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

2021 ◽  
Vol 36 (5) ◽  
pp. 519-528
Author(s):  
J.-L. Li ◽  
C.-T. Gao ◽  
X. Sun ◽  
S.-G. Peng ◽  
Y.-W. Wang ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Laser Raman Spectroscopy ◽  
Mass Ratio ◽  
Limiting Oxygen Index ◽  
Laser Raman ◽  
Cone Calorimeter Test ◽  
Ul 94 ◽  
Synergistic Flame Retardant

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.

scholarly journals Flame-Retardant Performance of Transparent and Tensile-Strength-Enhanced Epoxy Resins

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 317 ◽  
Author(s):  
Liang Li ◽  
Zaisheng Cai
Keyword(s):  
Tensile Strength ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Epoxy Resins ◽  
Diglycidyl Ether ◽  
Laser Raman Spectroscopy ◽  
Limiting Oxygen Index ◽  
Laser Raman ◽  
Ul 94 ◽  
Amine Curing

In this study, a flame-retardant additive with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) groups denoted DSD was successfully synthesized from DOPO, 4,4′-diaminodiphenyl sulfone (DDS), and salicylaldehyde. The chemical structure of DSD was characterized by FTIR–ATR, NMR, and elemental analysis. DSD was used as an amine curing agent, and the transparent, tensile strength-enhanced epoxy resins named EP–DSD were prepared via thermal curing reactions among the diglycidyl ether of bisphenol A (DGEBA), 4,4′-diaminodiphenylmethane (DDM), and DSD. The flame-retardancy of composites was studied by the limiting oxygen index (LOI) and UL-94 test. The LOI values of EP–DSD composites increased from 30.7% for a content of 3 wt % to 35.4% for a content of 9 wt %. When the content of DSD reached 6 wt %, a V-0 rating under the UL-94 vertical test was achieved. SEM photographs of char residues after the UL-94 test indicate that an intumescent and tight char layer with a porous structure inside was formed. The TGA results revealed that EP–DSD thermosets decomposed ahead of time. The graphitization degree of the residual chars was also investigated by laser Raman spectroscopy. The measurement of tensile strength at breaking point shows that the loading of DSD increases the tensile strength of epoxy thermosets. Py-GC/MS analysis shows the presence of phosphorus fragments released during EP–DSD thermal decomposition, which could act as free radical inhibitors in the gas phase. Owing to the promotion of the formation of intumescent and compact char residues in the condensed phase and nonflammable phosphorus fragments formed from the decomposition of DOPO groups, EP–DSD composites displayed obvious flame-retardancy.

scholarly journals PREPARATION OF IRON- REDUCED GRAPHENE OXIDE/ EPOXY RESIN COMPOSITE AND ITS FLAME RETARDANCY AND THERMAL STABILITY

10.6036/10327 ◽  
2022 ◽  
Vol 97 (1) ◽  
pp. 98-103
Author(s):  
XIAN WANG ◽  
JINLONG ZHUO ◽  
TIANQING XING ◽  
Xingran Wang
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Iron Powder ◽  
Flame Retardancy ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Industrial Manufacture ◽  
Ul 94

In order to reduce flammability, smoke release and enhance thermal stability of epoxy resin (EP), iron powder is mixed with graphene oxide/ epoxy resin (GO/EP) composite by mechanical blending. The combustion performance of composite material is investigated through limiting oxygen index (LOI), Underwriters Laboratory (UL)-94 test, and cone calorimeter test (CCT). Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and scanning electron microscope (SEM) are also used to explore the mechanism of flame retardancy and smoke suppression. Results show that, with the addition of 0.5% mass fraction of GO and the corresponding iron powder combination (EP3 sample), the LOI value can achieve 32.5% while reaching the UL-94 V0 rating. Compare with EP0, the peaks of heat release rate, smoke production rate, and smoke factor values of EP3 are decreased by 42%, 60%, and 50%, respectively. The char and TG-FTIR data of EP3 reveal that it has a more compact structure, good thermal stability, and produce fewer toxic gases and smoke. Reduction of GO could inhibit the degradation of EP, and iron catalyzes the formation of carbonaceous char on the surface. Thus, the thermal stability and flame retardancy of EP are improved significantly. This study provides a suitable way to prepare graphene/EP composites that contain iron catalyst and can be extended to the industrial manufacture of flame retardant polymer composites. Keywords: iron powder; epoxy resin; graphene oxide; flame retardant; thermal stability

The synergistic flame retardancy of modified expandable graphite and metal hydroxides on HDPE/EVA composites

