Thermoset Plastic Types

like TPs, offer a wide range of matrix materials for reinforcement by fibers, flakes, beads, or particulate materials such as talc and mica. They are compounded with reinforcing materials. Among the fibers, glass is the main reinforcement. Examples of these TPs follow  

With correct additives, they can exhibit outstanding resistance to heat [some up to 290C (550F)] and electrical insulation properties. They can be either liquid or solid in form and can be formulated to cure either at room temperature or with the aid of heat. Heat curing is the more common for situations where maximum performance is required. Epoxies generally cure more slowly than other TSs. 

They are often used in contact molding, for tooling and pipefitting. A major use is for filament winding. Applications are particularly in aerospace and defense, chemical plant, high-performance components 

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Thermoplastics plastics that can be repeatedly heated and reformed Thermosetting Plastics type of plastics that harden into final form after being heated once... 

Whilst the term thermosetting plastics arose out of the fact that early products of this type were cross-linked by subjecting the intermediate-stage materials to elevated temperature, the term is also widely used where cross-linking takes place at normal ambient temperatures. 

Such reactions allow chain extension and/or cross-linking to occur without the elimination of small molecules such as water, i.e. they react by a rearrangement polymerisation type of reaction. In consequence these materials exhibit a lower curing shrinkage than many other types of thermosetting plastics. 

John Hyatt was the first to make plastics. He made celluloid in 1868. Leo Baekeland made bakelite. Synthetic plastics are made from petroleum products. There are two types of plastics thermoplastics and thermosetting plastics. 

For commodity applications, there are four major classes of resins that are used in FRP applications. They are phenolic resin, epoxy resin, unsaturated polyester resin, and epoxy vinyl ester resins. A more complete description of these types of resins and their many variations can be found in Handbook of Thermoset Plastics. This is not a comprehensive list of resins used in composite manufacture, as commodity materials like polyurethanes and isocyanurate resins are sometimes used as well to make FRP parts. However, these materials are not covered in this chapter owing to their limited use, but, the principals of fire safety that apply for the resins described subsequently apply to these materials as well. 

Plastic types are variable, ranging from flexible to rigid and from thermoplastic to thermoset. Because of these variations, the type of coating applied to them also varies, depending on cure response, solvent sensitivity, and modulus. The type of coating also depends upon the end use of the coated plastic. For example, topcoats can be applied directly to the plastic without the use of a conductive primer if two-toning or blackout areas are not part of the styling latitude. Adhesion promoters also are often utilized if a particularly difficult-to-adhere-to plastic is encountered (i.e., polypropylenes or thermoplastic polyolefins (TPOs), a blend of elastomer and olefin). 

The polyamides are thermoplastic polymers. The term thermoplastic means that the polymer can he repeatedly melted and hardened by alternate heating and cooling. By contrast, certain other types of polymers, known as thermosetting plastics, can not be re-melted once they have hardened. 

The range of plastics used as (matrix type) binders for inhibited CM is extremely broad and includes practically the whole list of commercial thermal and thermosetting plastics [36-45]. 

The Kinel materials produced by Rhone-Poulenc are polybismaleinimides of the type shown in Figure 4.22. These materials have chain-end double bonds, as explained previously, can be processed like conventional thermosetting plastics. The properties of the cured polymers are broadly similar to the polyimides and polyamide-imides. Molding temperatures are usually from 200°C to 260°C. Post-curing at 250°C for about 8 h is necessary to obtain the optimum mechanical properties. 

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