scholarly journals Flame-Retardant Mechanism of Layered Double Hydroxides in Asphalt Binder

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 801 ◽  
Author(s):  
Kai Zhu ◽  
Yunhe Wang ◽  
Daquan Tang ◽  
Qiang Wang ◽  
Haihang Li ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Layered Double Hydroxides ◽  
Photoelectron Spectroscopy ◽  
Cone Calorimeter ◽  
Asphalt Binder ◽  
Bound Water ◽  
Asphalt Binders ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Double Hydroxides

The flame retardancy of asphalt binders with layered double hydroxides (LDHs) was investigated using limiting oxygen index (LOI) and cone calorimeter tests. The flame-retardant mechanism of the LDHs was also studied with thermogravimetry and differential scanning calorimetry (TG–DSC), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The cone calorimeter testing results indicated that 2 wt.% of the LDHs can decease the peak heat and smoke release rate of asphalt binders. Because a low dose of LDHs can be well dispersed in asphalt binder and favor the formation of polyaromatic structures during combustion, the thermal oxidation resistance and compactness of the char layer can be improved. The LOI of asphalt binder can be increased and the heat and smoke release during combustion can be decreased with 25 wt.% LDHs. The decomposition of LDHs can absorb the heat release of the initial two stages of asphalt combustion and reduce the burning rate of asphalt. Due to the loss of loosely bound water in the LDHs during the blending process and the decrease of dispersibility at a high LDH dose, the improvement of thermal stability is limited.

scholarly journals Performance of Warm-Mixed Flame Retardant Modified Asphalt Binder

2019 ◽  
Vol 9 (7) ◽  
pp. 1491
Author(s):  
Ruixia Li ◽  
Kaiwei Zhang ◽  
Jiahui Wu ◽  
Wenjuan Liu
Keyword(s):  
High Temperature ◽  
Flame Retardant ◽  
Performance Test ◽  
Asphalt Binder ◽  
Negative Influence ◽  
Viscosity Reduction ◽  
Asphalt Binders ◽  
Index Test ◽  
Flame Resistance ◽  
Limiting Oxygen Index

In order to analyze the effect of flame retardant and warm mix asphalt (WMA) additives-Sasobit on the flame-retardant performance and pavement performance of asphalt binder, the limiting oxygen index test, conventional performance test, and Superpave evaluation index tests were performed on asphalt binders in the study. The test results show that flame retardant can effectively improve the flame resistance of asphalt binder, while Sasobit has a certain combustion-supporting effect. Therefore, when warm-mixed flame-retardant technology is applied, the concentration of Sasobit should be controlled appropriately. These two modifiers can significantly enhance the high-temperature performance of asphalt binder, but both of them have a slight negative influence on the low-temperature cracking resistance. Sasobit can substantially reduce the high-temperature viscosity of asphalt binder, which helps to improve the construction workability of asphalt binder, while the flame retardant adversely affects the viscosity reduction effect of Sasobit to a certain extent, but the overall impact is not large.

Synergistic flame retardant effect between nano-silicon dioxide and layered double hydroxides in ethylene vinyl acetate composites

2017 ◽  
Vol 31 (10) ◽  
pp. 1295-1309 ◽  
Author(s):  
Yi Qian ◽  
Shaojie Zhou ◽  
Xilei Chen
Keyword(s):  
Silicon Dioxide ◽  
Heat Release ◽  
Flame Retardant ◽  
Vinyl Acetate ◽  
Layered Double Hydroxides ◽  
Ethylene Vinyl Acetate ◽  
Limiting Oxygen Index ◽  
Nano Silicon ◽  
Synergistic Flame Retardant ◽  
Double Hydroxides

Layered double hydroxides (LDHs) were synthesized by a coprecipitation method. The synergistic flame retardant effect of nano-silicon dioxide (nano-SiO2) on ethylene vinyl acetate (EVA)/LDHs composites was studied using limiting oxygen index (LOI), cone calorimeter test (CCT), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Results showed that the LOI values of the EVA/LDHs/nano-SiO2 composites were basically higher than that of the EVA/LDHs composite, and the EVA composite with 48% LDHs and 2% nano-SiO2 reached an LOI value of up to 31.2%. The CCT results indicate that the addition of nano-SiO2 greatly reduced the heat release rate, total heat release, mass loss, smoke production rate, total smoke release, and smoke factor. The morphology and structures of residues investigated by SEM gave positive evidence that char layers formed from the EVA/LDHs/nano-SiO2 composites were improved. The TGA data showed that the EVA/LDHs/nano-SiO2 composites show a higher thermal stability than the EVA/LDHs composites.

