Enhancing cellular structure, mechanical properties, thermal stability and flame retardation of EVA/NR blend nanocomposite foams by silicon dioxide-based flame retardant

2021 ◽  
pp. 147776062110420
Author(s):  
Alif Walong ◽  
Bencha Thongnuanchan ◽  
Nattapon Uthaipan ◽  
Tadamoto Sakai ◽  
Natinee Lopattananon
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Silicon Dioxide ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Cellular Structure ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Nanocomposite Foams ◽  
Blend Nanocomposites

Flame retardant rubber foams of ethylene vinyl acetate (EVA)/natural rubber (NR)/layered silicate blends filled with silicon dioxide (SiO2) were prepared by using azodicarbonamide (ADC) as a blowing agent. Specifically, SiO2 was added in EVA/NR blend nanocomposites to produce good flame retardant foams. The properties of EVA/NR blend nanocomposite foams with different SiO2 loading (0, 20, 30, 40 parts per hundred rubber, phr) were investigated through transmission electron microscopy (TEM), scanning electron microscopy (SEM), rheological property test, mechanical property measurement, flammability tests, thermogravimetry analysis (TGA) and pyrolysis-gas chromatography-mass spectrometry (Pyrolysis-GC-MS). Compared with the simple EVA/NR blend nanocomposite, the added SiO2 increased the blend compatibility between EVA and NR phases and melt strength/viscosity of the EVA/NR blend nanocomposites, thus promoting cellular structure of the EVA/NR nanocomposite foams. Increasing SiO2 loading resulted in higher cell density, smaller cell size, and lower volume of void. These improvements caused higher strength and elastomeric recovery. The LOI test results showed that flame retardancy of the EVA/NR blend nanocomposite foams increased at higher SiO2 loading as a result of formation of insulation silicon dioxide-based char. TGA and pyrolysis-GC-MS analyses also validated the finding that the silicon dioxide-based char in the foamed samples containing higher SiO2 loading was more effective on improving thermal stability, which was responsible for lower material combustibility and better flame retardancy. Based on our finding, it was concluded that a good flame retardant EVA/NR blend nanocomposite foam with the best improvement in strength and elastomeric recovery was achieved when combined with 40 phr SiO2.

Influence of silicon dioxide addition and processing methods on structure, thermal stability and flame retardancy of EVA/NR blend nanocomposite foams

2020 ◽  
pp. 147776062095343
Author(s):  
Alif Walong ◽  
Bencha Thongnuanchan ◽  
Tadamoto Sakai ◽  
Natinee Lopattananon
Keyword(s):  
Thermal Stability ◽  
Silicon Dioxide ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Layered Silicate ◽  
Melt Mixing ◽  
Limiting Oxygen Index ◽  
Char Layer ◽  
Nanocomposite Foams ◽  
Silicon Based

Rubber nanocomposite foams based on 60/40 ethylene vinyl acetate (EVA)/natural rubber (NR) were melt-mixed with flame retardant silicon dioxide (SiO2) (20 parts per hundred rubber, phr), and foamed by compression molding process. In this study, the effect of mixing phenomena of SiO2 through two different compounding techniques such as direct mixing (DM) and phase selective mixing (PSM) methods on structure, thermal stability, combustility and flame retardancy of EVA/NR blend nanocomposite foams were investigated. DM method is a melt mixing of EVA, NR, layered silicate and SiO2, followed by foaming. PSM is a new method based on pre-mixing EVA with SiO2, then melt mixing of EVA/SiO2 masterbatch with NR and layered silicate, and finally foaming. Based on TEM technique, it was found that the SiO2 was exclusively located in dispersed NR phase for the sample prepared by DM method, and the SiO2 was preferably dispersed in continuous EVA matrix when PSM method was employed. However, the different mixing methods did not significantly alter their cellular structures. The thermal stability and char residue content of foamed samples with SiO2 increased obviously when compared with those of corresponding foams without SiO2. The results based on limiting oxygen index (LOI) test and oxygen bomb calorimetry indicated that the foams combined with SiO2 had better combustion resistance and flame retardancy due to barrier effect of thermally stable silicon-based char layer. Further, the SiO2 filled foamed system obtained from the PSM method showed a higher degree of improvement in thermal stability, combustion resistance and flame retardancy than that of DM method because the homogeneous dispersion of SiO2 in EVA matrix rather than the selective dispersion in NR phase. This resulted in the continuity of flame retardant EVA/SiO2 phase in the 60/40 EVA/NR nanocomposite foams, which exerted more efficient fire barrier of the silicon-based char layer.

