scholarly journals Flame-Retardant Performance of Transparent and Tensile-Strength-Enhanced Epoxy Resins

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 317 ◽  
Author(s):  
Liang Li ◽  
Zaisheng Cai
Keyword(s):  
Tensile Strength ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Epoxy Resins ◽  
Diglycidyl Ether ◽  
Laser Raman Spectroscopy ◽  
Limiting Oxygen Index ◽  
Laser Raman ◽  
Ul 94 ◽  
Amine Curing

In this study, a flame-retardant additive with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) groups denoted DSD was successfully synthesized from DOPO, 4,4′-diaminodiphenyl sulfone (DDS), and salicylaldehyde. The chemical structure of DSD was characterized by FTIR–ATR, NMR, and elemental analysis. DSD was used as an amine curing agent, and the transparent, tensile strength-enhanced epoxy resins named EP–DSD were prepared via thermal curing reactions among the diglycidyl ether of bisphenol A (DGEBA), 4,4′-diaminodiphenylmethane (DDM), and DSD. The flame-retardancy of composites was studied by the limiting oxygen index (LOI) and UL-94 test. The LOI values of EP–DSD composites increased from 30.7% for a content of 3 wt % to 35.4% for a content of 9 wt %. When the content of DSD reached 6 wt %, a V-0 rating under the UL-94 vertical test was achieved. SEM photographs of char residues after the UL-94 test indicate that an intumescent and tight char layer with a porous structure inside was formed. The TGA results revealed that EP–DSD thermosets decomposed ahead of time. The graphitization degree of the residual chars was also investigated by laser Raman spectroscopy. The measurement of tensile strength at breaking point shows that the loading of DSD increases the tensile strength of epoxy thermosets. Py-GC/MS analysis shows the presence of phosphorus fragments released during EP–DSD thermal decomposition, which could act as free radical inhibitors in the gas phase. Owing to the promotion of the formation of intumescent and compact char residues in the condensed phase and nonflammable phosphorus fragments formed from the decomposition of DOPO groups, EP–DSD composites displayed obvious flame-retardancy.

Synergistic Flame-Retardant Effect of Aluminum Diethyl Phosphinate in PP/IFR System and the Flame-Retardant Mechanism

2021 ◽  
Vol 36 (5) ◽  
pp. 519-528
Author(s):  
J.-L. Li ◽  
C.-T. Gao ◽  
X. Sun ◽  
S.-G. Peng ◽  
Y.-W. Wang ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Laser Raman Spectroscopy ◽  
Mass Ratio ◽  
Limiting Oxygen Index ◽  
Laser Raman ◽  
Cone Calorimeter Test ◽  
Ul 94 ◽  
Synergistic Flame Retardant

Abstract Synergistic flame-retardant effect of aluminum diethyl phosphinate (AlPi) in intumescent flame retardant polypropylene (PP/IFR) system and the flame-retardant mechanism were investigated. The flame retardancy of PP/IFR/AlPi (the mass ratio of IFR to AlPi is 2 : 1) was the best, which was proved by the results of the limiting oxygen index (LOI) test, UL-94 test, and cone calorimeter test ( CCT) test. Here, the LOI value of the sample was as high as 34% and passed the V–0 rating in UL–94 test. The peak heat release rate (PHRR) decreased by 92.57%, the total heat release (THR) reduced by 90.52%. Thermogravimetric (TGA) data showed that the introduction of AlPi improved thermal stability and changed the thermal degradation behavior of PP/IFR composites. Interestingly, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS) and laser Raman spectroscopy (LRS) proved that PP/IFR/AlPi had formed more residual carbon, but the flame retardancy was worse than PP/IFR/AlPi. This is because when the mass ratio of IFR to AlPi is 2 : 1, the synergy between IFR and AlPi was significant, gas-phase flame retardant and condensed-phase flame retardant reached a balance and obtained the best flame retardant effect.

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 Preparation and properties of flame-retardant epoxy resins containing reactive phosphorus flame retardant

2020 ◽  
Vol 15 ◽  
pp. 155892502090132
Author(s):  
Sang-Hoon Lee ◽  
Seung-Won Oh ◽  
Young-Hee Lee ◽  
Il-Jin Kim ◽  
Dong-Jin Lee ◽  
...  
Keyword(s):  
Impact Strength ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Flame Retardancy ◽  
Epoxy Resins ◽  
Phosphorus Content ◽  
Phosphorus Compound ◽  
Phosphorus Compounds ◽  
Limiting Oxygen Index ◽  
The Impact