Synthesis, characterization and thermal degradation kinetics of azomethine-based halogen-free flame-retardant polyphosphonates

2018 ◽  
Vol 31 (1) ◽  
pp. 86-96 ◽  
Author(s):  
R Vini ◽  
S Thenmozhi ◽  
SC Murugavel
Keyword(s):  
Tensile Strength ◽  
Thermal Degradation ◽  
Flame Retardant ◽  
Degradation Kinetics ◽  
Thermal Degradation Kinetics ◽  
Spectroscopic Techniques ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Weight Percentage ◽  
Ul 94

In this study, azomethine polyphosphonates were synthesized by solution polycondensation of phenylphosphonic dichloride with various azomethine diols such as [4-(4-hydroxy phenyl) iminomethyl] phenol, [(4-(4-hydroxy-3-methoxy phenyl) iminomethyl)] phenol and [4-(4-hydroxy-3-ethoxy phenyl) iminomethyl] phenol using triethylamine catalyst at ambient temperature. The structure of the synthesized polymers was confirmed by Fourier transform infrared and 1H-, 13C- and 31P- nuclear magnetic resonance spectroscopic techniques. Thermal properties of the polymers were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry under nitrogen atmosphere. The TGA data showed that the synthesized polyphosphonates produce high char yield at 600°C due to the presence of phosphorous atom in the polymer chain and hence have good flame-retardant properties. One of the synthesized polyphosphonate was blended with commercial diglycidyl ether of bisphenol-A (DGEBA) resin in various weight percentage and cured with commercial curing agent triethylene tetramine (TETA). The polyphosphonates-blended epoxy thermosets have tensile strength in the range of 5–41 MPa and the percentage of elongation at breaks was 4–18. It was found that the incorporation of polyphosphonates into epoxy thermoset decreased the tensile strength from 41 MPa to 5 MPa, whereas the elongation at break value increased with increase in the weight percentage of polyphosphonate. The influence of polyphosphonates on the flame retardancy of blended thermosets was examined by limiting oxygen index (LOI) and vertical burning (UL-94) tests and found that the polymer samples achieved an increased UL-94 rating and the LOI values were in the range of 24–26. Broido and Horowitz–Metzger methods have been used to study the thermal degradation kinetic parameters.

scholarly journals Application of Plasma Activation in Flame-Retardant Treatment for Cotton Fabric

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1575
Author(s):  
Huong Nguyen Thi ◽  
Khanh Vu Thi Hong ◽  
Thanh Ngo Ha ◽  
Duy-Nam Phan
Keyword(s):  
Tensile Strength ◽  
Mechanical Strength ◽  
Flame Retardant ◽  
Cotton Fabric ◽  
Photoelectron Spectroscopy ◽  
Curing Temperature ◽  
Sem Images ◽  
Limiting Oxygen Index ◽  
Xps Spectra ◽  
Plasma Activation

Cotton fabric treated by Pyrovatex CP New (PCN) and Knittex FFRC (K-FFRC) using the Pad-dry-cure method showed an excellent fire-retardant effect. However, it needed to be cured at high temperatures for a long time leading to a high loss of mechanical strength. In this study, atmospheric-pressure dielectric barrier discharge (APDBD) plasma was applied to the cotton fabric, which then was treated by flame retardants (FRs) using the pad–dry-cure method. The purpose was to have a flame-retardant cotton fabric (limiting oxygen index (LOI) ≥ 25) and a mechanical loss of the treated fabric due to the curing step as low as possible. To achieve this goal, 10 experiments were performed. The vertical flammability characteristics, LOI value and tensile strength of the treated fabrics were measured. A response model between the LOI values of the treated fabric and two studied variables (temperature and time of the curing step) was found. It was predicted that the optimal temperature and time-to-cure to achieve LOI of 25 was at 160 °C for 90 s, while the flame-retardant treatment process without plasma pretreatment, was at 180 °C and 114 s. Although the curing temperature and the time have decreased significantly, the loss of mechanical strength of the treated fabric is still high. The tensile strength and scanning electron microscopy (SEM) images of the fabric after plasma activation show that the plasma treatment itself also damages the mechanical strength of the fabric. X-ray photoelectron spectroscopy (XPS) spectra of the fabric after plasma activation and energy-dispersive spectroscopy (EDS) analysis of the flame retardant-treated (FRT) fabric clarified the role of plasma activation in this study.

