Effects of poly(dimethylsiloxane) and inorganic fillers in halogen free flame retardant poly(ethylene-co-vinyl acetate) compound: A chemometric approach

A quaternary system based on poly(ethylene-co-vinyl acetate) has been studied by Mixture Design in order to analyse the effect of additives on flame retardant properties. The FR components of the system are magnesium hydroxide (MDH), a silicon additive (Sil) based on poly(dimethylsiloxane) and a calcium borate additive (CaB). Many parameters from different flame retardant tests (LOI, UL94-V, DIN 4102 B2 and Cone Calorimeter) are selected as experimental responses and mathematical models with good quality are obtained for most of them. Principal Components Analysis (PCA) on flame retardant parameters points out no particular strong correlations among the three FR tests. The Experimental Design (DoE) approach allows minimization of the number of experiments and analysis of the influence of each component and of the interactions among them. Sil additive shows positive effects on LOI results and in the heat release rate and the fillers, mostly MDH, have positive influence on Cone Calorimeter and vertical burning test performance. Two optimal formulations have been obtained with improved stability of the residue together with LOI value in one case and Cone Calorimeter performance in the other case.