Poly ethylene terephthalate, 1,4-cyclohexane

Ak2o has been iastmmental ia developiag a new process for the stereospecific synthesis of 1,4-cyclohexane diisocyanate [7517-76-2] (21). This process, based on the conversion of poly(ethylene terephthalate) [25038-59-9] circumvents the elaborate fractional crystallisation procedures required for the existing -phenylenediamine [108-45-2] approaches. The synthesis starts with poly(ethylene terephthalate) (PET) (32) or phthaUc acid, which is converted to the dimethyl ester and hydrogenated to yield the cyclohexane-based diester (33). Subsequent reaction of the ester with ammonia provides the desired bisamide (34). The synthesis of the amide is the key... 

As an alternative way, carbon has been loaded on Ti02 particles. This can be put in practice through the introduction of carbonaceous precursors on the Ti02 particles formed, and subsequent carbonization to produce Ti02-carbon composites. The carbon materials, derived from various carbonaceous precursors, have been practically introduced by means of thermal treatment in n-hexane, ethanol, or cyclohexane vapor [145-147,182-185] and carbonization of a mixture of Ti02 with poly(vinyl alcohol), poly(ethylene terephthalate), cellulose, sucrose, or citric acid [87,132-144,148,149,151]. A chemical vapor deposition method was also used to prepare MWCNTs deposited on Ti02 [198]. 

Unlike poly(ethylene terephthalate), the polyester from dimethyl terephthalate and cyclohexane-1,4-dimethylol can be manufactured with initially equivalent monomer quantities. It has improved dyeability, just as in the case of the copolymer of dimethyl terephthalate, ethylene glycol, and 5-10% p-hydroxybenzoic or isophthalic acid. 

Another property recently reported in detail for polyarylate is in the polymer blend area. An early French patent [33] noted that Bisphenol A polyarylate and poly(ethylene terephthalate) yield interesting mixtures. Further studies by Kimura et al. [34] and Robeson [35] found that with modest ester-exchange polyarylate and poly(ethylene terephthalate) form miscible mixtures (thus transparent with Tg values between the constituent values). Polyarylate and poly(butylene terephthalate) were noted to be miscible without ester-exchange [36]. Miscibility of three different cyclohexane dimethanol based polyesters with polyarylate was observed under minimum time and temperature exposure conditions [35]. 

Table 10.3. Comparative properties of various forms of poly (ethylene terephthalate) and poly (cyclohexane-1,4-dimethylene terephthalate)...

This polymer has a sUghtly stiffer chain than poly (ethylene terephthalate) and hence the glass-transition temperature (about ISO C) and melting point (about 290°C) are somewhat higher. The polymer is available in both fibre and film form and is of interest mainly because of its superior resistance to water and weathering. Some properties of poly(cyclohexane-1,4-dimethylene terephthalate) are shown in Table 10.3. 

Poly(ethylene terephthalate) copolymers containing 1,4-cyclohexane dicarbox-ylate units. 41 1493-1501. 

Poly(ethylene-co-1,4-cyclohexane dimethylene terephthalate) The thermal and photochemical oxidation processes of a polyester based on poly(ethylene-co-l,4-cyclohexanedimethylene terephthalate) (PECT) with approximately 30% of 1,4-cyclohexanedimethanol have been studied by means of chemiluminescence [88], Also, the stabilization activity of some commercial antioxidants has been evaluated, and it has been related to hydroperoxide levels in the polymer. 

It is thus anticipated that the small-molecule breakdown products will be l,4-bis(methylene)cyclohexane and 4-methylenecyclohex-anemethanol. Such by-products have been found in the pyrolysis of the copolymer poly(ethylene- o-l,4-cyclohexylenedimethylene terephthalate) [87]. 

Studies have been carried out on the UV degradation of poly(ethylene-co-l,4-cyclohexanedimethylene terephthalate) [35,38,56]. The PET sections of the chain will undergo the various initiation, abstraction and oxidation processes already considered, but a tertiary hydrogen on the cyclohexane ring of the poly(l,4-cyclohexanedimethylene terephthalate) units means that formation of tertiary alkyl radicals and subsequent autoxidation at this site will predominate over formation of secondary alkyl radicals on methylene units or elsewhere... 

See listed abbreviations in Polymers forCoextmded Films section. Poly(ethylene glycol-co-cyclohexane-l,4-dimethanol terephthalate). 

Poly(butylene terephthalate) has been reported to exhibit miscibility with a cyclohexane di-methanol/ethylene glycol/terephthalic acid (1/2/3) copolymer (PETG) a retardation in PBT crystallization rate was observed [228]. 

Poly( 1,4-cyclohexane dimethylene terephthalate-eo-ethylene terephthalate) Dimethyl terephthalate-ethylene glycol-1,4-bis(hydroxy niethyl)-cyclohexane copolymer 25640-14-6 1,4-Benzenedicarlx)xylic acid, dimethyl ester, polymer with 1,4-cyclohexanedimethanol and 2-ethanediol R (C i()H 10O4 CsH 16O2 C2H602)... 

PCTG Poly (cyclohexane dimethanol-co-ethylene glycol terephthalate)... 

PCX, PCTG Poly(cyclohexane terephthalate- glycol), copolymer of cyclohexanedimethanol (66 mol%), ethylene glycol, (34 mol%), and terephthalic acid... 

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