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%.

Synthesis of a boron/nitrogen-containing compound based on triazine and boronic acid and its flame retardant effect on epoxy resin

2016 ◽  
Vol 29 (5) ◽  
pp. 513-523 ◽  
Author(s):  
Tie Zhang ◽  
Weishi Liu ◽  
Meixiao Wang ◽  
Ping Liu ◽  
Yonghong Pan ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Boronic Acid ◽  
Cone Calorimeter ◽  
Oxygen Index ◽  
Triazine Ring ◽  
Limiting Oxygen Index ◽  
Ul 94 ◽  
Flame Retardant Properties ◽  
Boron Nitrogen

With the aim of developing a novel organic flame retardant, an organic boronic acid derivative containing a triazine ring (2,4,6-tris(4-boronic-2-thiophene)-1,3,5-triazine (3TT-3BA)) was synthesized. The thermal properties of 3TT-3BA and its corresponding intermediate products were investigated by thermogravimetric analysis. The results show that 3TT-3BA has a high char yield (56.9%). The flame retardant properties of epoxy resin (EP) with 3TT-3BA were investigated by cone calorimeter, limiting oxygen index (LOI) test, and vertical burning test (UL 94). The LOI of EP with 20% 3TT-3BA is 31.2% and the UL 94 V-0 rating is achieved for EP with 20% 3TT-3BA. The flame retardant mechanism of 3TT-3BA in EP was investigated using TGA–Fourier transform infrared spectroscopy and scanning electron microscopy.

scholarly journals Analysis of the Fire Behavior of Polymers (PP, PA 6 and PE-LD) and Their Improvement Using Various Flame Retardants

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5756
Author(s):  
Dieter Hohenwarter ◽  
Hannelore Mattausch ◽  
Christopher Fischer ◽  
Matthias Berger ◽  
Bernd Haar
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Heat Release Rate ◽  
Release Rate ◽  
Radiation Intensity ◽  
Cone Calorimeter ◽  
Flame Retardants ◽  
Fire Behavior ◽  
Expandable Graphite ◽  
Aging Effects

The fire behavior of polymers is examined primarily with the time-dependent heat release rate (HRR) measured with a cone calorimeter. The HRR is used to examine the fire behavior of materials with and without flame retardants, especially Polypropylene (PP-Copo) and Polyethylene (PE-LD). Polypropylene is stored for up to 99 days under normal conditions and the heat release rate shows especially changes about 100 s after irradiation with cone calorimeter, which may be caused by aging effects. The effect of crosslinking to the burning behavior of PP was examined too. Polyamides (PA 6) are irradiated with a radiation intensity of 25 kW/m2 to 95 kW/m2 and fire-related principles between radiation intensity and time to ignition can be derived from the measurement results. In order to comprehensively investigate the fire behavior of PP (also with flame retardant additives), the samples were also exposed to a flame, according to UL 94 with small power (50 W) and is inflamed with the power of a few 100 W. The irradiation causes different trigger mechanisms for the flame retardant additives in a plastic than the flame exposure. It is shown that the compound, which is favorable for irradiation, is not necessarily good for flame exposure. It can be seen that expandable graphite alone or with the addition of other additives is a very effective flame retardant for PP.

Flame Retardant Epoxy Resins Containing Microcapsules

2011 ◽  
Vol 197-198 ◽  
pp. 1346-1349 ◽  
Author(s):  
Fa Chao Wu
Keyword(s):  
Flame Retardant ◽  
Cone Calorimeter ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Melamine Resin ◽  
Element Analysis ◽  
Ul 94

Bis(2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane-4-methanol) melaminium salt (Melabis) and microcapsules of Melabis with melamine resin shell as flame retardants (FR), respectively, were synthesized. Their structures were characterized by NMR, IR, SEM, TG and element analysis. 20% weight of microcapsules was doped into epoxy resins (EP) to get 28.5 % of LOI and UL 94 V-0. The heat and smoke release of EP containing microcapsules was valued by cone calorimeter.