The flame retardancy and pyrolysis mechanism of polyimide fibers investigated by cone calorimeter and pyrolysis–gas chromatography–mass spectrometry

2017 ◽  
Vol 48 (2) ◽  
pp. 465-481 ◽  
Author(s):  
Xiansheng Zhang ◽  
Xiong Yan ◽  
Meiwu Shi
Keyword(s):  
Electron Microscopy ◽  
Heat Flux ◽  
Flame Retardancy ◽  
Cone Calorimeter ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Mechanism ◽  
Pyrolysis Gas Chromatography ◽  
Polyimide Fibers ◽  
Scanning Electron

In the present research, the flame retardancy and pyrolysis mechanism of polyimide fibers were investigated by cone calorimeter, scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and pyrolysis–gas chromatography–mass spectrometry. As it turned out, the polyimide fibers possessed excellent thermal stability and flame retardancy. The onset thermal degradation temperature ( Tonset 10%) of polyimide was 587℃ and 610℃ at nitrogen and air atmospheres, respectively. The polyimide fibers cannot be ignited at the heat flux of 35 and 50 kW/m2, while they can be ignited at the heat flux of 75 kW/m2 with the time to ignition of 33 s and peak heat release rate of 53.4 kW/m2. Moreover, the flame retardancy of woven and knitted fabrics was also discussed, which demonstrated that knitted fabric was easier to become thermally thick than woven fabric. Scanning electron microscopy analysis of the residual chars of fibers showed that the shape of fiber can be maintained irrespective of heat flux, but the chemical structure of the fiber was destroyed at the heat flux of 75 kW/m2. The pyrolysis combustible volatiles at 700℃ include benzonitrile, aniline, and phenol, which can interpret the ignition of polyimide fibers. The results obtained in the present research revealed the flame retardancy and pyrolysis mechanism of polyimide fibers, which can guide its application and further modification.

A transparent and intumescent phosphaphenanthrene/phenylpyrazole-containing epoxy resin system and its flame retardancy

2021 ◽  
pp. 095400832199241
Author(s):  
Zijin Luo ◽  
Zhe Chen ◽  
Jun Wei ◽  
Dongchao Wang ◽  
Han Chen ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Flame Retardancy ◽  
Gas Chromatography Mass Spectrometry ◽  
Control Group ◽  
Pyrolysis Gas ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Epoxy Resin System ◽  
Index Value

A novel intumescent flame retardant, PPMD, was designed from phosphaphenanthrene and nitrogen heterocycles through the two-step gut reactions of 1,4-phthalaldehyde and 3-methyl-1-phe-nylpyrazol-5-ylamine. After determination of its structure by nuclear magnetic resonance and Fourier-transform infrared analyses, PPMD was added to an epoxy resin (EP) to facilitate a curing process. Thus, EP/PPMD samples with excellent transparency and flame retardancy were acquired. For example, the EP sample satisfied the UL-94 V-0 standard and achieved a limiting oxygen index value of 30.5% because of the incorporation of 5 wt% PPMD. The cone calorimeter test of the EP/5% PPMD sample revealed that its total smoke production (TSP) and total heat release (THR) values of EP/5% PPMD was only 22.5% and 56.4% of the control group, respectively. Moreover, the average effective heat of combustion (av-EHC) value of EP/5% PPMD was reduced by 34.1%, indicating that PPMD possessed high flame-inhibition activity and smoke suppression efficiency. The flame-retardant mechanisms of PPMD were also investigated in gas phase by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and in condensed phase by XPS and IR.

