Non-structural adhesives

The aerospace field is a broad one and has a complex history. A comprehensive review of structural adhesive applications on currently flying aerospace vehicles alone could fill its own book. Hence this chapter will concentrate on the aerospace commercial transport industry and its use of adhesives in structural applications, both metallic and composite. Both primary structure, that is structure which carries primary flight loads and failure of which could result in loss of vehicle, and secondary structure will be considered. Structural adhesives use and practice in the military aircraft and launch vehicle/spacecraft fields as well as non-structural adhesives used on commercial aircraft will be touched on briefly as well. 

Non-structural adhesives used on CELCXDN arc usually one-component, room-temperature-curing systems based either on thermoplastic resins or elastomeric materials dispersed in solvents. They are normally used in applications which will not be exposed to temperatures over 180°F. Neoprene rubber adhesives are examples. (7). 

In addition to paints, sealants are also used. Sealants are mostly based on polysulfides, containing solvents as discussed in the previous section. Also, non-structural adhesives containing solvents are used as gaskets around windows and for carpeting. 

The determination of tensile strength and elongation-at-break [21] gives information on the mechanical resistance of non-structural adhesive films. The results are reported in Table 6. 

Randow, C.L., Mechanisms and Mechanics of Non-Structural Adhesion. MS Thesis, Virginia Tech, Blacksburg, 1996. 

BS EN 204 1991 Classification of non-structural adhesives for joining of wood and derived timber products. 

EN 204 Classification of Non-structural Adhesives for Joining of Wood and Derived Timber Products. 

Typical applications for adhesives and sealants are shown in Table 3.3 (we included non-structural adhesives and sealants here for completeness). 

Although many non-structural adhesives ean be solvent or water based, in aerospace applications, this format is usually the preserve of the surface protection and corrosion inhibiting primers. However, as indicated, there are exceptions and these are often those adhesives which are based on phenolic resoles (for example, Redux 775 Liquid) or on polyimides (for example, PMR -2). 

Non-structural adhesives Polychloroprene Di-acrylic esters Cyanoacrylate... 

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