scholarly journals A Synergistic Flame Retardant System Based on Expandable Graphite, Aluminum (Diethyl-)Polyphospinate and Melamine Polyphosphate for Polyamide 6

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2712
Author(s):  
Florian Tomiak ◽  
Angelina Schoeffel ◽  
Klaus Rathberger ◽  
Dietmar Drummer
Keyword(s):  
Flame Retardant ◽  
Expanded Graphite ◽  
Polyamide 6 ◽  
Partial Substitution ◽  
Expandable Graphite ◽  
Heating Rates ◽  
Sem Images ◽  
Decomposition Products ◽  
Solid Decomposition ◽  
Synergistic Flame Retardant

Expandable graphite (EG), aluminum (diethyl)polyphosphinate (AlPi) and melamine polyphophate (MPP) was used as flame retardant multi-material additive in a polyamide 6 (PA6) matrix. Flame inhabitation performances were conducted by cone calorimeter, LOI and UL-94 tests, synergisms identified analyzed by TGA-FTIR and TGA-GC/MS and effects found were comprehensively discussed. SEM images were used for char residue characterization. For PA6 containing 20 wt.% EG and 5 wt.% AlPi/MPP (3:2), a well working synergism in limiting oxygen indices could be identified exhibiting the highest oxygen index (OI) measured: 46%. The study shows that the synergism due to the partial substitution of EG by AlPi/MPP can be attributed to two effects: (1) When PA6/AlPi/MPP mixtures decompose predominantly CO2 evaporates in early decomposition stages. CO2 evaporations was found to be sensitive to the heating rate applied, whereas specifically high heating rates increased the CO2 yield measured. (2) Solid decomposition products of AlPi/MPP act as “glue” between expanded graphite and thus increase the mechanical residue stability.

scholarly journals Chain Extension and Synergistic Flame-Retardant Effect of Aromatic Schiff Base Diepoxide on Polyamide 6/Aluminum Diethylphosphinate Composites

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2217 ◽  
Author(s):  
Tianxiang Liang ◽  
Jianan Cai ◽  
Shumei Liu ◽  
Hualin Lai ◽  
Jianqing Zhao
Keyword(s):  
Schiff Base ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Polyamide 6 ◽  
Chain Extension ◽  
Cone Calorimetry ◽  
The Matrix ◽  
Flame Retarded ◽  
Ul 94 ◽  
Synergistic Flame Retardant

A way to suppress the deterioration in mechanical properties of polyamide 6 (PA6) is required, especially with high loading of flame retardants in the matrix. In this study, a novel aromatic Schiff base diepoxide (DES) was synthesized. It exhibited an efficient chain extension effect on PA6 and a synergistic flame-retardant effect with aluminum diethylphosphinate (AlPi) for PA6. The PA6 composite with 16 wt.% AlPi only passed UL-94 V-0 rating at 1.6 mm thickness, while the combination of 1.5 wt.% DES with 13 wt.% AlPi induced PA6 to achieve a UL-94 V-0 rating at 0.8 mm thickness. The tensile, flexural, and Izod notched impact strengths were increased by 16.2%, 16.5%, and 24.9%, respectively, compared with those of V-0 flame-retarded PA6 composites with 16 wt.% AlPi. The flame-retarded mechanism of PA6/AlPi/DES was investigated by cone calorimetry and infrared characterization of the char residues and pyrolysis products. These results showed that DES had a synergistic effect with AlPi in condensed-phase flame retardation by promoting the production of aluminum phosphorus oxides and polyphosphates in the char residues.

scholarly journals Preparation and Characterization of Flame-Retarded Poly(butylene terephthalate)/Poly(ethylene terephthalate) Blends: Effect of Content and Type of Flame Retardant

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1784 ◽  
Author(s):  
Weizhou Zhang ◽  
Cheng Zheng ◽  
Yuhui Zhang ◽  
Weihong Guo
Keyword(s):  
Flame Retardant ◽  
Resin Matrix ◽  
Expandable Graphite ◽  
Sem Images ◽  
Household Products ◽  
Flame Retarded ◽  
Automotive Parts ◽  
Ul 94 ◽  
Poly Ethylene ◽  
And Migration

