Aluminum Diethylphosphinate Research Articles

Simultaneously Enhancing the Fire Retardancy and Heat Resistance of Stereo-Complex-Type Polylactic Acid.

Polylactic acid (PLA) is considered to be the material with great application potential in the 21st century which has aroused wide research interest. However, PLA is a highly flammable material and exhibits low heat distortion temperature, which greatly limits its application in many fields. In this work, aluminum diethyl phosphinate (ADP) and poly (d-lactic acid) (PDLA) are used to improve fire retardancy and heat resistance of poly (l-lactic acid) (PLLA). PLLA/PDLA with the presence of 15 wt % ADP exhibited the limiting oxygen index (LOI) value at 26%, and the peak heat release rate (pHRR) and total heat release decreased, respectively, by 14.03 and 24.42% from 500 to 429 kW/m2 and 86 to 65 MJ/m2. The melt dripping phenomenon was suppressed obviously. The addition of ADP realized the flame-retardant effect from both the condensed phase and gas phase. Moreover, the results showed that the addition of ADP promoted the formation of stereo crystals and increased the crystallization temperature to 175 °C. The heat distortion temperature (HDT) of the PLLA/PDLA sample with 15 wt % ADP can be as high as 170.4 °C, which marks significant improvement in the heat resistance of PLA. The mechanical property test results showed that ADP has little effect on the mechanical properties of the composites. This work opens a window to realize the heat-resistant and anti-dripping fire-retardant PLA.

A Series of Novel Flame Retardants Produced with Nanosilica, Melamine, and Aluminum Diethylphosphinate to Improve the Flame Retardancy of Phenolic Resin.

To facilitate the flame retardancy of phenolic resin (PF), a series of novel flame retardants with nano-SiO2, melamine, and aluminum diethylphosphinate (ADP) were freshly prepared and tested. A thermogravimetric analysis, cone calorimeter, and scanning electron microscopy were employed to determine the thermal decomposition, flame retardancy, combustion properties, and structure of the carbon residue layer of PF. The pyrolysis kinetic parameters of modified PF were then computed, and the pyrolysis process was appraised. The results indicated that when 1.5 wt % of nano-SiO2, 3 wt % of melamine, and 15 wt % of ADP were added to PF, the limiting oxygen index value reached 39.6%, and UL-94 passed the V-0 level. A substantial synergistic effect was also observed. The thermogravimetric analysis revealed that the char residue at 800 °C reached 59.93 wt %. Furthermore, in the cone calorimeter test, the total thermal release and thermal release rate decreased to 30.7 MJ/m2 and 105.7 kW/m2, respectively.

Flame‐retardant, thermal and mechanical properties ofPLA/ramie fiber composites

AbstractAlthough the natural fiber composites are preferable for sustainable and green product due to the environmental friendliness, they suffer from the high flammability. In this study, the flame retardant ramie fiber reinforced poly(lactic acid) composites were prepared and the synergistic barrier effect of aluminum diethylphosphinate, melamine cyanurate and silica was investigated. When the mass ratio of each flame retardant was 10%, the composites reached UL‐94 V0 rating with the limiting oxygen index of 30.1%. The excellent flame retardancy was resulted from the formation of high‐quality char layers, the chain reaction of free radicals as well as the dilute effect of inert gases generated during the combustion process. Besides, the cone calorimeter test showed that the peak heat release rate and total heat release decreased by 22.5% and 15.0%, respectively. Importantly, the flame retardants did not deteriorate the mechanical properties, thanks to the fiber reinforcement and high‐adhesion work between the flame retardants and the matrix which was demonstrated by the contact angle test.

Aluminum Diethylphosphinate-Incorporated Flame-Retardant Polyacrylonitrile Separators for Safety of Lithium-Ion Batteries.

