Hydroxide Flame Retardant Research Articles

Urchin-like NiCo-based bimetallic hydroxide decorated with DOPO as highly hydrophobic flame retardant for remarkably reducing fire hazard of poly (L-lactic acid)

Designing high-performance flame retardants for poly (L-lactic acid) (PLA) materials and exploring a simple and scalable strategy have been hot topics in research. In this work, a novel and highly efficient flame retardant, that is, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) decorated urchin-like NiCo-based bimetallic hydroxide (NiCo-BH@DOPO), was synthesized and incorporated into PLA to prepare PLA and NiCo-BH@DOPO (PLA/NiCo-BH@DOPO) composite. Benefiting from the DOPO organic modification, NiCo-BH@DOPO had superb hydrophobicity and presented excellent dispersion in the PLA matrix. When 20 wt% NiCo-BH@DOPO was added, the LOI value of PLA/NiCo-BH@DOPO composites reached 33.2 %, passed the V-0 level of UL-94 grade, and its maximum peak heat release rate (PHRR) and total heat release (THR) were reduced by 13.2 % and 17.3 %, respectively, compared with PLA/NiCo-BH composites. Furthermore, the residue of PLA/NiCo-BH@DOPO at 800 °C reached 19.8 wt% and the T10% (temperature at 10 % weight loss) increased by 33 °C. More importantly, the residual PLA/NiCo-BH@DOPO char exhibits a significantly reduced presence of large cracks compared to PLA/NiCo-BH, indicating a more compact formation of residual char. NiCo-BH@DOPO endowed PLA with outstanding flame retardancy, thermal stability and carbonization properties, which were owing to the multi-coordinating effect transition metal (NiCo-BH) catalyzed the char formation to form a char layer barrier and DOPO free radicals captured to inhibit the combustion reaction chain. This investigation provided a facile strategy for the novel multi-function NiCo-based bimetallic hydroxide flame retardant, expanding NiCo-BH potential applications in PLA.

Synthesis of magnesium hydroxide flame retardant based on microcrystalline magnesite and its application in epoxy resin

Abstract A nanoscale hexagonal flake magnesium hydroxide (MH) flame retardant was prepared by a hydrothermal method using Tibetan microcrystalline magnesite as the raw material. The synthesized samples were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FSEM), thermogravimetric analysis-differential scanning calorimetry (TG-DSC), and laser particle size analysis. When subjected to hydrothermal treatment at 180 °C for a duration of 8 h in a solution containing 6 mol l−1 NaOH, and with the incorporation of 4 wt% of the surfactant polyethylene glycol 2000 (PEG2000), hexagonal flake MH, possessing an average particle size of 378.3 nm, was successfully synthesized. The study conducted an examination of the thermal, mechanical, and flame-retardant properties of both EP and EP/MH composites. The results revealed that the incorporation of 9 wt% MH led to a notable reduction in the peak heat release rate, total smoke production, and mass loss rate of the EP/MH composites by 36%, 14.5%, and 33.3% respectively, as compared to the pure EP. Remarkably, the tensile and flexural strength of the composite exhibited minimal impact.

Preparation and characterization of ethylene‐propylene‐diene monomer rubber/metal hydroxide composites by electron beam irradiation

AbstractEthylene‐propylene‐diene monomer (EPDM) rubber has widespread uses in various applications due to its ozone and oxidation stability, weatherability, electrical insulation, and elasticity. However, its further use is limited by low flame retardancy and low thermal stability. This study incorporated metal hydroxide flame retardant to enhance flame retardancy and electron beam cross‐linking to simultaneously enhance mechanical properties, thermal stability, and flame retardancy. The utilization of electron beam irradiation resulted in an increase in gel content and a decrease in swelling ratio with increasing absorbed doses, indicating the successful formation of cross‐linked network structures. The hot‐set elongation was significantly reduced to 0.6%–0.8%, while the decomposition temperature increased with increasing absorbed doses, indicating improved thermal stability. The results from limiting oxygen index measurements and burning tests demonstrate that the flame retardancy of EPDM was improved by the combined effect of metal hydroxide flame retardant and electron beam cross‐linking.Highlights EPDM/metal hydroxide composites were prepared via electron beam irradiation. Metal hydroxide flame retardants were incorporated to enhance flame retardancy. EBI simultaneously enhanced mechanical property and thermal stability.

Effect of Compounded Aluminum Hydroxide Flame Retardants on the Flammability and Smoke Suppression Performance of Asphalt Binders.