Influence of Intumescent Flame Retardant on Flammability and Tensile Behavior of Oil-Extended SEBS

2013 ◽  
Vol 749 ◽  
pp. 65-70
Author(s):  
Xiao Yan Li ◽  
Yan Chun Li ◽  
Chen Jie Shi ◽  
Si Si Cai ◽  
Xia Wang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Intumescent Flame Retardant ◽  
Degradation Behavior ◽  
Char Layer ◽  
Micro Holes ◽  
Ul 94 ◽  
Limited Oxygen

A kind of intumescent flame retardant (IFR) were used for flame retarding of oil-extended hydrogenated styrene-butylenes-styrene (O-SEBS). The samples were systemically characterized by limited oxygen index (LOI), vertical burning test (UL-94), and scanning electron microscopy (SEM); Thermogravimetric (TG) analysis. The results showed that the IFR retardant can promote residual chars with multi-micro holes on the surface of SEBS to inhibit flame; with 45% IFR content, the LOI is 28.3 and flame retardant level is UL-94 classification of V-0, with no dripping. The morphological structures observed by SEM demonstrated that higher IFR content promote to form larger and compact films cover on bubbles of the intumescent char layer. The TG data revealed that the IFR could change the degradation behavior of the O-SEBS, enhance the thermal stability and increase the char residue, The tensile strength of all the O-SEBS/IFR blends had the tensile strength of more than 4MPa and the elongation of more than 850%.

scholarly journals Influence of the Characteristics of Expandable Graphite on the Morphology, Thermal Properties, Fire Behaviour and Compression Performance of a Rigid Polyurethane Foam

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 168 ◽  
Author(s):  
Pablo Acuña ◽  
Zhi Li ◽  
Mercedes Santiago-Calvo ◽  
Fernando Villafañe ◽  
Miguel Rodríguez-Perez ◽  
...  
Keyword(s):  
Particle Size ◽  
Oxygen Index ◽  
Fire Behavior ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Size Distributions ◽  
Limiting Oxygen Index ◽  
Compression Performance ◽  
Cone Calorimeter Test

Three types of expandable graphite (EG) differing in particle size and expansion volume, are compared as flame retardant additives to rigid polyurethane foams (RPUFs). In this paper we discuss microstructure, thermal stability, fire behavior, and compression performance. We find that ell size distributions were less homogeneous and cell size was reduced. Furthermore, thermal conductivity increased along with EG loading. Thermogravimetric analysis (TGA) showed that EG only increased residue yield differently. The results indicate that a higher expansion of EG increased the limiting oxygen index (LOI) value, whereas a bigger particle size EG improved the rating of the vertical burning test (UL94). Results from the cone calorimeter test showed that a bigger particle size EG effectively reduced peak of heat release rate (pHRR). Furthermore, a higher expansion, led to a decrease in smoke production (TSP). The combination of both characteristics gives extraordinary results. The physical–mechanical characterization of the EG/RPUF foams revealed that their compression performance decreased slightly, mostly due to the effect of a bigger size EG.

scholarly journals Synthesis of Novel Polymeric Acrylate-Based Flame Retardants Containing Two Phosphorus Groups in Different Chemical Environments and Their Influence on the Flammability of Poly (Lactic Acid)

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 778 ◽  
Author(s):  
Jacob Sag ◽  
Philipp Kukla ◽  
Daniela Goedderz ◽  
Hendrik Roch ◽  
Stephan Kabasci ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Mode Of Action ◽  
Flame Retardants ◽  
Fire Behavior ◽  
Heat Fluxes ◽  
Poly Lactic Acid ◽  
Cone Calorimetry ◽  
Scanning Calorimetry ◽  
Fire Scenarios ◽  
Physical Phenomena

Novel polymeric acrylate-based flame retardants (FR 1–4) containing two phosphorus groups in different chemical environments were synthesized in three steps and characterized via nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mass spectrometry (MS). Polylactic acid (PLA) formulations with the synthesized compounds were investigated to evaluate the efficiency of these flame retardants and their mode of action by using TGA, UL94, and cone calorimetry. In order to compare the results a flame retardant polyester containing only one phosphorus group (ItaP) was also investigated in PLA regarding its flame inhibiting effect. Since the fire behavior depends not only on the mode of action of the flame retardants but also strongly on physical phenomena like melt dripping, the flame retardants were also incorporated into PLA with higher viscosity. In the UL94 vertical burning test setup, 10% of the novel flame retardants (FR 1–4) is sufficient to reach a V-0 rating in both PLA types, while a loading of 15% of ItaP is not enough to reach the same classification. Despite their different structure, TGA and cone calorimetry results confirmed a gas phase mechanism mainly responsible for the highly efficient flame retardancy for all compounds. Finally, cone calorimetry tests of the flame retardant PLA with two heat fluxes showed different flame inhibiting efficiencies for different fire scenarios.

