Enhancement of an organic-metallic hybrid charring agent on flame retardancy of ethylene-vinyl acetate copolymer.

Bo Xu,Lijun Qian,Lushan Shao,Wen Ma,Yong Qiu

doi:10.1098/rsos.181413

Bo Xu, Lijun Qian + Show 3 more

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https://doi.org/10.1098/rsos.181413

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Abstract

An organic triazine charring agent hybrid with zinc oxide (OTCA@ZnO) was prepared and well characterized through Fourier transform infrared spectrometry (FTIR), solid-state nuclear magnetic resonance (SSNMR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The flame retardancy and thermal behaviour of intumescent flame retardant ethylene-vinyl acetate (EVA) composites combining OTCA@ZnO and ammonium polyphosphate (APP) were investigated using limited oxygen index (LOI), UL-94 vertical burning, cone calorimetry and TGA. The structure and morphology of chars were investigated by scanning electron microscopy (SEM), FTIR, laser Raman spectroscopy analysis (LRS) and X-ray photoelectron spectroscopy (XPS). Results revealed that OTCA@ZnO exhibited excellent thermal stability and dispersity after hybridization. The flame retardancy and smoke suppression properties of EVA were significantly improved by introducing APP/OTCA@ZnO. TGA results indicated that APP/OTCA@ZnO presented an excellent synergistic effect and promoted the char formation of EVA composites. Residue analysis results showed more char with high quality connected by richer P–O–C, P–N and P–O–Si structures was formed in APP/OTCA@ZnO system than APP/HOTCA/ZnO system, which consequently suppressed more efficiently the combustion and smoke production due to the in situ catalytic carbonization effect of hybrid.

Highlights

An organic triazine charring agent hybrid with zinc oxide (OTCA@ZnO) was prepared and well characterized through Fourier transform infrared spectrometry (FTIR), solid-state nuclear magnetic resonance (SSNMR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA)
Residue analysis results showed more char with high quality connected by richer P–O –C, P–N and P –O– Si structures was formed in ammonium polyphosphate (APP)/OTCA@ZnO system than APP/ HOTCA/ZnO system, which suppressed more efficiently the combustion and smoke production due to the in situ catalytic carbonization effect of hybrid
Sheng et al [17] investigated the comZnO, nano-ZnO, zeolite 4A and Al(H2PO2)3 as synergistic agents combined with intumescent flame retardants (IFRs) in PP, and Wu & Yang [18] investigated some transition metal oxides like MnO2, ZnO and Ni2O3, which were applied into PP/IFR system

Summary

Introduction

An organic triazine charring agent hybrid with zinc oxide (OTCA@ZnO) was prepared and well characterized through Fourier transform infrared spectrometry (FTIR), solid-state nuclear magnetic resonance (SSNMR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Qian et al [5] prepared the ethylene-vinyl acetate/layered double hydroxides/zinc borate (EVA/LDHs/ZB) composite, and found the ternary composites possessed a higher thermal stability than the EVA/LDH composites Among these halogen-free flame retardants, intumescent flame retardants (IFRs) with the advantages of non-toxicity, environmental and low smoke have become one of the best candidates in flame retardant polymer fields in recent years [6,7]. Sheng et al [17] investigated the comZnO, nano-ZnO, zeolite 4A and Al(H2PO2) as synergistic agents combined with IFR in PP, and Wu & Yang [18] investigated some transition metal oxides like MnO2, ZnO and Ni2O3, which were applied into PP/IFR system The results indicated it was the interaction between APP and metal oxides that enhanced the flame retardant properties of polymer. The organic surface modification of metal oxides, especially employing those modifiers with fire resistance, may be a prospective method, which would settle the above matters, and bring more efficient synergistic effect of metal oxides within one compound unit with flame retardants

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