doi: 10.1080/00218468408074919pmid: N/A
Abstract This is a scanned image of the original Editorial Board page(s) for this issue.
doi: 10.1080/00218468408074921pmid: N/A
Abstract As keynote speaker for this 2nd Annual International Symposium on Adhesion and Adhesives for Structural Materials, I would like to extend a welcome to all the attendees. Your presence here this morning indicates a vital interest in structural materials and the rapidly developing technology of adhesives. Certainly the international aspect of this meeting is very much in evidence-both in the participation on the program and in the attendance.
Kuo, Mon-Lin; Dicarlo, Daniel; Hse, Chung-Yun
doi: 10.1080/00218468408074922pmid: N/A
Abstract White and southern red oak veneers were subjected to four methods of drying followed by five surface treatments. The four drying methods were mill drying at 350°F, laboratory drying at 350 and 212°F, and air drying. The five surface treatments were no treatment, surface scraping, soaking and dipping in 1% NaOH aqueous solution, and water extraction. Plywood panels were prepared by using a phenol-formaldehyde resin. Even with the best drying-surface treatment combination, wood failure was only 35% for white oak and 39% for southern red oak. Overall, mill drying was the best drying method. Soaking the veneers in 1% NaOH solution significantly increased the bond quality. Mill drying of veneers caused water-soluble extractives to migrate from the interior portions to veneer and lathe check surfaces. SEM examinations of the glue failure surface revealed that gluelines failed to adhere to the cell walls. Difficulties in bonding white and southern red oak veneers may be caused by extractive contamination.
doi: 10.1080/00218468408074923pmid: N/A
Abstract Rheological changes in four cured wood adhesives exposed to temperature and humidity conditions were determined using torsional braid analysis. The adhesives ranged from thermosetting to thermoplastic types. Creep extension in shear also was measured for wood laminates bonded with these adhesives and exposed to conditions of 27°C/90% RH and 60°C/60% RH. A positive trend was found between creep extension and both the maximum rigidity change and the damping loss occurring during humidity and temperature exposure. These findings suggested TBA can be a useful method for predicting wood adhesive creep and failure behavior in the presence of heat and moisture.
doi: 10.1080/00218468408074924pmid: N/A
Abstract As China is a developing country, its wood-based panel industry is also developing. The annual output of wood-based panels was 690,000 m3 in in 1981, and the amount of adhesives utilized in their manufacture was about 40,000 T annually of which 7&75% was amino resins, 15-20% was phenol resins, and the rest was protein binders.
doi: 10.1080/00218468408074925pmid: N/A
Abstract Extracts containing tannins and related polyphenols were obtained from Pinus rudiata bark by extraction with hot water containing small amounts of sodium carbonate and/or sodium sulphite. The extracts had excessive viscosities (< 10 Pa.s) at the concentrations required for adhesive formulation, but this problem was readily overcome by reducing the pH of the extract solution to below 4.5 with acetic acid, adding a small amount of phenol, and heating the mixture. Adhesive performance was best between pH 4.5–6.0, and the bonds were resistant to boiling water. However, joints bonded with early adhesive formulations tended to fail within the adhesive, necessitating some form of adhesive fortification in later formulations. The results obtained with a number of different additives as fortifiers are presented. Softwood plywood which passed the bond quality requirements of the boiling test described in U.S. Product Standard 1-74 was made in the laboratory using these fortified adhesives.
Plagemann, Walter L.; Price, Eddie W.; Johns, William E.
doi: 10.1080/00218468408074926pmid: N/A
Abstract This study assesses the effect of high temperature drying on chemical and mechanical properties of flakes and correlates changes in flake quality with board properties. The high temperature drying of flakes was found to have a significant effect on the internal bond (IB) of the resulting panels. The highest IB values were observed in boards produced from flakes dried at 150°C. Boards produced from flakes dried at 20°C and 350°C exhibited consistently lower values for IB. Opposite trends were noted for total acid content of flake. Multiple regression and correlation analysis revealed a strong relationship between IB, total acid content, and dryer temperature. A significant species effect was also present. Increased levels of flake total acids. acid buffering capacity, and the ratio of acid to base buffering capacities resulted in decreased board property values. Flake bending tests indicated that, in general, the strength and stiffness of the flakes were adversely affected by high temperature drying. This effect did not manifest itself, however, in the resulting panels. Possible reasons for this phenomenon are discussed.
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