Polyester commodity applications

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. 

Growing awareness in maintaining a healthy environment has resulted in the development and implementation of eco-friendly products. Biodegradable polyester based composites are widely used in biomedical and commodity applications, because of their degradability and non-toxic properties. 

Yields of 1 kg of polymer for 3 or 4 kg of glucose and fermentation times of 4-5 days have made the production of PH As expensive. Alternative synthetic methods are being considered but commodity applications appear to be distant. A number of novel polyesters based on the polycondensation of hydroxydecanoic adds that are isolated from the hydrolysis of suberin are also being considered [19]. Suberin is an abundant component of the baik cell walls of higher plants and a major component of code [20]. 

Additives and copolymers have extended the use of PET fibers into areas where the original commodity products had deficiencies, in, for example, soil-resistance, static protection or poor dyeability. Newer members of the polyester family have found applications in markets where more stretchiness or resiliency were desired (using longer aliphatic chains) or to gain higher modulus, temperature resistance and strength (with fully aromatic polymers). 

PHAs can consist of a diverse set of repeating unit structures and have been studied intensely because the physical properties of these biopolyesters can be similar to petrochemical-derived plastics such as polypropylene (see Table 1). These biologically produced polyesters have already found application as bulk commodity plastics, fishing lines, and for medical use. PHAs have also attracted much attention as biodegradable polymers that can be produced from biorenewable resources. Many excellent reviews on the in vivo or in vitro synthesis of PHAs and their properties and applications exist, underlining the importance of this class of polymers [2, 6, 7, 12, 26-32]. 

Acrylic ester polymers Acrylonitrile polymers Cellulose esters). Engineering plastics (qv) such as acetal resins (qv), polyamides (qv), polycarbonate (qv), polyesters (qv), and poly(phenylene sulfide), and advanced materials such as liquid crystal polymers, polysulfone, and polyetheretherketone are used in high performance applications they are processed at higher temperatures than their commodity counterparts (see Polymers containing sulfur). 

Poly(ethylene terephthalate) (PET) is a commercial polymer used in bottles, films, and molded articles due to its excellent mechanical and thermal properties and commodity cost (Table 4.11). Like all polymers, the use of various stabilizer chemistries in polyesters may enhance esthetics, performance, or durability of the polymer during manufacturing, during converting operations, or in end-use application [61]. 

Engineering thermoplastic resins (ETP) are those whose set of properties (mechanical, thermal, chemical) allows them to be used in engineering applications. They are more expensive than commodity thermoplastics and generally include polyamides (PA), polycarbonate (PC), linear polyesters such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polyphenylene ether (PPE) and polyoxymethylene (POM). Specialty resins show more specialized performance, often in terms of a continuous service temperature of 200°C or more and are significantly more expensive than engineering resins. This family include fluoropolymers, liquid crystal polymers (LCP), polyphenylene sulfide (PPS), aromatic polyamides (PARA), polysulfones (P ), polyimides and polyetherimides. 

Since the early 1980s, the viscose-based staple fibers have, like the cuprammo-nium and viscose filament yarns in the 1970s, ceased to be commodities. They have been repositioned from the low cost textile fibers that were used in a myriad of applications regardless of suitability, to premium priced fashion fibers delivering comfort, texture, and attractive colors in ways hard to achieve with other synthetics. They are still widely used in blends with polyester and cotton to add value, where in the 1980s they would have been added to reduce costs. 

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