Copolyester elastomer

Liquid crystalline polymers such as thermoplastic elastomer copolyesters are being used in lower power, higher speed gears because it allows them to tolerate inaccuracies and reduce noise while providing sufficient dimensional stability and stiffness [7]. 

Like most elastomers, copolyesters can be bonded with cyanoacrylates and in these trials [2] no improvement was gained by using the primer (Table 4.2). 

Thermoplastic copolyester elastomers are generally block copolymers produced from short-chain aUphatic diols, aromatic diacids, and polyalkjlene ether-diols. They are often called polyesterether or polyester elastomers. The most significant commercial product is the copolymer from butane-l,4-diol, dimethyl terephthalate, and polytetramethylene ether glycol [25190-06-1J, which produces a segmented block copolyesterether with the following stmcture. 

Uses. Approximately 70% of the U.S. production is used to make poly(tetramethylene ether glycol) [25190-06-1] (PTMEG), also known as poly-THE, which is used in the production of urethane elastomers, polyurethane fibers (ether-based spandex), and copolyester—ether elastomers. PTMEG is also the fastest growing use (see PoLYETPiERS, TETRAHYDROFURAn). The remaining production is used as a solvent for the manufacture of poly(vinyl chloride) cements and coating, precision magnetic tape, a reaction solvent in the production of pharmaceuticals, and other miscellaneous uses. 

Hie most representative member of this class of polyesters is the low-molar-mass (M 1000-3000) hydroxy-terminated aliphatic poly(2,2/-oxydiethylene adipate) obtained by esterification between adipic acid and diethylene glycol. This oligomer is used as a macromonomer in the synthesis of polyurethane elastomers and flexible foams by reaction with diisocyanates (see Chapter 5). Hydroxy-terminated poly(f -caprolactonc) and copolyesters of various diols or polyols and diacids, such as o-phthalic acid or hydroxy acids, broaden the range of properties and applications of polyester polyols. 

A route to compatibility involving ionomers has been described recently by Eisenberg and coworkers [250-252]. The use of ionic interactions between different polymer chains to produce new materials has gained tremendous importance. Choudhury et al. [60] reported compatibilization of NR-polyolefin blends with the use of ionomers (S-EPDM). Blending with thermoplastics and elastomers could enhance the properties of MPR. The compatibility of copolyester TPE, TPU, flexible PVC, with MPR in aU proportions, enables one to blend any combination of these plastics with MPR to cost performance balance. Myrick has reported on the effect of blending MPR with various combinations and proportions of these plastics and provided a general guideline for property enhancement [253]. 

Schmalz H., Abetz V., Lange R., and Soliman, M. New thermoplastic elastomers by incorporation of nonpolar soft segments in pbt-based copolyesters, Macromolecules, 34, 775, 2001. 

The effect of °Co y-ray irradiation on the mechanical properties, surface morphology, and fractography of blends of plasticized PVC and thermoplastic copolyester elastomer, Hytrel (E.I. Du Pont de Nemours Company, Inc., Wilmington, Delaware), have been studied by Thomas et al. [445]. Radiation has two major effects on the blend cross-linking of the Hytrel phase and degradation of PVC phase. Both effects are found more prominent at higher radiation dose. 

See also Carbon monoxide (CO) Copolyamides, random, 19 762-763 Copoly(disulfide)s, as electroactive materials, 23 713—714 Copolyestercarbonates, 19 822 Copolyester elastomers, thermoplastic, 20 70-71... 

Guenther, K.H. (1990) Thermoplastic copolyester elastomer binder for propellants. Eur. Patent EP 358,845 Chem. Abstr., (1990) 112, 237798k. 

The segmented block copoly(ether ester)s, based on poly(butylene terephthalate) (PBT) and on polyoxytetramethylene (POTM) are typical examples for this class of thermoplastic elastomers . They can be described as random copolyesters of tereph-thalic acid with 1,4-butanediol and a-hydro-hard phase whereas the remaining ester segments mix with the ether segments and build up the soft matrix. 

While the first efforts [11, 12] of the biotechnological generation of aliphatic homopolyesters and random copolyesters have been restricted essentially on monomers from 3-hydroxybutyric acid (3HB) and 3-hydroxypentanic acid (3HV), newer investigations concentrate on mraiomers with branches in the range of medium chain length, the so-called thermoplastic elastomers [13—15]. Steinbiichel et al. [3] catalogued more than 100 hydroxyalkanoic acids as craistituents of biosynthetic PHAs. 

Although this paper is concerned primarily with polytetramethylene ether glycol as the polymeric component of the copolyester elastomer, other polyglycols can be used for example, polyethylene ether glycol and poly-1,2-propylene ether glycol. Various combinations of short-chain diols and dicarboxylates may be used also, as mentioned (4). 

Du Font s Hytrel copolyester thermoplastic elastomers are slightly higher in price than the polyurethane types and have grown rapidly. They have a wide range of service temperatures and have found major uses in recreational vehicles, belting, hydraulic hose, and mechanical goods. 

There are two classes of polyolefin blends elastomeric polyolefin blends also called polyolefin elastomers (POE) and nonelastomeric polyolefin blends. Elastomeric polyolefin blends are a subclass of thermoplastic elastomers (TPEs). In general, TPEs are rubbery materials that are processable as thermoplastics but exhibit properties similar to those of vulcanized rubbers at usage temperatures (19). In TPEs, the rubbery components may constitute the major phase. However, TPEs include many other base resins, which are not polyolefins, such as polyurethanes, copolyamides, copolyesters, styrenics, and so on. TPEs are now the third largest synthetic elastomer in total volume produced worldwide after styrene-butadiene rubber (SBR) and butadiene mbber (BR). 

Ektar Performance Plastic s trade name for its family of copolyester thermoplastic elastomer, elastic constant See modulus of elasticity, elastic deformation See deformation, elastic en-ergy, plastic work rheology, elastic fracture See melt fracture, elastic hysteresis See hysteresis, elastic, elasticity A property that causes plastic to return to its original size and shape after removal of a force causing deformation. See coefficient of elasticity deformation and toughness extruder-web stretching and... 

Riteflex Hoechst-Celanese s tradename for its family of copolyester thermoplastic elastomers, rivet, fabricating See forging, riveting See joining, rivet. 

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