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179 results on '"Yagoubi N"'

47. Extraction of polypropylene additives and their analysis by HPLC.

Author

Mansouri, H., Yagoubi, N., and Ferrier, D.

Abstract

The polypropylene additives were extracted by dissolution-precipitation and Soxhlet. The Soxhlet method was adapted for the extraction of phosphorous antioxidants. The RP HPLC method with quaternary gradient elution separated five chemical groups of additives: lower molecular mass di-tert-butyl phenol (D.T.B.P.), hindered amine light stabilizers (Tinuvin 326), hindered phenolic antioxidants (Irganox 1010) and phosphorous antioxidants (Irgafos 168 and Ultranox 626) with their degradation products. [ABSTRACT FROM AUTHOR]

Published
1998
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48. Plasmabased sterilization: Effect on surface and bulk properties and hydrolytic stability of reprocessed polyurethane electrophysiology catheters

Author

Lerouge, S., Guignot, C., Tabrizian, M., Ferrier, D., Yagoubi, N., and Yahia, LH.

Abstract

Plasmabased sterilization is a promising alternative to ethylene oxide EO for reprocessing of electrophysiology catheters. To assess its safety in terms of material damage, modifications of surface and bulk properties as well as hydrolytic stability of sterilized catheters were evaluated. Polyurethane PU singleuse electrophysiology catheters were subjected to one, five, and ten sterilization cycles by Sterrad100S® and Plazlyte™, as well as by pure EO for comparison. Surface analysis techniques ATRFTIR, XPS, DCA showed oxidation limited to the nearsurface layer induced by both plasmabased sterilizers, whereas EO induced slight but deeper alkylation. Using bulk analysis techniques RPHPLC, SEC, oligomer alteration was observed after all three sterilization techniques, without modification of molecular weights. Hydrolytic stability of catheters was slightly changed by plasmabased sterilization, with a small increase in released oligomers. Finally, although Plazlyte and Sterrad are both plasmabased techniques, they induced different impacts on catheters, such as the degradation of an additive with Sterrad, and a clear difference in coloration with Plazlyte. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 52, 774–782, 2000.

Published
2000
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49. Propylene oligomers: extraction methods and characterization by FTIR, HPLC, and SEC

Author

Mansouri, H. El, Yagoubi, N., Scholler, D., Feigenbaum, A., and Ferrier, D.

Abstract

Propylene oligomers were isolated from polymer matrix by dissolution precipitation and Soxhlet methods and characterized by Fourier transform infrared spectrometry, ultraviolet, high-performance liquid chromatography, and gel permeation chromatography. Both extracts showed that these hydrocarbon chemicals have a maximal absorption at 210 nm and are eluted from a C8 column with a strong mobile phase (tetrahydrofuran). However, their average molecular weights are different depending upon the quality of extraction: the fraction obtained by the dissolution-precipitation method is homogeneous in molecular weight, whereas the one obtained by Soxhlet extraction has a higher polydispersity index (Mn/Mw). The specific migration test of propylene oligomers in a food simulant (isooctane) shows total diffusion within 60 min. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 371–375, 1999

Published
1999
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