scholarly journals Surface Coating for Flame Retardancy and Pyrolysis Behavior of Polyester Fabric Based on Calcium Alginate Nanocomposites

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 875 ◽  
Author(s):  
Zhenhui Liu ◽  
Jiao Li ◽  
Xihui Zhao ◽  
Zichao Li ◽  
Qun Li
Keyword(s):  
Thermal Stability ◽  
Flame Retardancy ◽  
Textile Industry ◽  
Calcium Alginate ◽  
Polyester Fabric ◽  
Gas Chromatography Mass Spectrometry ◽  
Calcium Borate ◽  
Cone Calorimetry ◽  
Pyrolysis Gas ◽  
Limiting Oxygen Index

A polyester fabric, coated with calcium alginate and nano-calcium borate composites (CAB-PL), was fabricated by a post-cross-linking method, with remarkable improvement of flame retardancy and thermal stability, as compared with the original polyester fabric (PL). The mechanical properties of CAB-PL and PL were studied, and characterizations and tests including Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM), limiting oxygen index (LOI), cone calorimetry (CONE) and thermogravimetric analysis (TGA) were employed to evaluate the flame retardancy and thermostability. The test results of CAB-PL showed excellent mechanical strength and anti-dripping properties. In comparison with PL, TGA results indicate that the presence of surface-coated composites produced more char residue and can effectively inhibit the heat transmission, and the LOI value of CAB-PL was improved from 25 to 33. Moreover, CONE results show that 88.65% reduction of total smoke release (TSR) values was induced by the presence of CAB. In addition, the possible pyrolysis mechanisms for CAB-PL have been proposed based on the results of pyrolysis-gas chromatography–mass spectrometry (Py-GC-MS) analysis. The combined results can provide useful information for understanding the flame retardant mechanisms of alginates as well. In summary, polyester fabric was upgraded by coating it with the calcium alginate/nano-calcium borate, thus achieving extraordinary flame retardancy and thermal stability for various applications within the textile industry.

An efficient flame retardant for epoxy resin: Preparation and pyrolytic behaviour

2018 ◽  
Vol 31 (9-10) ◽  
pp. 1009-1019 ◽  
Author(s):  
Baoping Yang ◽  
Xiang Li ◽  
Lurong Wang ◽  
Yabin Zhang ◽  
Jinfeng Cui ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Flame Retardancy ◽  
High Efficiency ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Test Results ◽  
Pyrolysis Gas ◽  
Spectrometry Analysis ◽  
Combined Test

Using 4,4-diaminodiphenyl methane as a curing agent, three kinds of monomers, 4,4′-dihydroxybenzophenone, diphenyl chlorophosphite and 1,4-phenylene diisocyanate (NCO), were introduced into a thermosetting resin (DGEBA). The flame retardancy properties of the composites were studied, and the results were compared with those of 5 wt% bis(bis(4-((diphenoxyphosphoryl)oxy)phenyl)methyl) 1,4-phenylenedicarbamate (DHPP-OH-NCO), 10 wt% DHPP-OH-NCO and 15 wt% DHPP-OH-NCO curing agents. The results showed that 15 wt% DHPP-OH-NCO had an improved flame retardancy, the limited oxygen index reached 33.5% and the vertical burning test (UL94) achieved a V-0 level. A cone calorimeter experiment showed that the addition of the flame retardant significantly reduced the amount of generated smoke and heat. Macroscopic digital images, scanning electron microscopy images and thermogravimetric analysis results further revealed that the epoxy resin (EP) with DHPP-OH-NCO exhibited greater char yields. The flame retardancy mechanism of the flame retardant was preliminarily shown by pyrolysis–gas chromatography–mass spectrometry analysis. The combined test results demonstrate that a high-efficiency phosphorous-containing flame retardant for EPs was successfully developed.

