Combination Of Ammonium Polyphosphate Research Articles

Benign design of intumescent fire protection coatings for steel structures containing biomass humic acid as carbon source

The application of biomass materials in engineering has received a great deal of attention. In this work, a new eco-friendly biomass-based intumescent coating, composed of natural and sustainable biomass humic acid (HA), ammonium polyphosphate (APP), melamine (MEL), and zinc borate (ZB), was developed to endow steel structures with excellent fire resistance and fire retardancy. When exposed to a butane torch, the intumescent coating (1.5 mm thickness) reduced the maximum temperature observed on the backside of a 3 mm thick steel plate by over 350 °C. Moreover, the cone calorimeter results showed that thanks to the formation of an extremely intumescent and dense char layer, the peak heat release rate (pHRR) and total heat release (THR) of intumescent coatings (S5) were reduced by 86 % and 61 %, respectively, as compared to that of the control epoxy coating, meanwhile, significant reductions in fire growth rate (FIGRA, −89 %) and maximum average rate of heat emission (MARHE, −86 %) were also observed, suggesting that 2 wt% ZB loading is required to achieve optimal level of fire resistance and fire retardancy. Furthermore, the mechanism of action was elucidated by SEM-EDX, FTIR, Raman, and XRD analyses. Results revealed that the combination of APP, MEL, HA, and ZB promoted the formation of a continuous and cohesive graphitized intumescent char layer on the surface of the steel plate, reinforced by borophosphate and zinc-containing species, which effectively prevents the transfer of heat and fuel, thereby enhancing the fire resistance and fire retardancy of the intumescent coating. This eco-friendly intumescent coating provides a strategy for developing new green fire protection systems using widely available, low-cost biomass materials without using hazardous ingredients.

Experimental Investigation on the Thermal Management for Lithium-Ion Batteries Based on the Novel Flame Retardant Composite Phase Change Materials

Thermal management systems are critical to the maintenance of lithium-ion battery performance in new energy vehicles. While phase change materials are frequently employed in battery thermal management systems, it’s important to address the concerns related to their leakage and flammability, as they can pose hazards to the safety performance of batteries. This paper proposes a novel flame retardant composite phase change material (CPCM) consisting of paraffin, high-density polyethylene, expanded graphite, ammonium polyphosphate, red phosphorus, and zinc oxide. The performance of CPCMs containing different ratios of flame retardants is investigated, and their effects when applied to battery thermal management systems are compared. The results demonstrate that the leakage rate of the flame retardant CPCMs is maintained within 1%, indicating excellent flame retardant performance and thermal management efficiency. The combination of ammonium polyphosphate and red phosphorus in the flame retardant exhibits effective synergistic effects, while zinc oxide may help phosphate compounds create their bridging bonds, which would then make it possible to construct a char layer that would separate heat and oxygen. Under a 2C discharge rate, the maximum temperature of the battery pack remains below 50 °C, and the temperature difference can be controlled within 5 °C. Even under a 3C discharge rate, the maximum temperature and temperature difference are reduced by 30.31% and 29.53%, respectively.

Self-Assembled Serpentine Ni3Si2O5(OH)4 Hybrid Sheets with Ammonium Polyphosphate for Fire Safety Enhancement of Polylactide Composites.

Biodegradable polylactide (PLA) has been widely utilized in people's daily lives. In order to improve the fire safety of PLA, ammonium polyphosphate (APP) was self-assembled onto the surface of serpentine Ni3Si2O5(OH)4 through the electrostatic method, followed by mixing with PLA by melt compounding. The APP-modified serpentine (serpentine@APP) dispersed uniformly in the PLA matrix. Compared with pure PLA, the PLA composite with 2 wt% serpentine@APP reduced the peak heat release rate (pHRR) and total heat release (THR) by 43.9% and 16.3%, respectively. The combination of APP and serpentine exhibited suitable synergistic flame-retardant effects on the fire safety enhancement of PLA. In addition, the dynamical rheological tests revealed that the presence of APP and serpentine could reduce the viscosity of PLA composites. The plasticizing effects of APP and serpentine benefited the processing of PLA. The mechanical properties of PLA/serpentine@APP maintained suitable performance as pure PLA. This study provided a feasible way to enhance the fire safety of PLA without sacrificing its mechanical properties.

