Polyester elastomers

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. 

Polyester elastomers are resistant to a variety of common solvents including aqueous acids or bases. The chemical resistance of copolyesterether elastomers is shown in Table 13 (193) which gives examples of solvent resistance and is not inclusive. 

VJteflex Thermoplastic Polyester Elastomer Chemical Resistance Table, Mateiial Monogiaph MRE-002, Hoechst-Celanese Coip., Summit, N.J. 

A smaller but rapidly growing area is the use of PTMEG ia thermoplastic polyester elastomers. Formation of such polyesters iavolves the reaction of PTMEG with diacids or diesters. The diols become soft segments ia the resulting elastomeric materials. Examples of elastomeric PTMEG polyesters iaclude Hytrel (Du Pont) and Ecdel (Eastman Chemicals). 

Epichlorohydrin. Commercial polyester elastomers include both the homopolymer and the copolymer of epichl orohydrin with ethylene oxide. The very polar chloromethyl groups create basic resistance to oil for these polymers, and they have been extensively used in fuel lines however, the desire for lower fuel permeation is causing a search to be made for other polymers (10) (see Elastomers, synthetic-polyethers). 

Table 12. Properties of Polyester/Elastomer Block Copolymers ...

In Chapters 3 and 11 reference was made to thermoplastic elastomers of the triblock type. The most well known consist of a block of butadiene units joined at each end to a block of styrene units. At room temperature the styrene blocks congregate into glassy domains which act effectively to link the butadiene segments into a rubbery network. Above the Tg of the polystyrene these domains disappear and the polymer begins to flow like a thermoplastic. Because of the relatively low Tg of the short polystyrene blocks such rubbers have very limited heat resistance. Whilst in principle it may be possible to use end-blocks with a higher Tg an alternative approach is to use a block copolymer in which one of the blocks is capable of crystallisation and with a well above room temperature. Using what may be considered to be an extension of the chemical technology of poly(ethylene terephthalate) this approach has led to the availability of thermoplastic polyester elastomers (Hytrel—Du Pont Amitel—Akzo). 

Thermoplastic polyester elastomers such as the Du Pont product Hytrel were developed later than the polyurethane materials, being first introduced in 1972. They have similar characteristics to the polyurethanes but there is an upward shift in the hardness range (i.e. the softest grades are not so soft, but the hardest grades are harder than the corresponding extreme grades in the polyurethanes). 

If polypropylene is too hard for the purpose envisaged, then the user should consider, progressively, polyethylene, ethylene-vinyl acetate and plasticised PVC. If more rubberiness is required, then a vulcanising rubber such as natural rubber or SBR or a thermoplastic polyolefin elastomer may be considered. If the material requires to be rubbery and oil and/or heat resistant, vulcanising rubbers such as the polychloroprenes, nitrile rubbers, acrylic rubbers or hydrin rubbers or a thermoplastic elastomer such as a thermoplastic polyester elastomer, thermoplastic polyurethane elastomer or thermoplastic polyamide elastomer may be considered. Where it is important that the elastomer remain rubbery at very low temperatures, then NR, SBR, BR or TPO rubbers may be considered where oil resistance is not a consideration. If, however, oil resistance is important, a polypropylene oxide or hydrin rubber may be preferred. Where a wide temperature service range is paramount, a silicone rubber may be indicated. The selection of rubbery materials has been dealt with by the author elsewhere. ... 

Recently Developed Thermoplastic Polyurethane and Polyester Elastomers , ERDE TR 136 (1973) 4) RP. Rastogi K. Kishore, Poly-... 

Figure 2.2 Stress-strain curve of polyester elastomer containing 58 wt% PBT. A, slope = Young s modulus B, yield stress. (Reprinted with permission from ref. 190, p. 96. Copyright 1988 John Wiley Sons, Inc.)...

Hytrel Bulletin 1-25, Blends of Hytrel polyester elastomer with PVC, E.I. DuPont de Nemours and Co., Delaware, 1976. 

Liu QY, Tian M, Ding T, Shi R, and Zhang LQ. Preparation and characterization of a biodegradable polyester elastomer with thermal processing abilities. J Appl Polym Sci, 2005, 98, 2033-2041. 

Webb A, Yang J, and Ameer G. Biodegradable polyester elastomers for tissue engineering. Exp Opin Biol Ther, 2004, 4(6), 801-812. 

Polyester elastomers, 20 70-71, 74 Polyesterether elastomers chemical resistance of, 20 75t manufacture of, 20 75-76 market for, 20 77-78 models for two-phase structure in, 20 72-73... 

A 100% natural polymer based entirely on agricultural products, the polyester elastomer obtained by reacting castor oil with a castor oil derivative, sebacic acid, was the basis for the synthesis of SIN s. 

Thermoplastic polyester elastomers (COPEs or TPEEs) are block copolymers of ... 

A very wide range of plastics are coloured with pigments including PVC, polystyrene, polyurethane, polyamide, polycarbonate, polyester, elastomers, thermosets and thermoplastics. The choice of pigment is obviously dependent on which plastic... 

S—EB—S (compounds) polyurethane/elastomer block copolymers polyester/elastomer block copolymers polyamide/elastomer block copolymers polyetherimide/polysiloxane block copolymers polypropylene/EPDM or EPR blends polypropylene/EPDM dynamic vulcanizates polypropylene/butyl rubber dynamic vulcanizates polypropylene/natural rubber dynamic vulcanizates polypropylene/nitrile rubber dynamic vulcanizates PVC/ nitrile rubber blends... 

Thermoplastic polyester elastomers Tripropylene glycol diacrylate Triphenyl phosphate Thermoplastic polyurethane Trimethylolpropanetrimethacrylate Thermal volatilisation analysis Transmitter signal... 

A number of such combinations are mentioned in the literature, and may be offered by various manufacturers. They combine the soft flexible rubberiness of polyether or polyester elastomers with the high strength, heat-, oil-,... 

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