Enhanced thermal stability and mechanical property of EVA nanocomposites upon addition of organo-intercalated LDH nanoparticles

Lee, Ji Hee; Zhang, Wei; Ryu, Hyeon-Ju; Choi, Gun; Prakash, Nunna Guru

doi:10.1016/j.polymer.2019.06.011

Cited by 35 publications

(17 citation statements)

References 47 publications

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“…Hydrotalcite, also known as layered double hydroxide (LDH), is a typical anion clay that has been widely used in the fields of catalysis, biomedicine, energy storage, and flame retardancy. − Among them, as one of the most typical hydrotalcites, MgAl-LDH is easy to prepare and of low cost, and there are abundant CO 3 2– and H 2 O in the interlayers of MgAl-LDH, which can dilute oxygen and reduce the surface temperature of the polymers when heated. In particular, as a halogen-free, environmentally friendly, and smoke-suppressing FR, MgAl-LDH has greatly attracted the interest of researchers. − Nevertheless, the agglomeration phenomenon of pristine LDH prevented it from being well dispersed in the polymer matrix. , Moreover, to achieve the flame-retardant rating required by the polymer, it is often necessary to add a high loading of LDH, which would seriously damage the excellent mechanical properties and processing properties of the polymer. , Consequently, seeking an innovative strategy that can not only enhance the flame retardancy of LDH but also improve its dispersion is of great significance for the flame retardancy of polymers.…”

Section: Introductionmentioning

confidence: 99%

Dual Modification of Layered Double Hydroxide by Phosphonitrilic Chloride Trimer and Aniline for Enhancing the Flame Retardancy of Polypropylene

Wang

et al. 2022

ACS Appl. Polym. Mater.

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Owing to the poor dispersion of layered double hydroxide (LDH) in a polypropylene (PP) matrix and its own flameretardant efficiency being finite, the development of high-performance PP/LDH-based composites is still a tremendous challenge. To improve the dispersion of LDH and its inherent flame retardancy, phosphonitrilic chloride trimer (HCCP) was grafted onto the surface of LDH through the bridging effect of (3-aminopropyl)triethoxysilane and then further modified with aniline to replace the chlorine element in HCCP, so a flame-retardant (LDH@HA) was successfully synthesized. The flame retardancy and smoke suppression of LDH@HA with PP composites (PP/LDH@HA) were tested with the limit oxygen index (LOI), UL-94, and cone calorimetry tests. With a loading of 20 wt % LDH@HA, the peak heat release rate, total heat release, and total smoke rate of PP/ LDH@HA composites were 300.1 kW•m −2 , 57.7 MJ•m −2 , and 697.5 m 2 •m −2 , respectively, which were decreased by 64.4, 46.4, and 49.1% in comparison to those of PP, and the LOI value of PP/LDH@HA reached 30.6% and achieved the UL-94 V-0 rating. The improvements in flame retardancy and smoke suppression were due mainly to the physical barrier effect of LDH and the catalytic carbonization effect of HCCP together with the nonflammable gases formed by the decomposition of aniline, which diluted the combustible gas concentration. Compared with PP/LDH, the optimization of the mechanical properties of composites was due mainly to the introduction of HCCP and aniline, which significantly enhanced the compatibility between LDH and PP and promoted the uniform distribution of LDH in the PP matrix. In conclusion, LDH@HA has low cost, easy fabrication, and an excellent smoke suppression effect, and the strategy provides a specific idea for the preparation of fire-resistant PP composites.

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Section: Introductionmentioning

confidence: 99%

Dual Modification of Layered Double Hydroxide by Phosphonitrilic Chloride Trimer and Aniline for Enhancing the Flame Retardancy of Polypropylene

Wang

et al. 2022

ACS Appl. Polym. Mater.

