Bonding strength of polyvinyl acetate PVAc and casein adhesives in small diameter beech wood

Abstract

As a matter of fact, beech wood is one of the most important commercial hardwood species in southeastern Europe. Beech is utilized mainly as round wood and fuel wood. Overall harvest of beech wood is comparable to those of pine and oak forests. Effective and maximum value use of small-diameter hardwood timber has long been of interest to forest managers and researchers. Gluing or bonding wood has been widely used for many centuries. Moreover, a wide variety of adhesives types is utilised, due to their extensive use in many different applications with wood. Beech wood Fagus sylvatica L. , was used in order to investigate the bond ability of beech wood. For the bonding the used adhesives were PVAc and casein glue, both of D3. The adhesives were applied to one or two surfaces and the half of them were immersed in water in order to investigate the influence of moisture on bonding strength. According to the results, the average modulus of rapture was influenced by the type of adhesive. The samples of beech wood bonded with PVAc had higher modulus of rapture compared to the samples of beech laminated with glue Casein-gap from 1.03 to 2.2 N/mm². Additionally, the highest average modulus of rapture rate recorded in beech samples coated with PVAc on both bonding surfaces reaches 21.05 N/mm². The statistical analysis of the results revealed that the average bonding strength of those samples only air-conditioned, did not show any statistically significant difference from the average bonding strength of the samples immersed in water

Keywords

• beech wood,bonding,casein,PVAc,shear strength

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