Thermoplastic copolyesters segmented

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. 

Polyether-based thermoplastic copolyesters show a tendency toward oxidative degradation and hydrolysis at elevated temperature, which makes the use of stabilizer necessary. The problem could be overcome by incorporation of polyolehnic soft segments in PBT-based copolyesters [31,32]. Schmalz et al. [33] have proposed recently a more useful technique to incorporate nonpolar segments in PBT-based copolyesters. This involves a conventional two-step melt polycondensation of hydroxyl-terminated PEO-PEB-PEO (synthesized by chain extension of hydroxyl-terminated hydrogenated polybutadienes with ethylene oxide) and PBT-based copolyesters. 

Thermoplastic copolyesters are condensation block copolymers based on a crystalline polyester hard segment and an amorphous long-chain polyether soft s ment. The hard segment, for example, formed... 

Thermoplastic elastomers contain sequences of hard and soft repeating units in the polymer chain. Elastic recovery occurs when the hard segments act to pull back the more soft and rubbery segments. Cross-linking is not required. The six generic classes of TPEs are, in order of increasing cost and performance, styrene block copolymers, polyolefin blends, elastomeric alloys, thermoplastic urethanes, thermoplastic copolyesters, and thermoplastic polyamides. 

Thermoplastic copolyester elastomers are multiblock copolymers built up from so-called short crystallizable hard segments and long flexible segments. Owing to such chemical structure, TPEEs exhibit unusual combination of thermoplastic and elastomeric behavior. Physical and mechanical properties of these copolymers strongly depend on the chemical composition and the molecular structure... 

The chemical structure, chain length and content of the soft segments primarily control physical and chemical properties of thermoplastic copolyester elastomers, such as resistance to heat, light, oxygen and water, as well as low temperature properties and tear strength, but have less influence on melting temperatures, hardness and modulus. 

Witsiepe, W, K., Segmented Thermoplastic Copolyester Elastomers. U.S. Patent 3651014.March 21,1972. 

Slonecki J (1992) The effect of mass fraction and molecular weight of segments on the conditions of preparation, structure and properties of thermoplastic copolyester-ethers (KPEE). Part 111. The effect of mass fraction and molecular weight of segments on some mechanical properties of KPEE, Polimery 37 19-24 (in Polish). 

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 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. 

General Description Amitel is DSM Engineering Plastics family of copolyesters (COPEs) and thermoplastic elastomers (TPEs). These resins are multiblock copolymers in which butylene terapthalate hard segments andpoly(alkylene oxide) soft segments alternate repeatedly along the polymer backboned 1... 

Polysulfone is thermo-mechanical and chemically durable thermoplast. But in solution, which is catalyzed by alkali, it becomes sensitive to nucleoph-ylic replacements. In polar aprotone dissolvents at temperatures above 150 °C in the presence of spirit solution of K COj it decomposes into the bisphenol A and diarylsulfonic simple esters. The analogous hydrolysis in watery solution of K2CO3 goes until phenol products of decomposition. This reaction is of preparative interest for the synthesis of segmented block-copolyester simple polyester - polysulfone. The transetherification of polysulfone, being... 

FIGURE 2 Structures of commercially important thermoplastic elastomers HS = hard segment, SS = soft segment, (a) SBS (b) MDI-BD-PTMO polyurethane (c) PTMT and PTMO copolyester (d) nylon 66 and PTMO copolyamide (e) random copolymer ionomer E-MAA neutralized with sodium. 

The underlying morphology will have a large effect on the physical properties. The soft phase is usually the continuous phase to maintain the elastomeric behavior of the material. In materials that have crystalline hard segments, such as copolyesters and polyurethanes, both phases are essentially continuous. Thermoplastic elastomers almost never have the soft segment as the isolated phase and the hard segment as the continuous phase. The most... 

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