FRP mechanisms

This chapter deals with the description of the FRP mechanism and presents a review of the latest advances in the termination reaction control. 

Technical Aspects The reaction mechanism in the synthesis of HIPS involves the basic reactions present in any FRP initiation (thermal and chemical), propagation, transfer to monomer, and termination, mainly by combination (see Chapter 4 for the basic FRP mechanism). In addition... 

A subsequent review of stress analysis and strength prediction of fibre reinforced plastic (FRP) mechanically fastened joints [41] identified five common failure modes tension, shear, bearing, cleavage and pull-through (See Fig. 2.11). The tensile strength of a single hole joint is said to depend... 

Figure 2.11 Five possible failure modes for FRP mechanical joints (after Camanho and Matthews [41])...

This common FRP mechanism is summarized by the following scheme of reactions [11 ... 

It is important to achieve an understanding of how the basic FRP mechanisms control polymerization rate and average polymer chain length. This section starts with the derivation of appropriate kinetic expressions for a single monomer system. Complicating (but industrially important) secondary reactions are then introduced, followed by the extension to multi-monomer systems. Dispersed throughout are up-to-date estimates for important free-radical polymerization rate coefficients, and descriptions of how they are obtained experimentally. 

The basic set of FRP mechanisms includes initiation, propagation, termination, and transfer to monomer and solvent or transfer agent, as shown in Scheme 4.3. 

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Under mechanical and environmental stresses, composites are dimensionally stable. They maintain their shape and functionaHty, a critical requirement in such appHcations as dish antennas, constmction girders, and in appHance and business machines. Color and surface texture can often be molded into an FRP product for long lasting, low maintenance permanent surface appearance. Boats are a good example. The surface color is molded in and requires minimum maintenance, an advantage in saltwater environments. 

The lack of homogeneity and the friable nature of FRP composite structures dictate that caution be followed in mechanical design, vendor selection, inspection, shipment, installation, and use. 

The advantages of composites are inherent in their construction. A variety of resin/fiber systems can yield possible solutions for many types of situations. Depending on the product and application, FRP products for civil and mechanical applications can deliver the following benefits ... 

The U.S. Navy has sponsored research at Virginia Tech to look at structural performance of FRP for the previously mentioned deck applications. This included work on determining the postftre structural properties. This work was reported in detail in the doctorate dissertation of Steven Boyd in 1996.27 Gibson et al.28 did work on modeling the residual mechanical properties of composites after fire. There have been recent studies on the mechanical properties of composites after fire,29-31 some of which have been cited previously in this chapter.1314 The requirements for the Navy applications have been described by Sorathia.19 20 32... 

Epoxy resins are superior in heat resistance, adhesion, corrosion resistance and also mechanical properties among thermosetting resins and are widely used for coatings, adhesives, electric insulating materials and matrices for FRP in areas such as aircrafts, electronics, electric power, and building and civil engineering. 

Fibre reinforced plastic (FRP) composites are gaining a wide reeognition as an alternative to the traditional metallic materials in a variety of applieations. As a result a reasonable step is to understand the mechanics of composites and provide the designers and industry with the knowledge based on reliable data stemmed from extensive researeh. 

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