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

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.

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An Effective Method for Preparation of Liquid Phosphoric Anhydride and Its Application in Flame Retardant Epoxy Resin

Materials ◽

10.3390/ma14092205 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2205

Author(s):

Qian Li ◽

Yujie Li ◽

Yifan Chen ◽

Qiang Wu ◽

Siqun Wang

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Epoxy Resins ◽

Oxygen Index ◽

Decomposition Temperature ◽

Ease Of Use ◽

Limiting Oxygen Index ◽

Good Thermal Stability ◽

Low Viscosity ◽

The Impact

A novel liquid phosphorous-containing flame retardant anhydride (LPFA) with low viscosity was synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and methyl tetrahydrophthalic anhydride (MeTHPA) and further cured with bisphenol-A epoxy resin E-51 for the preparation of the flame retardant epoxy resins. Both Fourier transform infrared spectroscopy (FT-IR), mass spectrometry (MS) and nuclear magnetic resonance (NMR) measurements revealed the successful incorporation of DOPO on the molecular chains of MeTHPA through chemical reaction. The oxygen index analysis showed that the LPFA-cured epoxy resin exhibited excellent flame retardant performance, and the corresponding limiting oxygen index (LOI) value could reach 31.2%. The UL-94V-0 rating was achieved for the flame retardant epoxy resin with the phosphorus content of 2.7%. With the addition of LPFA, the impact strength of the cured epoxy resins remained almost unchanged, but the flexural strength gradually increased. Meanwhile, all the epoxy resins showed good thermal stability. The glass transition temperature (Tg) and thermal decomposition temperature (Td) of epoxy resin cured by LPFA decreased slightly compared with that of MeTHPA-cured epoxy resin. Based on such excellent flame retardancy, low viscosity at room temperature and ease of use, LPFA showed potential as an appropriate curing agent in the field of electrical insulation materials.

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Preparation and Properties of Naringin Epoxy/UiO-66 Composites

10.21203/rs.3.rs-853871/v1 ◽

2021 ◽

Author(s):

Yonggang Du ◽

Gonghui Shi ◽

Hui Wang ◽

Ge Zhao ◽

Wei Li ◽

...

Keyword(s):

Impact Strength ◽

Epoxy Resin ◽

Flame Retardancy ◽

Oxygen Index ◽

Glycidyl Ether ◽

Casting Process ◽

Curing Agent ◽

The Novel ◽

Limiting Oxygen Index ◽

The Impact

Abstract The novel bio-based epoxy resin based on naringenin was synthesized. The naringenin epoxy/UiO-66 composites were prepared by casting process with UiO-66 as modifier and maleic anhydride as curing agent. The influences of UiO-66 content on mechanical properties, thermal stability and flame retardancy of naringenin epoxy/UiO-66 composites were investigated. The results showed that the impact strength, glass transition temperature and limiting oxygen index of pure naringenin epoxy resin were 2.0 kJ/m2, 96 ℃ and 1.2% higher than that of di-glycidyl ether of bisphenol A (DGEBA), respectively. UiO-66 can significantly improve the impact strength of naringenin epoxy resin while assisting improve its flame retardancy. When UiO-66 content was 4 wt%, the impact strength and limiting oxygen index of the naringenin epoxy/UiO-66 composite were 7.6 kJ/m2 and 24.5%, which were 85.4% and 3.5% higher than that of pure naringin epoxy resin, respectively.

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Synthesis of a phosphorus–nitrogen-containing flame retardant and its application in epoxy resin

High Performance Polymers ◽

10.1177/0954008318756496 ◽

2018 ◽

Vol 31 (2) ◽

pp. 186-196 ◽

Cited By ~ 12

Author(s):

