Alkylene terephthalate

Alternative technology for modifying a poly(aLkylene terephthalate) by incorporation of a phosphinate stmcture has been developed by Enichem. Phosphinate units of the stmcture —P(CgH5) (0)CH20— are introduced into a polyester such as PET or PBT by transesterification with an oligomer comprised of the aforementioned units (136). 

Manufacture. The manufacture of 1,4-cyclohexanedimethanol can be accompHshed by the catalytic reduction under pressure of dimethyl terephthalate ia a methanol solution (47,65). This glycol also may be prepared by the depolymerization and catalytic reduction of linear polyesters that have alkylene terephthalates as primary constituents. Poly(ethylene terephthalate) may be hydrogenated ia the presence of methanol under pressure and heat to give good yields of the glycol (see Polyesters) (66,67). 

Work had gone on in both the United States and Europe, notably at Du Pont and ICI Ltd. in the United Kingdom, on exploring the whole series of alkylene terephthalate polymers in connection with new synthetic fibers. Poly(l,4-butylene terephthalate) (PBT) was investigated in detail, as it had very... 

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,... 

Poly(poly(alkylene terephthalate)-Woc -poly(oxyalkylene)) thermoplastic elastomers are prepared by the bulk polycondensation of dimethyl terephthalate with a mixture of 1,4-alkanediol and hydroxy-terminated poly(oxyalkylene) in... 

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... 

Alkyl dimethyl glycinates, 24 148 Alkyl diphenyl phosphates, 11 494 Alkyl dithiocarbazate esters, 13 568 Alkyleneamine, pK values, 8 487t Alkylenediamines, 8 485 Alkylene terephthalate polymers, 20 32 Alkyl ether phosphates, 24 146 Alkyl ethers, 10 574, 575 uses for, 10 580-581 Alkyl fumarates, 15 491... 

Rafler el al. [105] applied the two-film model to the mass transfer of different alkane diols in poly(alkylene terephthalate) melts and demonstrated a pressure dependency of the mass-transfer coefficient in experiments at 280 °C in a small 3.6L stirred reactor. They concluded that the mass-transfer coefficient kij is proportional to the reciprocal of the molecular weight of the evaporating molecule. 

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],... 

ISO 3451-2 1998 Plastics - Determination of ash - Part 2 Poly(alkylene terephthalate) materials... 

The structure of the diol in alkylene terephthalate/PTME terephthalate copolymers has an important effect on the properties of these block copolymers, as evident from the results shown in Tables II, III, and IV. The 50% tetramethylene terephthalate/PTME terephthalate copolymer prepared from 1,4-butanediol (4G) which was previously noted in Table I serves as our reference copolymer for purposes of discussing the effects of changing the structure of the crystallizable ester segments. The outstanding properties of the 4G-based copolymer are ease of synthesis, a rapid rate of crystallization from the melt, a high melting point, and excellent tensile and tear strengths. 

A plot of the observed melting points of the 50% alkylene tereph-thalate/PTME terephthalate copolymers vs. the range of melting points of the poly (alkylene terephthalate) homopolymers as taken from the literature (16,18-25) results in the linear relationship shown in Figure 3. 

Up to this point the discussion has been concerned with alkylene terephthalate/PTME terephthalate copolymers in which the concentration of alkylene terephthalate and the chemical structure of the alkylene groups have been varied. The next section of this report is concerned with polyether-ester copolymers in which aromatic esters other than terephthalate are used in combination with PTME glycol and various diols. The objective is the same, to correlate changes in copolymer structure with changes in copolymerization results and copolymer properties. Once again the 50% tetramethylene terephthalate/PTME terephthalate copolymer (Tables I and II) with its excellent properties and relative ease of synthesis will be used as the point of reference to which the other polymers will be compared. 

Alkylene 2,6-Naphthalenedicarboxylate/PTME 2,6-Naphthalene-dicarboxylate Copolymers. Fifty percent alkylene 2,6-naphthalenedicar-boxylate/PTME 2,6-naphthalenedicarboxylate copolymers were prepared using each of the straight-chain, hydroxy-terminated diols from ethylene glycol (2G) to 1,10-decanediol (10G) (Table VIII). In contrast to many of the 50% alkylene terephthalate/PTME terephthalate copolymers of Table II, all of the 2,6-naphthalenedicarboxylate-based copolymers tested exhibit excellent tensile strength and tear strength regardless of the diol used or the melting point of the copolymer. As a consequence of their excellent properties, the 2,6-naphthalenedicarboxylate copolymers have been the subject of several patents (32,33,34). 

C. McNeill and M. Bounekhel Thermal degradation studies of terephthalate polyesters 1. Poly(alkylene terephthalates), Polym. Degrad. Stab., 34, 187-204 (1991). 

Table 15.1 Enzymatic modification of poly(alkylene terephthalates). ...

McNeill, I. C. and Bounekel, M., Thermal degradation studies of therephthalate polyesters 1. Poly(alkylene terephthalate), Polym. Deg. Stab., 34,187,1991. 

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-... 

Poly(alkylene terephthalate). Common name of the thermoplastic polyesters poly-(butylene terephthalate) and poly(ethylene terephthalate). 

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] ... 

Although the potential number of poly(alkylene terephthalate) copolymers is vast, only a few appear to have merited interest due to their thermal degradation properties. These include ... 

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. 

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