Influence of glycidyl methacrylate grafted poly (butylene succinate) (PBS‐g‐GMA) on flame retardancy and mechanical properties of water hyacinth fiber/ammonium polyphosphate/poly (butylene succinate) composites

AbstractIn this study, water hyacinth fiber (WHF) was used as a carbon source in combination with ammonium polyphosphate (APP) to formulate an environmentally friendly intumescent flame retardant for poly (butylene succinate) (PBS) composites. Glycidyl methacrylate grafted poly (butylene succinate) (PBS‐g‐GMA) was prepared via a reactive melt grafting reaction to serve as a compatibilizer for WHF/APP/PBS composites. Effects of incorporating APP and WHF, and PBS‐g‐GMA on mechanical properties, thermal properties and flame retardancy of PBS composites were investigated. Results showed that the addition of PBS‐g‐GMA greatly improved tensile strength, flexural strength and crystallization rate of WHF/APP/PBS composites. According to UL‐94 and limiting oxygen index (LOI) tests, the presence of 15 wt% WHF, 30 wt% APP, and 15 wt% PBS‐g‐GMA enabled the WHF/APP/15PBS‐g‐GMA/PBS composite to achieve a V‐0 rating and the maximum LOI value of 29.2%. Char residue analysis revealed that the combination of APP and WHF promoted the formation of an expanded char layer, whereas the addition of PBS‐g‐GMA induced the formation of compact, highly graphitized residues. Findings will contribute to the development of biodegradable flame‐retardant polymer composites for engineering applications.

Synergistic effects of halloysite nanotubes with metal and phosphorus additives on the optimal design of eco-friendly sandwich panels with maximum flame resistance and minimum weight

Abstract The present work addresses the optimal design of sandwich panels made of flax fabric (FF)/vinyl ester (VE) composite face sheets and honeycomb VE core. The sandwich structures are first optimized in terms of flammability by obtaining the best combination of ammonium polyphosphate (APP), halloysite nanotube (HNT), and magnesium hydroxide (MH) as three flame retardants (FRs). Using the Taguchi method and horizontal burning test, it is shown that [6, 3, and 3%] and [1, 0.5, and 0%] are the optimal combinations of APP, HNT, and MH for the face sheets and core, respectively. Cone calorimeter test results indicate that the optimal FR combinations significantly decrease the mass lost rate (MLR), heat rate release (HRR), total smoke release (TSR), and maximum average release heat emission (MARHE). The FR sandwich structures are then geometrically optimized under compressive loads based on their weight. Different failure modes are considered as the design constraints of the optimization problem. Imperialist competitive algorithm (ICA), as a powerful meta-heuristic algorithm, is implemented to considerably reduce the computational cost of the optimization process. The results of this study show that proper combinations of FR additives can increase the flame retardancy while decreasing the weight of sandwich panels.

One Pot Facile Synthesis of Self-extinguishable Metal Based Flame Retardant for Cotton Fabric

ABSTRACT An efficient metal-based flame-retardant was prepared for cotton fabric (CF) by a convenient pad-dry-cure method, which involves the consecutive deposition of intumescent containing different combination of ammonium polyphosphate, melamine, pentaerythritol with Copper and Zinc metal ions. We studied different properties like thermal, mechanical, flammability, and laundering durability of treated CF samples. The intumescent-coated CF shows remarkable high-efficiency flame-retardant properties: (1) a self-extinguishing property (5 s) without lateral spreading of flame during the vertical flame test with a lower smoke release character; (2) the limiting oxygen index (LOI) values of coated CF are improved with increasing add-on level. The Zn-based samples exhibited a high limiting oxygen index value of 36%. Consequently, the resultant fabrics were observed to show great flame retardancy with high thermal stability as 35% of char yield at 600°C. The durability of modified cotton was tested after five laundering cycles, which showed that the coating maintains 84% of its initial mass. It is reported that in addition to durable flame retardancy, the mechanical properties of cotton were also enhanced. The present work provides eco-friendly one pot facile synthesis of intumescent-based flame retardant for CF which may be used in numerous applications. Abbreviations: ammonium polyphosphate; PER: pentaerythritol; MEL: melamine; LOI: limiting oxygen index; TGA: thermogravimetric analysis; DTG: derivative thermogravimetry; GSM: gram per square meter; FR: flame retardant; CP: plain cotton fabric; CT: twill cotton fabric; CF: cotton fabric; Int: intumescent; FTIR: Fourier Transformation Infrared; BEL: burn entire length; DNI: did not ignite; SE: self-extinguish; HGMs: hollow glass microspheres; CH/PA/Ba/PA: Chitosan/ Phytic Acid/Barium/Phytic Acid; DPPMA: diphenylphosphinic acid with melamine; PBS/30PA-GU: poly(butylene succinate/30 phytic acid-guanosine; PET: polyethyleneimine; Tri-HTAC: 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride; TA/B@PDA: tannic acid/Borax@polydopamine; P10H5: 5wt% HCCP(Hexachlorocyclotriphosphazene). ammonium polyphosphate; PER: pentaerythritol; MEL: melamine; LOI: limiting oxygen index; TGA: thermogravimetric analysis; DTG: derivative thermogravimetry; GSM: gram per square meter; FR: flame retardant; CP: plain cotton fabric; CT: twill cotton fabric; CF: cotton fabric; Int: intumescent; FTIR: Fourier Transformation Infrared; BEL: burn entire length; DNI: did not ignite; SE: self-extinguish; HGMs: hollow glass microspheres; CH/PA/Ba/PA: Chitosan/ Phytic Acid/Barium/Phytic Acid; DPPMA: diphenylphosphinic acid with melamine; PBS/30PA-GU: poly(butylene succinate/30 phytic acid-guanosine; PET: polyethyleneimine; Tri-HTAC: 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride; TA/B@PDA: tannic acid/Borax@polydopamine; P10H5: 5wt% HCCP(Hexachlorocyclotriphosphazene).