Compounded aluminum hydroxide (ATH) flame retardants have been widely used for their low cost and environmentally friendly characteristics. However, previous research lacks a systematic and comprehensive comparison. In addition, the combustion characteristics and phase characterization of asphalt binders are not taken into account either. In this work, flame retardants, for instance, APP, Sb2O3, ZB, and LDHs, were compounded with ATH. The flame retardant behavior, together with the smoke suppression behavior, of asphalt binders with compounded flame retardants was determined by LOI and CCT. Furthermore, mechanisms on flame retardants were investigated. It was found that ATH compounded with ZB significantly reduced the heat smoke release and suppressed the formation of toxic volatiles during asphalt combustion. This was because ATH/ZB facilitated the formation of polyaromatic structures and improved the resistance of the char layer. ATH compounded with APP showed an antagonistic effect in the limiting oxygen test because the reaction between ATH and APP inhibited and delayed the decomposition of ATH during asphalt combustion with more aluminum phosphate presenting relatively poor barrier properties produced.

Preparation of magnesium hydroxide by modifier-directed hydration and its effect on flame retardancy and mechanical properties of polypropylene

With the rapid development of the polymer materials industry and the improvement of people's environmental awareness, magnesium hydroxide has been widely used in polymer materials due to its high decomposition temperature, non-toxic smoke suppression, and the advantages of neutralizing harmful gases produced by polymer combustion. However, the conventional preparation methods of magnesium hydroxide exhibit several issues, including high hydrophilicity, elevated polarity, and limited compatibility with polymers. This research proposes an improved method by adding sodium stearate and KH560 modifier, controlling the rate of magnesium oxide and preparing magnesium hydroxide flame retardants using a modifier-directed hydration method. Various characterizations confirmed its morphology, particle size and structure. The magnesium hydroxide exhibits low polarity, small particle size, stable structure and excellent hydrophobicity (with a contact angle of 120.32°, and a free energy of 1.34mN/m). In parallel, the magnesium hydroxide/polypropylene composites demonstrate excellent flame retardancy (LOI of 25%, V-1 grade) and simultaneously enhance the dispersion of magnesium hydroxide within the polypropylene matrix, improving the material's toughness and strength.

Analyzing Temperature Distribution Patterns on the Facing and Backside Surface: Investigating Combustion Performance of Flame-Retardant Particle Boards Using Aluminum Hypophosphite, Intumescent, and Magnesium Hydroxide Flame Retardants.

Particle boards are manufactured through a hot pressing process using wood materials (natural polymer materials) and adhesive, which find common usage in indoor decorative finishing materials. Flame-retardant particleboard, crucial for fire safety in such applications, undergoes performance analysis that includes assessing temperature distribution across its facing surface and temperature increase on the backside surface during facade combustion, yielding critical insights into fire scenario development. In this study, a compact flame spread apparatus is utilized to examine the flame retardancy and combustion behavior of particle boards, with a specific emphasis on the application of cost-effective flame retardants, encompassing aluminum hypophosphite (ALHP), an intumescent flame retardant (IFR) comprising ammonium polyphosphate (APP), melamine (MEL), and Dipentaerythritol (DPE), alongside magnesium hydroxide (MDH), and their associated combustion characteristics. The D300°C values, representing the vertical distance from the ignition point (IP) to P300°C (the temperature point at 300 °C farthest from IP), are measured using a compact temperature distribution measurement platform. For MDH/PB, APP + MEL + DPE/PB, and ALHP/PB samples, the respective D300°C values of 145.79 mm, 117.81 mm, and 118.57 mm indicate reductions of 11.11%, 28.17%, and 27.71%, compared to the untreated sample's value of 164.02 mm. The particle boards treated with ALHP, IFR, and MDH demonstrated distinct flame-retardant mechanisms. MDH/PB relied on the thermal decomposition of MDH to produce MgO and H2O for flame retardancy, while APP + MEL + DPE/PB achieved flame retardancy through a cross-linked structure with char expansion, polyphosphate, and pyrophosphate during combustion. On the other hand, ALHP/PB attained flame retardancy by reacting with wood materials and adhesives, forming a stable condensed P-N-C structure. This study serves as a performance reference for the production of cost-effective flame-resistant particleboards and offers a practical method for assessing its fire-resistant properties when used as a decorative finishing material on facades in real fire situations.