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“…However, EVA is flammable and releases CO gas during burning [2]. In recent years, layered double hydroxides (LDHs) and intumescent flame retardants (IFRs) have been used to increase the flame retardancy and smoke suppression of the EVA matrix [3,4]. The LDH is composed of positively charged brucite-like layers, meanwhile containing charge-compensating anions and water molecules in the interlayer gallery [5].…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Composite Flame Retardants for Improving the Flame Retardancy, Thermal Stability, Smoke Suppression, and Mechanical Properties of EVA

Liu

et al. 2020

Materials

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Ethylene vinyl acetate (EVA) copolymer has been used extensively in many fields. However, EVA is flammable and releases CO gas during burning. In this work, a composite flame retardant with ammonium polyphosphate (APP), a charring–foaming agent (CFA), and a layered double hydroxide (LDH) containing rare-earth elements (REEs) was obtained and used to improve the flame retardancy, thermal stability, and smoke suppression for an EVA matrix. The thermal analysis showed that the maximum thermal degradation temperature of all composites increased by more than 37 °C compared with that of pure EVA. S-LaMgAl/APP/CFA/EVA, S-CeMgAl/APP/CFA/EVA, and S-NdMgAl/APP/CFA/EVA could achieve self-extinguishing behavior according to the UL-94 tests (V-0 rating). The peak heat release rate (pk-HRR) indicated that all LDHs containing REEs obviously reduced the fire strength in comparison with S-MgAl. In particular, pk-HRR of S-LaMgAl/APP/CFA/EVA, S-CeMgAl/APP/CFA/EVA and S-NdMgAl/APP/CFA/EVA were all decreased by more than 82% in comparison with pure EVA. Furthermore, the total heat release (THR), smoke production rate (SPR), and production rate of CO (COP) also decreased significantly. The average mass loss rate (AMLR) confirmed that the flame retardant exerted an effect in the condensed phase of the composites. Meanwhile, the combination of APP, CFA, and LDH containing REEs allowed the EVA matrix to maintain good mechanical properties.

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“…As seen in Figure , all of these degradation curves included two steps. The first steps in the temperature range of 300–400 °C can be attributed to the degradation of fillers and loss of acetic acid in EVA, whereas the second steps that occur between 400 and 520 °C are considered to the degradation of ethylene-based chains and volatilization of the residual polymer. , Meanwhile, the derivative weight peak of the CFR (A5) appears near 355 °C, which is 10 and 13 °C higher than those of the PM (A4) and brucite (A2), respectively. Additionally, sample A5 exhibits the lower maximum weight loss rate of 3.01 wt %/min at 355 °C compared with A2 and A4, and its final residue is 34.61 wt % at 800 °C, which is higher than any other blends.…”

Section: Results and Discussionmentioning

confidence: 99%

Reinforcing Condensed Phase Flame Retardancy through Surface Migration of Brucite@Zinc Borate-Incorporated Systems

Chen

et al. 2020

ACS Omega

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An efficient brucite@zinc borate (3ZnO•3B 2 O 3 •3.5H 2 O) composite flame retardant (CFR), consisting of an incorporated nanostructure, is designed and synthesized via a simple and facile electrostatic adsorption route. It has been demonstrated that this incorporated system can enhance the interfacial interaction and improve the mechanical properties when used in ethylene−vinyl acetate (EVA) composites. Meanwhile, in the process of burning, the CFR particles can successively migrate and accumulate to the surface of the burning zone, increasing the local concentration and rapidly generating a compact barrier layer through a condensed phase reinforcement mechanism even at a lower loading value. Especially, compared with the EVA/physical mixture (PM, with the same proportion of brucite and zinc borate), the heat release rate (HRR), the peak of the heat release rate (PHRR), the total heat released (THR), the smoke production rate (SPR), and mass loss are considerably reduced. According to this study, controlling the nanostructure of flameretardant particles, to improve the condensed phase char layer, gives a new approach for the design of green flame retardants.

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Enhanced thermal stability and mechanical property of EVA nanocomposites upon addition of organo-intercalated LDH nanoparticles

Cited by 35 publications

References 47 publications

Dual Modification of Layered Double Hydroxide by Phosphonitrilic Chloride Trimer and Aniline for Enhancing the Flame Retardancy of Polypropylene

Dual Modification of Layered Double Hydroxide by Phosphonitrilic Chloride Trimer and Aniline for Enhancing the Flame Retardancy of Polypropylene

Highly Efficient Composite Flame Retardants for Improving the Flame Retardancy, Thermal Stability, Smoke Suppression, and Mechanical Properties of EVA

Reinforcing Condensed Phase Flame Retardancy through Surface Migration of Brucite@Zinc Borate-Incorporated Systems

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