Tetramethylene glycol polyester

The hard-soft block copolymer approach employed to produce segmental PUs (Section 7.6) has also been used with polyesters, with the hard block formed from 1,4-butadienediol and terephthalic acid while the soft block is provided by oligomeric (approximate molecular weight of 2000 Da) poly(tetramethylene glycol) and is sold under the trade name Hytrel. 

Preparation of Cast Elastomers. The cast elastomers were prepared in a two-step procedure. First prepolymers were made from one polyether polyol (poly(oxy-tetramethylene) glycol of 1000 M.W., (POTMG)) and two polyester polyols (adipate polyester of 2000 M.W. (PAG) and polycaprolactone of 1250 M.W. (PCL)) by reaction with the corresponding diisocyanates (MDI, PPDI, CHDI or NDI) at an NCO/OH ratio of 2/1. The temperature was maintained at 80°C and periodic samples were withdrawn to determined the isocyanate content. When the isocyanate content of the mixture reached within 0.3% of the calculated value, the reaction was stopped by cooling. The prepolymer could be kept for a period of six months in the absence of moisture. The isocyanate-terminated prepolymers were then chain-extended with... 

Butylene Glycol n (1,4-butanediol, tetramethylene glycol) A stable, hygroscopic, colorless liquid used in the production of polyesters by reaction with dibasic acids, and in the production of polyurethanes by reaction with diisocyanates. 

In general, nonabsorbable sutures can retain their tensile strength longer than 2 months [113]. The synthetic polymers used to make nondegradable sutures include polypropylene (PP), polyamides, polyesters such PET and polybutylene terephthalate (PBT), and polyether-ester based on poly(tetramethylene glycol), 1,4-butanediol, and dimethyl terephthalic acid [114]. The base polymer and filament configuration for common nonabsorbable sutures are summarized in Table 8.2. 

Polyesters of tetramethylene glycol and a- 3-dimethoxysuccinic acids were prepared. 

Although these polyethers produced good foams they were rather expensive and were soon displaced by the cheaper propylene oxide-based polyethers. However, these polymers of tetrahydrofuran (commonly called poly(oxy-tetramethylene)glycol) now find use in the preparation of polyamide, polyester and polyurethane thermoplastic elastomers (see sections 10.3, 11.8 and 16.6.3). 

Polyurethane thermoplastic elastomers may also be produced in fibrous form to give elastic fibres (spandex fibres). Such fibres are made either by solution spinning or by reaction spinning. In the first process, a hydroxyl-terminated polyester (e.g. an adipate) or polyether (e.g. poly(oxy-tetramethylene) glycol) is treated with an excess of diisocyanate (e.g. diphenyl-methane diisocyanate) to give an isocyanate-terminated pre-polymer similar to those used for cast elastomers (section 16.6.1). The pre-polymer is dissolved in a strongly polar solvent (e.g. dimethylformamide) and treated with an... 

Transitions with the participation of liquid crystals sometimes show characteristic phenomena. If a nematic modification turns to a smectic A or smectic C phase, transient stripes in the form of a myelinic texture (also called chevron texture or striated texture) are often visible. Typically for the polyester prepared from di-w-propyl-/ -terphenyl-4,4" carboxylate and tetramethylene glycol, the nematic phase separates from the isotropic liquid on cooling in droplets which coalesce and form large domains. Cooling of the threaded-schlieren texture produces a transition to the smectic A phase this change is characterized by transition phenomena, mostly stripes, which broaden into larger areas ( transition bars ). 

Mitrach K, Pospiech D, Haubler L, Voigt D, Jehnichen D and Ratzsch M (1993) Thermotropic block copol5oners polyesters with flexible poly(tetramethylene glycol) units in the main chain. Polymer 34 3469-3474. 

The most important tetrahydrofuran polymers are the hydroxy-terrninated polymers, that is, the a,C0-poly(tetramethylene ether) glycols used commercially to manufacture polyurethanes and polyesters (see Urethane polymers Polyesters, thermoplastic). 

PTT is made by the melt polycondensation of PDO with either terephthalic acid or dimethyl terephthalate. The chemical structure is shown in Figure 11.1. It is also called 3GT in the polyester industry, with G and T standing for glycol and terephthalate, respectively. The number preceding G stands for the number of methylene units in the glycol moiety. In the literature, polypropylene terephthalate) (PPT) is also frequently encountered however, this nomenclature does not distinguish whether the glycol moiety is made from a branched 1,2-propanediol or a linear 1,3-propanediol. Another abbreviation sometimes used in the literature is PTMT, which could be confused with poly(tetramethylene terephthalate),... 

A segmented polyether-polyester (H49) was synthesized via melt transesterification from 1-4 dimethyl terephthalate, 1-4 butanediol and poly(tetramethylene ether)glycol ... 

QO Poiymeg . [QO Ghent] Poly-tetramethylene ether glycol polyol used in urethane elastomers, fibers, coatit, and adhesives, in the prod, of high-perfmmance theniioset and ther-moplifitic dastomeis, elastomeric polyesters, as polyester modifiers. 

In addition, there are thermoplastic polyester elastomers. These are produced by equilibrium melt transesteiification of dimethyl terephthalate, 1,4-butanediol, and a poly(tetramethylene oxide) glycol (molecular weight about 10(X)). Because equilibrium conditions exist in the melt, the products are random copolymers ... 

Polyarylate resin Polyarylether ketone resin Polyester carbonate resin Polyetherimide resin Polyethylene, chlorinated Polyethylene glycol Polyethylene, medium density Poly (p-methylstyrene) Poly (p-methylstyrene), rubber-modified Poly (oxy-1,2-ethanediyloxycarbonyl-2,6-naphthalenediylcarbonyl) resin Poly (oxy-p-phenylenesulfonyl-p-phenyleneoxy-p-phenyleneisopropylidene-p-phenylene) resin Poly (phenyleneterephthalamide) resin Polysulfone resin Poly (tetramethylene terephthalate) Polyvinylidene chloride Potassium sorbate Potato (Solanum tuberosum) starch Silica, colloidal Silicone Sodium N-alkylbenzenesulfonate Sodium bicarbonate Sodium tetraborate pentahydrate Starch, pregelatinized Styrene/acrylates copolymer Styrene/butadiene polymer Styrene/DVB copolymer , 1,1 -Sulfonylbis (4-chlorobenzene) polymer with 4,4 -(1-methylethylidene) bis (phenol) and 4,4 -sulfonylbis (phenol) Synthetic wax Tapioca starch Tetrafluoroethylene/perfluoro (propyl vinyl ether) copolymer Tocopherol Triglycidyl isocyanurate VA/crotonates copolymer Vinyl chloride/ethylene copolymer Wheat (Triticum vulgare) starch... 

Poly(butylene terephthalate) is the polyester from terephthalic acid and 1,4-butylene glycol, and, because of this, is also called poly(tetramethylene terephthalate). PTMT can be processed at lower temperatures than PET, but this advantage is paid for with a lower glass transition temperature and somewhat poorer mechanical properties. 

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