Properties modification of PET vascular prostheses

• Published in: Journal of physical organic chemistry Vol. 22; no. 5; pp. 550 - 558
• Main Authors: Chaouch, W., Dieval, F., Chakfe, N., Durand, B.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.05.2009
• Subjects: 1H NMR spectroscopy; chemical aging; polyethylene terephthalate; vascular prosthesis
• ISSN: 0894-3230; 1099-1395
• DOI: 10.1002/poc.1541

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 1H NMR technique to determine the hydroxyl and carboxyl end‐group concentrations. In order to validate the 1H 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 (Mν) for the explants. Copyright © 2009 John Wiley & Sons, Ltd. Ageing was investigated in terms of chemical scission caused by hydrolytic reaction. The chemical constraints after implantation modify the structure of the polymer and create a significant degradation of PET proceeded by a random scission. This is often due to the hydrolysis of the bonds connecting the polymer chain, which in turn leads to an increase of the end‐group concentrations and therefore a decrease in the macromolecular weight of the polymer.