A non-destructive study on the degradation of polymer coating II: Modelling of degradation depth profiles

A previous paper reported the development and application of novel step-scan photoacoustic fourier transform infrared spectroscopy (SSPA-FTIR) and confocal Raman microscopy (CRM) quantification methods in polymer coating degradation depth profile study [1]. The degradation trends obtained using the two techniques are consistent and suggest the coating surface is more likely to undergo accelerated degradation. A degradation mechanism was also proposed. Moreover, the difference in signal origins of the two techniques was also explained. It was then concluded that CRM has higher depth resolution than SSPA-FTIR in depth profiling polymer coating. Although the CRM quantification method developed in the previous paper is suitable for monitoring the degradation depth profile in polymeric coatings with high depth resolution, data collection at individual sampling depth is time consuming. This paper introduces a model that can be used to predict degradation depth profile in the polymer coating with over 60% reduction in CRM data collection.