Herein, we developed polyacrylonitrile (PAN)-based nanoporous composite membranes incorporating aluminum diethylphosphinate (ADEP) for use as a heat-resistant and flame-retardant separator in high-performance and safe lithium-ion batteries (LIBs). ADEP is phosphorus-rich, thermally stable, and flame retardant, and it can effectively suppress the combustibility of PAN nanofibers. Nanofibrous membranes were obtained by electrospinning, and the content of ADEP varied from 0 to 20 wt%. From the vertical burning test, it was demonstrated that the flame retardancy of the composite membranes was enhanced when more than 5 wt% of ADEP was added to PAN, potentially increasing the safety level of LIBs. Moreover, the composite membrane showed higher ionic conductivity and electrolyte uptake (0.83 mS/cm and 137%) compared to those of commercial polypropylene (PP) membranes (Celgard 2400: 0.65 mS/cm and 63%), resulting from interconnected pores and the polar chemical composition in the composite membranes. In terms of battery performance, the composite membrane showed highly stable electrochemical and heat-resistant properties, including superior discharge capacity when compared to Celgard 2400, indicating that the PAN/ADEP composite membrane has the potential to be used as a heat-resistant and flame-retardant separator for safe and high-power LIBs.

Expandable Graphite, Aluminum Diethylphospinate and Melamine Polyphosphate as Flame Retarding System in Glass Fiber-Reinforced PA6.

A flame retardant system based on expandable graphite (EG), aluminum diethylphosphinate (AlPI) and melamine polyphosphate (MPP) was investigated in glass fiber- (GF) reinforced polyamide 6 (PA6). Burning characteristics were evaluated via cone calorimeter, limiting oxygen index (LOI) and UL-94 tests. Thermogravimetric analysis (TGA) and coupled Fourier transform infrared spectroscopy (FTIR) was used to investigate the decomposition process as well as flame retardant modes of actions. Specifically, in the cone calorimeter tests, formulations containing EG showed excellent flame retardant properties for non-reinforced and reinforced PA6. The best performance was achieved for 25 wt.% glass fiber-reinforced PA6 containing solely 20 wt.% EG, corresponding to a measured pHRR of 134 kW/m2 and a total smoke production of 1.2 m2. Higher glass fiber contents of 45 wt.% (30 vol.%) revealed a lower char volume, which was attributed to both the limited space available for expansion and the sheer-induced reduction in particle size during processing. All of the reinforced PA6 formulations only achieved V2 classifications, but this was at low filling degrees (10 wt.%) for both net EG or EG/AlPi/MPP combinations. For GF-reinforced PA6 containing EG/AlPi/MPP mixtures, a synergistic effect was found to improve the oxygen index up to 30.6%.

Aluminum Diethylphosphinate as a Flame Retardant for Polyethylene: Investigation of the Pyrolysis and Combustion Behavior of PE/AlPi-Mixtures

The popularity of organic polymers despite their high flammability forces the introduction of flame retardants (FR) such as metal phosphinates into the combustible material. The thermal behavior of aluminum diethylphosphinate (AlPi) as FR in the widely used polymer ultra-high molecular weight polyethylene (UHMWPE) is investigated here. The study focuses on the effect of the FR on the gas phase activity when a polymer is pyrolyzed or burned. For this purpose, the fast pyrolysis of AlPi was investigated by differential mass-spectrometric thermal analysis (DMSTA). Also, the thermal and chemical structures of diffusion flames of UHMWPE + AlPi specimens were investigated using micro thermocouples and molecular beam mass spectrometry, respectively. Small amounts of AlPi (2.5 wt.%) decrease the gas temperature significantly by a maximum of 155 K related to FR-free polymer flames, indicating a retardancy effect of the additive on the flame. From the results of subsequent limiting oxygen index (LOI) tests, it is obvious that a PE burn-up cannot be achieved in a self-sustained flame when an additive content above 10 wt.% is used as FR. In the mass-spectrometric studies, the phosphorus-containing species produced in the pyrolysis experiments (DMSTA) of the neat AlPi as well as the species which are formed in flames during combustion experiments can be detected. In the flames, the concentration of the phosphorus containing compounds peaks at low heights above the polymer surface which indicate a gas phase activity of AlPi or its pyrolysis products. Besides a charring layer on top of the burning surface could be noticed. The use of AlPi as a FR for UHMWPE shows flame retardant effects in both the condensed and the gas phase.

