Thermosets unsaturated polyester

Thermosetting unsaturated polyester resins constitute the most common fiber-reinforced composite matrix today. According to the Committee on Resin Statistics of the Society of Plastics Industry (SPl), 454,000 t of unsaturated polyester were used in fiber-reinforced plastics in 1990. These materials are popular because of thek low price, ease of use, and excellent mechanical and chemical resistance properties. Over 227 t of phenoHc resins were used in fiber-reinforced plastics in 1990 (1 3). PhenoHc resins (qv) are used when thek inherent flame retardance, high temperature resistance, or low cost overcome the problems of processing difficulties and lower mechanical properties. 

Bisphenol A Polyester A thermoset unsaturated polyester based on bisphenol A and fumaric acid. 

Polyvinyl Chloride Thermosets Unsaturated polyester resins 34.48-62.07 1-25 1.33-1.45 0.03-0.062 [30]... 

Because of its superior mechanical and chemical properties, thermoset unsaturated polyester resin (UPR) is widely used in fibreglass reinforced plastics and polyester fibres. Driven strongly by the surging consumption, China s demand for UPR has been increasing by 20.3% annually, reaching 365 000 tonnes by 1998. Demand for thermoset polyester reached 678 000 tonnes in 2003, and is currently growing by 13.2% each year. 

Polyethylene terephthalate, or polyester, has become the most widely used synthetic fiber, particulariy when combined with cotton. It is also a veiy popular thermoplastic resin for bottle and film production and new polyesters are now being developed. Thermosetting unsaturated polyesters are based on maleic anhydride with a range of glycols. Polyethylene terephthalate is produced finm... 

Alkyds are formulated from polyester resins, cross-linking monomers, and fillers of mineral or glass. The unsaturated polyester resins used for thermosetting alkyds are the reaction products of polyfunctional organic alcohols (glycols) and dibasic organic acids. 

Polyester Resins. Reinforced polyester resins are thermosets based on unsaturated polyesters from glycols and dibasic acids, either or both of which contain reactive double bonds. The ratio of saturated to unsaturated components controls the degree of cross-linking and thus the rigidity of the product (see Polyesters, unsaturated). Typically, the glycols and acids are esterified until a viscous Hquid results, to which an inhibitor is added to prevent premature gelation. Addition of the monomer, usually styrene, reduces the viscosity to an easily workable level. 

Certain state highway authorities are studyiag the use of ftber-reiaforced polymers, typically thermosets such as epoxy or unsaturated polyester, for bridge constmction. On an even more futuristic scale, fiber optics that employ polymeric jacketing and, ia some cases, optically active polymeric cores, may someday be employed ia place of wines for home security systems, climate control, etc (10,91). 

Modified Bismaleimides. Bismaleknide resins may be further modified and blended with other thermoset resins or reactive diluents to achieve either specific end-use properties or processibiUty. Thermoset resins that can be used for modification are unsaturated polyesters, vinylesters, cyanate esters, and epoxies. 

Nowadays the major thermosetting resins used in conjunction with glass fibre reinforcement are unsaturated polyester resins and to a lesser extent epoxy resins. The most important advantages which these materials can offer are that they do not liberate volatiles during cross-linking and they can be moulded using low pressures at room temperature. Table 3.1 shows typical properties of fibre reinforced epoxy. 

Thermosetting Polyester Resins 2.1.2.3.1 Unsaturated Polyester Resins... 

Polyester thermosetting resins Unsaturated polyester resins (UPRs)... 

Unsaturated polyesters (UPs), 4, 18, 19 from PET waste, 560-561 Unsaturated polyester/styrene resin, preparation and cure of, 101 Unsaturated polyester thermosetting resins, syntheses of, 101-103 Unstirred interfacial process, 155 U-Polymer, 77... 

---