Dynamic mechanical analysis and Vickers micro hardness correlation for polymer coating UV ageing characterisation

摘要

The aim of this study is to investigate UV ageing of a paint system by means of two types of mechanical analysis. In a first step, UV irradiation was studied by investigating the glass transition temperature (T_α) of each coat. A new method based on dynamic mechanical analysis (DMA) was studied using a single cantilever test. We can observe that the surface coat is aged, whereas the primer layer is not affected. A simple equation is proposed to correlate this kind of evolution versus exposure time. In a second step, the UV ageing was studied by Vickers micro hardness (H_ν) test. Hardness of the surface coat increases with exposure time. This evolution versus time is controlled by the same relationship as before. In this way, we have shown that a linear correlation can be drawn between T_α results and micro hardness measurements : H_ν = A. T_α + B.