Polyesters polyethylene terephthalate

Condensation polymerization differs from addition polymerization in that the polymer is formed by reaction of monomers, each step in the process resulting in the elimination of some easily removed molecule (often water). E.g. the polyester polyethylene terephthalate (Terylene) is formed by the condensation polymerization (polycondensation) of ethylene glycol with terephthalic acid ... 

Polyesters exhibit excellent high temperature strength and electrical properties making them a good choice for many demanding applications. They also are physiologically inert allowing them to be used in food contact applications. The two common polyesters, polyethylene terephthalate and polybutylene terephthalate, are both used in injection molded products. Polyethylene terephthalate is often used in both extrusion and blow molded processes also. 

PBT resin has been reviewed in many articles, often as part of a larger review of polyesters [1-3], A recent article provides an historic account of polyester development as an alternative to nylon fibers [4], while the review of Kirsch and Williams in 1994 gives a business perspective on polyesters [5], However, an understanding of PBT in the context of the more common polyester polyethylene terephthalate) (PET) is often overlooked. PET dominates the large volume arenas... 

Poly(trimethylene terephthalate) (PTT) is a newly commercialized aromatic polyester. Although available in commercial quantities only as recently as 1998 [1], it was one of the three high-melting-point aromatic polyesters first synthesized by Whinfield and Dickson [2] nearly 60 years ago. Two of these polyesters, polyethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), have become well-established high-volume polymers. PTT has remained an obscure polymer until recent times because one of its monomers, 1,3-propanediol (PDO), was not readily available. PDO was sold as a small-volume fine chemical at more than 10/lb., and was therefore not suitable as a raw material for commercial polymers. 

Graphite is an excellent but expensive reinforcement for plastics. Aramid (aromatic polyamide), polyester (polyethylene terephthalate PET), and boron filaments are also used as reinforcements for polymers. 

The largest commercial use of ethylene glycol is its reaction with dicarboxylic acids to form linear polyesters. Polyethylene terephthalate) [25038-59-9] (PET) is produced by esterification of terephthalic acid [100-21 -0] (1) to form bishydroxyethyl terephthalate [959-26-2] (BHET) (2). BHET polymerizes in a transesterification reaction catalyzed by antimony oxide to form PET (3). 

Fig. 19.11A,B presents, as an example, data of drawing series of nylon 6 and polyester filaments (Van der Meer, 1970). The additional data for the polyester (polyethylene terephthalate) are given in Table 19.8 by stretching the Young modulus increases by a factor 8 and the tensile strength by a factor 5.5 (Fig. 19.13).

Acetic acid is used in the manufacture of a wide variety of products including adhesives, polyester fibres, plastics, paints, resins and solvents. About 40% of the acetic acid made industrially is used in the manufacture of vinyl acetate monomer for the plastics industry other large uses are to make cellulose acetate, a variety of acetate esters that are used as solvents, as well as monochloracetic acid, a pesticide. Acetic acid is also used as a solvent for the oxidation of p-xylene to terephthalic acid, a precursor to the important polyester, polyethylene terephthalate (PET). A minor, but important use is as non-brewed condiment, a vinegar substitute widely used in British fish and chip shops this is made using food-grade industrial acetic acid and is less expensive than fermentation vinegar. 

An alternative method is to dissolve away the fabric substrate and leave the coating behind. Nylon can be dissolved in cold meta-cresol in about 1 min, or 90%v/v formic acid. Polyester (polyethylene terephthalate) will dissolve in hot meta-cresol, but PVC may also be affected. Alternatives are ort/zo-cresol and chloroform or ort/zo-chlorophenol. 

Polyesters. The first synthetic fiber forming polymer produced by Carothers and coworkers was an aliphatic polyester made from trimethylene glycol and a hexadecamethylene dicarboxylic acid. This polymer was low-melting (70°C) and hydrolytically unstable. In 1941, Whinfield and Dickson synthesized the first high-melting symmetrical linear aromatic polyester, polyethylene terephthalate, and found it to be a very useful product. ... 

Saturated Polyesters - Polyethylene Terephthalate (PET-S) and Polybutylene Terephthalate (PBT-S)... 

Polystyrene films and polyester (polyethylene terephthalate) films are only used in the biaxially stretched form, because unstretched films are very weak and brittle. To a lesser extent this is also true for polypropylene films. Roll-quenched flat film is used for many packaging applications, but below 0°C these films become brittle. Biaxially oriented polypropylene film, on the other hand, is not brittle at a temperature as low as — 50°C and is suitable for packaging frozen foods. 

