scholarly journals Halogen-Free Flame Retardant Polypropylene Fibers with Modified Intumescent Flame Retardant: Preparation, Characterization, Properties and Mode of Action

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2553
Author(s):  
Qibin Xu ◽  
Lei Wu ◽  
Xiang Yan ◽  
Shengchang Zhang ◽  
Linan Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Release ◽  
Flame Retardant ◽  
Protective Layer ◽  
Intumescent Flame Retardant ◽  
X Ray Diffraction ◽  
Limiting Oxygen Index ◽  
Action Mode ◽  
Combustible Gases ◽  
Halogen Free

A novel intumescent flame retardant (IFR) agent designated as Dohor-6000A has been used to prepare halogen-free flame retardant polypropylene (PP) fibers via melting spinning. Before being blended with PP resin, a surface modification of Dohor-6000A was carried out to improve its compatibility with the PP matrix. The rheological behavior of flame retardant Dohor-6000A/PP resin, the structure, morphology, mechanical properties, flammability of the Dohor-6000A/PP fibers were studied in detail, as well as the action mode of flame retardant. X-ray diffraction (XRD) showed that the addition of Dohor-6000A did not damage the crystal as well as the orientation structure of PP matrix, which was helpful to the maintenance of mechanical properties. The presence of the IFR significantly improved the flame retardant performance and thermal stability of PP fibers. When the content of Dohor-6000A reached 25%, the fibers displayed a limiting oxygen index (LOI) value of 29.1% and good melt-drop resistance. Moreover, the peak heat release rate (PHRR) and total heat release (THR) from microscale combustion colorimetry (MCC) tests were decreased by 26.0% and 16.0% in comparison with the same conditions for pure PP fibers. In the condensed phase, the IFR promoted a carbonization process and promoted the formation of a glassy or stable foam protective layer on the surface of the polymer matrix. In addition, the IFR decomposed endothermically to release of non-combustible gases such as NH3 and CO2 which dilutes the combustible gases in the combustion zone.

scholarly journals Development of Biodegradable Flame-Retardant Bamboo Charcoal Composites, Part I: Thermal and Elemental Analyses

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2217 ◽  
Author(s):  
Shanshan Wang ◽  
Liang Zhang ◽  
Kate Semple ◽  
Min Zhang ◽  
Wenbiao Zhang ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Residue Analysis ◽  
Fire Retardant ◽  
Protective Layer ◽  
Growth Index ◽  
Raw Material ◽  
Bamboo Charcoal ◽  
Limiting Oxygen Index ◽  
Plastic Composite

In this study, bamboo charcoal (BC) was used as a substitute filler for bamboo powder (BP) in a lignocellulose-plastic composite made from polylactic acid (PLA), with aluminum hypophosphite (AHP) added as a fire retardant. A set of BC/PLA/AHP composites were successfully prepared and tested for flame-retardancy properties. Objectives were to (a) assess compatibility and dispersibility of BC and AHP fillers in PLA matrix, and (b) improve flame-retardant properties of PLA composite. BC reduced flexural properties while co-addition of AHP enhanced bonding between PLA and BC, improving strength and ductility properties. Adding AHP drastically reduced the heat release rate and total heat release of the composites by 72.2% compared with pure PLA. The formation of carbonized surface layers in the BC/PLA/AHP composites effectively improved the fire performance index (FPI) and reduced the fire growth index (FGI). Flame-retardant performance was significantly improved with limiting oxygen index (LOI) of BC/PLA/AHP composite increased to 31 vol%, providing a V-0 rating in UL-94 vertical flame test. Adding AHP promoted earlier initial thermal degradation of the surface of BC/PLA/AHP composites with a carbon residue rate up to 40.3%, providing a protective layer of char. Further raw material and char residue analysis are presented in Part II of this series.

scholarly journals Effects of chemical pre-treatment on structure and property of polyacrylonitrile based pre-oxidized fibers

2020 ◽  
Vol 15 ◽  
pp. 155892501989894
Author(s):  
Xiaolu Sun ◽  
Jiayin Song ◽  
Jin Zhang ◽  
Jingyan Liu ◽  
Huizhen Ke ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Energy Dispersive Spectrometer ◽  
Chemical Compositions ◽  
Limiting Oxygen Index ◽  
X Ray ◽  
Pre Treatment

