Flame retardancy of organic-anion-intercalated layered double hydroxides in ethylene vinyl acetate copolymer

In this study, two layered double hydroxides (LDHs), ZnAl-LDH, and MgAl-LDH, were combined with intumescent flame retardant (IFR) consisting of ammonium polyphosphate and tris (2-hydroxyethyl) isocyanurate to prepare flame retardant high density polyethylene composites. The thermal and flame retardant properties of these composites were investigated by thermogravimetric analysis, limiting oxygen index measurement, and cone calorimetry, while the morphology and chemical structure of the char residue were analyzed by scanning electron microscopy, Fourier transfer infrared spectroscopy, and laser Raman spectroscopy. The results showed that the peak heat release rate (PHRR) of both HD/IFR/Zn-LDH and HD/IFR/Mg-LDH composites was 52.0% and 12.0% lower than that of HD and HD/IFR, respectively, suggesting that there was no difference in the reduction of PHRR between the two LDHs. The use of LDHs resulted in the formation of compact char residue with a high graphitic degree, but no significant increase in tensile strength.

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“…The planes are also observed at higher 2θ values. [35][36][37] Similarly, the basal diffraction peaks of ZnAl-LDH are observed at 11.6 and 23.4…”

Section: Measurement and Characterizationsmentioning

confidence: 99%

Effects of layered double hydroxides on the thermal and flame retardant properties of intumescent flame retardant high density polyethylene composites

Khanal

Jin

et al. 2021

Fire and Materials

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“…Various types of anions can be intercalated in its interlayer space. It has been extensively reported by both inorganic [11,12] and organic [13,14] chemistry researchers. The ability of LDH to intercalate anions makes them useful as catalysts, anion exchangers, and adsorbents.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Desorption Mechanisms of Rare Earth Elements (REEs) by Layered Double Hydroxide (LDH) Modified with Chelating Agents

et al. 2019

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In order to obtain the adsorption mechanism and adsorption structures of Rare Earth Elements (REEs) ions adsorbed onto layered double hydroxides (LDH), the adsorption performance of LDH and ethylenediaminetetraacetic acid (EDTA) intercalated LDH for REEs was investigated by batch experiments and regeneration studies. In addition to adsorption capacity, the partition coefficient (PC) was also evaluated to assess their true performance metrics. The adsorption capacity of LDH increases from 24.9 μg·g−1 to 145 μg·g−1 for Eu, and from 20.8 μg·g−1 to 124 μg·g−1 for La by intercalating EDTA in this work; and PC increases from 45.5 μg·g−1·uM−1 to 834 μg·g−1·uM−1 for Eu, and from 33.6 μg·g−1·μM−1 to 405 μg·g−1·μM−1 for La. Comparison of the data indicates that the adsorption affinity of EDTA-intercalated LDH is better than that of precursor LDH no matter whether the concept of adsorption capacity or that of the PC was used. The prepared adsorbent was characterized by XRD, SEM-EDS and FT-IR techniques. Moreover, quantum chemistry calculations were also performed using the GAUSSIAN09 program package. In this calculation, the molecular locally stable state structures were optimized by density functional theory (DFT). Both the quantum chemistry calculations and the experimental data showed that REEs ions adsorbed by EDTA-intercalated LDH are more stable than those adsorbed by precursor LDH. Furthermore, the calculation results of adsorption and desorption rates show that adsorption rates are larger for Eu(III) than for La(III), which agrees with the experimental result that Eu(III) has a higher adsorption ability under the same conditions. The LDHs synthesized in this work have a high affinity for removing REEs ions.

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“…10,11 Many researchers have focused on the modification of LDHs to promote its dispersion in the polymer matrix by changing the surface energy of LDHs or expanding its interlayer distance. [12][13][14] And expanding its interlayer distance by flame retardant materials such as ferrocene, polyborosiloxane and alginate, is a commonly used modification method. Because the flame retardant modifier can achieve synergistic flame retardant effect with LDHs.…”

Section: Introductionmentioning

confidence: 99%

“…The non‐homogeneously dispersed LDHs not only reduces the flame retardant efficiency, but also deteriorates the mechanical properties of the polymers 10,11 . Many researchers have focused on the modification of LDHs to promote its dispersion in the polymer matrix by changing the surface energy of LDHs or expanding its interlayer distance 12–14 . And expanding its interlayer distance by flame retardant materials such as ferrocene, polyborosiloxane and alginate, is a commonly used modification method.…”

Section: Introductionmentioning

confidence: 99%

Flame retardancy of carboxylated polyhedral oligosilsesquioxane modified layered double hydroxide in the process of leather fatliquoring

Lyu

Kou

Gao

et al. 2022

J of Applied Polymer Sci

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Carboxyl polyhedral oligomeric silsesquioxane(P[POSS‐MAA]) modified layered double hydroxides (LDHs) (P[POSS‐MAA]‐LDHs) was prepared by exfoliating and recombination method, which used P(POSS‐MAA) and LDHs attracted each other through electrostatic force and hydrogen bond. The structure and morphology of P(POSS‐MAA)‐LDHs were characterized by X‐ray diffraction and transmission electron microscope, which showed that LDHs was exfoliated and P(POSS‐MAA) was on the surface of LDHs. Then it was introduced into the modified zanthoxylum bungeanum seed oil(MZBMSO) to obtain MZBMSO/P(POSS‐MAA)‐LDHs and applied it in leather fatliquoring process. The effect of the introduction of P(POSS‐MAA)‐LDHs on the flame retardancy, thermal stability, thermal insulation and smoke suppression of leather was investigated. Compared to the MZBMSO treated leather, the after flame time of MZBMSO/P(POSS‐MAA)‐LDHs treated leather decreased from 84 s to 32 s, and the limiting oxygen index increased from 23.1% to 27.5%, which exhibited improvement on flame retardancy of the leather. The temperature at 50% mass loss of MZBMSO/P(POSS‐MAA)‐LDHs treated leather increased from 375.1 to 408.3°C, which showed improvement on thermal stability of the leather. And the leather treated by MZBMSO/P(POSS‐MAA)‐LDHs had reduction of the total heat release and the total smoke production around 26.8% and 65.7%, respectively, which showed that MZBMSO/P(POSS‐MAA)‐LDHs treated leather had heat insulation and smoke suppression. Flame retardant mechanism of MZBMSO/(P(POSS‐MAA)‐LDHs) treated leather involved a combination of the gaseous phase and condensed phase flame retardancy. This work provided a new material for the flame retardant field and expanded the application range of polyhedral oligomeric silsesquioxane(POSS).

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Flame retardancy of organic-anion-intercalated layered double hydroxides in ethylene vinyl acetate copolymer

Cited by 16 publications

References 37 publications

Effects of layered double hydroxides on the thermal and flame retardant properties of intumescent flame retardant high density polyethylene composites

Effects of layered double hydroxides on the thermal and flame retardant properties of intumescent flame retardant high density polyethylene composites

Adsorption and Desorption Mechanisms of Rare Earth Elements (REEs) by Layered Double Hydroxide (LDH) Modified with Chelating Agents

Flame retardancy of carboxylated polyhedral oligosilsesquioxane modified layered double hydroxide in the process of leather fatliquoring

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