Polymer polyethylene terephthalate

Concerns about health effects caused by low levels of residual monomers in PVC and acrylonitrile resins promoted the consideration of condensation polymers such as poly(ethylene terephthalate) (PET) (41). Packaging resins based on acrylonitrile are extraordinarily good barriers that were considered for carbonated beverage bottles. The furor over residual monomers in these materials stunted their growth in spite of improved technology to reduce residuals to barely detectable levels. The step reaction polymer, polyethylene terephthalate(PET) has intrinsically much lower residual monomers in the as-made polymer, and it has become the material of choice for the carbonated beverage market (42). 

If you take ethylene glycol, with its alcohol functional groups on both carbons, and react it with terephthalic acid, with its two organic acid functional groups, you can eliminate water and form the condensation polymer polyethylene terephthalate (PET), a polyester. Figure 16-7 shows the synthesis of PET. 

A process developed by Hitachi for the production of the polymer polyethylene terephthalate from ethylene glycol and polyethylene terephthalic acid by esterification and polycondensation is performed in three reactors, whereas the traditional process... 

This polymer, polyethylene terephthalate (PET), exhibits multiple ester linkages and is therefore called a polyester. PET is sold under many trade names, including Dacron and Mylar . It is primarily used in the manufacture of clothing. There are many different kinds of polyamides and polyesters, serving a variety of purposes. Kevlar, for example, is stronger than steel and is used in bulletproof vests ... 

FIGURE 15-30 Terephthalic acid and ethylene glycol react to give the condensation polymer polyethylene terephthalate (PET), a polyester. 

Crystallization of Polymers Polyethylene Terephthalate and Polyphenylene Sulfide... 

Table 12,2 Value ofl2/lo = N/(l - s) for samples of differing amounts of pre-orientation (polymer polyethylene terephthalate, see Reference [79]).

Choy, C. L., and Grieg, D., The Low Temperature Thermal Conductivity of a Semi-crystalline Polymer, Polyethylene Terephthalate, /. Phys. C Solid State Phys. 8, 3121,1975. [Mylar]... 

The glass transition, denoted p (or a ), is almost worth its own chapter. The amorphous component is constrained by the crystals and the glass transition is much broader in a semicrystalline polymer than in a fully amorphous polymer. Polyethylene terephthalate (PETP) can be quenched to a fully amorphous state and it can be crystallized to 60% at elevated pressures. Figure 7.49 shows the dielectric loss process (Wg) and the great difference between two PETP samples of different crystallinity. The amorphous polymer displays a sharper ot transition than the crystalline. The amorphous polymer shows a clearly asymmetric curve, whereas the semicrystalline polymer shows a symmetric curve. 

Polyether imide. see High-temperature polymers Polyether sulfone. see High-temperature polymers Polyethylene terephthalate. see Polyester, thermoplastic... 

Synthetic fiber-forming polymers Polyethylene terephthalate... 

Murthy NS, Correale ST, Minor H. Structure of the amorphous phase in crystaUizable polymers Polyethylene terephthalate. Macromolecules 1991 24 1185-1189. 

Condensation polymerization differs from addition polymerization in that the polymer is formed by reaction of monomers, each step in the process resulting in the elimination of some easily removed molecule (often water). E.g. the polyester polyethylene terephthalate (Terylene) is formed by the condensation polymerization (polycondensation) of ethylene glycol with terephthalic acid ... 

Those polymers which are the condensation product of two different monomers are named by applying the preceding rules to the repeat unit. For example, the polyester formed by the condensation of ethylene glycol and terephthalic acid is called poly(oxyethylene oxyterphthaloyl) according to the lUPAC system, as well as poly (ethylene terephthalate) or polyethylene terephthalate. 

The primary substrates or support iaclude many types of paper and paperboard, polymer films such as polyethylene terephthalate, metal foils, woven and nonwoven fabrics, fibers, and metal cods. Although the coating process is better suited to continuous webs than to short iadividual sheets, it does work very well for intermittent coating, such as ia the printing process. In general, there is an ideal coater arrangement for any given product. 