To prepare flame-retardant epoxy resin, phosphorus compound containing di-hydroxyl group (10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phospha phenanthrene-10-oxide, DOPO-HQ) was reacted with uncured epoxy resin (diglycidyl ether of bisphenol A, YD-128) and then cured using a curing agent (dicyandiamide, DICY). This study focused on the effect of phosphorus compound/phosphorus content on physical properties and flame retardancy of cured epoxy resin. The thermal decomposition temperature of the cured epoxy resins (samples: P0, P1.5, P2.0, and P2.5, the number represents the wt% of phosphorus) increased with increasing the content of phosphorus compound/phosphorus (0/0, 19.8/1.5, 27.8/2.0, and 36.8/2.5 wt%) based on epoxy resin. The impact strength of the cured epoxy resin increased significantly with increasing phosphorus compound content. As the phosphorus compound/phosphorus content increased from 0/0 to 36.8/2.5 wt%, the glass transition temperature (the peak temperature of loss modulus curve) increased from 135.2°C to 142.0°C. In addition, as the content of phosphorous compound increased, the storage modulus remained almost constant up to higher temperature. The limiting oxygen index value of cured epoxy resin increased from 21.1% to 30.0% with increasing phosphorus compound/phosphorus content from 0/0 to 36.8/2.5 wt%. The UL 94 V test result showed that no rating for phosphorus compounds less than 19.8 wt% and V-1 for 27.8 wt%. However, when the phosphorus compound was 36.8 wt%, the V-0 level indicating complete flame retardancy was obtained. In conclusion, the incorporation of phosphorus compounds into the epoxy chain resulted in improved properties such as impact strength and heat resistance, as well as a significant increase in flame retardancy.

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.

scholarly journals PREPARATION OF IRON- REDUCED GRAPHENE OXIDE/ EPOXY RESIN COMPOSITE AND ITS FLAME RETARDANCY AND THERMAL STABILITY

10.6036/10327 ◽  
2022 ◽  
Vol 97 (1) ◽  
pp. 98-103
Author(s):  
XIAN WANG ◽  
JINLONG ZHUO ◽  
TIANQING XING ◽  
Xingran Wang
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Iron Powder ◽  
Flame Retardancy ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Industrial Manufacture ◽  
Ul 94

In order to reduce flammability, smoke release and enhance thermal stability of epoxy resin (EP), iron powder is mixed with graphene oxide/ epoxy resin (GO/EP) composite by mechanical blending. The combustion performance of composite material is investigated through limiting oxygen index (LOI), Underwriters Laboratory (UL)-94 test, and cone calorimeter test (CCT). Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and scanning electron microscope (SEM) are also used to explore the mechanism of flame retardancy and smoke suppression. Results show that, with the addition of 0.5% mass fraction of GO and the corresponding iron powder combination (EP3 sample), the LOI value can achieve 32.5% while reaching the UL-94 V0 rating. Compare with EP0, the peaks of heat release rate, smoke production rate, and smoke factor values of EP3 are decreased by 42%, 60%, and 50%, respectively. The char and TG-FTIR data of EP3 reveal that it has a more compact structure, good thermal stability, and produce fewer toxic gases and smoke. Reduction of GO could inhibit the degradation of EP, and iron catalyzes the formation of carbonaceous char on the surface. Thus, the thermal stability and flame retardancy of EP are improved significantly. This study provides a suitable way to prepare graphene/EP composites that contain iron catalyst and can be extended to the industrial manufacture of flame retardant polymer composites. Keywords: iron powder; epoxy resin; graphene oxide; flame retardant; thermal stability

Epoxy Resins Treated with Metal-Containing Flame Retardant

2012 ◽  
Vol 466-467 ◽  
pp. 495-499 ◽  
Author(s):  
Ming Gao ◽  
Ying Juan Sun
Keyword(s):  
Flame Retardant ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Decomposition Temperature ◽  
Char Yield ◽  
Initial Decomposition Temperature ◽  
Limiting Oxygen Index ◽  
Smoke Density ◽  
Integral Procedure ◽  
Ul 94

A novel cheap macromolecular intumescent flame retardants (Zn-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-silicon characterized by IR. Epoxy resins (EP) were modified with Zn-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Zn contents of 3.0 % get a LOI of 27.5% and char yield of 20.5%. Dilatation, SDR and MSD of EP/Zn-MIFR decreased. The degradation behavior of the EP/Zn-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Zn and P at the residue were increased.

Epoxy resin/cyanate ester composites containing DOPO and wollastonite with simultaneously improved flame retardancy and thermal resistance

2020 ◽  
Vol 32 (6) ◽  
pp. 710-718
Author(s):  
Zhengzhou Wang ◽  
Xin Gao ◽  
Wenfeng Li
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Oxygen Index ◽  
Thermal Studies ◽  
Cyanate Ester ◽  
Total Heat Release ◽  
Limiting Oxygen Index ◽  
Peak Heat Release Rate ◽  
Ul 94

Flame-retardant epoxy (EP) resin/cyanate ester (CE) composites were prepared with 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and wollastonite (Wo). The combustion behavior of the flame-retardant EP/CE composites was investigated by limiting oxygen index (LOI), UL-94, and cone calorimeter tests. It is found that the EP/CE composite containing 7 wt% DOPO and 3 wt% Wo (sample 7DO/3Wo/EP/CE) exerts the best flame retardancy (LOI 35.5% and UL-94 V-0 rating). The peak heat release rate and total heat release of sample 7DO/3Wo/EP/CE increase slightly, while total smoke release decreases about 14% compared with the EP/CE composite containing 10 wt% DOPO (sample 10DO/EP/CE). Thermal studies indicate that the glass transition temperature and temperature at 5% mass loss of sample 7DO/3Wo/EP/CE are higher than that of sample 10DO/EP/CE. Moreover, the mechanical properties of EP/CE composites were investigated.

