Layer-by-Layer Assembly of Multifunctional Flame Retardant Based on Brucite, 3-Aminopropyltriethoxysilane, and Alginate and Its Applications in Ethylene-Vinyl Acetate Resin

Abstract

An efficient and multifunctional brucite/3-aminopropyltriethoxysilane (APTES)/nickel alginate/APTES (B/A/Nia/A) hybrid flame retardant was fabricated via the layer-by-layer assembly technique with brucite, silane coupling agents, nickel chloride, and sodium alginate. The morphology, chemical composition, and structure of the hybrid flame retardant were characterized. The results confirmed the multilayer structure and indicated that the assembled driving forces were electrostatic interactions, dehydration condensation, hydrogen bonds, and coordination bonds. When used in ethylene-vinyl acetate (EVA) resin, the multifunctional flame retardant had better performance than brucite in improving the flame retardancy, smoke suppression, and mechanical properties. With 130 phr loading, the multifunctional flame retardant achieved a limiting oxygen index value of 32.3% and a UL 94 V-0 rating, whereas the brucite achieved only 31.1% and a V-2 rating, respectively. The peak heat release rate and total heat released decreased by 41.5% and 8.9%, respectively. The multifunctional flame retardant had an excellent performance in reducing the smoke, CO, and CO2 production rates. These improvements could be attributed to the catalyzing carbonization of nickel compounds and the formation of more protective char layers. Moreover, the elongation at break increased by 97.5%, which benefited from the improved compatibility and the sacrificial bonds in the nickel alginate. The mechanism of flame retardant, smoke suppression, and toughening is proposed.

Bio‐based Mg(OH)2@M‐Phyt: improving the flame‐retardant and mechanical properties of flexible poly(vinyl chloride)

“…To determine the chemical bonding state of oxygen atoms, the O 1s peaks were deconvoluted. For MH, there are two mixed O 1s peaks at 530.9 eV and 531.9 eV, which are attributed to oxygen Mg–O and –OH . In comparison, three new peaks of 532.1, 530.9 and 530.2 eV appearing in M‐Phyt (M ≡ Cu, Zn) are associated with the bindings of P–O–M (M ≡ Cu, Zn), Mg–O and P–O–C, respectively .…”

“…(a), it appears that the samples contain Mg, Si, C and O elements. The photoelectron peaks located at 305.4 and 532.8 eV correspond to Mg and O with reference to the C 1s transition at 284.6 eV . To determine the chemical bonding state of oxygen atoms, the O 1s peaks were deconvoluted.…”

“…The combination of MH with other types of flame retardants can improve its efficiency, but the mechanical properties are still poor . Usually, modifications using low molecular weight coupling agents are employed to improve the flame‐retardant efficiency and enhance the interfacial interaction; however, coupling agents have a migration tendency. Superfine/nanotechnology can improve the dispersibility and efficiency of flame retardants, but it cannot fundamentally change the surface energy of the MH, thereby affecting compatibility between the flame retardants and PVC and the processing behavior .…”

Effect of natural basalt fiber for EVA composites with nickel alginate‐brucite based flame retardant on improving fire safety and mechanical properties

“…In particular, natural brucite, as a unique mineral that contains more than 94 wt% MH, can be used as economic FR directly . However, state‐of‐the‐art of the poor dispersion and interfacial interaction between brucite and EVA matrix lead to forced high loading (more than 60 wt%) to meet the desired flame‐retardant demands, and then resulted in bad mechanical properties and processing properties of the resulting materials . Limited by the chemical composition and flame‐retardant mechanism of brucite (mainly Mg (OH) 2 ), the effect‐raising study of brucite should major in promoting interfacial compatibility with polymer matrix and charring effect in condensed phase during combustion …”

“…Among these agents, silane coupling agents for improving compatibility and transition metals for promoting charring effect have been widely concerned . In our past studies, several metal alginates and silane coupling agents have been layer‐by‐layer deposited onto brucite particles, which enhanced both charring effect and the interfacial interaction with polymers . Among these FRs, the nickel alginate‐brucite based NiFR exerted highest efficiency in promoting charring when used in EVA composites .…”