides, pressing time and glue spread are the most influential factor respectively on the bonding property of PRF and API adhesives with Larch Glulam. Comparison analysis is made between PRF and API adhesives structural glulam regarding bonding properties in terms of shear strength, wood failure percentage and delamination. It indicates that PRF is superior to API.The bonding mechanism:of the two adhesives with Larch Glulam are analyzed by means of contact angle and Scanning Electron microscope to learn the wettablility and penetrability property of adhesives on wood surfaces, and explanation is given in terms of mechanic combination theory and chemical bond theory.