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Weichmacherverlust bei PVC-Objekten von Joseph Beuys – Versuche zu kurativen und konservatorischen Massnahmen
ANHANG III: ZUSAMMENSTELLUNG VON ABSTRACTS
Substitution
Lakshmi, S.; Jayakrishnan, A. (2003): Properties and performance of sulfide-substituted plasticized
poly(vinyl chloride) as a biomaterial. In: Journal of Biomedical Materials Research, Volume 65B, Issue 1, Date:
15 April 2003, S. 204-210
Plasticized poly(vinyl chloride) (PVC) was surface modified by nucleophilic substitution of the chlorine atoms of PVC
by sulfide ions in aqueous media in the presence of a phase-transfer catalyst (PTC) to make it migration resistant.
The modified PVC was sterilized by steam autoclaving and gamma radiation and subjected to plasticizer extraction in
an extraction medium such as hexane. Virtually no plasticizer migrated out of modified PVC into the medium even
after prolonged incubation for 30 d. The properties of the modified surface were evaluated by contact angle
measurements, scanning electron microscopy (SEM), cell-culture studies, hemolysis assay, and whole-blood clotting
time measurements. The mechanical properties of modified sheets were evaluated by measurements of tensile
strength and strain at break after subjecting the specimens to different modes of sterilization. The modified PVC
surface showed enhanced wettability and was found to be non-hemolytic and non-cytotoxic. Whole-blood clotting
profiles of unmodified and modified PVC were virtually the same. Modification imparted slight yellow color to the
material. Surface modification resulted in an 8% decrease in the ultimate stress and 28% decrease in the strain at
break values. The sulfide-substituted PVC was found to be blood compatible and would be useful in applications
such as tubing for transfusion, dialysis etc., where migration resistance is important.
Reyes-Labarta, Juan; Herrero, Miguel; Tiemblo, Pilar; Mijangos, Carmen; Reinecke, Helmut (2003): Wetchemical
surface modification of plasticized PVC. Characterization by FTIR-ATR and Raman microscopy. In:
Polymer, vol. 44, issue 8, April 2003, S. 2263-2269
The chemical modification of plasticized PVC films with amino thiophenol in mixtures of DMF/H20 has been studied.
The degree of modification and the distribution of modified groups within the films were determined using Raman
spectroscopy and FTIR-ATR. The amounts of plasticizer (bis-2-ethylhexyl phtalate, DOP) bleached out during the
reaction and the amount of dimethylformamide (DMF) penetrated into the film were analysed in control reactions
without the reactant using 1H NMR spectroscopy and Raman spectroscopy.
Reaction kinetics and surface selectivity of the modification reaction were compared with the corresponding
reactions of PVC films without plasticizer.
Lakshmi, S.; Jayakrishnan, A. (2002): Iodination of plasticized poly(vinyl chloride) in aqueous media via
phase transfer catalysis. In: Journal of Applied Polymer Science, Volume 84, Issue 3, Date: 18 April 2002, S.
493-499
Nucleophilic substitution of chlorine on plasticized poly(vinyl chloride) (PVC) was carried out using potassium iodide
(KI) in the presence of a phase transfer catalyst (PTC) in aqueous media. Iodination was confirmed using energy
dispersive X-ray analysis (EDAX). The extent of iodination was studied with respect to time, temperature,
concentration of the reactants, as well as different PTCs. Among the different PTCs examined, tetrabutylammonium
bromide (TBAB) and tetrabutylammonium hydrogen sulfate (TBAH) were found to be highly efficient for the reaction.
About 25% increase in weight was observed for PVC sheets iodinated under optimal reaction conditions. The
thermal stability of the modified PVC was found to be impaired upon iodination. The iodinated PVC released iodide
ions when kept in distilled water, as evidenced by UV spectroscopy. Sustained release of iodide ion in distilled water
was followed up for about 30 days. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 493-499, 2002; DOI
10.1002/app.10176