2020 ◽  
pp. 089270572092513
Author(s):  
Xincheng Guo ◽  
Nian Liu ◽  
Lingtong Li ◽  
Zhuyu Bai ◽  
Xiaolang Chen ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardancy ◽  
Synergistic Effects ◽  
Zinc Borate ◽  
Expandable Graphite ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Ul 94

In this article, the flammable behaviors and synergistic effects of modified expanded graphite (MEG) with zinc borate (ZB) on flame-retardant high-density polyethylene/ethylene vinyl acetate (HDPE/EVA) composites containing magnesium hydroxide (MH) and aluminum hydroxide (ATH) are investigated by the Underwriters Laboratories-94 (UL-94) test, limiting oxygen index (LOI), cone calorimeter test (CCT), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), differential scanning calorimetry, and tensile tests. The LOI, UL-94, and CCT results show that the synergistic effect of MEG and ZB can improve the flame retardancy of the composites. With the addition of ZB and MEG, the LOI value increases, and the UL-94 reaches the V-0 rating. The heat release rate and total heat release decrease, respectively. The data obtained from the TGA indicate that the synergistic effects of ZB with MEG increase the decomposition temperature when 2 phr ZB and 8 phr MEG are added into the composites. The data from FTIR show that HMEG8 and HMEG10 composites produce phosphate at high temperatures, which promotes the formation of stable and compact charred layer. All the results show that ZB and MEG have positive synergistic effects on HDPE/EVA composites containing MH and ATH. However, ZB and MEG play a negative role in the tensile properties of the HDPE/EVA composites.

Epoxy resin/cyanate ester composites containing DOPO and wollastonite with simultaneously improved flame retardancy and thermal resistance

2020 ◽  
Vol 32 (6) ◽  
pp. 710-718
Author(s):  
Zhengzhou Wang ◽  
Xin Gao ◽  
Wenfeng Li
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Oxygen Index ◽  
Thermal Studies ◽  
Cyanate Ester ◽  
Total Heat Release ◽  
Limiting Oxygen Index ◽  
Peak Heat Release Rate ◽  
Ul 94

Flame-retardant epoxy (EP) resin/cyanate ester (CE) composites were prepared with 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and wollastonite (Wo). The combustion behavior of the flame-retardant EP/CE composites was investigated by limiting oxygen index (LOI), UL-94, and cone calorimeter tests. It is found that the EP/CE composite containing 7 wt% DOPO and 3 wt% Wo (sample 7DO/3Wo/EP/CE) exerts the best flame retardancy (LOI 35.5% and UL-94 V-0 rating). The peak heat release rate and total heat release of sample 7DO/3Wo/EP/CE increase slightly, while total smoke release decreases about 14% compared with the EP/CE composite containing 10 wt% DOPO (sample 10DO/EP/CE). Thermal studies indicate that the glass transition temperature and temperature at 5% mass loss of sample 7DO/3Wo/EP/CE are higher than that of sample 10DO/EP/CE. Moreover, the mechanical properties of EP/CE composites were investigated.

Investigation on the effect of supported synergistic catalyst with intumescent flame retardant in polypropylene

2021 ◽  
Vol 41 (4) ◽  
pp. 281-288
Author(s):  
Hongmei Peng ◽  
Qi Yang
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Flame Retardants ◽  
Supported Catalyst ◽  
Intumescent Flame Retardant ◽  
Limiting Oxygen Index ◽  
Polypropylene Composites ◽  
Cone Calorimeter Test ◽  
Microscale Combustion Calorimetry

Abstract In this paper, cerium nitrate supported silica was prepared as a new type of catalytic synergist to improve the flame retardancy in polypropylene. When 1% of Ce(NO3)2 supported SiO2 was added, the vertical combustion performance of UL-94 of polypropylene composites was improved to V-0, the limiting oxygen index (LOI) was increased to 33.5. From the thermogravimetric analysis (TGA), the residual carbon of C and D was increased by about 6% at high temperature compared with B. When adding supported catalyst, the heat release rate (HRR) and total heat release (THR) were significantly reduced according to the microscale combustion calorimetry (MCC), the HRR of sample E with 2% synergist was the lowest. The combustion behaviors of intumescent flame retardant sample B and sample D were analyzed by cone calorimeter test (CCT), the HRR of sample D with supported synergist was significantly reduced, and the PHRR decreased from 323 kW/m2 to 264 kW/m2. The morphologies of the residue chars after vertical combustion of polypropylene composites observed by scanning electron microscopy (SEM) gave positive evidence that the supported synergist could catalyze the decomposition of intumescent flame retardants into carbon, which was the main reason for improving the flame retardancy of materials.

