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Weichmacherverlust bei PVC-Objekten von Joseph Beuys – Versuche zu kurativen und konservatorischen Massnahmen
ANHANG III: ZUSAMMENSTELLUNG VON ABSTRACTS
Rodríguez-Fernández, O. S.; Gilbert, M. (1997): Aminosilane grafting of plasticized poly(vinyl chloride) I.
Extent and rate of crosslinking. In: Journal of Applied Polymer Science, Vol. 66, Issue 11, S. 2111-2119
The grafting of poly(vinyl chloride) (PVC) by reactive aminosilane compounds, which make them moisture-curable, has
been investigated. Plasticized poly-(vinyl chloride) has been successfully grafted with aminosilane during extrusion. The
grafted polymer was crosslinked in the presence of moisture. Although the hydrolysis and condensation of the
crosslinking agent is very rapid, the speed of the reaction is controlled by the rather slow diffusion of water in the
plasticized PVC. This water diffusion speed follows Fick's Law and is strongly dependent on temperature. To achieve
a high crosslinking speed, the extruded PVC has to be placed in warm water or in a steam heated vessel. The effects
of catalyst concentration, moisture concentration, and immersion time and temperature on the rate and degree of
crosslinking were investigated. Since the formulation used contained a tin stabilizer, the addition of a tin catalyst to
the immersion water had little effect. Crosslinking did occur in samples stored at room temperature due to the
presence of moisture, but the reaction rate was increased substantially if the sample was immersed in water.
Reaction rate was very temperature dependent and followed an Arrhenius relationship.
Ikada, Y. (1994): Surface modification of polymers for medical applications. In: Biomaterials, Vo. 15, Issue
10, S. 725-736
(...) This review article focuses on the surface modification of polymers by grafting techniques, which have long been
known in polymer chemistry but are not yet widely applied to biomaterials. A grafted surface can be produced
primarily either by graft polymerization of monomers or covalent coupling reaction of existing polymer molecules onto
the substrate polymer surface. The major surface properties that should be modified include two kinds of
biocompatibility. One is the surface property that elicits the least foreign-body reactions and the other is the cell- and
tissuebonding capability. In addition, physiologically active surfaces with, for instance, selective adsorbability may be
required. Attempts to produce these biocompatible or biospecific surfaces by grafting techniques are briefly
overviewed in this article.
Krishnan, V. Kalliyana; Jayakrishnan A.; Francis, Joseph D. (1991): Radiation grafting of hydrophilic monomers on to
plasticized poly (vinyl chloride) sheets : II. Migration behaviour of the plasticizer from N-vinyl pyrrolidone grafted
sheets. In: Biomaterials, Volume 12, Issue 5 , July 1991, S. 489-492
The grafting of N-vinyl pyrrolidone, a hydrophilic monomer, on to flexible poly(vinyl chloride) sheets used in medical
applications using ionizing radiation from a 60Co source was studied. The graft yield was found to increase linearly
with monomer concentration and also with increasing radiation doses. The migration of the plasticizer di-(2-
ethylhexyl)phthalate into a strong organic extractant such as n-hexane was studied at different time intervals for
different grafted systems of poly(viny) chloride) at 30°C. The results indicated a drastic reduction in the leaching of the
plasticizer from grafted systems versus ungrafted controls. Incorporation of ethylene dimethacrylate cross-linker
during grafting did not seem to affect the graft yield considerably but appeared to further reduce the plasticizer
migration. Surface energy calculations of the grafted samples indicate that the surfaces are highly hydrophilic
compared to ungrafted poly(viny) chloride) and the polar and dispersion components tend to vary with increasing
cross-linker concentration.