Synergistic flame retardancy of linear low-density polyethylene with surface modified intumescent flame retardant and zinc borate

Aluminum diethylphosphinate (ADP) was surface modified with the silane coupling agent KH-560, and mixed intumescent flame retardants (IFRs) were prepared with neopentyl glycol (NPG) and melamine (MEL). Then mixed IFRs and zinc borate (ZB) were compounded and added into linear low-density polyethylene (LLDPE) material. The morphology, composition, and structure of LLDPE/IFRs/ZB composites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The maximum limiting oxygen index of LLDPE/IFRs/ZB composites is 28.7%, and the combustion grade is V0. The thermogravimetric analysis results showed that the thermal degradation rate of LLDPE/IFRs/ZB composites decreased, and the carbon residue reached 15.3 wt% at 700 ℃. The cone calorimeter test showed that peak heat release rate (PHRR), total heat release rate (THR), peak smoke release rate (PSPR), and total flue gas output (TSP) of LLDPE/IFRs/ZB composites decreased by 52.5%, 24.7%, 30%, and 15.5%, respectively, compared with pure LLDPE, significantly improving the flame retardant and smoke suppression performances of LLDPE. The residual carbon analysis shows that the CC and POC bonds in the modified mixed IFR strengthen the carbon layer structure and form a denser intumescent carbon layer, effectively hindering flame propagation. The experimental results show that the new intumescent flame retardant is a remarkable breakthrough in both flame retardancy and smoke suppression compared with ordinary intumescent flame retardants, and is more suitable for flame retardant polymer materials than traditional intumescent flame retardants.

Effect of the Flame Retardants and Glass Fiber on the Polyamide 66/Polyphenylene Oxide Composites.

In this work, polyamide 66/polyphenylene oxide (PA66/PPO) composites, including the flame retardants 98 wt% aluminum diethylphosphinate + 2 wt% polydimethylsiloxane (P@Si), Al(OH)3-coated red phosphorus (RP*), and glass fiber (GF), were systematically studied, respectively. The limiting oxygen index (LOI), UL-94 vertical burning level, and thermal and mechanical properties of the PA66/PPO composites were characterized. The results showed that the P@Si and RP flame retardants both improved the LOI value and UL-94 vertical burning level of the PA66/PPO composites, and PA66/PPO composites passed to the UL-94 V-0 level when the contents of P@Si and RP* flame retardants were 16 wt% and 8 wt%. On the other hand, the mechanical properties of the PA66/PPO composites were reduced from a ductile to a brittle fracture mode. The addition of GF effectively made up for these defects and improved the mechanical properties of the PA66/PPO composites containing the P@Si and RP*, but it did not change the fracture mode. P@Si and RP* flame retardants improved the thermal decomposition of PA66/PPO/GF composites and reduced the maximum mass loss rates, showing that the PA66/PPO/GF composites containing the P@Si and RP* flame retardants could be used in higher-temperature fields.

Clariant begins construction of flame retardants production facility in China

Specialty chemical company Clariant will invest approximately CHF 60 million to construct its first Chinese production facility for Exolit OP flame retardants at its existing site in Daya Bay, Huizhou, Guangdong Province. The Exolit OP range is based on aluminum diethyl-phosphinate (DEPAL) and offers fire resistance to electronic devices like smartphones and computers as well as slowing fire and smoke spread in infrastructure applications.

Synthesis of aluminum alkylphosphinates under atmospheric pressure

Alkylphosphinates have received extensive attention in the past few decades because of their very useful mechanical properties, electrical properties, low density, and low toxicity, and have been widely used in flame-retardant materials and other fields. In this work, aluminum diethylphosphinate is successfully synthesized under atmospheric pressure. More importantly, two novel dialkylphosphinates, aluminum dioctylphosphinate and aluminum didecylphosphinate, are first synthesized and characterized. The structures of these aluminum dialkylphosphinates are confirmed by nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and high-resolution mass spectrometry, and the microscopic morphology and thermal stability are analyzed by scanning electron microscopy and thermogravimetric analysis, respectively. Furthermore, conditions for the synthesis of aluminum dioctylphosphinate are optimized. Compared with the traditional method of synthesizing dialkylphosphinates under high pressure, the method reported in this paper has the advantages of high safety, easy operation, and low economic cost, which makes it suitable for industrial production.

