Carbons, terephthalate

For the same purpose, a composition consisting of Bisphenol A copoly (carbonate-terephthalate) and BPA/DC was reinforced with polyamide fibers. After crosslinking at 270 °C, a glass transition temperature of 212 °C was obtained [39]. The same di-cyanate monomer was added to polycarbonate in order to decrease the brittleness [40]. 

Melting temperature Trimethylene carbonate Terephthalic acid... 

Lead sesquioxide is used as an oxidation catalyst for carbon monoxide ia exhaust gases (44,45) (see Exhaust control), as a catalyst for the preparation of lactams (46) (see Antibiotics, P-lactams), ia the manufacture of high purity diamonds (47) (see Carbon, diamond-natural), ia fireproofing compositions for poly(ethylene terephthalate) plastics (48), ia radiation detectors for x-rays and nuclear particles (49), and ia vulcanization accelerators for neoprene mbber (50). 

Henkel Rearrangement of Benzoic Acid and Phthalic Anhydride. Henkel technology is based on the conversion of benzenecarboxyhc acids to their potassium salts. The salts are rearranged in the presence of carbon dioxide and a catalyst such as cadmium or zinc oxide to form dipotassium terephthalate, which is converted to terephthahc acid (59—61). Henkel technology is obsolete and is no longer practiced, but it was once commercialized by Teijin Hercules Chemical Co. and Kawasaki Kasei Chemicals Ltd. Both processes foUowed a route starting with oxidation of napthalene to phthahc anhydride. In the Teijin process, the phthaHc anhydride was converted sequentially to monopotassium and then dipotassium o-phthalate by aqueous recycle of monopotassium and dipotassium terephthalate (62). The dipotassium o-phthalate was recovered and isomerized in carbon dioxide at a pressure of 1000—5000 kPa ( 10 50 atm) and at 350—450°C. The product dipotassium terephthalate was dissolved in water and recycled as noted above. Production of monopotassium o-phthalate released terephthahc acid, which was filtered, dried, and stored (63,64). 

Vinylidene Chloride Copolymer Latex. Vinyhdene chloride polymers are often made in emulsion, but usuaUy are isolated, dried, and used as conventional resins. Stable latices have been prepared and can be used direcdy for coatings (171—176). The principal apphcations for these materials are as barrier coatings on paper products and, more recently, on plastic films. The heat-seal characteristics of VDC copolymer coatings are equaUy valuable in many apphcations. They are also used as binders for paints and nonwoven fabrics (177). The use of special VDC copolymer latices for barrier laminating adhesives is growing, and the use of vinyhdene chloride copolymers in flame-resistant carpet backing is weU known (178—181). VDC latices can also be used to coat poly(ethylene terephthalate) (PET) bottles to retain carbon dioxide (182). 

Polyester C rbon te Copolymers. Polyester carbonate resins have molecular stmctures composed of iso- and terephthalate units in conjunction with the standard bisphenol A PC moieties. 

A convenient method of compositional designation uses molar percentages of ester and carbonate linkages coupled with the molar percentages of iso- and terephthalate units in the polymer. A 70% ester, 30% carbonate polyester carbonate with 60 parts of isophthalate and 40 parts of terephthalate is designated 70(60/40)30. Similarly, a standard PC resin is 0(0/0)100, and a polyarjlate resin composed of a 1 1 molar ratio of iso- to terephthalate units esterfied with bisphenol A is designated 100(50/50)0. 

Blends of the polysulfone tesia have been made with ABS, poly(ethylene terephthalate), polytetrafluoroethylene (PTFE), and polycarbonate. These ate sold by Amoco under the Miadel trademark. Additional materials ate compounded with mineral filler, glass, or carbon fiber to improve properties and lower price. 

Bis-(P-hydroxyethyl) terephthalate and related compounds can be produced ia this manner using finely divided carbon catalyst (92). The carbon functions not only as a catalyst but also helps to remove color from the reaction mixture upon removal of the carbon by hot filtration. 

