Prediction of the thermal degradation–induced colour change of acrylonitrile butadiene styrene products as a function of temperature and titanium dioxide content

In this study, we examined the thermal degradation–induced colour change of acrylonitrile butadiene styrene (ABS)–based titanium dioxide (TiO₂)–doped products as a function of TiO₂ content and temperature. Based on the time–temperature superposition (tTS) principle and the CIELAB colour space, we proposed a methodology for developing a robust model to estimate the long-term colour change of polymers doped with TiO₂ at elevated temperatures. We used 800 h of measurement data to develop the model and validated the colour change predictions of the model in 1600 h. The average colour difference between the measured and modelled results at the application temperature range (below 80 °C) was <1.5, smaller than the just noticeable difference (JND) in the CIELAB colour space. We found that above a certain TiO₂ content (approximately 3 wt%), the colour retention of the ABS/TiO₂ specimens can no longer be improved by increasing their TiO₂ content. To show the applicability of the model, we present two simple case studies predicting the colour and appearance of a polymer product under constant and variable heat loads. The proposed methodology provides an excellent tool for design, as it can be used to determine the optimum amount of TiO₂. Moreover, it accelerates and simplifies the design process.