Flammability characterization and effects of magnesium oxide in halogen-free flame-retardant EVA blends

Zhang, Yan; Peng, Rui-qun; Zhou, G. H.; Fang, Zhengping; Li, Xiaonan

doi:10.1007/s10118-015-1722-z

Cited by 23 publications

(21 citation statements)

References 32 publications

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“…Metal hydroxides, such as aluminum [Al(OH) 3 ] and magnesium hydroxides [Mg(OH) 2 ], are commonly used as a halogen‐free fire retardants [7]. But they need to be incorporated in very high loadings, as high as 60 wt%, in order to achieve the required fire retardancy with the consequent reduction in the polymer mechanical properties and the increase in the polymer viscosity with the consequent difficulty in the processing of the polymer composite [8–10]. Numerous attempts have been reported trying to minimize the total hydroxide loading on the composite without sacrificing its flame‐retardant properties [11–13].…”

Section: Introductionmentioning

confidence: 99%

Organopalygorskite and Molybdenum Sulfide Combinations to Produce Mechanical and Processing Enhanced Flame‐Retardant PE/EVA Blend Composites with Low Magnesium Hydroxide Loading

Sánchez-Valdés¹,

Ramı́rez-Vargas²,

Rodríguez-González³

et al. 2020

Vinyl Additive Technology

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The effect of organopalygorskite (OPGS), molybdenum sulfide (MoS2), and magnesium hydroxide (MH) combinations on fire retardant and flammability characteristics of low‐density polyethylene/ethylene vinyl acetate (LDPE/EVA) blends was investigated using the limited oxygen index (LOI), horizontal burning test (UL‐94), and cone calorimeter measurements. The combination of OPGS with exfoliated MoS2 nanosheets is employed to reduce the conventional hydroxide content and enhance the PE/EVA blend flame‐retardant properties with a notable improvement in mechanical and processing characteristics. The flame‐retardant properties of the composites were compared with a reference PE/EVA sample with 55 wt% of MH, which is commonly used for wire coating. The effect of each additive and the use of a maleated polyethylene (PEgMA) as a compatibilizing agent on PE/EVA flame‐retardant properties were analyzed. The results of the LOI and UL‐94 tests confirmed that the addition of OPGS combined with MoS2 substantially increases the LOI value (26%) and reduces the burning rate (66%) and the pHRR (83%) compared with neat polymer blend and passes V‐0 rating during UL‐94 vertical test, which were very similar to the values obtained for the reference sample with higher MH content. In addition, the results indicate that the addition of these additives simultaneously increases the tensile modulus with mechanical properties even higher than the reference sample. Most important, the results indicated that these additive combination allows to reduce the total MH filler content to achieve the flame‐retardant requirements and with enhanced mechanical properties and with higher melt flow rates and lower viscosities facilitating the processing of the polymer composites at lower pressure in the processing extruder. Therefore, this additives combination provides a favorable way to obtain efficient flame‐retardant materials with halogen‐free, low smoke, and easy processing characteristics. J. VINYL ADDIT. TECHNOL., 26:434–442, 2020. © 2020 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Organopalygorskite and Molybdenum Sulfide Combinations to Produce Mechanical and Processing Enhanced Flame‐Retardant PE/EVA Blend Composites with Low Magnesium Hydroxide Loading

Sánchez-Valdés¹,

Ramı́rez-Vargas²,

Rodríguez-González³

et al. 2020

Vinyl Additive Technology

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“…To address the above problems, addition of small amounts of metal oxides (e.g., TiO 2 , MgO, Al 2 O 3 ) to intumescent formulations has been adopted by many 19–23 . Lewin et al 20 have suggested the formation of salt bridges between metal oxides and APP.…”

Section: Introductionmentioning

confidence: 99%

Acrylic‐based fire‐retardant coatings for steel protection: Employing the concept of in situ ceramization