The high yields of ethyl ester obtainable from the product attest its purity. A mixture of 50 g. of terephthalic acid, 500 ml. of absolute ethyl alcohol, and 25 ml. of sulfuric acid was boiled for 16 hours and then distilled to half its volume and poured into dilute aqueous sodium carbonate. There was obtained 56.7 g. of diethyl terephthalate (m.p. 42-44°), and from the wash water there was recovered 4.6 g. of terephthalic acid these materials account for 93.3% of the original substance. 

Terephthalic acid has been obtained from a great many /)-disubstituted derivatives of benzene or cyclohexane by oxidation with permanganate, chromic acid, or nitric acid. The following routes appear to have preparative value from />-toluic acid, />-methylacetophenone,2 or dihydro-/)-tolualdehyde by oxidation with permanganate from f>-cymene by oxidation with sodium dichromate and sulfuric acid from />-dibromobenzene or from /i-chloro- or -bromobenzoic acid by heating at 250° with potassium and cuprous cyanides and from />-dibromo-benzene, butyllithium, and carbon dioxide. ... 

Developments in the USA have led to the availability of terephthalate plasticisers, for example dioctyl terephthalate (DOTP). Whilst these materials are very similar to the corresponding o-phthalate esters they are generally less volatile and are best compared with d-phthalates with one or more carbon atom in the alkyl chain. As with the linear dialkyl phthalates the terephthalates show good fogging resistance. This is a phenomenon in which new cars on storage fields awaiting delivery develop misting on the windows due, apparently, to the volatility of additives in PVC compounds used with the car. 

Carothers also produced a number of aliphatic linear polyesters but these did not fulfil his requirements for a fibre-forming polymer which were eventually met by the polyamide, nylon 66. As a consequence the polyesters were discarded by Carothers. However, in 1941 Whinfield and Dickson working at the Calico Printers Association in England announced the discovery of a fibre from poly(ethylene terephthalate). Prompted by the success of such a polymer, Farbenfabriken Bayer initiated a programme in search of other useful polymers containing aromatic rings in the main chain. Carbonic acid derivatives were reacted with many dihydroxy compounds and one of these, bis-phenol A, produced a polymer of immediate promise. 

Another recent development is the preparation of a polyester-polycarbonate copolymer. The polymers involve a polyester component based on the reaction between bis-phenol A and iso- or terephthalic acid with the carbonate component arising from the reactions described in Section 20.3 (see Section 20.9). 

These materials have the general structure shown in Figure 20.11 and are prepared by reaction of bisphenol A with iso- and/or terephthalic acid and a carbonate group donor (e.g. phosgene or diphenyl carbonate). 

With the expiry of the basic ICI patents on poly(ethylene terephthalate) there was considerable development in terephthalate polymers in the early 1970s. More than a dozen companies introduced poly(butylene terephthalate) as an engineering plastics material whilst a polyether-ester thermoplastic rubber was introduced by Du Pont as Hytrel. Polyfethylene terephthalate) was also the basis of the glass-filled engineering polymer (Rynite) introduced by Du Pont in the late 1970s. Towards the end of the 1970s poly(ethylene terephthalate) was used for the manufacture of biaxially oriented bottles for beer, colas and other carbonated drinks, and this application has since become of major importance. Similar processes are now used for making wide-neck Jars. 

Friedrich et al. also used XPS to investigate the mechanisms responsible for adhesion between evaporated metal films and polymer substrates [28]. They suggested that the products formed at the metal/polymer interface were determined by redox reactions occurring between the metal and polymer. In particular, it was shown that carbonyl groups in polymers could react with chromium. Thus, a layer of chromium that was 0.4 nm in thickness decreased the carbonyl content on the surface of polyethylene terephthalate (PET) or polymethylmethacrylate (PMMA) by about 8% but decreased the carbonyl content on the surface of polycarbonate (PC) by 77%. The C(ls) and 0(ls) spectra of PC before and after evaporation of chromium onto the surface are shown in Fig. 22. Before evaporation of chromium, the C(ls) spectra consisted of two components near 284.6 eV that were assigned to carbon atoms in the benzene rings and in the methyl groups. Two additional... 