Impact on flame retardancy and degradation behavior of intumescent flame‐retardant EP composites by a hyperbranched triazine‐based charring agent

The flame retardancy and thermal degradation behavior of intumescent flame retardant EP (EP‐IFR) composites based on ammonium polyphosphate (APP) and a hyperbranched triazine carbon forming agent (HTCFA) were investigated by the means of limited oxygen index (LOI), vertical combustion test (UL‐94), thermogravimetric analysis (TGA) and cone calorimeter test (CONE). The results exhibited that the combination of APP and HTCFA obviously imparted better flame retardancy to EP than them applied alone. EP composites containing 10 wt% APP/HTCFA (4/1) passed UL‐94V‐0 rating with a LOI value of 32%, while there was no rating for EP‐APP or EP‐HTCFA. In addition, the combination of APP and HTCFA influenced the fire behavior of composites with more efficient heat/smoke release suppression. The carbonaceous residues after cone presented expanded structures with compact and continuous surfaces. TGA results presented that there was an obvious synergistic effect between them, significantly enhancing the thermal stability and promoting the formation of char residues. The flame retardant mechanism was also involved based on the residue analysis by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FTIR) and laser Raman spectrometer (LRS). Results illustrated high‐quality foamed cellular char layers with highly graphitic degree contributed to better flame retardant and smoke suppression properties of EP‐APP/HTCFA composite.

Efficient flame retardant interplay of unsaturated polyester resin formulations based on ammonium polyphosphate

The flame retardant effects of ammonium polyphosphate (APP) in combination with different mineral flame retardants as well as the combination of APP and phosphorus based flame retardants in unsaturated polyester resin was investigated. Flammability and thermal stability of unsaturated polyester (UP) composites were evaluated with UL-94 vertical burning, thermogravimetric analysis (TG) and cone calorimetry. The morphology of char residues was examined via scanning electron microscopy (SEM). An interaction between APP and phosphinate salts was observed. A combination of 20 wt-% APP and aluminum diethylphosphinate (AlPi) passed UL 94 V-0 classification. In contrast the combination of APP and mineral flame retardants did not show sufficient burning behavior in UL 94 vertical burning test. Furthermore, PHRR and THR was reduced by introduction of phosphinate salts or mineral flame retardants, compared with a formulation containing solely APP. SEM of the residues showed that the combination of APP and the phosphinate salts forms a though and dense residue that can protect underlying material. An incorporation of mineral fillers and APP leads to a fragile residue.

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

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.