Flame-retardant cotton fabrics modified with phosphoramidate derivative via electron beam irradiation process

2019 ◽  
pp. 152808371988181
Author(s):  
Ying Liu ◽  
Li Zhou ◽  
Fang Ding ◽  
Shanshan Li ◽  
Rong Li ◽  
...  
Keyword(s):  
Electron Beam ◽  
Flame Retardant ◽  
Photoelectron Spectroscopy ◽  
Electron Beam Irradiation ◽  
Cotton Fabrics ◽  
Beam Irradiation ◽  
Limiting Oxygen Index ◽  
Flammability Test ◽  
Lower Temperature ◽  
Irradiation Process

In this study, a novel flame-retardant diethyl methacryloylphosphoramidate containing phosphorus and nitrogen was synthesized and characterized by Fourier transform infrared and nuclear magnetic resonance. The synthesized compound was grafted onto cotton fabrics using electron beam irradiation and pad dry cure processes. Scanning electron microscope and X-ray photoelectron spectroscopy were used to characterize the surfaces of the modified cotton fabrics to confirm that diethyl methacryloylphosphoramidate was grafted on cotton fabrics successfully. Both electron beam–cotton and pad dry cure–cotton exhibited efficient flame retardancy which was proved by limiting oxygen index and vertical flammability test. Thermogravimetric analysis results showed that both electron beam-cotton and pad dry cure–cotton degraded at lower temperature and produced higher yields at 600℃. The tensile loss of electron beam–cotton was lower than that of pad dry cure–cotton, and within the acceptable range in flame retardant finishing.

Synthesis and Characterization of Phosphorus-Containing Flame Retardant Polyamide 66

2020 ◽  
Vol 977 ◽  
pp. 102-107
Author(s):  
Yu Lei Zheng ◽  
Shuang Chen ◽  
Jia Hui Wang ◽  
Ru Xiao
Keyword(s):  
Flame Retardant ◽  
Oxygen Index ◽  
Mechanical And Thermal Properties ◽  
Index Test ◽  
Polyamide 66 ◽  
Scanning Calorimetry ◽  
One Pot ◽  
Limiting Oxygen Index ◽  
Step Process ◽  
Phosphorus Containing

Polyamide 66 (PA66) benefits from excellent mechanical properties and good chemical resistance, which enabled wide application of this material in various industrial fields; however, it suffers from high flammability. Generally, preparation of a flame retardant PA from a reactive flame retardant involves a two-step process. In this study, the flame retardant PA66s (FRPA66s) are synthesized via a one-pot melt copolycondensation route by using a reactive phosphorus-containing flame retardant (FR-B). Then, molecular weight, some mechanical and thermal properties along with flame retardant properties of FRPA66s were investigated by gel permeation chromatography (GPC), instron material testing, differential scanning calorimetry (DSC), thermogravimetry (TG) analysis, vertical burning test (UL 94), and limiting oxygen index test (LOI) techniques. The experimental results confirmed that FRPA66s synthesized by the one-pot method have very similar properties compared to those obtained via the two-step process. Moreover, the prepared materials showed good non-flammability behavior with limiting oxygen index value of over 30% and a vertical burning test result of V-0 rating.

scholarly journals Development of Bioepoxy Resin Microencapsulated Ammonium-Polyphosphate for Flame Retardancy of Polylactic Acid

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4123 ◽  
Author(s):  
Kata Decsov ◽  
Katalin Bocz ◽  
Beáta Szolnoki ◽  
Serge Bourbigot ◽  
Gaëlle Fontaine ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Flame Retardant ◽  
Polylactic Acid ◽  
Ammonium Polyphosphate ◽  
Cone Calorimetry ◽  
Scanning Calorimetry ◽  
Electron Microscopic ◽  
Sem Images ◽  
Limiting Oxygen Index ◽  
Microencapsulated Ammonium Polyphosphate

Ammonium-polyphosphate (APP) was modified by microencapsulation with a bio-based sorbitol polyglycidyl ether (SPE)-type epoxy resin and used as a flame retardant additive in polylactic acid (PLA) matrix. The bioresin-encapsulated APP (MCAPP) particles were characterized using Fourier transform infrared (FTIR) spectroscopy and Raman mapping, particle size distribution was determined by processing of scanning electron microscopic (SEM) images. Interaction between the APP core and the bioresin shell was revealed by combined thermogravimetric analysis (TGA)‑FTIR spectroscopy. The APP to SPE mass ratio of 10 to 2 was found to be optimal in terms of thermal, flammability, and mechanical properties of 15 wt% additive containing biocomposites. The bioresin shell effectively promotes the charring of the APP-loaded PLA composites, as found using TGA and cone calorimetry, and eliminates the flammable dripping of the specimens during the UL-94 vertical burning tests. Thus, the V-0 rating, the increased limiting oxygen index, and the 20% reduced peak of the heat release rate was reached compared to the effects of neat APP. Furthermore, better interfacial interaction of the MCAPP with PLA was indicated by differential scanning calorimetry and SEM observation. The stiff interphase resulted in increased modulus of these composites. Besides, microencapsulation provided improved water resistance to the flame retardant biopolymer system.

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