Panel-type composites

At the same time, the FSTG has been investigating flammability test results based on composite parts of varied materials, sire, thickness and construction. Among the test specimens are honeycomb core sandwich panels and composite laminates. The flammability performance of single components is also being studied. These specimens include different types, densities, and thicknesses of honeycomb core, unpainted panels, and panels coated with a variety of paint and ink colors, as weU as panels that have been bonded, potted and/or edge sealed. 

Aerospace struetwes made of composite. As part of the evaluation of the developed ultrasonic spectroscopy system the NSC software was tested on ultrasonic resonance spectra from composite panel samples. Spectra were collected with four different types of damages, and from flawless samples. The damages included a small cut in one of the carbon fiber... 

The physical properties of the reinforced polyester product made from chopped glass are Hsted in Table 1. The chemical resistance varies according to the composition but is generally good. Its principal uses in building products are for sanitary ware, eg, tub-shower units, and for panels, especially translucent or cement-filled types for roofing and walls of commercial or industrial buildings. 

The so-called El-emission class describes a wood panel presenting formaldehyde emission which is low enough to prevent any danger, irritation or inflammation of the eyes, nose and mouth mucous membranes. However, it is important that not only the boards themselves, but also the veneering and carpenter s adhesive resins, laquers, varnishes and other sources of formaldehyde are under control, since they also might contribute to the mixture steady state formaldehyde concentration [9]. Table 3 gives an overview on some European regulations. However, it is necessary here to introduce the principal types of composite wood products, especially panels, that are produced in this industry ... 

Only a small amount of work has been done up to now concerning the prediction of bond strengths and other properties based on the results of the analysis of the resin. Ferg et al. [59] worked out correlation equations evaluating the chemical structures in various UF-resins with different F/U molar ratios and different types of preparation on the one hand and the achievable internal bond as well as the subsequent formaldehyde emission on the other hand. These equations are valid only for well defined series of resins. The basic aim of such experiments is the prediction of the properties of the wood-based panels based on the composition and the properties of the resins used. For this purpose various structural components are determined by means of - C NMR and their ratios related to board results. Various papers in the chemical literature describe examples of such correlations, in particular for UF, MF, MUF and PF resins [59-62]. For example one type of equation correlating the dry internal bond (IB) strength (tensile strength perpendicular to the plane of the panel) of a particleboard bonded with PF adhesive resins is as follows [17]... 

The ultrasonic C-scan technique is the most widely used nondestructive method of locating defects in the composite microstructure. The through transmission C-scan is easy to implement and a large composite panel can be scanned in a matter of minutes. The problem with this technique is that a C-scan cannot reveal the type of defect present. Hence, there is no way to determine if a flaw detected by the C-scan is due to incomplete contact of an interply interface or some other type of defect in the composite microstructure. 

Biblos and Coleman investigated another type of potential structural composite product (53). They made and tested panels consisting of a particleboard core from sawdust and bark and faces of veneer. All material was southern pine, and 9% urea formaldehyde served as binder. Strength tests indicated the composite panels were superior to conventional two-layer floor systems of 1/2-inch plywood plus 5/8-inch particleboard underlayment. 

Composite boards and panels faced with decorative laminates are specified in BS 4965 1991.5 This Standard gives the types of substrates, decorative laminates, and adhesives that may be used in combination to obtain various levels of performance. The requirements are classified in the following terms ... 

BS 4965 for composite boards and panels includes very few tests for physical properties but specifies precisely the individual components for each type of composite construction, referring to the appropriate standards. 

Although pictographs and petroglyphs have withstood hundreds, perhaps thousands of years of exposure, modem pollutants and vandalism, coupled with natural elements, have accelerated their destruction. Recently, scientists have used microscopic mineral sampling to measure the types of chemical elements found in picto-graph pigments. Additionally, studies have included the use of diversional watersheds, shelters, and application of protective adhesives to prevent rock art erosion. The continuing study of chemical compositions and rates of panel decay could one day lead to the discovery of a proper means by which to preserve these features indefinitely. 

Performance of refractories exposed to chlorides can best be determined by measuring relative performance of different refractory types in actual service using small test panels of different compositions and physical properties. A modified ASTM C279 acid solubility test using an HCI solution can also give insights into the relative performance of various types of refractory brick in chloride containing environments. 

Processing Facilities. The phenolic-foam-producing process is simUar to that used with rigid polyurethane foams. Production of composite sandwich panels, board-type products, pipe covers, are possible. 

In this section, a new type of structural panel manufactured with a combination of these two wood resources is discussed. Waste wood chips were processed to particle and used as a core material. Small diameter logs were cut by a disk flaker to produce wafer or strand , which was used in Wafer-board or OSB production in North America. These strands were used as face layers of three-layer structural board in this experiment. Strength properties of the composite board made from Sugi-strand and recycled wood particle were evaluated. 

Researehers have demonstrated that wood treated with heavy metals ean be chipped or flaked and reused to form durable panel produets or wood-cement composites. However, this type of reuse has not gained commercial acceptance beeause of eoneems with processing the treated wood, with the introduction of pesticides into the panel fabrication process, and with the leaching or environmental impacts from the final product (Kartal and Clausen, 2001). 

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