M. Irigoyen et al., UV ageing characterisation of organic anticorrosion coatings by dynamic mechanical analysis, Vickers microhardness, and infra-red analysis, POLYM DEGR, 74(1), 2001, pp. 59-67
To monitor the UV degradation of organic anticorrosion coatings, different
kinds of information provided by different characterisation methods are com
pared. Vickers microhardness (HV) results are correlated with T-g measureme
nts, by the pin point method. This technique is investigated during UV-A ar
tificial ageing taking into account the influence of coating thickness and
mineral pigments. After verifying the high quality and accuracy of the Tg i
nformation, the HV data are corrected, to prevent distortion of the measure
ments by thickness and pigment concentration. A corrective method is discus
sed and checked. The chemical degradation and mechanisms, identified by FT-
IR spectroscopy, are also correlated to Tg changes. This has allowed us to
validate the previous method. The main interest of this study is a correlat
ion the mechanical modifications of the top-coat which are macroscopic cons
equences of the UV ageing, with photochemical degradations which directly c
orrespond to the molecular modifications induced by UV radiation. For that
the T-g measurements are of great interest. (C) 2001 Elsevier Science Ltd.
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