scholarly journals Flame Retardancy, Fire Behavior, and Flame Retardant Mechanism of Intumescent Flame Retardant EPDM Containing Ammonium Polyphosphate/Pentaerythrotol and Expandable Graphite

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4035 ◽  
Author(s):  
Junsheng Wang ◽  
Lei Xue ◽  
Bi Zhao ◽  
Guide Lin ◽  
Xing Jin ◽  
...  

The intumescent flame retardant ethylene–propylene–diene rubber (EPDM) was prepared using intumescent flame retardant (IFR), including ammonium polyphosphate (APP) /pentaerythrotol (PER) and expandable graphite (EG), as the flame retardant agent. The effects of IFR and EG on the flame retardancy, fire behavior, and thermal stability of the EPDM were investigated. The results show that IFR and EG have excellent synergistic flame retardant effects. When the mass ratio of IFR to EG is 3:1 and the total addition content is 40 phr, the limiting oxygen index (LOI) value of the EPDM material (EPDM/IFR/EG) can reach 30.4%, and it can pass a V-0 rating in the vertical combustion (UL-94) test. Meanwhile, during the cone calorimetry test, the heat release rate and total heat release of EPDM/IFR/EG are 69.0% and 33.3% lower than that of the pure EPDM, respectively, and the smoke release of the material also decreases significantly, suggesting that the sample shows good fire safety. In addition, the flame retardant mechanism of IFR and EG is systematically investigated by thermogravimetric analysis/infrared spectrometry (TG-IR), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), and the results indicate that IFR and EG have only physical interaction. Moreover, the reason why IFR exhibits a poor flame retardant effect in EPDM materials is explained.

2021 ◽  
Vol 41 (4) ◽  
pp. 281-288
Author(s):  
Hongmei Peng ◽  
Qi Yang

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.


2021 ◽  
pp. 089270572110523
Author(s):  
Yasin Demirhan ◽  
Recep Yurtseven ◽  
Nazım Usta

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.


2018 ◽  
Vol 89 (10) ◽  
pp. 2031-2040 ◽  
Author(s):  
Fanglong Zhu ◽  
QQ Feng ◽  
YF Xu ◽  
JF Hu

Flame retardant mixtures of multi-walled carbon nanotubes (MWCNTs) and intumescent flame retardant (IFR) coatings were applied to polyamide 6,6 (PA 6,6) fabrics to explore whether MWCNTs acted as a good synergist on the thermal stability and flame resistance of the IFR system. The influence of MWCNTs on the flame retardant properties and thermal degradation of the PA 6,6 fabrics were investigated by limiting oxygen index (LOI), vertical burning test (VBT), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM) and cone calorimeter test (CCT). The peak heat release rate and total heat release of the IFR-PA 6,6 fabric with three kinds of wt% MWCNTs were lower than those of the only traditional IFR-PA 6,6 fabric (reduced by 74.2–76.4% and 74.3–76.5%, respectively). As compared to the traditional IFR coating, it was found that no enhancements for thermal stability and flame retardancy in terms of the ability to retard ignition were achieved for the MWCNT/IFR coating. These results demonstrated that the introduction of MWCNTs into an IFR coating can improve the flame retardancy of PA 6,6 fabric in terms of the heat release rate from CCT analysis, but it failed other burning measurements, such as LOI and VBT.


Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 668 ◽  
Author(s):  
Yang ◽  
Liu ◽  
Jiang ◽  
Chen ◽  
Wan

The current study aims at comparatively investigating the effect of apparent density on flame retardancy, thermal degradation and combustion behaviors of rigid polyurethane foam (RPUF), RPUF/ expandable graphite (EG) and RPUF/ ammonium polyphosphate (APP). A series of RPUF, RPUF/EG and RPUF/APP samples with different apparent densities (30, 60 and 90 kg/m3) were prepared. The flame retardancy, thermal degradation, and combustion behaviors of each sample were investigated. Limiting oxygen index (LOI) results indicated that increasing apparent density was beneficial to the flame retardancy of all foam systems. The effect of apparent density on the enhancement of flame retardancy followed the sequence of RPUF < RPUF/APP < RPUF/EG. Thermogravimetric analysis (TGA) results showed that an increase in the apparent density can cause more weight loss in the first degradation stage and less weight loss in the second degradation stage for all foam systems. The combustion behaviors also showed significant differences. The samples with a higher apparent density showed a longer duration of heat release and higher total heat release (THR). The findings in this study demonstrated that apparent density played an important role in flame retardancy, thermal degradation, and combustion behaviors of RPUF, which must be paid more attention in the studies of flame-retardant RPUF.


