Zur Analyse polymerhomologer Reihen des Nylon 6, 6.6 und Poly-äthylenterephthalats

Heidemann, Gerhard; Kusch, Peter; Nettelbeck, Heidi

doi:10.1007/bf00519384

Cited by 33 publications

(5 citation statements)

References 19 publications

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“…Zahn and Krzikalla 6 were the first to separate a linear polyethylene terephthalate oligomer series by paper chromatography. The other techniques used for isolation and characterization of number of oligomers from polyethylene terephthalate were column chromatography, 7 thin-layer chromatography, 8 silica gel column chromatography, 9 and gas chromatography. 10 Gueris and Meybeck 11 have reported on preparative gel-permeation chromatography of linear oligomers.…”

Section: Introductionmentioning

confidence: 99%

Estimation and characterization of polyester oligomers

Shukla

Kulkarni

1999

J. Appl. Polym. Sci.

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Oligomers were obtained from polyester samples by solvent extraction and dissolution methods. Dioxane, chloroform, and chlorobenzene were used for the extraction method, whereas dimethyl formamide and phenol : tetrachloroethane (1 : 1 mixture) were used for the dissolution method. The oligomers were separated and analyzed by a thin-layer chromatographic technique. It was observed that extraction with chloroform and dissolution with phenol : tetrachloroethane gave higher oligomer contents. Also, the values were higher for as-spun fibers. Thin-layer chromatographic analysis showed that in all the cases lower oligomers were obtained with a maximum of the cyclic trimer, whereas the efficiencies of solvents varied for removal of higher oligomers.

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Section: Introductionmentioning

confidence: 99%

Estimation and characterization of polyester oligomers

Shukla

Kulkarni

1999

J. Appl. Polym. Sci.

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“…6 The five esters were heated at 270'C in sealed ampoules, all for 1, 2, 3,4, 5, 6, and 7 hours. The amounts of DEG in the heated samples were determined by hydrazinolysis of the esters (15 min refluxing with hydrazine), followed by gas chromatographic analysis (column material, Porapak Q; stainless steel column; column temperature, 215°C; carrier gas : wet Nz; flame ionization detector).…”

Section: Experimental and Resultsmentioning

confidence: 99%

Formation of diethylene glycol as a side reaction during production of polyethylene terephthalate

Hovenkamp

Munting

1970

J. Polym. Sci. A‐1 Polym. Chem.

100

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synopsisPolymers of poly(ethy1ene terephthalate) (PET) always contain a certain amount of incorporated diethylene glycol (DEG), substituting the incorporated glycol. DEG is formed in a side reaction during the ester interchange of dimethyl terephthalate (DMT) with ethylene glycol or during direct esterification of terephthalic acid with ethylene glycol, and to a smaller extent during the polycondensation of the low-molecular material. DEG is formed via an unusual type of reaction: ester + alcohol + ether + acid.Some evidence of this type of reaction is given by the formation of dioxane in low molecular PET and of methyl Cellosolve and methyl carbitol during the ester interchange of DMT with ethylene glycol and diethylene glycol, respectively. The strongest support for this type of reaction, however, was obtained from kinetic data. Polyesters of low molecular weight with OH group contents ranging from 3 to 0.5 mole/kg were heated at 270°C in sealed tubes for 1-7 hr. The kinetic equation for the proposed reaction is: [ester]. With the aid of one rate constant the formation of DEC in all esters could be described.

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“…Sodium p-hydroxybenzenesulfonate (98%, Aldrich), formaldehyde (37% aqueous solution, Fisher), sulfuric acid (Mallinkrodt), hydroquinone (Sargent-Welch), 2-propanol (HPLC grade, Mallinkrodt), ethanol (HPLC grade, Aldrich), ethyl acetate (HPLC grade, Burdick & Jackson), hexane (HPLC grade, Aldrich), acetonitrile (Mallinkrodt), and potassium chloride (Mallinkrodt) were used as received. Reagent grade methanol (Sargent-Welch) was further purified following the procedure of Wolfhagen and Soltese (7). Quinone (Eastman) was purified by double-sublimation just prior to use.…”

Section: Methodsmentioning

confidence: 99%

“…Double-bond isomer separation is an important analytical problem in the area of retinoid chemistry. Retinoids are involved in many major biological functions such as growth promotion, reproduction, and differentiation and maintenance of epithelial tissue (7). Retinoids also serve as visual pigments that play a critical role in photoreception and phototransduction (S).…”

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confidence: 99%