Bio-mediated MOF-derived core–shell flame retardant: Towards styrene–butadiene–styrene asphalt with enhanced flame safety and pavement performance

In order to improve the flame retardancy of magnesium hydroxide (MH) in styrene– butadiene–styrene (SBS) asphalt, two hierarchically structured bio-based flame retardants (FRs) (MH@SA-MOF and MH@SA-LDH) with MH as the core as well as metal organic framework (MOF) or derived layered double hydroxide (LDH) as the shell, were engineered via an alginate-mediated assembly and etching strategy in this study. The flame retardancy and smoke suppression properties of SBS asphalt were found to be remarkably improved by the addition of the bio-based FRs. In addition, the SBS asphalt with added MH@SA-MOF had a higher limiting oxygen index (LOI) than the SBS asphalt samples to which had been added the same amount of MH or MH@SA-LDH. The peak heat release rate (pHRR) and total heat release (THR) of the bio-based MH@SA-MOF FR asphalt (FRA) was 32.9% and 8.9% lower, respectively, than those of the MH FRA. The MH@SA-MOF and MH@SA-LDH FRs had similar impacts on the flame retardancy of SBS asphalt, but the MH@SA-LDH FR had a stronger smoke suppression effect. In addition, bio-based FRs can enhance the anti-aging and anti-deformation performance of SBS asphalt. Moreover, hierarchical catalytic charring structure was observed, suggesting application prospects in flame-retardant asphalt tunnel pavement for the new FRA designs based on bio-remediation of conventional hydroxide flame retardants.

Phosphate intercalated Mg/Al layered double hydroxide nanosheets as a novel flame retardant for leather: Synthesis, characterization, and application studies

Ammonium polyphosphate (APP) modified Mg/Al layered double hydroxide (LDH) flame retardants (FR) were synthesized by varying the APP concentration between 5 and 15% (PLDH-5, PLDH-10, PLDH-15). Synthesized PLDH (APP modified LDH) were characterized for their microstructural, physicochemical, and thermal properties. FE-SEM images of the PLDH showed agglomerated nanosheets indicating the interaction of APP with the LDH. XRD studies of the PLDH confirmed the intercalation of phosphate ions into the interlayer gallery, leading to an increase in the interlayer distance from 0.76 to 1.07 nm. Emphasis was given to the thermogravimetric (TGA/DTG) and differential scanning calorimetric (DSC) examination of the PLDH, and PLDH treated leathers to understand their thermal insight. The PLDH-treated leathers showed an increase in the thermal stability of the collagen. The endothermic dehydroxylation and decomposition observed in the DSC studies indicated the suitability of the PLDH as flame-retardant material. Application of 3% PLDH during leather making improved the flammability degree of leather by 18.2%. The synthesized PLDH exhibited equivalent or better flame retardant performance as compared to the other flame retardant chemicals reported in the literature for leather applications. The flame retardant mechanism of PLDH was also discussed.

Preparation and Sound Insulation Performance of Polystyrene Building Flame Retardant and Thermal Insulation Building Materials.

In this study, magnesium hydroxide (MH) was modified by sodium dodecylbenzene sulfonate (SDBS) to prepare modified magnesium hydroxide (MMH) flame retardant, which was mixed with polystyrene (PS) to obtain flame retardant PS composite plate. The micromorphology, mechanical properties, thermal stability, and flame retardancy of flame retardant PS composite plate were analyzed. The experimental results show that MMH is well dispersed in PS matrix, PS-MMH-3 has the best tensile strength and elongation at break, the limit oxygen index (LOI) is 44.3% higher than that of pure PS, and the combustion rate is slow, indicating that PS-MMH-3 has good flame retardant properties.

Flammability, morphological and mechanical properties of sugar palm fiber/polyester yarn-reinforced epoxy hybrid biocomposites with magnesium hydroxide flame retardant filler

