Tapered Double Cantilever Beam Fracture Tests of Phenolic-Wood Adhesive Joints: Part II. Effects of Surface Roughness, the Nature of Surface Roughness, and Surface Aging on Joint Fracture Energy

Tapered double cantilever beam specimens were used to test the effect of surface roughness, the nature of surface roughness, and surface aging on the fracture energy of phenolic-wood adhesive joints. The fracture energy and the failure characteristics of the joints were found to depend not only on the surface roughness but also on the method of surface preparation. The fracture energy increased monotonically with surface roughness for specimens derived from hand-sanded surfaces but exhibited a minimum for specimens obtained from machine-sanded surfaces. Generally, joints from hand-sanded surfaces had higher fracture energies than those derived from the machine-sanded surfaces. Within the joints derived from the machine-sanded surfaces, those sanded perpendicular to the direction of crack growth had higher fracture energies than those sanded parallel to the direction of crack growth. Aging surfaces prior to bonding significantly decreased adhesive joint strength.Notwithstanding the differences in roughness, microscopic examination revealed little difference in the appearance of the sanded surfaces. Adhesive did not penetrate hand-sanded surfaces to any appreciable extent, but did deeply penetrate both the vessel and fiber lumens on the machine-sanded surfaces. Microscopic examination of the fractured surfaces did reveal significant differences that related to the fracture toughness of the bond

Polymer Science And technology

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Statistical Analysis as a Tool in the Assessment of Detergents Produced from Seed Oils

Detergents are materials whose solutions aid in the removal of dirt or other foreign matter from contaminated surfaces. Until the 1940s, soap was the only important detergents. Today, soap is but one of a great many detergent products. The primary ingredient used in detergent manufacture is often called surface active agent or surfactant because it acts upon a surface. Detergents were produced from neat, benzene-modified and esterified seed oils; their properties were compared with those of OMO using statistical analysis (ANOVA). The analyses showed that: rubber seed oil is better than cherry seed oil in the production of detergent, esterification of the oil improved the detergent action and unmodified rubber and cherry seed oils produced soap and not detergent. Keywords: Detergents, soap, statistical analysis, ANOVA, seed oil, and esterificatio