scholarly journals Flame Retardancy and Toughness of Poly(Lactic Acid)/GNR/SiAHP Composites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1129 ◽  
Author(s):  
Ningjing Wu ◽  
Jihang Yu ◽  
Wenchao Lang ◽  
Xiaobing Ma ◽  
Yue Yang
Keyword(s):  
Lactic Acid ◽  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
High Performance ◽  
Poly Lactic Acid ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Interfacial Compatibility ◽  
Aluminum Hypophosphite

A novel flame-retardant and toughened bio-based poly(lactic acid) (PLA)/glycidyl methacrylate-grafted natural rubber (GNR) composite was fabricated by sequentially dynamical vulcanizing and reactive melt-blending. The surface modification of aluminum hypophosphite (AHP) enhanced the interfacial compatibility between the modified aluminum hypophosphite by silane (SiAHP) and PLA/GNR matrix and the charring ability of the PLA/GNR/SiAHP composites to a certain extent, and the toughness and flame retardancy of the PLA/GNR/SiAHP composites were slightly higher than those of PLA/GNR/AHP composites, respectively. The notched impact strength and elongation of the PLA composite with 20 wt. %GNR and 18 wt.% SiAHP were 13.1 kJ/m2 and 72%, approximately 385% and 17 fold higher than those of PLA, respectively, and its limiting oxygen index increased to 26.5% and a UL-94 V-0 rating was achieved. Notedly, the very serious melt-dripping characteristics of PLA during combustion was completely suppressed. The peak heat release rate and total heat release values of the PLA/GNR/SiAHP composites dramatically reduced, and the char yield obviously increased with an increasing SiAHP content in the cone calorimeter test. The good flame retardancy of the PLA/GNR/SiAHP composites was suggested to be the result of a synergistic effect involving gaseous and condensed phase flame-retardant mechanisms. The high-performance flame-retardant PLA/GNR/SiAHP composites have great potential application as replacements for petroleum-based polymers in the automotive interior and building fields.

Modified expandable graphite as an effective flame retardant for LLDPE/EVA composites filled with Mg(OH)2/Al(OH)3

2019 ◽  
Vol 33 (7) ◽  
pp. 938-955
Author(s):  
Nian Liu ◽  
Na Wang ◽  
Lingtong Li ◽  
Weidi He ◽  
Jianbing Guo ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Synergistic Effects ◽  
Ethylene Vinyl Acetate ◽  
Gas Production ◽  
Expandable Graphite ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Ul 94

The flammability, thermal properties, and synergistic effects of modified expandable graphite (MEG) with magnesium hydroxide (MH) and aluminum hydroxide (ATH) on the linear low-density polyethylene/ethylene vinyl acetate (LLDPE/EVA) blends are investigated by Underwriters Laboratories-94 (UL-94) vertical combustion test, limiting oxygen index (LOI), thermogravimetric analysis (TGA), cone calorimeter test (CCT), and scanning electron microscopy (SEM). The results show that the MEG improves the flame-retardant efficiency of LLDPE/EVA blends. The addition of MEG apparently improves the LOI values and the UL-94 rating of LLDPE/EVA composites. The data obtained from the CCT show that the heat release rate (HRR), the total heat release (THR), and the gas production rate of composites with MEG decrease remarkably with increasing the content of MEG. When 10 phr of MEG is added, the char residues of LEMEG10 increase to 38.2% from 2.7% of LLDPE/EVA. The results of SEM and CCT present that MEG can improve the quality of char layers. The rate of char formation is enhanced also due to the existence of MEG, which plays an important role to improve the flame retardancy of the LLDPE/EVA composites.

The effect of boric acid on flame retardancy of intumescent flame retardant polypropylene composites including nanoclay

2021 ◽  
pp. 089270572110523
Author(s):  
Yasin Demirhan ◽  
Recep Yurtseven ◽  
Nazım Usta
Keyword(s):  
Thermal Conductivity ◽  
Boric Acid ◽  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Boron Oxide ◽  
Experimental Studies ◽  
Intumescent Flame Retardant ◽  
Limiting Oxygen Index ◽  
Ul 94