Shuang Yang ◽

Yefa Hu ◽

Qiaoxin Zhang

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Epoxy Resin ◽

Heat Release Rate ◽

Flame Retardancy ◽

Release Rate ◽

Epoxy Resins ◽

Proton Nuclear Magnetic Resonance ◽

Scanning Calorimetry ◽

Cone Calorimeter Test

In this article, a phosphorus–nitrogen-containing flame retardant (DOPO-T) was successfully synthesized by nucleophilic substitution reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and cyanuric chloride. The chemical structure of DOPO-T was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) and phosphorous-31 NMR, and elemental analysis. DOPO-T was then blended with diglycidyl ether of bisphenol-A to prepare flame-retardant epoxy resins. Thermal properties, flame retardancy, and combustion behavior of the cured epoxy resins were evaluated by differential scanning calorimetry, thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the glass transition temperature ( Tg) and temperature at 5% weight loss of epoxy resin (EP)/DOPO-T thermosets were gradually decreased with the increasing content of DOPO-T. DOPO-T catalyzed the decomposition of EP matrix in advance. The flame-retardant performance of EP thermosets was significantly enhanced with the addition of DOPO-T. EP/DOPO-T-0.9 sample had an LOI value of 36.2% and achieved UL94 V-1 rating. In addition, the average of heat release rate, peak of heat release rate, average of effective heat of combustion, and total heat release (THR) of EP/DOPO-T-0.9 sample were decreased by 32%, 48%, 23%, and 31%, respectively, compared with the neat EP sample. Impressively, EP/DOPO-T thermosets acquired excellent flame retardancy under low loading of flame retardant.

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The application of a phosphorus nitrogen flame retardant curing agent in epoxy resin

e-Polymers ◽

10.1515/epoly-2019-0058 ◽

2019 ◽

Vol 19 (1) ◽

pp. 545-554 ◽

Cited By ~ 1

Author(s):

Anxin Li ◽

Pingli Mao ◽

Bing Liang

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Adhesive Strength ◽

Chemical Structure ◽

Phosphorus Content ◽

Raw Material ◽

Curing Agent ◽

Thermal Degradation Behavior ◽

Overall Performance ◽

The Impact

AbstractIn order to improve the compatibility of flame retardant and epoxy resin, a phosphorus nitrogen flame retardant curing agent poly(p-xylylenediamine spirocyclic pentaerythritol bisphosphonate) (PPXSPB) was synthesized. FTIR, 1HNMR, and mass spectroscopy were used to identify the chemical structure of PPXSPB. Epoxy resin (E-44) and PPXSPB as the raw material, a series of thermosetting systems were prepared. The effects of PPXSPB on flame retardancy, water resistance, thermal degradation behavior, mechanical properties and the adhesive strength of EP/PPXSPB thermosets were investigated. The results show that with the increase of phosphorus content, the oxygen index and carbon residue of the system both increased significantly, and the heat release rate gradually decreased, which is of great significance in delaying the occurrence of fire. When the phosphorus content is 3.24% in EP/PPXSPB thermosets, EP-2 can successfully pass the UL94 V-0 flammability rating, the LOI value of EP-2 can reach 31.4%, the impact strength and tensile strength was 6.58 kJ/m2 and 47.10 MPa respectively, and the adhesive strength was 13.79 MPa, the system presents a good overall performance.

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Flame retardant epoxy resin based on organic titanate and polyhedral oligomeric silsesquioxane-containing additives with synergistic effects

RSC Advances ◽

10.1039/c7ra02529g ◽

2017 ◽

Vol 7 (42) ◽

pp. 26082-26088 ◽

Cited By ~ 15

Author(s):

Birong Zeng ◽

Yongzhou Liu ◽

Li Yang ◽

Wei Zheng ◽

Ting Chen ◽

...

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Flame Retardancy ◽

Epoxy Resins ◽

Synergistic Effects ◽

Polyhedral Oligomeric Silsesquioxane ◽

Tetrabutyl Titanate ◽

System P ◽

Oligomeric Silsesquioxane

In order to develop epoxy resins possessing good thermal, mechanical, and flame retardancy performance, a synthesized POSS-bisDOPO was used as co-additive with tetrabutyl titanate to construct the ternary phosphorous–silicon–titanium synergy system.

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Synergistic Flame Retardant Effect of Barium Phytate and Intumescent Flame Retardant for Epoxy Resin

Polymers ◽

10.3390/polym13172900 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2900

Author(s):

Linyuan Wang ◽

Yue Wei ◽

Hongbo Deng ◽

Ruiqi Lyu ◽

Jiajie Zhu ◽

...

