Enhancing Char Formation and Flame Retardancy of Ethylene-Vinyl Acetate Copolymer (EVA)/Aluminum Hydroxide (ATH) Composites by Grafting Ladder Phenyl/Vinyl Polysilsesquioxane (PhVPOSS)

Abstract

The ladder phenyl/vinyl polysilsesquioxane (PhVPOSS) was used to improve the flame-retardancy performances of ethylene-vinyl acetate copolymer (EVA)/aluminum hydroxide (ATH) composites due to the reactivity of its vinyl groups. FTIR, XPS, 1H NMR, and SEM-EDS data demonstrated the PhVPOSS grafting onto EVA molecular chains. The PhVPOSS improved the thermal stability of EVA/ATH composites, as shown by the thermogravimetric analysis (TGA). Furthermore, with the cone calorimeter (CONE) experiments, EVA/ATH/PhVPOSS showed better fire safety than the EVA/ATH composites, with the PHRR, PSPR, and PCOP reduced by 7.89%, 57.4%, and 90.9%, respectively. The mechanism investigations of flame retardancy revealed that the charring behaviors of the EVA/ATH/PhVPOSS composites were improved by the formation of Si-C bonds and Si-O bonds, and a more compact and denser char layer can contribute more to the barrier effect.

Synergistic effect of modified anhydrous magnesium carbonate and hexaphenoxycyclotriphosphazene on flame retardancy of ethylene-vinyl acetate copolymer

“…Therefore, in recent years, researchers have focused primarily on developing halogen-free ame retardants (HRRs) characterized by being cost-effective, non-toxic, and non-dripping. 5,8 These include phosphorusbased ame retardants (e.g., ammonium polyphosphate 9 and red phosphorus 6 ), nitrogen-based ame retardants (e.g., melamine cyanurate 10 ), silicon-based ame retardants (e.g., polyhedral oligomeric silsesquioxane 11 ), and metal hydroxides (e.g., magnesium hydroxide 5 and aluminum hydroxide 12 ). Among these, anhydrous magnesium carbonate (AMC) is recognized as a competitive halogen-free ame retardant, offering advantages including a high decomposition temperature, rapid decomposition, and high thermal stability.…”

“…, polyhedral oligomeric silsesquioxane 11 ), and metal hydroxides ( e.g. , magnesium hydroxide 5 and aluminum hydroxide 12 ). Among these, anhydrous magnesium carbonate (AMC) is recognized as a competitive halogen-free flame retardant, offering advantages including a high decomposition temperature, rapid decomposition, and high thermal stability.…”

Recent progress in ladder-like polysilsesquioxane: synthesis and applications

“…LPSQ's distinctive polymeric structure addresses some of the limitations associated with POSS, including aggregation, low solubility, and low molecular weight. 82,83 Based on these advantages, researchers have employed LPSQ as an additive or filler in polymer resins to enhance mechanical properties 84–87 and impart specific functionalities. 88–92 LPSQ is currently under active investigation as a base material for use in applications where POSS has encountered challenges, such as in hard coatings with various functionalities, 93–97 gate dielectrics, 82,98–101 battery separators, 102–104 ionic liquid gelators, 34,105,106 and gas separation membranes, 107–109 thereby broadening the range of applications of silsesquioxanes (Fig.…”