Polyacrylonitrile-based pre-oxidized fibers with improved thermal stability, flame retardant, and mechanical properties were made from the pristine polyacrylonitrile fibers through chemical pretreatment followed by pre-oxidation in air. The morphological structure of the polyacrylonitrile-based pre-oxidized fibers was investigated by Fourier transfer infrared spectra, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectrometer. The changes of characteristic functional groups and chemical compositions confirmed the successful modification of the polyacrylonitrile fibers during pre-treatment. The grooves and cracks on the surface of polyacrylonitrile-based pre-oxidized fibers were remarkably decreased in comparison with that of pristine polyacrylonitrile fibers. The evolution of crystalline structure of the polyacrylonitrile fibers proved the occurrence of cyclization reactions during pre-oxidation. Meanwhile, thermal stability, flame retardant, and mechanical properties of polyacrylonitrile-based pre-oxidized fibers were also investigated by thermogravimetric analyzer, oxygen index meter, micro combustion calorimeter, and single fiber tensile tester, respectively. The results demonstrated that the polyacrylonitrile-based pre-oxidized fibers initially pre-treated by hydroxylamine hydrochloride, followed by monoethanolamine, had a high limiting oxygen index of 40.1 and breaking strength of 2.03 cN/dtex. The peak of heat release rate and total heat release of polyacrylonitrile-based pre-oxidized fibers decreased significantly while its charred residues increased, contributing to the improved flame retardant property.

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, 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 ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Fire Behavior ◽  
Intumescent Flame Retardant ◽  
Ammonium Polyphosphate ◽  
Infrared Spectrometry ◽  
Expandable Graphite ◽  
Physical Interaction ◽  
Limiting Oxygen Index

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.

Halogen-free flame-retardant rigid polyurethane foam with a nitrogen–phosphorus flame retardant

2017 ◽  
Vol 35 (2) ◽  
pp. 99-117 ◽  
Author(s):  
Qianqiong Zhao ◽  
Congyan Chen ◽  
Ruilan Fan ◽  
Yong Yuan ◽  
Yalin Xing ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Polyurethane Foams ◽  
Nitrogen And Phosphorus ◽  
Initial Decomposition Temperature ◽  
Limiting Oxygen Index ◽  
Average Mass ◽  
Ul 94 ◽  
Halogen Free

A halogen-free flame retardant containing nitrogen and phosphorus, 2-[anilino-(6-oxobenzo[c][2,1]benzoxaphosphinin-6-yl)methyl]phenol (PDOP), has been synthesized by reaction of benzo[c][2,1]benzoxaphosphinine-6-oxide (DOPO) with 2-( N-phenyliminomethyl)phenol. Halogen-free flame-retardant rigid polyurethane foams (RPUF-PDOP) were prepared using PDOP as a flame retardant. The flammability was investigated using limiting oxygen index, a vertical burning test (UL-94), and a cone calorimeter. When PDOP (10 wt%) as flame retardant was added to RPUF (RPUF-PDOP10%), the limiting oxygen index value was increased from 18% to 27%, and a UL-94 V-0 rating was achieved; meanwhile, the peak heat release rate, total heat release, and the average mass-loss rates of RPUF-PDOP10% were reduced from 246 to 207 kW m−2, from 26.9 to 21.0 MJ/m2, and from 0.043 to 0.033 g/s, respectively. Especially, the initial decomposition temperature of RPUF-PDOP10% was decreased from 228°C to 209°C. The final residual char from decomposition of RPUF-PDOP10% was significantly increased up to 35.6%. The addition of PDOP did not markedly decrease the mechanical properties of the resulting flame-retardant RPUFs.

scholarly journals Improving flame-retardant, thermal, and mechanical properties of an epoxy using halogen-free fillers

2018 ◽  
Vol 25 (5) ◽  
pp. 939-946 ◽  
Author(s):  
Ramin Riahipour ◽  
Abolfazl Alizadeh Sahraei ◽  
Nekoda van de Werken ◽  
Mehran Tehrani ◽  
Karen Abrinia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Flame Retardant ◽  
Diglycidyl Ether ◽  
Thermal And Mechanical Properties ◽  
Limiting Oxygen Index ◽  
The Matrix ◽  
Stable Flame ◽  
Halogen Free ◽  
Nanostructured Silica

