High-performance polymers Thermoset Resins

Polyesters are one of the most versatile classes of polymers ever produced, covering a wide range of properties and applications. Polyesters are present in fibers, engineering thermoplastics, and high-performance polymers as well as in thermosetting resins and elastomers. Table 2.1 lists the chemical structure, abbreviations, and uses of some commercially important thermoplastic polyesters. 

Polyesters are a very important class of high performance polymers, which find extensive use in a number of diverse appHcations [19], Unsaturated polyester resins was chosen in the present study for making fiber-reinforced composites because of their good strength and low cost in comparison to other thermosetting resins. 

Synthetic thermosetting polymers used in the construction industry are polyester, vinylester and epoxies these materials are generally used to manufacture parts of the machines that produce sustainable energy generators. In addition, thermoplastic resins, such as polyetheretherketone (PEEK), polyethersulphone (PES) and various liquid crystal polymers (LCP) are also used. The latter high performance polymers also meet stringent out-gassing (relevant to space environments) and flammability requirements. 

Thermosets may be omitted In some lists of high performance polymers but they meet specifications and would not be used today If they were not high performance material. This criterion applies to carbon fibers, barrier resins, thermotropic polyesters, interpenetrating network polymers and many specialty elastomers. Likewise, the introduction of UV/EB curing techniques has brought about a new era in the polymer industry. 

Balamumgan R, Kannan P (2009) Synthesis and properties of a liquid crystalline thermoset epoxy resin containing 1,3,4-oxadiazole groups. High Perform Polym 21 251-264... 

A list of materials regarded as high-performance polymers (Table 17.10) overlaps the list of Table 17.9 to some extent, but also includes thermosets such as epoxy, phenolic, and silicone molding resins. As with most molded plastics, high-tanperature performance is enhanced by reinforcement with glass, boron, or carbon or aramid fibers. The thermosets are seldom used without reinforcement. Several are inclnded in Figures 17.6 and 17.7. 

FRP materials are made up of the polymer and reinforcing fibers. The polymer is typically a thermoset polymer thermoplastics can be used as well. Some typical thermoset polymers used are epoxy resins, unsaturated polyester resins, epoxy vinyl ester resins, phenolic resins, and high performance aerospace resins such as cyanate esters, polyimides, and bismaleimides. These resins... 

Epoxy resins are high-performance thermosetting resins, which display a unique combination of properties. Epoxy resins have been commercially available for almost a half-century. Epoxy resins are arguably one of the most versatile polymers with uses across an enormously wide variety of industries. The outstanding physical properties exhibited by epoxy resins include... 

Epoxy resins are among the most important of the high performance thermosetting polymers and have been widely used as structural adhesives and matrix for fiber composites. Epoxy resins are characterized by the presence of epoxide groups before cure, and they may also contain aliphatic, aromatic, or heterocyclic structures in the backbone. The epoxy group can react with amines, phenols, mercaptans. 

Hirayama, K.-I, Irie, T, Teramoto, N. and Shibata, M. (2009) High-performance bio-based thermosetting resins composed of dehydrated castor oil and bismaleimide. Journal of Applied Polymer Science, 114(2), 1033-1039. 

There are of course many plastics materials which have better high temperature performances than the polysulphones, for example the polyimides and fluorocarbon polymers, but most of these materials are thermosetting resins and all require somewhat specialised techniques for handling eg sintering or thin layer coating techniques (12). 

---