Epoxy Resins Treated with Novel Silicon-Containing Flame Retardant

2012 ◽  
Vol 560-561 ◽  
pp. 563-568 ◽  
Author(s):  
Ming Gao ◽  
Ying Juan Sun
Keyword(s):  
Flame Retardant ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Decomposition Temperature ◽  
Char Yield ◽  
Initial Decomposition Temperature ◽  
Limiting Oxygen Index ◽  
Smoke Density ◽  
Integral Procedure ◽  
Ul 94

A novel cheap macromolecular intumescent flame retardants (Si-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-silicon characterized by IR. Epoxy resins (EP) were modified with Si-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Si contents of 3.0 % get a LOI of 27.5% and char yield of 23.8%. Dilatation, SDR and MSD of EP/Si-MIFR decreased. The degradation behavior of the EP/Si-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Si and P at the residue were increased.

Poly(diallyldimethylammonium) and polyphosphate polyelectrolyte complex as flame retardant for char-forming epoxy resins

2020 ◽  
Vol 38 (4) ◽  
pp. 333-347
Author(s):  
Lichen Zhang ◽  
Deqi Yi ◽  
Jianwei Hao
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Polyelectrolyte Complex ◽  
Oxygen Index ◽  
Cone Calorimetry ◽  
Limiting Oxygen Index ◽  
Smoke Production ◽  
Ul 94

The flame retardant poly(diallyldimethylammonium) and polyphosphate polyelectrolyte complex and the curing agent m-Phenylenediamine were blended into diglycidyl ether of bisphenol A (DGEBA)-type epoxy resin to prepare flame-retardant epoxy resin thermosets. The effects of poly(diallyldimethylammonium) and polyphosphate on fire retardancy and thermal degradation behavior of epoxy resins (EP)/poly(diallyldimethylammonium) and polyphosphate composites were tested by Limiting Oxygen Index, UL-94, cone calorimeter tests, and thermogravimetric analysis and compared with pure EP. The results showed that the Limiting Oxygen Index value of EP/poly(diallyldimethylammonium) and polyphosphate composite could reach 31.9%, and UL-94 V-0 rating at 10 wt% poly(diallyldimethylammonium) and polyphosphate loading. Meanwhile the cone calorimetry peak heat release rate and total heat release were reduced up to 55.2% and 21.8%, respectively; smoke production rate and total smoke production were also declined significantly, compared with those of pure epoxy resins. Poly(diallyldimethylammonium) and polyphosphate played a very good flame-retardant effect on epoxy resins.

scholarly journals Effect of Thermal Conductive Fillers on the Flame Retardancy, Thermal Conductivity, and Thermal Behavior of Flame-Retardant and Thermal Conductive Polyamide 6

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4114 ◽  
Author(s):  
Fang Wang ◽  
Wenbo Shi ◽  
Yuliang Mai ◽  
Bing Liao
Keyword(s):  
Thermal Conductivity ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Combustion Process ◽  
Polyamide 6 ◽  
Gravimetric Analysis ◽  
Limiting Oxygen Index ◽  
Conductive Fillers ◽  
Ul 94 ◽  
The Impact

In this work, polyamide 6 (PA6) composites with improved flame retardancy and thermal conductivity were prepared with different thermal conductive fillers (TC fillers) such as aluminum nitride (AlN) and boron nitride (BN) in a PA6 matrix with aluminum diethylphosphinate (AlPi) as a fire retardant. The resultant halogen-free flame retardant (HFFR) and thermal conductive (TC) PA6 (HFFR-TC-PA6) were investigated in detail with a mechanical property test, a limiting oxygen index (LOI), the vertical burning test (UL-94), a cone calorimeter, a thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology of the impact fracture surface and char residue of the composites were analyzed by scanning electron microscopy (SEM). It was found that the thermal conductivity of the HFFR-TC-PA6 composite increased with the amount of TC fillers. The TC fillers exerted a positive effect for flame retardant PA6. For example, the HFFR-TC-PA6 composites with the thickness of 1.6 mm successfully passed the UL-94 V-0 rating with an LOI of more than 29% when the loading amount of AlN-550RFS, BN-SW08 and BN-NW04 was 30 wt%. The morphological structures of the char residues revealed that TC fillers formed a highly integrated char layer surface (without holes) during the combustion process, as compared to that of flame retardant PA6/AlPi composites. In addition, the thermal stability and crystallization behavior of the composites were studied.

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