Bonding Strength Of Plywood Research Articles

Evaluation of Phenol-Formaldehyde Resins Modified and Blended with Pyrolysis Bio-Oil for Plywood

Abstract The objective of this study was to compare the characteristics and bonding performance of phenol-formaldehyde (PF) resins modified and blended with crude bio-oil. For modified PF resins, crude bio-oil from the pyrolysis of pinewood was synthesized with phenol and formaldehyde at 10, 25, 50, and 75 percent phenol substitution percentages, respectively. For blended PF resins, crude bio-oil was physically blended with PF resin at 4, 13, 23, and 38 percent addition percentages, respectively. The physical properties of crude bio-oil and PF resins, such as viscosity, pH value, gel time, water content, and solid content, were measured. The bond strength of plywood was evaluated. The results indicated that incorporating crude bio-oil into PF resin either by synthesis or by blending at certain amounts could improve the bonding performance of PF resins. For blended PF resins, the best crude bio-oil addition percentage was 13 percent, while for synthesized (modified) PF resins, the best phenol substitution percentage was 25 percent. Further increment of the crude bio-oil content level decreased the bond performance of both modified and blended PF resins. This was mainly due to the increased viscosity and the acidity of blended PF resins at a high crude bio-oil addition percentage and a shortage of reactive phenolic compounds in modified PF resins at a high phenol substitution percentage. Plywood bonded with the resins could generally meet the requirement of Chinese National Standard GB/T 17657‐2013 and be suitable for outdoor applications.

Effect of Jatropha Seed Oil Meal and Rubber Seed Oil Meal as Melamine Urea Formaldehyde Adhesive Extender on the Bonding Strength of Plywood

Effect of Jatropha Seed Oil Meal and Rubber Seed Oil Meal as Melamine Urea Formaldehyde Adhesive Extender on the Bonding Strength of Plywood

Research Progress and Prospect of Inorganic Filler for Urea-Formaldehyde Resin Adhesive

The artificial plywood materials were prepared using natural minerals and inorganic oxide powders as the main fillers for urea-formaldehyde resin adhesive instead of flour. The method mentioned above has advantages in saving food resources, reducing cost of plywood, improving the quality of plywood and decreasing the release amount of free formaldehyde. On the basis of the research achievement both domestic, foreign and our experimental data, this paper mainly discussed the effect of filler on adhesive properties, bond strength of plywood, and free formaldehyde content, which provided reference for development of green environmental protection and low cost urea-formaldehyde resin adhesive minerals composite filler.

Application of Plywood with Water-Based Phenol-Formaldehyde Resin Impregnated Linerboards as Formwork for Concrete Structure

The front and back layers of plywood formwork consist of veneers made of Oceania timber (Shorea spp.). As the demand for Oceania timber has increased worldwide, it has become difficult to find good front and back layers for plywood. This study, therefore, has investigated plywood made with water-based phenolformaldehyde (PF) resin impregnated linerboards of different basis weights and pulp types. Manufactured plywood with water-based PF resin impregnated linerboards made of Korean recycled linerboard pulp layers, which were pressed at 140° C and 10 kg/cm2 for 3 min, had the highest internal bond strength. Furthermore, the internal bond strength of plywood with K2 linerboard was highest among all those tested. Based on the results of heat and cold cycle tests, alkali tests, abrasion tests, and boiling water tests, three types of linerboards: K2, KAC and KLB were found to be suitable for plywood formwork.

Effect of the addition of Acacia mangium bark on thermosetting of phenol–formaldehyde resin

The effect of addition of Acacia mangium bark powder on the thermosetting processes of two commercial phenol resins, PF-A and PF-B, was examined by bond strength test, torsional braid analysis, and differential scanning calorimetry. When the bark powder was added to PF-A, the bond strength of plywood pressed at 110°C increased and was comparable to that of plywood pressed at 120 and 130°C. However, when the bark powder was added to PF-B, the bond strength of plywood pressed at 110°C was still lower than that of plywood pressed at 120 and 130°C. The relative rigidity and loss tangent of PF-A cured with the bark powder obtained by heating at 100°C were comparable to those at 120 and 140°C, and the reaction enthalpy was increased by bark powder addition. In contrast, chemical reactions for cured PF-B were not enhanced by bark powder addition.