Anees

Dasari

2020

J of Applied Polymer Sci

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Traditional intumescent coatings are widely used as passive fire‐protective coatings for steel structures as they are capable of expanding in the range of 20–50 times the original thickness thereby providing excellent insulation. However, the fragile nature of such residue and susceptibility to thermo‐oxidation given their carbonaceous nature are key problematic issues. The concept of in situ ceramization is explored in this work as a means to form inorganic cohesive char with improved rigidity and thermo‐oxidative stability. Coating samples were prepared by incorporating ammonium polyphosphate, talc, Mg(OH)2, and polydimethylsiloxane as additives into acrylic resin at different weight fractions. Thermal analysis and x‐ray diffraction have confirmed the reactions between the additives to form various crystalline magnesium phosphate phases, and to a small extent, silicon phosphate, thereby ensuring the thermo‐oxidative stability of the residue. This is reiterated by the fire performance tests (by exposing the coatings to a temperature profile in a furnace similar to ISO 834 fire curve). Despite the advantages of rigid char and its thermo‐oxidative stability as a result of formation of inorganic phosphates, the lack of swelling has resulted in relatively poor insulation capabilities of the char, and subsequently, compromised the fire protection times (that are in the range of 45–55 min). However, pyrolysis flow combustion calorimeter results of the coatings are promising and have shown a significant drop of up to 70% in the peak of heat release rate values as compared to neat resin.

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“…For instance, some triazine‐based macromolecules have been used as charring‐foaming agents (CFAs) for IFR systems, and the results show excellent flame‐retardant performance because of their remarkable charring and foaming effects of CFAs. Zhang et al found that metal compounds, such as magnesium oxide, can improve flame retardancy of APP/pentaerythritol‐based IFR system in ethylene vinyl acetate copolymer …”

Section: Introductionmentioning

confidence: 99%

Preparation of piperazine cyanurate by hydrogen‐bonding self‐assembly reaction and its application in intumescent flame‐retardant polypropylene composites

Dong

Yuan

et al. 2019

Polymers for Advanced Techs

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Piperazine cyanurate (PCA) is designed and synthesized via hydrogen-bonding selfassembly reactions between piperazine and cyanuric acid. Chemical structure and morphology of PCA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The prepared PCA is combined with ammonium polyphosphate (APP) to prepare flame-retardant polypropylene (PP) composites. Thermostability, flammability, and combustion characteristics of PP composites are analyzed. The maximum thermal decomposition rate of flameretarded PP composites has an apparent reduction compared with that of pure PP, and obvious char is left for this intumescent flame retardant (IFR) system of APP and PCA. A high limiting oxygen index value and UL-94 V-0 rating are achieved with addition of APP and PCA. In cone calorimetry test, heat and smoke releases of PP are significantly decreased by this IFR system. Gaseous decomposition products during the thermal decomposition of flame-retardant composites are studied. Chemical structure and morphology of char residues are analyzed. The results illustrate that APP and PCA have a superb synergistic action in the aspect of improvement in fire safety of PP. A possible flame-retardant mechanism is concluded to reveal the synergism between APP and PCA. K E Y W O R D S intumescent flame retardant, mechanism, polypropylene, synergism 1 | INTRODUCTION Polymeric materials, which are now universally used in many areas, have been important to modern life for many years. Polypropylene (PP) is one of the universal polymers and has many advantages, such as easy processability, corrosion resistance, and low cost. However, it is a kind of easily combustible material, which seriously restricts its applications. Because of its emission of poisonous gases while burning, PP has high fire hazard potential for human life. 1,2 Therefore, PP materials must be modified with flame-retardant additives in order to achieve desired flame-retardant performance and meet the requirements in some application fields. Currently, considerable effort has been devoted to explore methods of reducing the inflammability of PP. Various flame retardants, such as metallic hydroxide, expandable graphite, halogencontaining flame retardants, and phosphorous-containing compounds, have been successfully developed to endow PP with flame retardancy. 3 For instance, metal hydroxides, including aluminum hydroxide and magnesium hydroxide, are used in PP, but mechanical properties of PP materials are easily destroyed by high loading of fillers. 4 As a kind of halogen flame retardants, bromine-containing compound has been regarded as the most effective flame retardant for PP. 5 However, some halogen-containing flame retardants are being phased out because of their health and environmental hazards,

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Flammability characterization and effects of magnesium oxide in halogen-free flame-retardant EVA blends

Cited by 23 publications

References 32 publications

Organopalygorskite and Molybdenum Sulfide Combinations to Produce Mechanical and Processing Enhanced Flame‐Retardant PE/EVA Blend Composites with Low Magnesium Hydroxide Loading

Organopalygorskite and Molybdenum Sulfide Combinations to Produce Mechanical and Processing Enhanced Flame‐Retardant PE/EVA Blend Composites with Low Magnesium Hydroxide Loading

Acrylic‐based fire‐retardant coatings for steel protection: Employing the concept of in situ ceramization

Preparation of piperazine cyanurate by hydrogen‐bonding self‐assembly reaction and its application in intumescent flame‐retardant polypropylene composites

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