2019 ◽  
Vol 14 ◽  
pp. 155892501987030
Author(s):  
Yinchun Fang ◽  
Xinhua Liu ◽  
Cuie Wang

Layer-by-layer assembly is a simple and effective method which has been widely studied to improve the flame retardancy of textiles in recent years. In this article, flame-retardant and anti-dripping polyethylene terephthalate fabrics were successfully prepared by layer-by-layer assembly branched polyethylenimine and ammonium polyphosphate on their surface. The results of limiting oxygen index values and vertical burning test revealed that the flame retardancy and anti-dripping performance of polyethylene terephthalate fabrics were improved after the layer-by-layer assembly treatment; especially, the dripping phenomenon was eliminated when the number of branched polyethylenimine/ammonium polyphosphate bilayers was over 10. The influence of alkali treatment of polyethylene terephthalate fabrics before layer-by-layer assembly was also investigated. The results showed that alkali treatment of the polyethylene terephthalate fabrics would promote the combination of polyethylene terephthalate fabrics and the charged flame retardants indicating better flame retardancy. The results of thermogravimetric analysis revealed that layer-by-layer assembly treatment of polyethylene terephthalate fabrics would promote char formation both under the nitrogen atmosphere and under the air atmosphere which may act through condensed phase action. The scanning electron microscopy images of the char residues revealed that the layer-by-layer assembly treatment of polyethylene terephthalate fabrics would promote the formation of a compact and intact char residue, which was beneficial for the improvement of flame retardancy and anti-dripping performance. This research would provide the experimental basis for the effective flame retardancy and anti-dripping performance of polyethylene terephthalate fabric.


2016 ◽  
Vol 87 (11) ◽  
pp. 1367-1376 ◽  
Author(s):  
Chaohong Dong ◽  
Zhou Lu ◽  
Peng Wang ◽  
Ping Zhu ◽  
Xuechao Li ◽  
...  

A novel formaldehyde-free flame retardant containing phosphorus and dichlorotriazine components (CTAP) for cotton fabrics was synthesized. As an active group, the dichlorotriazine could react with cotton fabric via covalent reaction. The addition of 20.7 wt% CTAP into the cotton fabric obtained a high limiting oxygen index value of 31.5%, which was 13.5% higher than the pure cotton fabric. The results of heat release rate, total heat release and effective heat combustion indicated that CTAP effectively imparted flame retardancy to cotton fabric by the cone calorimetry test. With respect to the untreated cotton fabrics, the treated cotton fabrics degraded at lower decomposition temperature and form a consistent and compact char layer, which could be observed by thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. Compared to the untreated cotton fabrics, CTAP performed an effective role in flame retardancy for treated cotton fabrics. Meanwhile, it stimulated the formation of char and promoted the thermal stability of treated cotton fabrics during combustion.


2017 ◽  
Vol 748 ◽  
pp. 51-54
Author(s):  
Pei Bang Dai ◽  
Lin Ying Yang ◽  
Ting Zheng ◽  
Chang Qin ◽  
Qi Chen Tang

A rigid polyurethane (PU) flame retardant composite foam was prepared by the compounding of polyols and diisocyanates with a modified intumescent flame retardant (MIFR). The MIFR was based on the three components of intumescent flame retardant normally used and was modified in a surfactant TX-10 solution. The flame retardancy of the PU flame retardant composite foams were evaluated by using the limiting oxygen index (LOI), the UL-94 (vertical flame) test and scanning electron microscopy (SEM). When MIFR was fixed at 20.0 wt% in PU/MIFR composite foams, the MIFR could enhance the flame retardancy and pass V-0 rating of UL-94 test. The microstructures observed by SEM demonstrate that a suitable amount of MIFR can promote formation of compact intumescent charred layers in PU foams.


2011 ◽  
Vol 399-401 ◽  
pp. 1376-1380
Author(s):  
Li Hua You ◽  
Yin Yin Hui ◽  
Xiang Ning Shi ◽  
Zhi Han Peng

In this study, a novel phosphorus-nitrogen containing intumescent flame retardant (P-N IFR) poly(melamine 2-carboxyethyl(phenyl) phosphate)(PMCEP) was prepared via the reaction of 2-carboxyethyl (phenyl) phosphinic acid (CEPPA) and melamine (MEL) in two-steps. Meanwhile, the molecular structure of the chemical compound was determined by FTIR,1H-NMR and elemental analysis; and the thermal properties was investigated by means of TGA. Combustion studies revealed high limiting oxygen index (LOI) indicative of better flame-retardancy properties for PBT resin.


Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2900
Author(s):  
Linyuan Wang ◽  
Yue Wei ◽  
Hongbo Deng ◽  
Ruiqi Lyu ◽  
Jiajie Zhu ◽  
...  

Recently, widespread concern has been aroused on environmentally friendly materials. In this article, barium phytate (Pa-Ba) was prepared by the reaction of phytic acid with barium carbonate in deionized water, which was used to blend with intumescent flame retardant (IFR) as a flame retardant and was added to epoxy resin (EP). Afterward, the chemical structure and thermal stability of Pa-Ba were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), respectively. On this basis, the flammability and flame retardancy of EP composites were researched. It is shown that EP/14IFR/2Ba composite has the highest limiting oxygen index (LOI) value of 30.7%. Moreover, the peak heat release rate (PHRR) of EP/14IFR/2Ba decreases by 69.13% compared with pure EP. SEM and Raman spectra reveal the carbonization quality of EP/14IFR/2Ba is better than that of other composites. The results prove that Pa-Ba can cooperate with IFR to improve the flame retardancy of EP, reducing the addition amount of IFR in EP, thus expanding the application range of EP. In conclusion, adding Pa-Ba to IFR is a more environmentally friendly and efficient method compared with others.


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