Char Studies: Flame Retarded Polycarbonate/PET Blend

1994 ◽  
Vol 12 (6) ◽  
pp. 551-581 ◽  
Author(s):  
Joseph Green
Keyword(s):  
Porous Structure ◽  
Flame Retardant ◽  
Cone Calorimeter ◽  
Oxygen Index ◽  
The Other ◽  
High Oxygen Concentration ◽  
Dsc Studies ◽  
Flame Retarded ◽  
Creep Modulus ◽  
Tga And Dsc

Bromine and phosphorus were shown to be synergistic in flame retarding a polycarbonate/PET blend as measured by oxygen index. This synergy is enhanced when both elements are present in the same molecule. Cone calorimeter data confirm these observations. Chars were formed by py rolysis in the TGA apparatus, by burning at high oxygen concentration in the oxygen index apparatus and by forced combustion in the cone calorimeter. Chars formed from the polymer blend containing the brominated phosphate gave 40-50% more char by weight than when bromine, phosphorus or blends of the two were used. Analyses of the chars showed no bromine and considerable phosphorus. TGA and DSC studies suggest that the polycarbonate and the PET undergo transesterification during pyrolysis above 400°C and the brominated phosphate acts as a transesterification inhibitor or stabilizer. SEM of the chars showed a considerable difference. When the brominated phosphate was used the char had a fine porous structure and thick solid skin. The other chars showed poorer structure and less to no skin. Measurement of the properties of the chars showed the char from the polymer containing the brominated phosphate to have a creep modulus 35 times greater than the char obtained from the polymer containing the bromine flame retardant.

Synergistic Effect between Montmorillonite Intercalated by Melamine and Intumescent Flame Retardant (IFR) on Polypropylene

2011 ◽  
Vol 295-297 ◽  
pp. 315-318
Author(s):  
Hong Fang Zhu ◽  
Juan Li ◽  
Liang Xu ◽  
Kang Tao ◽  
Li Xin Xue ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Flame Retardant ◽  
Cone Calorimeter ◽  
Oxygen Index ◽  
Intumescent Flame Retardant ◽  
Limited Oxygen Index ◽  
Cation Exchange Reaction ◽  
Melamine Salt ◽  
Better Than ◽  
Limited Oxygen

This Montmorillonite modified by melamine (MA-MMT) was prepared via cation exchange reaction by using melamine salt as intercalation reagent. MA-MMT and Na-MMT was combined with intumescent flame retardant (IFR) to be adopted into polypropylene (PP), respectively. The synergistic effect between MA-MMT and IFR and the influence of melamine in MMT layers on fire-resistant performance was evaluated. Results of limited oxygen index (LOI) tests and UL-94 tests indicate that melamine salts in MMT layers behaved better than Na-MMT in PP/IFR system. According to the results of cone calorimeter tests and scanning electron microscope (SEM), it concludes that melamine salts act as gas agent to provide migration impetus and expanded power, which caused a well-structured and strong char that had better ability to endure heat erosion. A good synergistic effect between MA-MMT and IFR is constructed.

Flame Retardant Effect of a Modified Intumescent Flame Retardant on a Rigid Polyurethane Foam

2017 ◽  
Vol 748 ◽  
pp. 51-54
Author(s):  
Pei Bang Dai ◽  
Lin Ying Yang ◽  
Ting Zheng ◽  
Chang Qin ◽  
Qi Chen Tang
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Oxygen Index ◽  
Intumescent Flame Retardant ◽  
Limiting Oxygen Index ◽  
Composite Foam ◽  
Composite Foams ◽  
Suitable Amount ◽  
Ul 94 ◽  
Pu Foams

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.

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