Terephthalic acid is an important monomer for producing polyesters. The main route for obtaining the acid is the catalyzed oxidation of paraxylene. It can also be produced from benzoic acid by a disproportionation reaction of potassium benzoate in the presence of carbon dioxide. Benzene is the coproduct ... 

Note-. Bisphenol-A and the diaryl esters of terephthalic acid and isophthalic acid are nonvolatile compounds, so that any excess of these components cannot completely be removed, resulting in a low-molar-mass, unusable polyester. Moreover, excess bisphenol-A causes a strong discoloration of the polyester melt due to thermal degradation at the high reaction temperature used. This can be avoided if the diaryl esters are mixed with 5 mol% of diphenyl carbonate. Any excess of this compound can easily be removed in vacuum at the polycondensation temperature. 

Experiment with addition of diphenyl carbonate Diphenyl terephthalate, 31.8 g (0.1 mol), 28.62 g (0.09 mol) of diphenyl isophthalate, and 2.37 g (0.011 mol) of diphenyl carbonate are polycondensed with 45.6 g (0.2 mol) of 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A) under the preceding conditions. A slighdy brownish, extremely tough, noncrystalline polyester is obtained with an inherent viscosity equal to 0.56 dL/g. The softening point of the polyester is equal to 200°C and the melting range is 215-285°C. 

Polymers are further defined based on the number of carbon atoms they contain. Thus, the PA based on 1,6-hexamethylene diamine and sebacic acid is named PA-6,10 and the polymer based on caprolactam, PA-6. Terephthalic and isophthalic acid units are coded T and I. Thus, PA-6,T represents the PA from hexamethylene diamine and terephthalic acid. 

See also PBT degradation structure and properties of, 44-46 synthesis of, 106, 191 Polycaprolactam (PCA), 530, 541 Poly(e-caprolactone) (CAPA, PCL), 28, 42, 86. See also PCL degradation OH-terminated, 98-99 Polycaprolactones, 213 Poly(carbo[dimethyl]silane)s, 450, 451 Polycarbonate glycols, 207 Polycarbonate-polysulfone block copolymer, 360 Polycarbonates, 213 chemical structure of, 5 Polycarbosilanes, 450-456 Poly(chlorocarbosilanes), 454 Polycondensations, 57, 100 Poly(l,4-cyclohexylenedimethylene terephthalate) (PCT), 25 Polydimethyl siloxanes, 4 Poly(dioxanone) (PDO), 27 Poly (4,4 -dipheny lpheny lpho sphine oxide) (PAPO), 347 Polydispersity, 57 Polydispersity index, 444 Poly(D-lactic acid) (PDLA), 41 Poly(DL-lactic acid) (PDLLA), 42 Polyester amides, 18 Polyester-based networks, 58-60 Polyester carbonates, 18 Polyester-ether block copolymers, 20 Polyester-ethers, 26... 

The Reeopet process for the ehemical recycling of PETP is described. The three-stage process, which allows the recovery of highly pure terephthalic acid, commences with continuous saponification followed by chromatographic purification with activated carbon and a final acidification step. 

Photocopies of journal articles relating to the Unipet process for the recycling of PETP developed by United Resource Recovery Corp. Details are given of the process which enables contaminated PETP to be recycled by the use of caustic soda which reacts with the PETP to yield ethylene glycol and terephthalic acid, followed by heating and evaporation of the EG which reduces organic impurities to carbon dioxide and water and leaves solid terephthalic salt. Its implications for the industry are also discussed. 

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