AbstractVarious nano- and micro-sized fillers can be integrated into polymers to enhance their flame-retardant performance. In this work, a diglycidyl-ether bisphenol A epoxy was used as the matrix and nanostructured silica aerogel (AG) and ammonium polyphosphate (APP) microparticles were investigated as fillers to improve the flame-retardant and thermal properties of the epoxy. The anti-flame, thermal, and mechanical properties of the composites were investigated for different volume fractions of filler particles. It was found that APP decreased the burning rate while significantly improving the thermal stability. To investigate the flame resistant properties of combined AG and APP, an optimized ratio of AG and APP was added to the epoxy, leading to a stable flame-retardant epoxy with a low thermal conductivity and improved glass transition temperature (Tg). The synergy between the AG and APP in composite samples resulted in an interesting burning behavior where sample core was relatively less deteriorated compared with the samples containing only APP or AG. This was attributed to the decrease of thermal conductivity due to the addition of AG. Lastly, samples containing APP showed the highest limiting oxygen index percentage and it was found that only small amounts of APP are required to make the epoxy flame-retardant.

Flame Retardancy of Lanthanum Phosphinate in Combination with Intumescen Flame-Retardant in Polypropylene

2012 ◽  
Vol 490-495 ◽  
pp. 3366-3369 ◽  
Author(s):  
Cong Liu
Keyword(s):  
Thermogravimetric Analysis ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Oxygen Index ◽  
Intumescent Flame Retardant ◽  
Limiting Oxygen Index ◽  
Ul 94 ◽  
Halogen Free

The flame-retardant of Lanthanum phenylphosphinate(LaPi) was prepared and its combination with intumescent flame retardant (IFR) in polypropylene (PP) was analysed using thermogravimetric analysis (TGA), limiting oxygen index (LOI) and the UL-94 test. Compared with using IFR alone, using the combination of LaPi and IFR gained the better classification in the UL 94 test thanks to the combination of the different mechanisms. When 20 wt% loading of flame retardant of LaPi and IFR, a halogen-free V-0 PP material was achieved with a LOI of 31%.

Metal compounds as catalysts in the intumescent flame retardant system for polyethylene terephthalate fabrics

2018 ◽  
Vol 89 (15) ◽  
pp. 2983-2997 ◽  
Author(s):  
Yarong Wu ◽  
Xiang Zhou ◽  
Zhiqi Xing ◽  
Jiangtao Ma
Keyword(s):  
Flame Retardant ◽  
Polyethylene Terephthalate ◽  
Catalytic Effect ◽  
Degradation Products ◽  
Protective Layer ◽  
Intumescent Flame Retardant ◽  
Laser Raman Spectroscopy ◽  
Metal Compounds ◽  
Limiting Oxygen Index ◽  
Char Formation

Forming a carbonaceous protective layer during combustion has been proven to be an effective way to improving the flame retardancy of polymers and it has been found that some metal compounds could promote dehydrogenation and aromatization of the degradation products. In this research, several divalent or multivalent metal compounds were added in the intumescent flame retardant (IFR) based on ammonium polyphosphate, pentaerythritol and melamine for polyethylene terephthalate (PET) fabrics. The prepared flame retardant dispersions containing 25 wt% IFR and 1 wt% metal compounds were applied on PET fabrics by the common pad-dry-cure method. None of the treated samples generated any dripping during the vertical burning test, with the highest limiting oxygen index being up to 33.4%. Thermogravimetric analysis showed that the catalytic effect of metal compounds may occur in promoting the formation of char residues. The morphology of char residues of two of the IFR/metal compound-treated PET fabrics, IFR/FeCl3 and IFR/ZnCl2, were smooth and compact, as shown by scanning electron microscopy. Laser Raman spectroscopy of the char residues suggested that a higher graphitization degree was obtained by adding the metal compounds. Real-time Fourier transform infrared spectroscopy showed that metal compounds made more phosphorus available for phosphorylation and char formation. The results of the present study indicate the possibility for enhancing char formation via the catalytic effect of metal compounds to improve the flame retardant and anti-dripping properties of the PET fabrics.

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.

Intumescent flame retardant coating for polyamide 6,6 (PA 6,6) fabrics containing carbon nanotubes: Synergistic effect of filler on thermal stability and flame retardancy

2018 ◽  
Vol 89 (10) ◽  
pp. 2031-2040 ◽  
Author(s):  
Fanglong Zhu ◽  
QQ Feng ◽  
YF Xu ◽  
JF Hu
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardant ◽  
Heat Release Rate ◽  
Flame Retardancy ◽  
Release Rate ◽  
Intumescent Flame Retardant ◽  
Flame Resistance ◽  
Limiting Oxygen Index

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.

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