Tensile Shear Strength and Microscopic Characterization of Veneer Bonding Interface with Polyethylene Film as Adhesive
Polyethylene film was selected as formaldehyde-free wood adhesive for plywood in this paper. In order to understand the impact of pressing conditions and wood surface properties on the penetration characteristics of polyethylene film into wood veneer tissues, light microscopy was employed to quantitatively measure the average penetration depth and bond-line thickness. The correlation between polyethylene penetration and tensile shear strength of plywood was also studied. Results showed that when polyethylene film layer increased from 1 to 4, the penetration depth and bond-line thickness increased by 163% and 169% respectively, which resulted in a 120% improvement in tensile shear strength of the three-layer plywood. Because of the high viscosity of polyethylene, a suitable hot-pressing temperature (160 °C) and hot-pressing time factor (1 min/mm) were necessary to finish the penetration step and form much more mechanical interlocking. Cold-pressing was a critical step to improve the performance of polyethylene bonded plywood. When cold-pressing time increased from 0 to 5 min, it caused 17% increase in penetration depth and 113% increase in tensile shear strength. Wood failure of all the untreated plywood was lower than 5%. Thermal-treatment on wood veneer changed its surface from hydrophilic to hydrophobic. It was an effective way to promote melted plastic flowing on the veneer surface during hot-pressing and thus maximize the adhesion penetration. Both tensile shear strength and wood failure of the plywood were improved due to thermal-treatment. When wood veneers were thermal-treated under the temperature above 160 °C, tensile shear strength of all the polyethylene bonded plywood could meet the requirement of type I grade plywood with their wood failure increased to more than 20%.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: September 1, 2019
More about this publication?
- Science of Advanced Materials (SAM) is an interdisciplinary peer-reviewed journal consolidating research activities in all aspects of advanced materials in the fields of science, engineering and medicine into a single and unique reference source. SAM provides the means for materials scientists, chemists, physicists, biologists, engineers, ceramicists, metallurgists, theoreticians and technocrats to publish original research articles as reviews with author's photo and short biography, full research articles and communications of important new scientific and technological findings, encompassing the fundamental and applied research in all latest aspects of advanced materials.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Ingenta Connect is not responsible for the content or availability of external websites