The effect of a phosphorus-based FR on the fire performance and flammability properties of basalt fiber-reinforced acrylonitrile-butadiene-styrene composites.

This study focuses on the improvement in fire performance, and flame retardancy (FR) properties of chopped basalt fiber-reinforced acrylonitrile-butadiene-styrene (ABS) composites. For this purpose, different amounts of aluminum diethyl phosphinate (AlPi) compound (5, 10, and 15 wt%) were incorporated in the composites. The FR properties of the composites were examined via limiting oxygen index (LOI), UL-94 standard, and mass loss calorimeter tests. Thermogravimetric analysis was carried out to analyze the decomposition behavior of the composites. SEM inspection was also performed to examine the char surfaces of the composites. The results and findings showed that the introduction of AlPi compound into the composite structure leads to promotion in the char yield and improves the fire performance of the ABS matrix. As the added amount of AlPi into the composite increased, the LOI value of the composite increased. The addition of 15 wt% AlPi resulted in a UL-94 rating of V1 and the LOI value of 31.4%.

Flame retardancy effect of melamine cyanurate in combination with aluminum diethylphosphinate in a fully waterborne epoxy system

A water-soluble sorbitol polyglycidyl ether (SPE) epoxy monomer was cured with a waterborne polyamine hardener to prepare a fully waterborne epoxy system. Aluminum diethyl phosphinate (AlPi) and melamine cyanurate (MC) flame retardants (FRs) were utilized to develop the flame retardancy of this epoxy matrix. The effect of loading different weights of MC with only 1%P-content from AlPi was discussed to investigate the possible cooperative effect of these two FRs. The best results were obtained at 5% MC loading with 1%P of AlPi as the self-extinguishing behavior was observed with a good limiting oxygen index (LOI). Furthermore, under forced flaming conditions in cone calorimetry measurements, the peak of heat release rate (pHRR) decreased by 27.4%, and the total heat release (THR) decreased by 14.5% compared to the reference epoxy system. This enhancement of flame retardant properties might indicate the synergistic effect between MC and AlPi in a waterborne system.

Synergistic Flame-Retardant Effect of Aluminum Diethyl Phosphinate in PP/IFR System and the Flame-Retardant Mechanism

Abstract Synergistic flame-retardant effect of aluminum diethyl phosphinate (AlPi) in intumescent flame retardant polypropylene (PP/IFR) system and the flame-retardant mechanism were investigated. The flame retardancy of PP/IFR/AlPi (the mass ratio of IFR to AlPi is 2 : 1) was the best, which was proved by the results of the limiting oxygen index (LOI) test, UL-94 test, and cone calorimeter test ( CCT) test. Here, the LOI value of the sample was as high as 34% and passed the V–0 rating in UL–94 test. The peak heat release rate (PHRR) decreased by 92.57%, the total heat release (THR) reduced by 90.52%. Thermogravimetric (TGA) data showed that the introduction of AlPi improved thermal stability and changed the thermal degradation behavior of PP/IFR composites. Interestingly, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS) and laser Raman spectroscopy (LRS) proved that PP/IFR/AlPi had formed more residual carbon, but the flame retardancy was worse than PP/IFR/AlPi. This is because when the mass ratio of IFR to AlPi is 2 : 1, the synergy between IFR and AlPi was significant, gas-phase flame retardant and condensed-phase flame retardant reached a balance and obtained the best flame retardant effect.

