Polyethylene terephthalate copolyester

The effect of incorporating p-hydroxybenzoic acid (I) into the structures of various unsaturated polyesters synthesised from polyethylene terephthalate (PET) waste depolymerised by glycolysis at three different diethylene glycol (DEG) ratios with Mn acetate as transesterification catalyst, was studied. Copolyesters of PET modified using various I mole ratios showed excellent mechanical and chemical properties because of their liquid crystalline behaviour. The oligoesters obtained from the twelve modified unsaturated polyesters (MUP) were reacted with I and maleic anhydride, with variation of the I ratio with a view to determining the effect on mechanical... 

With the exception of ethylene vinyl acetate added in the 1980 s, the list of materials and polymers approved as packaging for food irradiated products has remained static for decades. This article supplies details of the approved list, which includes such polymers as polyethylene terephthalate and polyvinyl chloride. The article provides an update on the latest proactive move to expand the list of packaging materials and polymers approved for the irradiation of foods. The expanded list would include ethylene vinyl alcohol, PVC film, ionomers, nylon 66, 6/12 and copolyesters among others. 

Takeda, H., Ehara, M Sakai, Y. and Choi., Thermal crystallization of polyethylene terephthalate) and its copolyesters effect of degree of polymerization and copolymerized components, Textile Res. J., 61, 429-432 (1991). 

Monomers commonly used in the manufacture of polyethylene terephthalate (PET) and copolyesters for food packaging. 

By the mid 1970s, Tennessee Eastman also announced development of a copolyester consisting of 60/40 PHBA/polyethylene terephthalate (PET) by direction reaction of acetoxybenozic acid with PET in the melt [2], This system had the advantage of lower costs, but its use temperature was limited to 90 °C which is just above its Tg. In the early 1980s, researchers at Celanese reported... 

Eq. (5) in conjunction with Eqs. (8) and (9) have, so far, provided adequate representation of experimental isotherms6 32, which are characterized by an initial con vex-upward portion but tend to become linear at high pressures. Values of K, K2 and s0 have been deduced by appropriate curve-fitting procedures for a wide variety of polymer-gas systems. Among the polymers involved in recent studies of this kind, one may cite polyethylene terephthalate (PET) l2 I4), polycarbonate (PC) 19 22,27), a polyimide l6,17), polymethyl and polyethyl methacrylates (PMMA and PEMA)l8), polyacrylonitrile (PAN)15), a copolyester 26), a polysulphone 23), polyphenylene oxide (PPO)25), polystyrene (PS) 27 28), polyvinyl acetate 29) and chloride 32) (PVAc and PVC), ethyl cellulose 24) (EC) and cellulose acetate (CA) 30,3I>. A considerable number of gases have been used as penetrants, notably He, Ar, N2, C02, S02 and light hydrocarbons. 

In the case of copolymers a calorimetric investigation by Dole and Wunderlich (1959) of the copolyester, polyethylene terephthalate and sebacate) at the 80/20. (80 moles of terephthalate units to 20 of sebacate)... 

The agreement between heats of fusion of the same polymer is excellent in some cases, but very poor in others. Obviously, in the case of polypropylene more work needs to be done before the heat of fusion of this substance will be known with any certainty. Heats of fusion calculated from the copolymer equation, Eq. (6), are uniformly low, except in the case of Rybnikar s data. As pointed out by Dole and Wunderlich (1957) this is probably due to the failure to measure the maximum melting of carefully annealed samples. Thus, Dole and Wunderlich (1959) found that the calorimetrically estimated melting point in the case of the carefully annealed copolyester, the 80/20 polyethylene terephthalate and sebacate, was 240° C, whereas the value calculated from Eq. (6) using the heat of fusion estimated from the calorimetric data of Smith and Dole (1956) was 245° C. The unannealed sample had a melting point of ca. 210°. 

Fig. 11. Specific heat of annealed80/20 copolyester of polyethylene terephthalate-sebacate in the neighborhood of the melting point. Dotted line, calculated values from adaptation of theory of Feory...

Among the many different classes of thermotropic polymers, only a limited number of polyesters based on aromatic ester type mesogenic units have been studied by rheological methods, beginning with the publication by Jackson and Kuhfuss of their work on the p-oxybenzoate modified polyethylene terephthalate, PET, copolymers. They prepared a series of copolyesters of p-hydroxybenzoic acid, HBA, and PET and measured the apparent melt viscosity of the copolymers as a function of their composition by use of a capillary rheometer. On inclusion of low levels of HBA into PET, the melt viscosity increased because of partial replacement of the more... 

