Polyethylene terephthalate solution

Depolymerization, e.g., polyethylene terephthalate and cellulose hydrolysis Hydrothermal oxidation of organic wastes in water Crystallization, particle formation, and coatings Antisolvent crystallization, rapid expansion from supercritical fluid solution (RESS)... 

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). 

Solution viscosity is an excellent method for quality control for relatively uniform polymer samples. There is an ASTM test method for determining inherent viscosity (ASTM D 4603) that uses polyethylene terephthalate) and one for determining intrinsic viscosity of cellulose (ASTM D 1795) that describes a one-point method for estimating intrinsic viscosity. The result is useful as it relates viscosity to molecular weight, which is useful for checking different batches of polymer in a production line to help ensure uniformity. 

Tri-Nasal spray is a metered-dose manual-spray pump in an amber polyethylene terephthalate bottle with 0.05% w/v triamcinolone acetonide in a solution containing citric acid, edetate disodium, polyethylene glycol 3350, propy-... 

Sometimes, small structural differences in morphology of polymer samples can be isolated by using a double subtraction technique. For example, with polyethylene terephthalate) PET, differences in the amorphous phase of the melt-quenched polymer and solution-cast polymer can be isolated by first subtracting out the contribution due to the trans isomer and then subtracting the two difference spectra from each other 214). (Fig. 16) shows the resultingdifference spectrum obtained after the second subtraction. Obviously the two amorphous structures are different from each other. 

Manufacture. The manufacture of 1,4-cyclohexanedimethanol can be accomplished by the catalytic reduction under pressure of dimethyl terephthalate in 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. Polyethylene terephthalate) may be hydrogenated in the presence of methanol under pressure and heat to give good yields of the glycol (see Polyesters) (66,67). 

Membranes with very regular pores of sizes down to around 10 nm can be prepared by track-etching [10], and, in principle, those membranes can be used for the fractionation of macromolecules in solution. A relatively thin (<35 pm) polymer film (typically from polyethylene terephthalate)/PET/or aromatic polycarbonate/PC/) is first bombarded with fission particles from a high-energy source. These particles... 

Other recent applications of AFM-SECM included the study of the iontophoretic transport of [Fe(CN)6]4 across a synthetic track-etched polyethylene terephthalate membrane by Gardner et al. [193]. They made the structure and flux measurements at the single pore level and found that only a fraction of candidate pore sites are active in transport. Demaille et al. used AFM-SECM technique in aqueous solutions to determine both the static and dynamical properties of nanometer-thick monolayers of poly(ethylene glycol) (PEG) chains end-grafted to a gold substrate surface [180]. 

A similarly poor efficiency in extraction can also be seen in Fig. 11, where the extraction result for the product obtained by the radiation grafting of styrene onto polyethylene terephthalate)(PET) fibers13 is shown. In this case the unreacted PET can be extracted after most of PS homopolymer has been extracted by repeated solution-precipitation of the sample. It should be mentioned here that the solution procedure is also necessary to extract the unreacted PET. Such a solution-precipitation procedure is also necessary for nylon-styrene13 and poly(vinyl chloride)-acrylo-nitrile14 graft products so as to remove the homopolymers to a sufficient extent. 

Samples. Polyethylene terephthalate (PET) samples are industrial (Mylar) biaxially oriented films (10 pm thick). Polymethyl-methacrylate (PMMA) has been spin coated on microscope glasses from a PMMA (1) / CHjClj (9) solution, giving thin layers of a few hundred A thickness. 

Saran (Dow polyvinylidene dichloride) is a tough, chemically resistant plastic available in a variety of forms that are useful in the laboratory. Saran pipe or tubing can easily be welded to itself or sealed to glass and is useful for handling corrosive solutions. Thin Saran film, available commercially as a packaging material, is useful for windows, support films, etc. Mylar (du Pont polyethylene terephthalate) film and other polyester films are also useful for these purposes. Mylar is chemically inert and has excellent electrical properties for electrical insulation and for use as a dielectric medium in capacitors. Much thinner than these are films that can be made in the laboratory by allowing a dilute ethylene dichloride solution of Formvar (polyvinyl acetal) to spread on a water surface and dry. 

Liquefaction of untreated wood can also be achieved at a lower temperature of 150°C and at atmospheric pressure in the presence of a catalyst [12]. Phenolsulfonic acid, sulfuric acid, hydrochloric acid, and phosphoric acid were used as catalysts. In this acid catalyst method, phenols and polyhydric alcohols can also be used for the coexisting organic solvents. Phenol, cresol, bisphenol A and F, and so forth are successfully adoptable as the phenols. Polyethylene glycols, polyether polyols (epoxide additionally reacted polyether polyol, polyethylene terephthalate polyol) have been found to liquify wood resulting in polyol solutions [13]. Liquefaction of wood in the presence of -caprolactone, glycerin, and sulfuric acid has also been accomplished. It was confirmed in this case that liquefaction and polymerization, the latter of which produces polycaprolactone, take place in the reaction system at the same time [14]. Besides the wood material, it has become apparent that trunk and coconut parts of palm, barks, bagasse, coffee bean wastes, and used OA papers can also be liquified [15]. 

Polyethylene terephthalate (PET) and methyl methacrylate (PMMA) are readily soluble in TFA-CH2CI2 mixtures, but they only form isotropic solutions. 

In a previous paper (1), phase segregation by spinodal decomposition in mixtures of polyethylene terephthalate and polyhydroxybenzoic acid copolymer (PET-PHB) and polycarbonate (PC) has been investigated. It was shown that thermally induced phase segregation takes place above the Tg of PC and exhibits a lower critical solution temperature (LCST). However, the phase separated domains do not grow until the temperature exceeds 255°C. Some disclinations developed within the liquid crystal rich regions. Even in the pure PET-PHB component, four dark brushes with negative sense of disclinations form around 240°C, indicating the presence of nematic liquid crystals. Paci and coworkers (2) claimed that a smectic-nematic transition exists near 270°C in this liquid crystalline copolyester. 

Evacuated blood tubes may be made of soda-lime or borosflicate glass or plastic (polyethylene terephthalate). Because of the decreased likelihood of breakage and hence exposure to infectious materials, many laboratories have converted from glass tubes to plastic tubes. Tubes made from the soda-lime glass may release trace elements, particularly calcium and magnesium, into solutions. Special tubes are available for trace element determination (Table 2-2). 

Doshi and Reneker have experimented with the spinning of PEO fibers from aqueous solutions and studied the relationship between process and solution parameters on fiber characteristics (Doshi and Reneker 1995). Electrospun fibers were about 0.05 to 5 pm in diameter Reneker and Chun demonstrated the spinning of polyethylene terephthalate fibers of 300 nm in diameter with cylindrical structures (Reneker and Chun 1996). 

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