Basic Study on the Analysis of Synthetic Materials in Museums : PGC and THM Applied to the Characterization of Alkyd Paints Containing Synthetic Organic Pigments
Synthetic materials are now frequently used in everyday life, and it
is not rare to encounter such materials in art, ethnologic or historical
museums, not only as a part of the collection (for example, modern art
or plastic tools) , but also as a constituent of the products used for exhibition,
storage, or conservation purposes.
In this article, taking alkyd paints as an example, we have tried to improve
upon an analytical method which can procure a maximum of information
about the nature of the medium and that of the synthetic organic
pigments possibly present, from a minimally small sample. Two
chromatographic techniques were experimented with and compared:
PGC (Pyrolysis-Gas Chromatography) and THM (Thermally assisted
Hydrolysis and Methylation) .
The results showed that these two techniques complement each
other. A first analysis by PGC differentiates alkyd resins from other synthetic
or natural products, and at the same time, it can detect a number
of synthetic organic pigments (especially azo ones) . Then, a complementary
analysis by THM will give more accurate information about
the constituents of the alkyd resins, that is to say, the nature of the
polyhydric alcohol, polybasic acid, and drying oil or fatty acids. It is interesting
to note that, with both techniques, the presence of organic or inorganic
pigments does not affect the characterization of an alkyd
medium.
We expect to develop and apply, in the future, this analytical protocol
to the characterization of synthetic materials generally encountered
in museums, considering that PGC is a rapid and efficaceous method for
the characterization of thermoplastic resins and some synthetic organic
pigments, and THM for the characterization of resins which cannot be
easily analysed by PGC.
合成素材の分析・識別法に関する基礎研究 : アルキド絵具を例として
KH_022_2_001.pdf
(1.66MB)