A flame retardant named TAD was synthesized by the reaction of 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and triallyl isocyanurate at first. Then, novel flameretarded materials based on PBT and PET resin were formulated via melt blending with TAD, expandable graphite (EG), and a mixture of both. The effect of flame retardant type and TAD content on the flame behavior of PBT/PET blend was carefully investigated. TAD contributed towards higher LOI value and better UL-94 performance than EG. However, the best V-0 rating in the UL-94 test was achieved by the incorporation of TAD/EG mixture into the resin matrix. TAD/EG combination exhibited clear synergistic effect on both reducing the flaming intensity and increasing the residual char layer, as confirmed by cone calorimeter tests and TGA results. SEM images combined with XPS analysis revealed that expansion and migration of EG locked the P-containing radicals from decomposing TAD into the condensed phase, which led to the formation of compact and continuous char layers. All the results in our studies demonstrate that incorporation of TAD with a charring agent EG is an effective and promising technique to develop flame-retarded PBT/PET material, which has high potential for applications in the areas of electronic devices, household products, and automotive parts.

scholarly journals Expandable Graphite for Flame Retardant PA6 Applications

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2733
Author(s):  
Florian Tomiak ◽  
Klaus Rathberger ◽  
Angelina Schöffel ◽  
Dietmar Drummer
Keyword(s):  
Flame Retardant ◽  
Cone Calorimeter ◽  
Oxygen Index ◽  
Fire Behavior ◽  
Polyamide 6 ◽  
Heat Fluxes ◽  
Expandable Graphite ◽  
Fire Tests ◽  
Inhibiting Effect ◽  
Ul 94

A new expandable graphite (EG) type was studied as a flame retardant additive in Polyamide 6 (PA6). The fire behavior was characterized by a cone calorimeter using external heat fluxes of 35, 50 and 65 kW/m2, limiting the oxygen index (LOI) and UL-94 burning tests. Additionally, electric and thermal conductivity as well as rheological properties were characterized to provide a general property overview. Fire tests were conducted using dry and humid conditioned samples. Cone Calorimeter tests showed a minimum filling degree of 15 wt.% (8.6 vol.%) EG was required to achieve a significant fire inhibiting effect in PA6 independent of the sample condition. UL-94 fire tests show a V0 classification at filling degrees greater than 20 wt.% (humid) and 25 wt.% (dry), although the associated LOI values of 39% and 38% demonstrate good flammability inhibition. Correlation analyses were conducted to identify major influences given by the sample condition for most important key figures measured in cone calorimeter tests. Accordingly, humid-conditioned samples containing between 2.5 (PA6 + 25 wt.% EG) and 4.2 wt.% (PA6) water were found to reduce the total heat evolved (THE) on average by 16% and the total smoke production (TSP) on average by 22%.

scholarly journals Flame Retardant Behavior of Ternary Synergistic Systems in Rigid Polyurethane Foams

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 207 ◽  
Author(s):  
Wang Xi ◽  
Lijun Qian ◽  
Linjie Li
Keyword(s):  
Flame Retardant ◽  
Mass Loss Rate ◽  
Dimethyl Ester ◽  
Ternary Systems ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Rigid Polyurethane Foams ◽  
Char Layer ◽  
Index Value ◽  
Synergistic Flame Retardant