Synergistic effect of ammonium polyphosphate and α-zirconium phosphate in flame-retardant poly(vinyl alcohol) aerogels

To overcome the flammability and melt dripping issues of poly(vinyl alcohol) (PVA) aerogel, a combination of ammonium polyphosphate (APP) and α-zirconium phosphate (α-ZrP) was used to enhance the flame retardancy of PVA aerogels, which were fabricated using a simple mixing and freeze-drying approach. Results obtained from transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirm that α-ZrP was successfully exfoliated by ultrasonic stripping. The effects of the exfoliated α-ZrP nano-plates on the microstructure, composition, flame retardancy, fire behavior of the aerogels was investigated using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), limiting oxygen index (LOI), UL-94 vertical burning, and cone calorimetry test. It was found that the incorporation of α-ZrP improved the 3D network structure of the PVA aerogel. The results showed that a sample with 2 wt% α-ZrP and 13 wt% APP could reach the maximal LOI value of 43.1%, achieved the UL-94 V-0 rating, and the peak heat release rate (PHRR) and total heat release (THR) of the sample reduced by 82.6% and 76.3%, respectively. Thermogravimetric analysis (TGA) revealed that α-ZrP improved the thermal stability of PVA-APP system. The residues analysis revealed that α-ZrP accelerated the formation of a compact and graphitization structure of residues and catalyzed the charring of PVA during burning.

Description of complementary actions of mineral and organic additives in thermoplastic polymer composites by Flame Retardancy Index

This work visualizes the complementary actions of organic and mineral additives in model thermoplastic polymer composites in terms of Flame Retardancy Index (FRI). Thermal and flame retardancy behaviors of ethylene‐vinyl acetate copolymer (EVA) composites containing calcium carbonate (CC) mineral and ammonium polyphosphate (APP) organic additives were studied varying composition of additives in the 80/20 EVA/(xCC + (20 − x)APP) composites with x denoting 0, 5, 10, 15, and 20 wt%. Thermogravimetric analysis (TGA) revealed that the onset temperature of composites and the remaining residue were increased by combination of APP and CC, while cone calorimetry results were indicative of a promising flame retardancy performance at a given composition of APP and CC. Based on FRI values, we made distinguished samples from flame retardancy performance viewpoint, where the best flame retardancy was obtained by combination of 15 wt% APP and 5 wt% CC, as reflected in FRI value of 3.08. By contrast, samples containing only APP or CC revealed low resistance against flame, as signaled by FRI values of 0.99 and 0.89, respectively. X‐ray diffraction (XRD) analysis was made on remaining residue collected at the end of cone calorimetry measurements. Moreover, Raman analysis confirmed barrier effect of flame retardancy for EVA/(5APP + 15CC) sample, featured by a higher graphitization level as well as a thicker yet more homogenous char layer. Mechanical behavior analysis of composites revealed an acceptable level of properties, particularly high elongation at break, which was almost independent of formulation. However, a minor loss in yield stress was observed, especially for EVA(10CC + 10APP) sample.

Improved Flame-Retardant and Ceramifiable Properties of EVA Composites by Combination of Ammonium Polyphosphate and Aluminum Hydroxide.

Ceramifiable flame-retardant ethylene-vinyl acetate (EVA) copolymer composites for wire and cable sheathing materials were prepared through melt compounding with ammonium polyphosphate (APP), aluminum hydroxide (ATH) and fluorophlogopite mica as the addition agents. The effects of ammonium polyphosphate, alumina trihydrate, and APP/ATH hybrid on the flame retardant, as well as on the thermal and ceramifiable properties of EVA composites, were investigated. The results demonstrated that the composites with the ratio of APP:ATH = 1:1 displayed the best flame retardancy and the greatest char residues among the various EVA composites. The tensile strength of the composites was 6.8 MPa, and the residue strength sintered at 1000 °C reached 5.2 MPa. The effect of sintering temperature on the ceramifiable properties, microstructures, and crystalline phases of the sintered specimen was subsequently investigated through X-ray diffraction, Fourier transform infrared, and scanning electron microscopy. The XRD and FTIR results demonstrated that the crystal structure of mica was disintegrated, while magnesium orthophosphate (Mg3(PO4)2) was simultaneously produced at an elevated temperature, indicating that the ceramization of EVA composites had occurred. The SEM results demonstrated that a more continuous and compact microstructure was produced with the rise in the sintering temperature. This contributed to the flexural strength improvement of the ceramics.

A comparative study on effects of natural and synthesised nano-clays on the fire and mechanical properties of epoxy composites

In this research, two nano-clays, halloysite nano-tube (HNT) and layered double hydroxide (LDH), were employed to compare fire and mechanical properties of epoxy composites based on ammonium polyphosphate (APP) and each of the two nano-clays. The results showed that the combination of APP and nano-clay achieved a significant reduction (approx. 87%) in peak heat release rate of epoxy resin. The comparative analysis also demonstrated that the total heat release of the composite including HNT was approx. 18% lower than that of the LDH based composite. Moreover, HNT generated higher tensile properties in the composite. Overall, the HNT (∼1.5 USD/kg) is a more cost-effective nano-clay than LDH (∼180 USD/kg) to effectively improve the fire resistance and maintain the mechanical properties of epoxy composites.