Although studies concerning main chain liquid crystalline polymers were originated by Onsager (la) and Ishihara (lb) in the late 1940 s, extensive work in this field did not really begin until the early 1970 s. Jackson and Kuhfuss (2) reported the first thermotropic polyester by modifying polyethylene terephthalate with various amounts of p-hydroxybenzoic acid (HBA). They found that the copolyester with HBA content of at least 35 mole % have opaque melts. Subsequent studies in the area of aromatic polyesters by various authors resulted in a large number of patents and publication. (3.) These polymers were all derived from unsubstituted and... 

In a previous paper (1), phase segregation by spinodal decomposition in mixtures of polyethylene terephthalate and polyhydroxybenzoic acid copolymer (PET-PHB) and polycarbonate (PC) has been investigated. It was shown that thermally induced phase segregation takes place above the Tg of PC and exhibits a lower critical solution temperature (LCST). However, the phase separated domains do not grow until the temperature exceeds 255°C. Some disclinations developed within the liquid crystal rich regions. Even in the pure PET-PHB component, four dark brushes with negative sense of disclinations form around 240°C, indicating the presence of nematic liquid crystals. Paci and coworkers (2) claimed that a smectic-nematic transition exists near 270°C in this liquid crystalline copolyester. 

Polyethylene terephthalate (PET) and polyethylene truxillate (PETx) were melt-mixed, 5delding a copolyester. The FAB mass spectrum was recorded, chain statistics was applied (Markoff distribution), and the extent of exchange (see above) was calculated. This study showed the potential of the MS... 

In a similar study, the FAB mass spectrum of a copolyester obtained by melt-mixing polyethylene terephthalate (PET) and of polyethylene adipate (PEA) was recorded. The authors computed the number average length of adipate and terephthalate blocks by applying chain statistics. The result was Uea = 7.1 Uet = 2 implying that the initial copolymer, obtained by meltmixing of the two polyesters, has a Markoffian (block) distribution of tire monomer sequence/ ... 

Wide angle X-ray scattering from an aligned sample of copolyester prepared from kO mol % polyethylene terephthalate and 60 mol % p.aceto benzoic acid was reported together with an lysis of the derived cylindrical distribution function (CDF)... 

Morton et al. [ 125] studied the isothermal crystallization kinetics of polyethylene terephthalate (PET) in blends with fully aromatic liquid crystalline copolyester (Vectra A). As Vectra fractions increase in the blend, both the PET crystallization rates and the percentage of PET that is crystalline decrease. 

Materials. Three thermotropic LCPs have been used in our studies. Vectra A900, an aromatic copolyester of 1,4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, and Vectra B950, a copolymer of 2,6-hydroxynaphthoic acid, 4-aminophenol and terephthalic acid, were supplied from the Hoechst Celanese Corporation. Both LCPs possess a melt temperature of 280 C. Rodrun LC3000, supplied by Unitika, is a copolymer of polyethylene terephthalate (PET) and 1,4-hydroxybenzoic acid, and possesses a melt temperature of 220 C. 

Saint-Loup, R., et ai, Synthesis of (polyethylene terephthalate/poly[epsilon]-caprolactone) copolyesters. Polymer, 44(12) p. 3437. 2003. 

Eastman Kodak Co USA Vectron LCC-10108 LCC-10109 Copolyesters based on n-oxy-benzoic acid and polyethylene-terephthalate... 

Because the types of exposures vary greafly depending on the nature of the work environment, materials also vary greatly. Materials considered for faceshields include polycarbonate (PC), cellulosics, polyethylene terephthalate glycol (PETG) and a new-generation copolyester recently introduced to the market that offers a combination of characterishcs to meet the changing needs of the face protechon market. 

TABLE 1.36 POLYETHYLENE TEREPHTHALATE-BASED COPOLYESTER-EASTMAN CHEMICAL PRODUCTS... 

Tillier and co-workers [49] carried out structural molecular weight and end-group studies on copolyesters of polyethylene terephthalate (PET) and e-caprolactone using GEC and MALDI-ToF-MS. The measurement of molar mass by MALDI-ToF-MS was shown to be inapplicable in the case of polymers exhibiting a polydispersivity index (1 ), greater than 1.10 such as PET and others. 

Bi-component fibres can be made from two variants of the same generic fibre (two types of polyester (PES), polyethylene terephthalate (PET), copolyester (coPES), polyacrylonitrile (PAN), polyamide (PA), polyethylene (PE) and polypropylene (PP)). The fibres can also be made from two different polymer compositions, e.g. PET/PA, PA/Spandex, etc. Different types of polymers, such as polyester, polyamides, polystyrene, polyurethane, polyolefines, polylactic acid, co-polyamides and soluble co-polyesters, have been used to spin bi-component fibres. 

Joseph, E.G., Wilkes, G.L., Baird, D.G. Preliminary thermal and structural studies of blends based on a thermotropic liquid crystalline copolyester and polyethylene terephthalate. In Polymer Liquid Crystals, Blum-stein, A., ed. Plenum Press, New York, 1985. 

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