Relationship between appearance and protective durability and coatings:

Abstract

Research in building materials has increasingly been focused upon procedures for service life prediction. For coatings, improved service life prediction will aid in the effective selection and use of materials and in the development of cost-effective maintenance strategies. However, quantitative measures of degradation are essential in predicting service life. Standard procedures are available to quantitatively measure small changes in the appearance properties of coatings, one of the two primary functions of coatings, the other being protection. However, quantitative measurements of early changes associated with the protective function usually are not possible. Hence, the objective of this report is to ascertain, based upon the literature, whether changes in appearance properties of coatings can be used to predict changes in the protective properties of the film. It was concluded, that for the most part, changes in appearance properties are not related to changes in the protective properties of a coating film.

Degradation of rubber to metals bonds during its cathodic delamination, validation of an artificial ageing test

“…At longer immersion time, the progression of the delamination front appears to slow down. This stage was also observed by several authors on epoxy/steel systems [23,24]. This slow down can be attributed either to a potential gradient under the coating [3,9].The accumulation of degraded species on delaminated areas can indeed create an ohmic drop.…”