Flame Retardancy of Low-Viscosity Epoxy Resins and Their Carbon Fibre Reinforced Composites via a Combined Solid and Gas Phase Mechanism.

Low viscosity, potentially renewable aliphatic epoxy resins, appropriate for processing with injection techniques were flame retarded with the use of resorcinol bis(diphenyl phosphate) (RDP), acting predominantly in the gas phase, ammonium polyphosphate (APP), acting in the solid phase, and their combination. Samples of gradually increasing phosphorus (P) content (1%, 2%, 3%, 4%, and 5%) and mixed formulations with 2% P from APP and 2% P from RDP were prepared. The fire retardancy of matrix and carbon fibre reinforced samples was examined by limiting oxygen index (LOI), UL-94 tests, and mass loss calorimetry. The thermal stability of the matrices was investigated by thermogravimetric analysis, whereas the effect of flame retardants (FRs) on the crosslinking process and glass transition temperature was evaluated by differential scanning calorimetry in matrices and by dynamic mechanical analysis in composites. According to the results, although the trifunctional glycerol -based (GER) and the tetrafunctional pentaerythritol-based (PER) epoxy resins have a similar initial LOI and horizontal burning rate, GER has an approximately 1.5 times higher peak of heat release rate (pHRR) than PER. At least 4% P content is necessary to reach a reasonable improvement in fire performance in these resin transfer molding (RTM)-compatible systems and with the same FR-content PER reaches better fire performance. RDP has an early gas phase effect at the beginning of degradation, while later on the solid phase action of APP prevails, although in composites hindered by the reinforcing carbon fibres. In PER composites, the combination of APP and RDP had a synergistic effect, leading to a pHRR of 218 kW/m2 and total heat release of 18.2 MJ/m2.

Influence of surface flame-retardant layer containing ammonium polyphosphate and expandable graphite on the performance of jute/polypropylene composites

Surface flame-retardant layer containing ammonium polyphosphate (APP) and expandable graphite (EG) combined with polypropylene (PP) was used to improve the flame retardancy and mechanical properties of jute/PP nonwoven felts composites. The flame retardancy of jute/PP composites had been investigated by limit oxygen index (LOI), horizontal burning rate (HBR) and cone calorimeter. The results showed that the jute/PP composites with APP/EG-retardant layer were less flammable with higher LOI value, longer time to ignition, lower value of the peak heat release rate, total heat release, effective heat combustion, total smoke production, and became self-extinguished in HBR test. The thermal degradation and residual structure of jute/PP composites were monitored by thermogravimetric analyses, Fourier transform infrared, X-ray photoelectron spectroscopy and scanning electron microscope. These results revealed that the char residual amount and the element of carbon in the residual char resulted by APP/EG were much higher than the values by APP and EG individually. The flame-retardant properties of J/P composites were enhanced greatly by the combination of APP and EG even the amount of flame retardant is only 5%. Furthermore, the mechanical properties of jute/PP composites were also enhanced by the surface flame-retardant layer.

Synergistic effect between ammonium polyphosphate and expandable graphite on flame-retarded poly(butylene terephthalate)

In this paper, the synergistic effect of ammonium polyphosphate (APP) and expandable graphite (EG) on flame-retarded poly(butylene terephthalate) (PBT) was systermically investigated using limiting oxygen index (LOI), UL-94 testing, microscale combustion calorimetry (MCC), thermal-gravimetric analysis (TGA) and scanning electronic microscopy (SEM). PBT composites containing 20 wt% of APP: EG (1:3) combinations exhibits a high LOI value of 29.8 and reaches V-0 rating in UL-94 testing, indicating that the flame retardant property is greatly enhanced compared to the composites solely with APP or EG. SEM images show that the combination of APP and EG could promote the formation of a compact char layer. The compact char layer protects the PBT resin efficiently by preventing penetration of heat flux inside the matrix and retards the decomposition of PBT, consequently improves the thermal stability of PBT materials as revealed by TGA. All of the results demonstrate that APP and EG are high efficiency synergists for improving the flame retardation of PBT materials.