This paper aims to study the surface morphology, flammability and tensile properties of sugar palm fiber (SPF) hybrid with polyester (PET) yarn-reinforced epoxy composite with the addition of magnesium hydroxide (Mg(OH)2) as a flame retardant. The composites were prepared by hybridized epoxy and Mg(OH)2/PET with different amounts of SPF contents (0%, 20%, 35% and 50%) using the cold press method. Then these composites were tested by horizontal burning analysis, tensile strength testing and scanning electron microscopy (SEM) analysis. The specimen with 35% SPF (Epoxy/PET/SPF-35) with the incorporation of Mg(OH)2 as a flame retardant showed the lowest burning rate of 13.25 mm/min. The flame took a longer time to propagate along with the Epoxy/PET/SPF-35 specimen and at the same time producing char. Epoxy/PET/SPF-35 also had the highest tensile strength of 9.69 MPa. Tensile properties of the SPF hybrid with PET yarn (SPF/PET)-reinforced epoxy composite was decreased at 50% SPF content due to the lack of interfacial bonding between the fibers and matrix. Surface morphology analysis through SEM showed uniform distribution of the SPF and matrix with less adhesion, which increased the flammability and reduced the tensile properties of the hybrid polymeric composites. These composites have potential to be utilized in various applications, such as automotive components, building materials and in the aerospace industry.

Renewable lignin-based surfactant modified layered double hydroxide and its application in polypropylene as flame retardant and smoke suppression

A novel and environmentally friendly lignin-based surfactant sodium lignosulfonate (SLS) modified layered double hydroxide (LDH) flame retardant (LDH-LS) was fabricated via co-precipitation method, and subsequently incorporated into polypropylene (PP) matrix to obtain the PP and LDH-LS composites (PP/LDH-LS) by melt blending method. The XRD, FT-IR and XPS results indicated that SLS had successfully modified LDH by adsorbing on the surface of the LDH nanosheet. The WCA and SEM results revealed that the hydrophobic property of LDH-LS had been evidently improved, and it displayed a more homogeneous dispersion than virgin LDH in the PP matrix. Furthermore, cone calorimetry tests (CCT) illustrated that the peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of PP/LDH-LS composites exhibited declines of 62.9%, 25.1%, and 43.3% compared with those of Neat PP, respectively. Besides, the PP/LDH-LS achieved a LOI value of 29.4% and a UL-94 V-0 rating, whereas the PP/LDH showed only a LOI value of 25.2% and a UL-94 V-2 rating at 20 wt% loading. These improvements of flame retardant properties can be attributed to that the well-dispersed LDH-LS and synergistic flame retardancy between LDH and SLS.

Magnesium hydroxide nanoparticles grafted by DOPO and its flame retardancy in ethylene‐vinyl acetate copolymers

AbstractMagnesium hydroxide (MH) nanoparticles have been considered as an excellent nonhalogen flame‐retardant. However, the drawbacks of easy aggregation and relatively low flame retardancy limit their applications in polymer materials. In this research, MH nanoparticles were successfully grafted by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) through the bridge of vinyl silane coupling agents (WD70). The grafted MH nanoparticles (MH‐WD70‐DOPO) were characterized by Fourier transform infrared spectra, 31P nuclear magnetic resonance spectra, thermogravimetric analysis, transmission electron microscopy, and X‐ray photoelectron spectroscopy spectra. MH‐WD70‐DOPO nanoparticles were incorporated into ethylene‐vinyl acetate copolymer (EVA) matrix by melt blending method. The results indicated that MH‐WD70‐DOPO nanoparticles were much homogenously dispersed in EVA matrix than unmodified MH particles. EVA/MH‐WD70‐DOPO nanocomposites with 51.32 wt% loading showed higher flame retardancy, better mechanical and processing properties compared with EVA/MH‐WD70 sample. These findings could provide a novel method to enhance the flame‐retardant efficiency of inorganic hydroxide flame retardants, while keeping good mechanical and processing properties of polymer materials.

Waste-to-resource strategy to fabricate environmentally benign flame retardants from waste phosphorus tailings

Abstract Environmentally benign magnesium hydroxide (MH) flame retardants with different morphologies were prepared from waste phosphorus tailings by a combination of acidolysis reaction and hydrothermal method. The morphology, structure and dispersibility of MH were characterized by X-ray power diffraction, scanning electron microscope, and transmission electron microscope. The influences of the synthesized MH on the flame retardancy and smoke suppression properties of thermoplastic polyurethane were studied by cone calorimeter test and the flame retardant mechanism was discussed.

