Lineare polyester mit carboxylendgruppen und deren bestimmung

Kern, Von W.; Munk, R.; Schmidt, K.-H.

doi:10.1002/macp.1955.020170116

Cited by 17 publications

(5 citation statements)

References 10 publications

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“…Kern et al 24. have reported a detailed study of the conversion of hydroxyl end‐groups into carboxyl end‐groups by reacting aliphatic polyesters after acylation with succinic anhydride.…”

Section: Methodsmentioning

confidence: 99%

“…Kern et al [24] have reported a detailed study of the conversion of hydroxyl end-groups into carboxyl end-groups by reacting aliphatic polyesters after acylation with succinic anhydride. This offers the possibility to determine the total number of carboxyl end-groups of PET by Pohl's titration methods.…”

Section: Concentrations Of Hydroxyl End-groupsmentioning

confidence: 99%

“…Determination of carboxyl end-groups (by eqn (1)) before and after reaction with succinic anhydride identifies the hydroxyl end-groups. [8,24]…”

Section: Concentrations Of Hydroxyl End-groupsmentioning

confidence: 99%

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Properties modification of PET vascular prostheses

Chaouch

Diéval

Chakfé

et al. 2009

J of Physical Organic Chem

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Aging mechanisms have been investigated on polyethylene terephthalate (PET) fibres extracted from various vascular prostheses in order to identify the different modifications of the material's degradation. NMR spectroscopy provides a comprehensive view of chemical structures of macromolecules. Examination of a series of PET fibres showed significant chemical differences between the virgin prostheses and the explants, especially for diethylene glycol (DEG) and cyclic oligomeric groups. These analyses revealed that PET failures in vascular prostheses are susceptible to hydrolysis during in vivo stay. We also extended this 1 H NMR technique to determine the hydroxyl and carboxyl end-group concentrations. In order to validate the 1 H NMR results, complementary techniques -chemical titration and classical viscosimetry -were used. The obtained results showed an increase in end-group concentrations and a decrease of the viscosity averaged macromolecular weight (Mn) for the explants.Large sample size requirement (for two methods: viscosimetry and titration). The sample size is a major problem for us, because of availability of the prostheses is insufficient. Typically, we should be able to work with a mass <5 mg to have conclusive results.(www.interscience.wiley.com)

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Section: Methodsmentioning

confidence: 99%

Section: Concentrations Of Hydroxyl End-groupsmentioning

confidence: 99%

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Properties modification of PET vascular prostheses

Chaouch

Diéval

Chakfé

et al. 2009

J of Physical Organic Chem

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“…Kern et al30 reported a detailed study of the conversion of hydroxyl end‐groups into carboxyl end‐groups by reacting aliphatic polyesters after acylation with succinic anhydride. This offers the possibility of determining the total number of carboxyl end‐groups of polyethylene terephthalate by Pohl's titration methods 15, 16…”

Section: Methodsmentioning

confidence: 99%

“…Determination of carboxyl end‐groups (by Formula 1) before and after reaction with succinic anhydride identifies the hydroxyl end‐groups 15, 30…”

Section: Methodsmentioning

confidence: 99%

Nuclear magnetic resonance spectroscopy spectroscopic investigation of the aging mechanism of polyethylene terephthalate vascular prostheses

Chaouch

Diéval

Nouën

et al. 2009

J of Applied Polymer Sci

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This article attempts to develop and prove a technique to determine the degradation of polyethylene terephthalate (PET) for vascular prostheses. The implicit goal is to be able to quantify the amount of degradation to study the effect of in vivo aging. Nuclear magnetic resonance spectroscopy ( 1 H-NMR) provides a comprehensive view of chemical macromolecular structures. Examination of a series of PET vascular prostheses showed significant chemical differences between the virgin prostheses and the explants collected after aging, especially for diethylene glycol and cyclic oligomers groups. Aging was investigated in terms of chemical scission of ester and ether linkages caused by hydrolytic reaction during the in vivo stay.Besides, we extended this 1 H-NMR technique to determine hydroxyl end-group concentrations and therefore the average number of macromolecular weight. To validate 1 H-NMR results, complementary techniques, the chemical titration method and the classical viscosimetric method, were used. The results showed an increase of hydroxyl end-group concentration and a decrease in the macromolecular weight for the explants.

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Über die konstitutionelle Exaktheit in der makromolekularen Chemie

Kern

1959

Angewandte Chemie

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Die makromolekulare Chemie hat die konstitutionelle Exaktheit und den hohen Stand der niedermolekularen organischen Chemie noch nicht erreicht, doch geht die Entwicklung in diese Richtung.Makromolekule einheitlicher GroOe (Molgewicht -4000) und definierter, insbesondere gestreckter Gestalt (8 in p-Stellung verknupfte Benzolringe, entsprechend 32 Atomen in einer Kette) wurden hergestellt und hijhermolekulare werden angestrebt; Fragen der Konstellation kBnnen a n solchen Molekulen untersucht werden. Die Synthese neuer makromolekularer Stoffe, insbesondere mit reaktiven Gruppen, ist zur Ausweitung der makromolekularen Chemie notwendig.

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Lineare polyester mit carboxylendgruppen und deren bestimmung

Cited by 17 publications

References 10 publications

Properties modification of PET vascular prostheses

Properties modification of PET vascular prostheses

Nuclear magnetic resonance spectroscopy spectroscopic investigation of the aging mechanism of polyethylene terephthalate vascular prostheses

Über die konstitutionelle Exaktheit in der makromolekularen Chemie

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