Polyethylene terephthalate oligomers

Dobias, J. Voldrich, M. Proks, M. Migration of polyethylene terephthalate oligomers from packaging into food simulant liquids. Potav. Vedy 1996, 14, 25-32. 

Bacillus sp. (Nitro-benzyl- esterases) Hydrolysis of polyethylene terephthalate) oligomers [61, 62]... 

Nechwatal, A., Blokesch, A., Nicolai, M., Krieg, M., Kolbe, A., Wolf, M., and Gerhardt, M. (2006) A contribution to the investigation of enzyme-catalysed hydrolysis of polyethylene terephthalate) oligomers. Macromol. Mater. Eng., 291 (12), 1486-1494. 

Peebles, L. H., Huffmann, M. W. and Ablett, C. T Isolation and identification of the linear and cyclic oligomers of polyethylene terephthalate... 

Dulio, V., Po, R., Borelli, R., Guarini, A. and Santini, C., Characterization of low-molecular-weight oligomers in recycled polyethylene terephthalate), Angew. Makromol. Chem., 225, 109-122 (1995). 

Bryant, J. J. L., and Semiyen, J. A., Cyclic polyesters 6. Preparation and characterization of two series of cyclic oligomers from solution ring-chain reactions of polyethylene terephthalate), Polymer, 38, 2475 (1997). 

The workhorse polyester is polyethylene terephthalate) (PET) which is used for packaging, stretch-blown bottles and for the production of fibre for textile products. The mechanism, catalysis and kinetics of PET polymerization are described in Chapter 2. Newer polymerization techniques involving the ring-opening of cyclic polyester oligomers is providing another route to the production of commercial thermoplastic polyesters (see Chapter 3). 

Begley, T.H., Dennison, J.L. and Hollifield, H.C. (1990). Migration into food of polyethylene terephthalate (PET) cyclic oligomers from PET microwave susceptor packaging. Food Addit. Contain., 7, 6, 797-803. 

Condensation polymerizations are equilibrium reactions, which means they eventually stop reacting when small molecular weight reaction products like water are no longer removed from the system. These characteristics of the condensation polymerization reaction also have an effect on the chemical properties of such plastics. In the presence of water, particularly at high temperatures, polyethylene terephthalate begins to hydrolyze and low molecular weight oligomers are produced which can be transferred into a food in contact with the plastic. 

Polyethylene terephthalate (PET). At temperatnres above 300°C PET pyrolysis proceeds via a random-chain scission of the ester links to yield a mixture of terephthalic acid monomer and vinyl ester oligomers [47], The presence in the monomer of oxygen and a benzene ring imphes that the decomposition prodncts contain aromatic and oxygenated carbon componnds, like CO2, ketones and aldehydes [27],... 

Begley, T.H. HoUifield, H.C. Migration of dibenzoate plasticizers and polyethylene terephthalate cyclic oligomers from microwave susceptor packaging into food-simulating liquids and foods. J. Food Prot. 1990, 53, 1062-1066. 

The production of polyethylene terephthalate is conducted in two steps. Dimethyl terephthalate is heated with ethylene glycol to give a mixture consisting of dihydroxyethyl terephthalate and higher oligomers. Further heating to 270 C under vacuum in the presence of a catalyst produces the final polymer. Refer to the following reaction scheme ... 

Kim DJ, Lee KT. Analysis of specific migration of monomers and oligomers from polyethylene terephthalate bottles and trays according to the testing methods as prescribed in the legislation of the EU and Asian countries. Polymer Test 2012a 31 (8) 1001-1007. 

Figure 3.7 shows an example of an oligomer separation achieved by this method for various POE-HPLC has also been applied to the determination of oligomers in polyesters [34], alkylphenyl formaldehyde resins [35, 36] and polyethylene terephthalate [37, 38]. 

Hydroxymethyl)phenylphosphinic acid (an adduct of formaldehyde and phenylphosphinic acid) can he thermally dehydrated to form oligomers which are useful in flame retarding polyethylene terephthalate (60). These may have reached commercial usage in Europe. 

Polyethylene terephthalate (PET) is a linear thermoplastic polymer, which was initially commercialized for packaging carbonated soft drinks due to its excellent gas barrier properties that allows it to retain CO. Raw materials used for production of PET are ethylene glycol and terephthalic acid (or dimethyl terephthalate). Production of PET is a two-step process in the first step trans-esterification or esterification takes place, depending on whether terephthalic acid or dimethyl terephthalate is used, and in the second step polycondensation of resulting oligomers produces PET (Massa et al.,2011). 

Supercritical fiuid extraction and chromatography and comparative complimentary phasing desorption mass spectrometry secondary ion mass spectrometry have been used to determine oligomers in polyethylene terephthalate. ... 

Perfluoroethylenes have been characterized by desorption chemical ionization and tandem mass spectrometry Fourier transform ion cyclotron resonance mass spectroscopy has also been applied to the identification of polymers, eg. polyethylene glycols. Comparative complimentary plasma desorption mass spectrometry/secondary ion mass spectrometry has been applied to the identification of oligomers of various polymers including polyethylene glycol, polytetrafluoroethylene, polycarbonate, polyacrylates, polyethylene terephthalate and siloxanes. ... 

Complementary HPLC-MS has also applied to structure elucidation in other polymers including polyethylene terephthalate [10], phenol oligomers [11], phosphoric acid containing polyarylene ethers [12], isocyanates [13], polyurethanes [14], polyamindoamine dendrimers [15], N-isopropyl acrylamide [16], oligo-(phenylene-vinylene) dimer [13], polyetherether ketone [17] and carbon blacks [18]. 

THERMAL STABILITY OF POLYETHYLENE TEREPHTHALATE PACKAGING DETERMINATION OF OLIGOMERS... 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

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