Exterior performance tests

Fujimoto [56] examined the weathering behavior of Japanese bass wood Tilia japonica) that had been chemically modified with a maleic acid-glycerol (MG) mixture. In a vertical outdoor exposure test, the surface smoothness of MG-treated samples was maintained over an 18-month period and the results suggested that this type of treatment might provide wood products with good exterior performance properties. 

The results of a 2 year field weathering test in Europe have confirmed that a UF resin to which has been added 15% melamine acetate salt at the glue mix stage, to obtain a melamine urea mass ratio of 10 90 solids on solids, imparts a better durability and better exterior performance to plywood glue lines than traditionally reactor-coreacted MUF resins of melamine urea mass ratio of 33 66 and even of commercial, prereacted PMUF resin where the relative mass proportions of the materials in the resin are 10 30 60 [23]. 

There are three general types of data contained in three data files. These are illustrated for the exterior hardboard exposure system in Table III. The first file contains the information about the substrate. This includes an identification number for the panel, the date, the location and type of exposure to which the panel was subjected, the manufacturer of the substrate, the trade name, and the results of a series of standard test to evaluate the properties of the substrate. This information allows correlations to be made between the performance of the coating and the particular properties... 

ThermoWood is not resistant to exterior weathering and the colour will gradually change to the grey that is characteristic of outdoor exposed wood. In addition, exposure in exterior conditions results in the formation of small cracks on the surface of uncoated wood. Unpigmented or low-build stain coatings do not protect the surface of the wood, but solvent-borne alkyds and water-borne acrylic paints have been found to exhibit better performance than on unmodified wood. VOC emissions from the heat-treated wood are lower compared to unmodified wood and the compositions of the emissions differ. The level of emissions is lower when the wood is treated at a higher temperature. Emissions of terpenes are reduced to very low levels, and the VOC content is dominated by furfural, hexanal and acetic acid (treated at 180 °C), and by acetic acid (treated at 230 °C). ThermoWood passes ecotoxicity tests. 

Waterborne UV curable polyurethane dispersions have been developed that yield excellent performance when tested for exterior weathering. They... 

Perform this test with the help of your supervisor. Place 1 drop of the solution labeled N03 in a cuvette. Add 1 drop of 0.1 M HC1 and fill to the top with distilled water. Shake. Nitrate strongly absorbs ultraviolet light at 220 nanometers (nm) under these conditions. Wipe the exterior of the cuvette with a paper towel, and place it in an ultraviolet (U V) spectrophotometer set at 220 nm. A high absorbance reading represents a positive test for nitrate. Compare with distilled water. 

The UV technology alluded to above holds out the promise of even more superior labels. In this process, ultraviolet cured inks are used as the printing medium. These are cured by exposure to industrial type UV mercury vapor lamps in either a non-inert system (air environment) or in an inert (oxygen-free) system. The result is excellent adhesion to vinyls, polyesters, polycarbonates, butyrates and acetates and a cured elongation of between 20 and 40% to avoid embrittlement of the substrate. Initial testing has exhibited little sign of degradation and excellent chemical resistance after three years of exterior exposure. Such UV labels as well as other techniques should be considered whenever use demands extended label performance. 

The silicone polymer backbone is composed of Si-O-Si bonds. This bond is very strong and stable with a bond energy of 87 Kcal/ mole. The polymer can tolerate 250°C to 300°C without decomposing.— The fully compounded silicone sealant, when cured to a rubber, can withstand 200°C for sustained periods of time with no special additives and even higher temperatures with polymer modifications and/or heat stability additives.— The Sl-O-Si molecular structure is also transparent to U.V., so silicone sealants are virtually unaffected by weather. Samples of silicone sealants used in exterior construction applications have been tested after 20 years of actual performance. These samples exhibited essentially no change in physical properties or adhesion during that time period. 

The first day progressed with no problems, and it rained the next day, which prevented further work on the outdoor tank. On the third day, the job resumed with the same two pipefitters and a welder joined the crew. Flammable gas testing of the area was performed on the exterior of the tank and the flammable gas probe was lowered a few feet into the tank through an atmospheric vent. The meter showed no evidence of a flarmnable mixtirre. 

A test in which the two exterior Li4oaded detectors were placed adjacent to eadi.other rather than 120 deg apart was performed to investigate spatial effects. Initial evaluatimi of the results indicates that such placement of the detectors may result in preferential sampling of short fission chains that occur immediately in front of the detectors, thereby yielding a distorted measurement of Gjj. Placing the detectors 120 deg apart on the tank surface appears preferable, since ttis permits the behavior of long fission chains to be correlated, with the result that global (rather than localized) stem properties are measured. 

It has been shown that an accelerated test method (the automatic boil test—ASTM D-3434) is convenient for evaluating adhesive performance and for predicting durability for exterior applications. Samples are subjected to 800 cycles, which corresponds to approximately 16 years of exterior exposure for a good wood adhesive. Figure 6 compares the perform-... 

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