Effect of Various Metal Hydroxide Flame Retardants on the Rheological Properties of Asphalt Binder

Metal hydroxide has been widely used as flame retardant to reduce the hazards of tunnel fire, however, few researches investigate its effect on the rheological properties of asphalt binder systemically. This study explores and compares the effect and mechanisms of magnesium hydroxide (MH), aluminium hydroxide (ATH), hydrated lime (HL), and layer double hydroxides (LDHs) on the rutting resistance, anti-aging resistance, as well as the thermal cracking resistance of asphalt binder. Rotational viscosity (RV) test, dynamic shear rheometer (DSR) test, and bending beam rheometer (BBR) test are involved in the project. Test results indicate: (1) the addition of metal hydroxide generally improves the rutting resistance of asphalt binder during high temperatures due to the typical filler effect, while weakens the resistance to thermal cracking of binder at low temperatures because of the stress concentration; (2) HL and LDHs enhance the anti-aging resistance of asphalt binder; (3) LDHs modified binder, which is proved with better rheological properties, including great rutting resistance, anti-aging resistance and passable resistance to thermal cracking, is recommended for further use. However, the high procurement price is still a big obstacle for its wider application. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.21572

Investigation on Smoke Suppression Mechanism of Hydrated Lime in Asphalt Combustion

In this study, cone calorimeter and thermogravimetric analyses were used to simulate the asphalt combustion process under the conditions of fire radiation and programmed temperature increase. The gaseous compositions and release rules were analyzed by infrared spectroscopy to investigate the influence of hydrated lime on the smoke suppression mechanism in the asphalt combustion process. The experimental results show that hydrated lime can promote the asphalt mastic surface to form a barrier layer during the combustion process. This barrier layer can reduce the burning intensity of asphalt. Although the compositions of gaseous products do not change much, the rates of CO production and smoke release are decreased. In addition, hydrated lime is alkaline and can thus neutralize acidic gases such as SO2 and reduce the toxicity of gaseous products. With the addition of 40 wt.% hydrated lime, the total smoke release and the CO release rate both decrease by more than 20% relative to the addition of the same amount of limestone fillers and decrease by more than 10% relative to the addition of the same amount of magnesium hydroxide flame retardant.

Synergistic Effect of Modified Expanded Graphite and Zinc Borate on the Flammability, Thermal Stability and Crystallization Behavior of LLDPE/EVA Composites with Mg(OH)2/Al(OH)3

In this work, modified expandable graphite (MEG) and zinc borate (ZB) are melt‐blended with metal hydroxide/aluminum hydroxide flame retardant linear low‐density polyethylene/ethylene vinyl acetate (LLDPE/EVA) blends. The synergistic effects of MEG with ZB on the flammability, thermal stability and crystallization behaviors of LLDPE/EVA composites are characterized and discussed by UL‐94 vertical burning, limiting oxygen index (LOI), thermogravimetric analysis, cone calorimeter test (CCT), carbon layer morphology, and differential scanning calorimetry (DSC). The addition of ZB and MEG apparently increases the LOI values and improves the UL‐94 rating of the flame retardant LLDPE/EVA composites. The data obtained from the CCT indicate that the heat release rate, the total heat release and the gas production rate of the flame retardant LLDPE/EVA composites decrease remarkably with increasing the MEG content and the residues of the composites increase to 38.2% from 2.7% of the LLDPE/EVA blends, which indicates that MEG enhances the thermal stability and layer carbon capacity of the composites. The DSC results describe that MEG can act as a nucleating agent to accelerate the crystallization rate of the flame retardant composites, but the crystallinity of polypropylene of the flame‐retardant composites firstly increases and then decreases with increasing the content of MEG. POLYM. COMPOS., 40:E687–E694, 2019. © 2018 Society of Plastics Engineers

Flame retardant mechanism and surface modification of magnesium hydroxide flame retardant

At present, a polymer material, as a representative of the fine chemical industry rapid development, promote the additives research and development process. Magnesium hydroxide flame retardant agent has green environmental protection low cost advantages, received more and more attention. Many countries use magnesium hydroxide as a name retardant instead of halogenated name retardant. Magnesium hydroxide has low fire retardant efficiency, it can achieve flame-retardant effect under large filling volume and then seriously deteriorate mechanical and processing properties of materials. In order to improve mechanical property of materials, and we must modify the surface properties of magnesium hydroxide. There have been researches about magnesium hydroxide surface modification, which normally applied surfactants or coupling agents as surface modification instead of not macromolecular surface modifiers. Increasingly becoming the focus of flame retardants research at home and abroad, magnesium hydroxide as flame retardant additives is easy to reunite dispersion such poor compatibility. Therefore, it’s an important inquisitive task to improve the surface properties.

Spray-Drying-Assisted Layer-by-Layer Assembly of Alginate, 3-Aminopropyltriethoxysilane, and Magnesium Hydroxide Flame Retardant and Its Catalytic Graphitization in Ethylene-Vinyl Acetate Resin.

