Effect of Amino alcohol functionalized polyethylene as compatibilizer for LDPE/EVA/clay/flame-retardant nanocomposites

• We evaluated the synergistic effect of MMT clay and nano-metallic hydroxides for wire coating applications.
• We analyzed the using of a new type of polymer-inorganic compatibilizer.
• We proposed a new flame-retardant mechanism for polymer blends/Clay/MH nanocomposites.

The synergistic effect of organo-modified montmorillonite (Nanomer I28E and Cloisite 20A) and metal hydroxides (magnesium hydroxide MH and alumina trihydrate ATH) as flame retardants in LDPE/EVA nanocomposites compatibilized with amino alcohol grafted polyethylene (PEgDMAE) was studied. Morphological characterization of nanocomposites was carried out by means of X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). Flame-retardant properties of nanocomposites were evaluated by the UL-94 horizontal burning and cone calorimeter tests and limiting oxygen index (LOI). Thermal degradation behavior was analyzed with a Fourier transform infrared coupled with the thermogravimetric analyzer (TG-FTIR). The XRD analysis showed a displacement of the d001 plane characteristic peak of clay to lower angles, which indicates an intercalated–exfoliated morphology. From STEM images it was observed a good dispersion of flame retardants (MH and ATH) throughout the polymer matrix which was reflected in flame-retardant properties. TG-FTIR showed a better thermal stability of nanocomposites and the gases evolved during combustion showed an important reduction. Based on thermal stability and thermal degradation results, the flame-retardant mechanism of LDPE/PEgDMAE/EVA/Clay/MH nanocomposites was proposed.