Flame-retardant wood polymer composites (WPCs) as potential fire safe bio-based materials for building products: Preparation, flammability and mechanical properties

Improving the efficiency of traditional flame retardant additives is a challenging task in the field of wood polymer composites (WPCs). In this work, novel flame retardant system for WPCs was developed based on the combination of ammonium polyphosphate (APP) with phytic acid modified layered double hydroxide (Ph-LDH). Thermogravimetric analysis illustrated that the incorporation of Ph-LDH resulted in earlier thermal degradation of the WPCs with more thermally stable products during degradation, giving improved char formation. Limiting oxygen index (LOI), vertical burning (UL-94) and cone calorimetry tests were used to study the flammability of WPCs and the results showed that the addition of Ph-LDH had a synergistic effect on their fire performance. The char residues of the WPCs after the cone calorimetry tests were characterised by scanning electron microscopy (SEM). Mechanical properties of the flame retardant WPCs were analysed using impact and tensile tests. Partial substitution of APP with polypropylene (PP) resulted in a deterioration in the tensile and impact properties, while co-incorporation of nano-fillers led to an enhancement of the mechanical performances of the flame retardant WPCs. This WPC with good flame retardant and mechanical properties could potentially be used in the fields of building or furniture which require high flame retardancy.

Effect of phytic acid–modified layered double hydroxide on flammability and mechanical properties of intumescent flame retardant polypropylene system

AbstractPhytic acid–modified layered double hydroxide (Ph‐LDH) was synthesized via coprecipitation method and subsequently was used in polypropylene (PP) by combining with an ammonium polyphosphate (APP) via melt compounding method. The synergistic effect between APP and Ph‐LDH on the thermal stability, flammability, and mechanical properties of the resultant PP composites was investigated by thermogravimetric analysis, limiting oxygen index, vertical burning test (UL‐94), cone calorimeter tests, tensile test, and impact test. Morphologies of the chars obtained from the samples after the cone calorimeter tests were studied by scanning electron microscopy. The combination of APP and Ph‐LDH slightly influenced the impact and tensile properties of PP. Also, the synergistic effect between APP and Ph‐LDH occurred in the cone calorimeter test. Moreover, the combination of APP and Ph‐LDH produced better quality char that effectively suppressed the spread of the flame and volatile and finally extinguished the fire.

An effective intumescent flame retardancy of LDPE induced by the combination of APP and CNCO‐HA

ABSTRACTA char‐forming agent poly(4,6‐dichloro‐N‐hydroxyethyl−1,3,5‐triazin‐2‐amine‐1,6‐diaminohexane) (CNCO‐HA) containing triazine rings was chosen for improving the flame retardant of low density polyethylene (LDPE). The synergistic effect of CNCO‐HA and Ammonium polyphosphate (APP) on the flame retardancy and char‐forming behavior of LDPE were investigated. The limited oxygen index (LOI) and vertical burning test (UL‐94) results indicated the optimal weight ratio of APP to CNCO‐HA was 3:1, and the LOI value of composite reached 31.0% with 30% intumescent flame retardant (IFR) loading. The cone calorimeter test analysis revealed that IFR presented excellent char forming and smoke suppression ability, and resulted in the efficient decrease of combustibility parameters. The thermogravimetric analysis results demonstrated that IFR reduced the thermal degradation rate at main stage of degradation. Scanning electron microscopy observed that IFR promoted to form a compact and continuous intumescent char layer. The Laser Raman spectroscopy spectra showed that larger graphitization degree was formed to enhance the strength of char, and Fourier transform infrared results presented that P‐O‐C and P‐O‐P structures in the residue char were formed to improve shield performance of the char layer to obtain better flame retardant properties of the composite. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43950.

Investigation of thermal stability and flammability of poly(methyl methacrylate) composites by combination of APP with ZrO2, sepiolite or MMT

The thermal degradation and flame retardancy of poly(methyl methacrylate) containing three mineral fillers, with different geometry, MMT: plate-like, sepiolite: fibrilar and zirconium oxide ZrO2: spherical, in combination with ammonium polyphosphate (APP) were studied. The flame behavior of composites was investigated using pyrolysis-combustion flow calorimeter, cone calorimeter and LOI tests. The results revealed that the composites containing APP and sepiolite present the best fire behavior. A rheological study was performed on composites to establish a relationship between viscosity and flammability. The residues of samples after cone calorimeter test were studied using X-ray diffraction and micro-tomography in order to investigate their chemical composition and also repartition of fillers. A better repartition of sepiolite during combustion could be the origin of the best results obtained for sample containing this filler.