Poly alkylene terephthalate s

In his papers and patents on aliphatic polyesters Carothers mentioned terephthalic acid as potential reaction partner of a,co-alkanediols, but a description of a concrete experiment or polyester was never published. Therefore, it is correct that 

The Calico printers Association sold their patent rights to ICI which registered the patent in 1946 [72]. Since October 1929 ICI and DuPont had an agreement to exchange information about patents and research development. On this basis DuPont purchased patent rights from ICI, filed two additional patents in 1949 [73, 74] and commercialized PET fibers under the trademark Dacron . Whinfield went to work for ICI in 1947 and supervised the development of the Terylene fiber. Whinfield was honored as Commander of the Order of the British Empire in 1954, he obtained the honorary fellowship of the textile Industry in 1953 and the Perkin Medal in 1956. He died in Dorking, Surrey, in July 1966. 

Although, poly(l,3-propylene terephthalate), PPT, was synthesized by Whin-field and Dickson in 1941, successful commercialization was delayed until 1998 [79]. The main reason for this delay was the high prize of 1,3-propanediol. New technologies of Shell and DEGUSSA (now Evonik, Germany) allowed for a sufficiently cheap production after 1980 and paved the way for the production of PPT. The Shell polyester was marketed under the name Conterra , while DuPont called its polyester Sorona 3GT. Table 6.4 presents a comparison of physical and mechanical data of PET, PBT, and PPT. 

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TABLE 2.4 Melting Point, Tm (°C), and Glass Transition Temperature, 7 (°C), of Poly(alkylene adipate)s and Poly(alkylene terephthalate)s... 

TABLE 2.7 Melting Temperatures of Isomeric Poly(alkylene terephthalate)s and... 

Poly(alkylene terephthalate)s are soluble only in solvents such as 1,1,2,2-tetrachloroethane-phenol or o-cresol-CHCl3 mixtures, o-chlorophenol,... 

Isomeric poly(alkylene terephthalate)s, melting temperatures of, 36 Isophthalaminonitrile, polymerization of, 344... 

Poly(alkylene terephthalate)s, 89 melting points of, 34 Poly(alkylene terephthalate) solvents, 90-91... 

The Tm values of the poly(alkylene-4,4 -diphenyldicarboxylate)s are much higher than those of the poly(alkylene terephthalate)s. Therefore, as polyarylates derived from substituted HQs and BB seemed to have higher Tms, the, LCPs derived from BB and alkylene glycols with higher carbon numbers have been investigated [24],... 

Poly(aIkylene terephthalate)s such as poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) are widely used in the fields of fibers and thermoplastics. Homologous series of poly(alkylene terephthalate)s — PET, poly(tri-... 

Attempts had been made to synthesise polyesters based on phthalic acid as the diacid component, but these products were amorphous, had low softening points, and were rapidly attacked by organic solvents and acids and bases. Research into polyesters made by the reaction of terephthalic acid (or esters thereof) with aliphatic diols, led to the discovery of polyesters of high commercial value poly(alkylene terephthalate)s [4]. This pairing of diols with terephthalic acid eventually led to the most commercially successful aromatic polyesters, but other synthetic pathways were also investigated towards such products in the early days of polyester development. These included the self-condensation of hydroxy acids of the structure -H0-R-Ph-C02H, where R-OH is para to the acid group and R is -(CH2)- or -(CH2)2- [5], and reactions of aliphatic diacids with 1,4-dihydroxy benzene and similar aromatic diols [6, 7]. Also synthesised about the same time were polyesters based on C2-Cg aliphatic diols and any of the isomeric naphthalene dicarboxylic acids [8]. 

Pyrolysis-gas chromatography studies of various poly(alkylene terephthalate)s (PAT) [16] appear to show very similar fragmentation products occur in all the materials studied (polyesters with 2-6 methylene groups). Various fragments with acid and/or unsaturated chain ends were identified, and decarboxylation reactions also confirmed. From PBT, the following species were identified ... 

A few studies have been made on the thermal degradation of poly(l,4-cyclohexylenedimethylene terephthalate) [84—86], although these have little to say concerning the likely breakdown mechanism. Assuming the same process is applied here as in straight-chain poly(alkylene terephthalate)s, the process might be deduced as follows [NB (CgHjo) denotes the 1,4-cyclohexyl moiety in the polymer backbone] ... 

Almost a mirror image of poly(alkylene terephthalate)s (PAT), these polymers are essentially polyesters formed from aliphatic diacids and hydroquinone (1,4-dihydroxybenzene), giving the general structure ... 

Photodegradation and Oxidation of Other Poly(alkylene terephthalate)s... 

Various techniques are known for the chemical breakdown of poly(alkylene terephthalate)s to feedstock materials, and these can be described under four main headings. Some less well-known and newer approaches have also been claimed, and these will be discussed later in this section. The four main categories are detailed below. 

Poly(alkylene terephthalate)s Poly(butylene naphthalate)... 

Poly(alkylene terephthalate)s undergo a gradual degradation due to thermal decomposition during processing. This degradation is due to thermal scission, and it is accompanied by a decrease in melt viscosity and a deterioration of the polyester s physical and mechanical properties. 

Bis(cyclic iminoesters) are very efficient coupling agents, much less sensitive to temperature than isocyanates, their polycondensation with molten poly(alkylene terephthalate)s being thus effected at 280°C (Scheme 26) [29]. 

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