Systematic evaluation of bromine‐free flame‐retardant systems in acrylonitrile‐butadiene‐styrene

AbstractA systematic investigation of phosphorus‐based flame‐retardant (PFR) systems in acrylonitrile‐butadiene‐styrene (ABS) is presented. The effect of various PFRs, combinations thereof and influence of different synergists is studied in terms of fire and mechanical performance, as well as toxicity of resulting ABS. Sustainable flame‐retardant systems with a promising effect on the fire‐retardant properties of ABS are identified: A combination of aluminum diethylphosphinate and ammonium polyphosphate is shown to exhibit superior flame‐retardant properties in ABS compared to other studied PFRs and PFR combinations. Among a variety of studied potential synergists for this system, a grade of expandable graphite with a high‐initiation temperature and a molybdenum‐based smoke suppressant show the most promising effect, leading to a significant reduction of the peak heat release rate as well as the smoke production rate. Compared to current state‐of‐the‐art brominated flame‐retardant for ABS, the identified flame‐retardant systems reduce the maximum smoke production rate by 70% and the peak heat release rate by 40%. However, a significant reduction of the impact performance of the resulting ABS is identified, which requires further investigation.

Fire-Retardant Synergy of Tris(1-Methoxy-2,2,6,6-Tetramethyl-4-Piperidinyl)Phosphite and Melamine Hydrobromide/Aluminum Diethylphosphinate in Polypropylene

The fire-retardant synergy of tris(1-methoxy-2,2,6,6-tetramethyl-4-piperidinyl)-phosphite (NORPM) and melamine hydrobromide (MHB)/aluminum diethylphosphinate (ADEP) in polypropylene (PP) was characterized by UL-94 tests, limiting oxygen index (LOI) determination and cone calorimetry tests (CCT). NORPM exhibits an exceptional synergy in PP. The LOI and fire-retardant effectivity (EFF) of S-3 (the loadings of MHB and ADEP 1.00 and 1.50 wt%, respectively, no NORPM) were 19.0% and 0.48%, respectively, however, the LOI and EFF of S-15 (the loadings of NORPM, MHB and ADEP 0.2, 1.00 and 1.50 wt%, respectively) significantly increased to 25.5% and 2.85%, respectively, synergistic effectivity (SE) of NORPM is 2.03, and the fire-retardant rating was improved from none to UL 94 V-2 and the total heat release (THR) and peak heat release rate (PHRR) dropped obviously by adding the 0.2 wt% NORPM. The analysis by thermogravimetry-mass spectrum analysis (TG-MS) of the PP samples and the residues in the CCT revealed that NORPM, MHB and ADEP induced the synergy primarily by the following modes: CH3O·, aminyl radicals, CH3·and nitro radicals formed through the cracking of NORPM, along with the free radicals such as PO·, PO2 · and HPO· pyrolyzed from ADEP and HBr from MHB, which quenched the active radicals, such as HO·, H·, ROO·, R· and broke down the radical source. The chain oxidation reaction of combustion was accordingly interrupted, which brought about the more exceptional fire-retardant effect than that of MHB/ADEP.

Synergistic effect of intumescent flame retardant and zinc borate on linear low‐density polyethylene

AbstractA series of novel intumescent flame retardant (IFR) based on melamine, neopentyl glycol, and aluminum diethylphosphinate were prepared and tested. In addition, the synergistic effect of the novel IFR and zinc borate (ZB) on the flame retardancy of LLDPE composites was investigated. The structures of novel IFR and ZB were characterized by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The limiting oxygen index (LOI) increased from 19.3% for the pure LLDPE to 27% for the 25 wt% IFR/5 wt% ZB composites and the composites achieved the desired V‐0 rating in the UL‐94 test. Thermogravimetric analysis showed that the addition of IFR/ZB reduced the pyrolysis rate of the LLDPE composites at high temperatures and increased the amount of the char residues, and the char residue of LLDPE‐5 reached 12.1 wt% at 700°C. Cone calorimetry (CCT) data showed that the peak of total heat release, heat release rate, and fire growth index were comparatively reduced, indicating that the addition of IFR/ZB decreased the fire hazard of LLDPE composites. The formation of a compact and thermally stable char layer on the surfaces of LLDPE composites was revealed from the scanning electrone microscopy images and digital photographs of the char residue after the CCT tests.

