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The aim of this project was to characterise and assess the
relative significance of the physical, chemical and microbial
changes that lead to failure of exterior wood coatings. The
overall objectives were to establish the mechanism of breakdown;
to produce guidelines for the development of wood coating systems
of enhanced durability; to disseminate the information obtained
and to encourage its commercial exploitation.
The work was based on a number of natural exposure trials
supplemented by appropriate laboratory - based investigations,
some of which involved accelerated weathering. The exposure
trials used a selection of model wood coatings which were
selected to be representative of those in current use. Natural
exposure of the model coatings was followed by laboratory - based
investigations of the degree of degradation produced. The results
were then used as the basis on which to reformulate the coatings
with the aim of improving durability. The reformulated coatings
were subsequently exposed and evaluated.
The reformulated coatings were assessed after twelve months
natural exposure and the results compared with those obtained
from controls exposed under the same conditions. In every case
the performance of the PRA reformulated coatings was comparable
with or better than the commercial coatings used as controls.
Ten guidelines were put forward for the formulation of wood
coatings with enhanced durability and attention is drawn to four
areas where there is thought to be need for further research. All
the test panels remained on exposure after the completion of the
project and annual reports of their condition are available on
request.
Further Information
If you are interested in this, or any other project, please contact Richard Holman.
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