Terephthalate esters

In 1930, in one of many pioneering studies, Carothers showed that certain condensation polymers could be cyclic or macrocyclic rather than exclusively linear. In addition to this very important observation, he showed that thermolysis in vacuo of certain polymers could also yield macrocyclic materials. Quite a number of papers have been published on this subject since that time, especially dealing with the chemistry of phthalate " , isophthalate " ", and terephthalate esters Many of these structures are tabulated at the end of this... 

Scheme 3.1 Preparation of cyclic terephthalate esters via acid chlorides or depolymerization, and polymerization to high-molecular-weight polymer...

Polybutylene terephthalate Figure 153. Structures of terephthalate esters. 

Synthesis of polyethylene terephthalate esters containing up to 4.6 mol% sulfurized terephthalate derivatives as a method of increasing char formation. 

Alkylene Ester/PTME Ester Copolymers Other Than Terephthalate Ester... 

The discovery of poly(ethylene terephthalate), PET, in the 1940s [1,2] and its commercialization initially by DuPont and by ICI in the 1950s created a large market demand for terephthalic acid and terephthalate esters of polymer purity. Because dimethyl terephthalate, DMT, is readily purified by distillation [3] (and also because the p-xylene oxidation/esteiification intermediate, methyl p-toluate, is more readily kept in solution than is p-toluic acid) the polyester fibers and films industry was initially based on terephthalate ester. With the development of improved oxidation and purification technologies, purified terephthalic acid, TPA, became available in commercial quantities by the mid 1960s. Over 75% of the worldwide PET manufacture (total world PET capacity is over six million tons/year) is currently based on TPA rather than DMT [4]. This preference for TPA results from the less complicated esterification catalysis and the absence of methanol handling when the acid is used directly. 

Polyolefins - An Arrhenius model has been developed for lifetime prediction of the light stability of polypropylene . Photooxidation processes in blends of polypropylene with poly(butylene terephthalate) (PBT) are complicated by the thermal sensitivity of the polypropylene and the screening effect of the terephthalate ester . This effect is shown in Scheme 1. 

The chemical shift anisotropies for the carbonyl and aromatic carbons of Hytrel were reconstructed from a Herzfeld-Beiger analysis (24) of the intensities of the sidebands from NMR magic angle spinning experiments. The results in Table III indicate that the carbonyl carbon chemical shift anisotropy is axially symmetric for each terephthalate ester. We attribute this axial symmetry to a general property of terephthalate esters, rather than as a consequence of molecular motion, as the highly crystalline dimethyl terephthalate also has an axially symmetric carbonyl carbon chemical shift tensor. 

Table 1. Glass transition temperatures, melting temperatures, and clearing temperatures of selected mono- and disubstituted poly-(p-phenylene terephthalate) esters with flexible substituents.

R. J. Whinfield and T. J. Dickson. Polymeric linear terephthalic esters. US Patent 2465 319, assigned to Du Pont, March 22, 1949. 

Higher molar ratios of diol / terephthalic ester lead to essentially the same molar mass since in this polymerization there is initially a polycondensation to products with glycol end groups. These products subsequently polycondense further to higher-molecular-weight products with the elimination of glycol. 

A Flory-Fox plot of the glass transition temperatures of poly-(isosorbide terephthalate) esters of different molar mass is shown in Figure 4.8. 

Higher molar ratios of diol/terephthalic ester lead to essentially the... 

Hydroxyether terephthalate ester Single Tg, T -depression FTIR - Liu et al. (2005b)... 

Ethylene terephthalate Ester-carbonate Single Tg I was from 1/2 = terephthalate/ bisphenol-A with ester and carbonate linkages Aharoni (1983)... 

Trimethylene terephthalate Ester Single Tg-, microscopy WAXD II was ethylene terej dialate or butylene terej thalate Chiu (2007), Kuo and Woo (2003), Supaphol et al. (2004)... 

Hydroxyether terephthalate ester Single 7g FTIR - Wang et al. (2008)... 

By using this concept, resorcinol poly(ester carbonate)s were developed and introduced under the trade name Lexan SLX grades. The block copolymers of Iso- and Terephthalate esters of iJesorcinol (ITR) and BPA polycarbonate can be prepared by melt, solution, or interfacial reactions [191], The properties of these resins are controlled by adjusting the percentage of resorcinol phthalate to BPA carbonate (Fig. 14.18). 

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