Oligomere und Pleionomere von synthetischen faserbildenden Polymeren

Zahn, Helmut; Gleitsmann, Günter B.

doi:10.1002/ange.19630751606

Cited by 56 publications

(7 citation statements)

References 109 publications

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“…This process was repeated several times and the combined BHET crystals were dried at 50 °C for 72 h. White needle‐shaped crystals with melting point 110 °C (lit. value27: 109–110 °C) were obtained by recrystallization from distilled water.…”

Section: Methodsmentioning

confidence: 99%

Poly(ethylene terephthalate) copolymers containing 5-nitroisophthalic units. I. Synthesis and characterization

Kint

Martínez

Ilarduya

et al. 2000

J. Polym. Sci. A Polym. Chem.

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Poly(ethylene terephthalate‐co‐5‐nitroisophthalate) copolymers, abbreviated as PETNI, were synthesized via a two‐step melt copolycondensation of bis(2‐hydroxyethyl) terephthalate and bis(2‐hydroxyethyl) 5‐nitroisophthalate mixtures with molar ratios of these two comonomers varying from 95/5 to 50/50. Polymerization reactions were carried out at temperatures between 200 and 270 °C in the presence of tetrabutyl titanate as a catalyst. The copolyesters were characterized by solution viscosity, GPC, FTIR, and NMR spectroscopy. They were found to be random copolymers and to have a comonomer composition in accordance with that used in the corresponding feed. The copolyesters became less crystalline and showed a steady decay in the melting temperature as the content in 5‐nitroisophthalic units increased. They all showed glass‐transition temperatures superior to that of PET with the maximum value at 85 °C being observed for the 50/50 composition. PETNI copolyesters appeared stable up to 300 °C and thermal degradation was found to occur in two well‐differentiated steps. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1934–1942, 2000

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Section: Methodsmentioning

confidence: 99%

Poly(ethylene terephthalate) copolymers containing 5-nitroisophthalic units. I. Synthesis and characterization

Kint

Martínez

Ilarduya

et al. 2000

J. Polym. Sci. A Polym. Chem.

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“…Several runs using a PET grade of higher mblecular weight, Mu, = 90,000, gave results similar to those obtained with the PET of M , = 57,200. The triphenylphosphite (TPP) used for all the reactions in this work was acquired from Borg-Warner Chemicals and Aldrich Chemicals. Two model compounds were prepared: 2-hydroxyethylterephthalate (HET) (mp 180°C) according to a procedure similar to Zahn et al [2][3][4][5] and bis(2-hydroxyethy1l)terephthalate (BHET) (mp 108°C). as described by Sorenson and CampbelLG…”

Section: Introductionmentioning

confidence: 99%

High‐temperature reactions of hydroxyl and carboxyl PET chain end groups in the presence of aromatic phosphite

Aharoni¹,

Forbes²,

Hammond³

et al. 1986

J. Polym. Sci. A Polym. Chem.

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When melt‐extruded in the presence of triphenylphosphite (TPP), the molecular weight of polyesters such as poly(ethylene terephthalate) (PET) increases with time. Analysis of the PET chain end groups and model studies of high‐temperature reactions indicate that, most likely, the process leading to chain extension of PET in the presence of TPP takes place in two steps. In the first step, TPP rapidly reacts with the hydroxyl end groups by displacing one phenoxy group from the TPP. In the second step, a slow reaction takes place between the alkyldiphenyl phosphite and carboxylic chain end groups, forming an ester bond between the carboxyl and alkyl groups, and producing diphenylphosphite (DPP) as a reaction by‐product. The DPP tautomerizes to its pentacovalently bonded stabler form of diphenylphosphate, the form in which the DPP was usually detected in our analyses. The ester formation results in the extension of the PET chains. Model studies are presented which support the proposed mechanism.

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“…It was shown by Zahn and Rathgeber [28] that already the low molecular 'nylon peptide' adipoyl-bis-hexamethylendiamine H 2 N(CH 2 ) 6 NH CO(CH 2 ) 4 CO NH(CH 2 ) 6 NH 2 delivers the same X-ray pattern as nylon powder. The field of oligomer research became the main area of my activities in Heidelberg and later in Aachen [29,30]. Not only were typical X-ray patterns of the crystalline domains found, but also low angle X-ray patterns of chainfolded lamellae in oligomers above a certain chain length.…”

Section: Synthesis Of Oligomers and Peptidesmentioning

confidence: 99%