Application of functional ANOVA to the study of thermal stability of micro–nano silica epoxy composites

The main purpose of this work is to use a new technique that combines functional data analysis and design of experiments, functional ANOVA for a one way treatment, to measure the influence of adding fumed silica on the thermal degradation of an epoxy resin. To achieve this, a design of experiments with a treatment factor (the amount of fumed silica) at three different levels (0, 10 and 20 wt.%) is performed. The data are obtained through the use of Thermogravimetric Analysis (TG), resulting in five degradation curves per level. The functional ANOVA uses all the information of each curve or functional data. The results obtained using this methodology with the TG rescaled data and their derivatives (DTG) indicate that the amount of fumed silica significantly affects the thermal stability of the compound. These facts may be indicative of the interaction between the organic phase and the inorganic particles. In addition, pairwise comparisons using the functional ANOVA method and a bootstrap distance based test are carried out to discern which factor levels provide different ways of degradation.