In order to explore flame retardant systems with higher efficiency in rigid polyurethane foams (RPUFs), aluminum hydroxide (ATH), [bis(2-hydroxyethyl)amino]-methyl-phosphonic acid dimethyl ester (BH) and expandable graphite (EG) were employed in RPUF for constructing ternary synergistic flame retardant systems. Compared with binary BH/EG systems and aluminum oxide (AO)/BH/EG, ATH/BH/EG with the same fractions in RPUFs demonstrated an increase in the limited oxygen index value, a decreased peak value of heat release rate, and a decreased mass loss rate. In particular, it inhibited smoke release. During combustion, ATH in ternary systems decomposed and released water, which captured the phosphorus-containing products from pyrolyzed BH to generate polyphosphate. The polyphosphate combined with AO from ATH and the expanded char layer from EG, forming a char layer with a better barrier effect. In ternary systems, ATH, BH, and EG can work together to generate an excellent condensed-phase synergistic flame retardant effect.

scholarly journals The Synergistic Effect of Ionic Liquid-Modified Expandable Graphite and Intumescent Flame-Retardant on Flame-Retardant Rigid Polyurethane Foams

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3095 ◽  
Author(s):  
Yongjun Chen ◽  
Yuanfang Luo ◽  
Xiaohui Guo ◽  
Lijuan Chen ◽  
Demin Jia
Keyword(s):  
Thermal Decomposition ◽  
Ionic Liquid ◽  
Flame Retardant ◽  
Polyurethane Foams ◽  
Molecular Structures ◽  
Intumescent Flame Retardant ◽  
Expandable Graphite ◽  
Thermal Decomposition Mechanism ◽  
Rigid Polyurethane Foams ◽  
Synergistic Flame Retardant

In this study, a nitrogen–phosphorus intumescent flame-retardant 3-(N-diphenyl phosphate) amino propyl triethoxy silane (DPES), the ionic liquid (IL) of 1-butyl-3-methyl-imidazole phosphate, and a phosphorous-containing ionic liquid-modified expandable graphite (IL-EG), were synthesized, and their molecular structures were characterized. The flame-retardant rigid polyurethane foams (RPUFs) were compounded with synergistic flame-retardant IL-EG/DPES to study the effects of the combination IL-EG and DPES on the pore structure, mechanical properties, thermal decomposition behavior and thermal decomposition mechanism of RPUF. The results showed that IL-EG/DPES had good thermal stability, and an excellent expansibility and char yield. The flame-retardant RPUF, modified with IL-EG and DPES at the ratio of 1:1, had a relatively uniform pore size, the highest compressive strength, and an excellent flame-retardant performance due to the form interwoven hydrogen bonds between IL-EG and DPES, as well as the new synergistic flame-retardant coating on the RPUF surface to restrict the transfer of gas or heat into the PU matrix.

scholarly journals Synergistic Flame Retardant Effects of Expandable Graphite and Ammonium Polyphosphate in Water-Blow Polyurethane Foam

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Weiguo Yao ◽  
Dongyang Zhang ◽  
Yixin Zhang ◽  
Tao Fu ◽  
Dongbo Guan ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Flame Retardant ◽  
Polyurethane Foam ◽  
Flame Retardants ◽  
Total Content ◽  
Compression Modulus ◽  
Ammonium Polyphosphate ◽  
Expandable Graphite ◽  
Limiting Oxygen Index ◽  
Synergistic Flame Retardant

In this research, expandable graphite (EG) and ammonium polyphosphate (APP) were incorporated into water-blow semirigid polyurethane foam (SPUF) as flame retardants. The synergistic flame retardant effects of EG with APP in SPUF had been studied by thermogravimetric analysis (TGA), limiting oxygen index (LOI), horizontal burning test, polarizing microscope, and scanning electron microscopy (SEM). The results indicated that APP and EG used together in SPUF could effectively improve the flame retardancy of SPUF. When the EG to APP ratio reached 2 : 1 under the total content of flame retardants was kept constant as 20%, the LOI value was increased by about 51% compared to pure SPUF, 2.9% to SPUF/EG and 16.3% to SPUF/APP. Besides, the residual char was increased up to 27.7% displayed by TG test results. SEM shows that burned residues of EG/APP/SPUF present more compact char and worm-like structure. Furthermore, EG shows negative effect on the mechanical property of SPUF with 21.7% decrease in compression modulus, but the mechanical property can be improved by the addition of appropriate content of APP.

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