Alginates (nickel alginate, NiA; copper alginate, CuA; zinc alginate, ZnA) and 3-aminopropyltriethoxysilane (APTES) were alternately deposited on a magnesium hydroxide (MH) surface by the spray-drying-assisted layer-by-layer assembly technique, fabricating some efficient and environmentally benign flame retardants (M-FR, including Ni-FR, Cu-FR, and Zn-FR). The morphology, chemical compositions, and structures of M-FR were investigated. With 50 wt % loading, compared with EVA28+MH, the peak heat release rate, smoke production rate, and CO production rate of EVA28+Ni-FR decreased by 50.78%, 61.76%, and 66.67%, respectively. The metals or metal oxide nanoparticles arising from alginates could catalyze the pyrolysis intermediates of EVA into graphene and amorphous carbon, which could bind the inorganic compounds (the decomposition products of MH and APTES) together and form some more protective barriers. For each M-FR, the flame retardant and smoke suppression efficiency were different, which were caused by the diverse carbonization and graphitization behaviors of three alginates. ZnA generated some ZnO aggregations and could not catalyze the graphitization of intermediates. For CuA, the catalytic graphitization was limited by the tightly binding graphene layer. As for NiA, the configuration of the Ni atom could not provide strong binding of Ni substrate and carbon. The liquid-like Ni nanoparticles could restructure and get out from firm graphene shells, so the catalytic graphitization of NiA was efficient and sustainable. This work displayed the catalytic graphitization mechanism of alginates while exploring a simple and novel strategy for fabricating efficient green flame retardants.

Preparation of microencapsulated carbon microspheres coated by magnesium hydroxide/polyethylene terephthalate flame–retardant functional fibers and its flame retardant properties

In order to improve the compatibility between the flame retardants of carbon microspheres coated by magnesium hydroxide (MH@CMSs) and the PET matrix and improve the spinnability of the masterbatch, MH@CMSs have been microencapsulated by PET to obtain microencapsulated carbon microspheres coated by magnesium hydroxide flame retardants – MMH@CMSs.Morphologies and structures of MMH@CMSs have been studied by scanning electron microscope (SEM), transmission electron microscopy (TEM), and FTIR, which showed that an organic shell layer of PET as capsule wall was coated on the surface of MH@CMSs. A series of MMH@CMSs/PET fibers with different MMH@CMSs contents were successfully prepared through the melt-spinning method. The morphology and structure of MMH@CMSs/PET fibers were characterized by SEM and FTIR. The flame retardancy of MMH@CMSs/PET fibers was determined via limiting oxygen index (LOI) test and cone calorimeter. Results showed that the MMH@CMSs/PET fibers possessed optimum flame retardancy when the MMH@CMSs content is 0.6 wt.%, at which the LOI reached a maximum of 25.8, and the pk-HRR, total heat release, and total smoke release were reduced by 27.4, 20, and 13.6%, compared with pure PET fibers, respectively. Moreover, the flame-retardant mechanism was studied by thermogravimetric analysis, thermogravimetric analysis-infrared spectrometry, and the SEM of the residue char, which disclosed that MMH@CMSs enhanced the thermal stability of PET fibers, and promoted PET fibers to form a dense and continuous protective char layer that effectively blocked heat transfer and combustible gas release.

Study on the Oil Resistance, Morphological and Dynamic Mechanical Properties, Flame Retardance of Ethylene Vinyl Acetate Copolymer and Ethylene Propylene Rubber Compounds

In this experiment, blends of ethylene vinyl acetate rubber (EVM) with a vinyl acetate (VA) content greater than 40 wt% and ethylene propylene rubber (EPM) were prepared by mechanical mixing; a number of parameters of the blends, including oil resistance, morphological and dynamic mechanical properties and flame retardancy, were subsequently measured. In the 100℃ oil resistance test, both the ammonium polyphosphate/dipentaerythritol/expandable graphite (APP/DPER/EG) and aluminum hydroxide (ATH) flame retardant systems showed an increase in volume change with increasing EPM content. For the ATH system, the dispersion shape was coarse and aggregation was observed. The results of a dynamic mechanical test showed slightly higher E` and E`` for the APP/DPER/EG flame retardant system when compared to the single ATH system. For both the APP/DPER/EG and ATH systems, the limited oxygen index (LOI) tests performed at increasing content of EPM showed a LOI value higher than 30, indicating excellent flame resistance.