The second of the two basic polymerization processes that results in linear chain molecules is the condensation reaction where, e.g., in the case of formation of the polyester, polyethylene terephthalate (PET), as shown in Fig. 2.3, two separate monomers, ethylene glycol and terephthalic acid, react and give off a reaction product, H2O, in a systematic process that results in a chain polymer. 

Polyesters UV absorbers have been used as efficient stabilizers of the linear polyesters, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) as well as for improving the lightfasmess of dyes in polyester fibers during outdoor exposure. Effective stabilization of high-molecular-weight PET fibers by a UV absorber was shown [106] to depend on the level of uptake and its uniform distribution throughout the fiber cross section. A benzophenone-type stabilizer provided considerably better protection than the benzotriazole- and benzotriazine-type stabilizers because it diffused throughout the fiber whereas the other two... 

Polyester (Polyethylene terephthalate) a) Product yield Photooxidative reactions and direct cleavage via Norrish reactions Quantum yields, ., for CO, CO2, -OH and -COOH products fored on photolysis of PE. [110,154] [166]... 

Saturated polyester, polyethylene terephthalate (PET) 15-25 Appliance panels automotive body panels power tool housings Improved strength Improved heat deformation temperature Improved dimensional stability... 

The traditional surgical repair method for ASD is a full sternotomy (open heart surgery), where the hole is either stitched closed or sealed using a synthetic patch or the patient s own pericardium, which forms the fluid-filled sac surrounding the heart. Typically, the synthetic patches are made of either polyester (polyethylene terephthalate) (Dacron ) or expanded poly-tetrafluoroethylene (ePTFE) (Goretex ) fabric. TTiis method is still used in severe cases of ASD. °... 

This survey covers measurements on plastics with all the reinforcing agents previously mentioned and includes a wide range of plastics now being used in plastics technology. It includes commonly used plastics such as polyamides, polyesters, polyethylene terephthalate, and epoxy resins, but also covers newer plastics, such as polyimides, polysulfones, polyethersulfone, polyphenylene sulfide, and polyether ether ketone, all of which have more specialized applications. 

Both cotton and polyester (polyethylene terephthalate) fiber show characteristic bands in the NIR region. Principal bands in NIR spectra of cotton and polyester are listed in Table 25.2. Band positions are calculated from the individual spectra of cotton and PET, as shown in Eigure 25.3. Usually a regression model consisting of three or four wavelengths can accurately determine the composition of a blend. 

The aliphatic polyester has a melting point of about 65°C, whereas the aromatic substituted dicarboxylic acid has a melting point of 265°C. Thus, the polyester polyethylene terephthalate (PETP) is commercially one of the most popular polymers marketed as Terylene or terene. 

PHA solutions of various densities were used to prepare transparent flexible films. The surface properties of PHB and P(HB-co-HV) fllm scaffolds were similar to each other and to those of synthetic polyesters (polyethylene terephthalate, poly (methyl methacrylate), polyvinyl chloride, and polyethylene) (Shishatskaya 2(X)7X The scaffold s surface properties are important for cell attachment and proliferation. To enhance cell adhesion to the surface, improve the gas-dynamic properties of scaffolds, and increase their permeability for substrates and cell metabolites, the scaffolds can be treated by physical factors or by chemical reagents. Biocompatibility of PHA scaffolds has been enhanced by immobilizing collagen fllm matrices on the scaffold surface and coating with chitosan and chitosan/polysaccharides (Hu et al. 2003). 

Hexible or floppy discs were developed early in the 1970s, initially in Sin disc form and later on as the 5 in mini-disc. Flexible disc storage media have become standard for the industry. The substrate in this case is a polyester-polyethylene terephthalate disc, again coated with ferrous oxide. The discs tend to be supplied in envelopes in... 

Noncellulosic organic fibers), for example, acrylic, acrylonitrile, casein fibers and filaments fluorocarbon, nylon fibers and filaments polyester, polyethylene terephthalate, polyolefin, polyvinyl ester, polyvinylidene chloride fibers protein... 

Polyolefin Polyethylene Polypropylene Polyester Polyethylene terephthalate Polybutylene terephthalate Aromatic polyester polycartonate Polyphenylene sulfide Polysulfone Polythiozyl silicones Polybenzimidazole... 

Because of its aromatic character and the dense packing of its molecular chains -compared to other polyesters - polyethylene terephthalate is very resistant to water, acids and bases, so that hydrolysis of the ester bond is initiated only above 100°C (Figure 5.316). 

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