In this study, different amounts of boric acid (BA, 1.25, 2.5, 3.75 and 5.0 wt%) were used to enhance the effectiveness of an intumescent flame retardant (IFR) system composed of ammonium polyphosphate (APP) and pentaerythritol (PER) in polypropylene (PP) including 2 wt% montmorillonite nanoclay (MMT). Meanwhile, metaboric acid and boron oxide which were generated by the decomposition of BA appeared in the melt compounding and the burning processes, respectively. Extensive experimental studies were performed to investigate the effects of BA/boron oxide and MMT combinations on the properties of PP/IFR. The fire resistances of the composites were studied by UL 94, limiting oxygen index (LOI) and cone calorimetry tests. The thermal properties were determined by using thermogravimetric analysis, differential scanning calorimetry and thermal conductivity measurements. In addition, the mechanical properties of the composites were examined. The experimental results revealed that although the additions of 1.25 and 2.5 wt% BA with 2 wt% MMT significantly enhanced thermal and flame resistances of PP composites, 3.75 and 5.0 wt% BA additions generated antagonistic effects and deteriorated the fire resistance of the composites. The sample including 2.5 wt% BA addition achieved the best flame retardancy. The LOI value was increased from 18 to 31% with UL 94 V-0 rating. In addition, the peak heat release rate was reduced from 668.6 to 150.0 kW/m2 and the total heat release value was decreased from 247.9 to 98.4 MJ/m2. In the meantime, the thermal conductivity was increased from 0.22 up to 0.28 W/mK. Furthermore, CO, CO2 and the smoke productions were significantly decreased with respect to PP. NO generation was decreased with BA replacements. At the same time, although there was a slight decrease in the tensile strength, the flexural strength significantly increased with BA and MMT additions.

scholarly journals Flame Retardancy and Mechanism of Novel Phosphorus-Silicon Flame Retardant Based on Polysilsesquioxane

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1304 ◽  
Author(s):  
Shengjie Zhu ◽  
Weiguang Gong ◽  
Ji Luo ◽  
Xin Meng ◽  
Zhong Xin ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Gas Phase ◽  
Condensed Phase ◽  
Flame Retardancy ◽  
Carbon Layer ◽  
Poly Lactic Acid ◽  
Limiting Oxygen Index ◽  
Synergistic Flame Retardant ◽  
Silicon Based

A novel phosphorus-silicon flame retardant (P5PSQ) was prepared by bonding phosphate to silicon-based polysilsesquioxane (PSQ) and used as flame retardant of poly (lactic acid) (PLA). The results show that PLA with 10 wt % P5PSQ has a limiting oxygen index (LOI) 24.1%, the peak heat release rate (PHRR) and total heat release (THR) of PLA decrease 21.8% and 25.2% compared to neat PLA in cone calorimetric test, indicating that P5PSQ shows better flame retardancy in comparison to PSQ. Furthermore, the study for the morphology and composition of carbon residue after the combustion of PLA and the gas release of PLA during combustion illustrate that P5PSQ has flame retardancy in condensed phase and gas phase simultaneously. In condensed phase, phosphorus from phosphate promotes the formation of more stable and better carbon layer containing Si and P, which inhibits the transfer of heat and oxygen in the combustion. In gas phase, the phosphate in P5PSQ emits phosphorus-containing compound that can restrain the release of C–O containing products, which may have effective flame retardancy for PLA in gas phase to a certain extent. In one word, P5PSQ is denoted as a good phosphorus-silicon synergistic flame-retardant.

Synthesis of a phosphorus–nitrogen-containing flame retardant and its application in epoxy resin

2018 ◽  
Vol 31 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Shuang Yang ◽  
Yefa Hu ◽  
Qiaoxin Zhang
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Heat Release Rate ◽  
Flame Retardancy ◽  
Release Rate ◽  
Epoxy Resins ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Cone Calorimeter Test

In this article, a phosphorus–nitrogen-containing flame retardant (DOPO-T) was successfully synthesized by nucleophilic substitution reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and cyanuric chloride. The chemical structure of DOPO-T was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) and phosphorous-31 NMR, and elemental analysis. DOPO-T was then blended with diglycidyl ether of bisphenol-A to prepare flame-retardant epoxy resins. Thermal properties, flame retardancy, and combustion behavior of the cured epoxy resins were evaluated by differential scanning calorimetry, thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the glass transition temperature ( Tg) and temperature at 5% weight loss of epoxy resin (EP)/DOPO-T thermosets were gradually decreased with the increasing content of DOPO-T. DOPO-T catalyzed the decomposition of EP matrix in advance. The flame-retardant performance of EP thermosets was significantly enhanced with the addition of DOPO-T. EP/DOPO-T-0.9 sample had an LOI value of 36.2% and achieved UL94 V-1 rating. In addition, the average of heat release rate, peak of heat release rate, average of effective heat of combustion, and total heat release (THR) of EP/DOPO-T-0.9 sample were decreased by 32%, 48%, 23%, and 31%, respectively, compared with the neat EP sample. Impressively, EP/DOPO-T thermosets acquired excellent flame retardancy under low loading of flame retardant.

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