Preparation, characterization and testing of flame retardant cotton cellulose material: flame retardancy, thermal stability and flame-retardant mechanism

Cellulose ◽  
2021 ◽  
Vol 28 (6) ◽  
pp. 3789-3805
Author(s):  
Ling Sun ◽  
Huixin Wang ◽  
Wennan Li ◽  
Jiaojiao Zhang ◽  
Zheng Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Cotton Cellulose ◽  
Cellulose Material

scholarly journals Investigation of the Structure-Property Effect of Phosphorus-Containing Polysulfone on Decomposition and Flame Retardant Epoxy Resin Composites

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 380 ◽  
Author(s):  
Wei Zhao ◽  
Yongxiang Li ◽  
Qiushi Li ◽  
Yiliang Wang ◽  
Gong Wang
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Phosphorus Content ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Inhibition Effect ◽  
Phosphorus Containing ◽  
High Degree ◽  
Thermal Stability Of

The flame retardant modification of epoxy (EP) is of great signification for aerospace, automotive, marine, and energy industries. In this study, a series of EP composites containing different variations of phosphorus-containing polysulfone (with a phosphorus content of approximately 1.25 wt %) were obtained. The obtained EP/polysulfone composites had a high glass transition temperature (Tg) and high flame retardancy. The influence of phosphorus-containing compounds (ArPN2, ArPO2, ArOPN2 and ArOPO2) on the thermal properties and flame retardancy of EP/polysulfone composites was investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), a UL-94 vertical burning test, and cone calorimeter tests. The phosphorus-containing polysulfone enhanced the thermal stability of EP. The more stable porous char layer, less flammable gases, and a lower apparent activation energy at a high degree of conversion demonstrated the high gas inhibition effect of phosphorus-containing compounds. Moreover, the gas inhibition effect of polysulfone with a P–C bond was more efficient than the polysulfone with a P–O–C bond. The potential for optimizing flame retardancy while maintaining a high Tg is highlighted in this study. The flame-retardant EP/polysulfone composites with high thermal stability broaden the application field of epoxy.

scholarly journals Synthesis of a Novel Phosphorous-Nitrogen Based Charring Agent and Its Application in Flame-retardant HDPE/IFR Composites

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1062 ◽  
Author(s):  
Junlei Chen ◽  
Jihui Wang ◽  
Aiqing Ni ◽  
Hongda Chen ◽  
Penglong Shen
Keyword(s):  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Fire Hazard ◽  
Weight Ratio ◽  
Charring Agent ◽  
Migration Percentage ◽  
Ul 94 ◽  
Thermal Stability Of

In this work, a novel phosphorous–nitrogen based charring agent named poly(1,3-diaminopropane-1,3,5-triazine-o-bicyclic pentaerythritol phosphate) (PDTBP) was synthesized and used to improve the flame retardancy of high-density polyethylene (HDPE) together with ammonium polyphosphate (APP). The results of Fourier transform infrared spectroscopy (FTIR) and 13C solid-state nuclear magnetic resonance (NMR) showed that PDTBP was successfully synthesized. Compared with the traditional intumescent flame retardant (IFR) system contained APP and pentaerythritol (PER), the novel IFR system (APP/PDTBP, weight ratio of 2:1) could significantly promote the flame retardancy, water resistance, and thermal stability of HDPE. The HDPE/APP/PDTBP composites (PE3) could achieve a UL-94 V-0 rating with LOI value of 30.8%, and had a lower migration percentage (2.2%). However, the HDPE/APP/PER composites (PE5) had the highest migration percentage (4.7%), lower LOI value of 23.9%, and could only achieve a UL-94 V-1 rating. Besides, the peak of heat release rate (PHRR), total heat release (THR), and fire hazard value of PE3 were markedly decreased compared to PE5. PE3 had higher tensile strength and flexural strength of 16.27 ± 0.42 MPa and 32.03 ± 0.59 MPa, respectively. Furthermore, the possible flame-retardant mechanism of the APP/PDTBP IFR system indicated that compact and continuous intumescent char layer would be formed during burning, thus inhibiting the degradation of substrate material and improving the thermal stability of HDPE.

Sign in / Sign up

Export Citation Format

Share Document