Effect of aluminum diethylphosphinate and its synergist on flame-retardant effects of epoxy resin

Effect of aluminum diethylphosphinate and its synergist on flame-retardant effects of epoxy resin

Investigating the Effect of Aluminum Diethylphosphinate on Thermal Stability, Flame Retardancy, and Mechanical Properties of Poly(butylene succinate)

Poly(butylene succinate) is one of the most promising biodegradable polymers, but its applications are limited by poor flame retardancy. In this work, poly(butylene succinate)/diethylphosphinate (PBS/AlPi) composites were fabricated to investigate the effect of AlPi on their thermal stability, flame retardancy, and mechanical properties. It was found that the high content of AlPi decreased the thermal stability of PBS, and the decrease became stronger under the air atmosphere. When the content of AlPi reached 25wt%, the flame retardancy was improved with limited oxygen index (LOI) of 29.5%, V0 rating in UL-94 vertical burning test, and 49.3% reduction on the peak of heat release rate (PHRR) in cone calorimeter test. Meanwhile, the addition of AlPi could improve the mechanical properties of PBS with high tensile strength and Young’s modulus, which was ascribed to the compatible effect of maleic anhydride-grafted poly(butylene succinate) (PBS-g-MA) with good filler dispersion and strong matrix-particles interaction. Thus, the AlPi was an effective flame retardant to PBS, so that PBS/AlPi composites displayed excellent flame retardancy without seriously sacrificing other comprehensive performances.

Fire‐retardant synergy of bis(1‐methoxy‐2,2,6,6‐tetramethyl‐4‐piperidinyl)sebacate and melamine hydrobromide/aluminum diethylphosphinate in polypropylene

SummaryThe fire‐retardant synergy of bis(1‐methoxy‐2,2,6,6‐tetramethyl‐4‐piperidinyl)sebacate (NORSM) and melamine hydrobromide (MHB)/aluminum diethylphosphinate (ADEP) in polypropylene (PP) has been studied using UL‐94 tests, limiting oxygen index (LOI) determination, and cone calorimetry tests (CCTs). The results indicate that NORSM exhibits exceptional fire‐retardant synergy with ADEP/MHB in PP. For a PP composite with 1.0 wt% of MHB and 1.5 wt% of ADEP, the LOI increased from 19.0% to 26.0%, fire retardation effectivity increased from 0.48 to 2.93, synergy effectivity was as high as 1.99, UL‐94 level was enhanced from none to V‐2, fire performance index increased from 56.4 to 84.8, and various heat release values decreased significantly when the PP composite just discussed combining 0.30 wt% of NORSM. NORSM plays a role in synergy with ADEP/MHB primarily through the following modes: radicals such as CH3O· and aminyl formed by the decomposition of NORSM; PO2·, PO·, and HPO· formed from ADEP; HBr formed from MHB; and quench active radicals such as HO· for combustion and breaking down the radical source, which terminates the chain oxidation reaction for combustion, leading to more exceptional fire retardation in the gaseous phase.

Improving thermal and flame retardant properties of sorbitol‐based bioepoxy systems by phosphorus‐based flame retardants

SummaryFlame‐retarded sorbitol‐based bioepoxy resins cured with cycloaliphatic amine hardener and containing different commercially available additive‐type flame retardants (FRs) have been prepared. Three different oxidation states of phosphorus, aluminium diethyl phosphinate (AlPi) (+1), phosphonate polyol (+3), ethyl ethylene glycol phosphate and ammonium polyphosphate (APP) (+5), have been studied. The effect of using melamine cyanurate with APP and AlPi has been assessed. The self‐extinguishing V‐0 rating according to UL‐94 flammability standard tests and very good limiting oxygen index for combustion are displayed for most flame‐retarded samples at 3 wt% phosphorus content. The flame retardancy effect for the additives was confirmed using cone calorimetry. The samples containing MC with APP at 3%P content showed a dramatic reduction of the total heat release by 60% and reduction of the peak of heat release rate by 70% compared to the reference epoxy matrix. The addition of these FRs together did not decrease the glass transition temperature significantly.