Friedrich et al. also used XPS to investigate the mechanisms responsible for adhesion between evaporated metal films and polymer substrates [28]. They suggested that the products formed at the metal/polymer interface were determined by redox reactions occurring between the metal and polymer. In particular, it was shown that carbonyl groups in polymers could react with chromium. Thus, a layer of chromium that was 0.4 nm in thickness decreased the carbonyl content on the surface of polyethylene terephthalate (PET) or polymethylmethacrylate (PMMA) by about 8% but decreased the carbonyl content on the surface of polycarbonate (PC) by 77%. The C(ls) and 0(ls) spectra of PC before and after evaporation of chromium onto the surface are shown in Fig. 22. Before evaporation of chromium, the C(ls) spectra consisted of two components near 284.6 eV that were assigned to carbon atoms in the benzene rings and in the methyl groups. Two additional... 

Polyethylene terephthalate (PET) an amorphous polymer is available in an engineering grade. It is extensively used in beverage bottles and films. 

In semi-cristalline polymers, rate-enhancement under stress has been frequently observed, e.g. in UV-photooxidation of Kapron, natural silk [80], polycaprolactam and polyethylene terephthalate [81]. Quantitative interpretation is, however, difficult in these systems although the overall rate is determined by the level of applied stress, other stress-dependent factors like the rate of oxygen diffusion or change in polymer morphology could occur concurrently and supersede the elementary molecular steps [82, 83], Similar experiments in the fluid state showed unequivocally that flow-induced stresses can accelerate several types of reactions, the best studied being the hydrolysis of DNA [84] and of polyacrylamide [85]. In these examples, hydrolysis involves breaking of the ester O —PO and the amide N —CO bonds. The tensile stress stretches the chain, and therefore, facilitates the... 

In this review recent theoretical developments which enable quantitative measures of molecular orientation in polymers to be obtained from infra-red and Raman spectroscopy and nuclear magnetic resonance have been discussed in some detail. Although this is clearly a subject of some complexity, it has been possible to show that the systematic application of these techniques to polyethylene terephthalate and polytetramethylene terephthalate can provide unique information of considerable value. This information can be used on the one hand to gain an understanding of the mechanisms of deformation, and on the other to provide a structural understanding of physical properties, especially mechanical properties. 

High Performance Polymers 13, No.2, June 2001, p.S365-71 SURFACTANTS BASED ON RECYCLED POLYETHYLENE TEREPHTHALATE FOR BREAKING WATER-IN-OIL EMULSIONS Abdel-Azim A-AA El-Sukkary M M A Egyptian Petroleum Researeh Institute... 

Polymer International 48,No.9, Sept. 1999, p.885-8 KINETICS OF GLYCOLYSIS OF POLYETHYLENE TEREPHTHALATE WITH ZINC CATALYST... 

Journal of Applied Polymer Science 69, No.l2, 19th Sept.1998, p.2311-9 GLYCOLYSIS OF POLYETHYLENE TEREPHTHALATE WASTES IN XYLENE Guclu G Kasgoz A Ozbudak S Ozgumus S Orbay M Istanbul,University Erzacibasi San.Ve Tic.A.S. 

Here the polymer grows by successive esterification with elimination of water and no termination step. Polymers formed by linking monomers with carboxylic acid groups and those that have alcohol groups are known as polyesters. Polymers of this type are widely used for the manufacture of artificial fibers. For example, the esterification of terephthalic acid with ethylene glycol produces polyethylene terephthalate. 

Many polymers are used in barrier applications, either to keep contents in or contaminants out. Food packaging is an excellent example of such usage. Plastic films and containers of many types are used to package food. Blow moldedbottles often contain numerous layers, each of which provides specific benefits. Polyethylene layers are excellent water barriers, polyvinyl alcohol is a good oxygen barrier, and polyethylene terephthalate impedes the diffusion of carbon dioxide from carbonated drinks. Other barrier applications include toothpaste tubes, diaper backsheets, tarpaulins, and geomembranes, which are used to line containment ponds and landfill pits. 

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