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Flame Retardancy ◽

Barium Carbonate ◽

Environmentally Friendly ◽

Intumescent Flame Retardant ◽

Limiting Oxygen Index ◽

Application Range ◽

Peak Heat Release Rate ◽

Synergistic Flame Retardant

Recently, widespread concern has been aroused on environmentally friendly materials. In this article, barium phytate (Pa-Ba) was prepared by the reaction of phytic acid with barium carbonate in deionized water, which was used to blend with intumescent flame retardant (IFR) as a flame retardant and was added to epoxy resin (EP). Afterward, the chemical structure and thermal stability of Pa-Ba were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), respectively. On this basis, the flammability and flame retardancy of EP composites were researched. It is shown that EP/14IFR/2Ba composite has the highest limiting oxygen index (LOI) value of 30.7%. Moreover, the peak heat release rate (PHRR) of EP/14IFR/2Ba decreases by 69.13% compared with pure EP. SEM and Raman spectra reveal the carbonization quality of EP/14IFR/2Ba is better than that of other composites. The results prove that Pa-Ba can cooperate with IFR to improve the flame retardancy of EP, reducing the addition amount of IFR in EP, thus expanding the application range of EP. In conclusion, adding Pa-Ba to IFR is a more environmentally friendly and efficient method compared with others.

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Preparation and Characterization of DOPO-Functionalized MWCNT and Its High Flame-Retardant Performance in Epoxy Nanocomposites

Polymers ◽

10.3390/polym12030613 ◽

2020 ◽

Vol 12 (3) ◽

pp. 613 ◽

Cited By ~ 2

Author(s):

Liqiang Gu ◽

Chen Qiu ◽

Jianhui Qiu ◽

Youwei Yao ◽

Eiichi Sakai ◽

...

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Epoxy Resin ◽

Epoxy Resins ◽

Phosphorus Content ◽

Co2 Production ◽

Peak Heat Release Rate ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

In this work, functionalized multi-walled carbon nanotubes (MWCNT) were synthesized by the reaction between acylated MWCNT and 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (ODOPB). The obtained MWCNT-ODOPB was well dispersed into epoxy resins together with aluminum diethylphosphinate (AlPi) to form flame-retardant nanocomposites. The epoxy resin nanocomposite with phosphorus content of 1.00 wt % met UL 94 V-0 rating, exhibited LOI value of 39.5, and had a higher Tg compared to neat epoxy resin, which indicates its excellent flame retardant performance. These experimental results indicated that MWCNT-ODOPB was a compatible and efficient flame retardant for epoxy resins. Moreover, cone calorimeter analysis showed that the peak heat release rate (pHRR), total heat release (THR) values, and CO2 production profiles of the composites decreased with an increase in the additional amount of phosphorus.

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Synthesis of a Flame Retardant and Hydrophobic Epoxy Resin with Multiple Elements Synergistic Effect for Tunnel Seepage Prevention Application

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.842.314 ◽

2020 ◽

Vol 842 ◽

pp. 314-325

Author(s):

Bin Lin

Keyword(s):

Flame Retardant ◽

Epoxy Resin ◽

Flame Retardancy ◽

Oxygen Index ◽

Fire Retardant ◽

Practical Application ◽

Water Contact ◽

Limiting Oxygen Index ◽

New Perspective ◽

Grouting Materials

Epoxy resin (EP) mortar usually used to repair the cracking of concrete structure under damp environment, but EP is extremely flammable, thus it’s extremely imperative to design a novel multifunction EP grouting materials with flame retardancy and waterproofness for the practical application. Targeting ingenious decoration of EP grouting materials, multiple flame retardant elements (phosphorus, nitrogen and fluorine) are concurrently introduced into a fire retardant and the fire retardant defined as DDM-FNP. The obtained DDM-FNP/EP grouting composite possess high thermal stability, flame retardancy and hydrophobicity. The limiting oxygen index (LOI) value of DDM-FNP/EP composites has a significant improve, which is increased from 26.7 (EP-0) to 35.8 (EP-4). Composites with more than 10 wt% of DDM-FNP could pass UL-94 V-0 rating without dripping. Compared with EP-0, the PHRR and THR of EP-4 are decreased by 31.1% and 21.6%, respectively. In addition, due to the introduction of the F element, the water contact angle of EP composites is changed from 75.2° (hydrophilicity) to 98.6° (hydrophobicity) after the introduction of a certain amount of DDM-FNP flame retardant. Therefore, this work provide a new perspective to design a multifunction EP grouting composite and improve the value of practical application on seepage prevention of tunnel.

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

DYNA INGENIERIA E INDUSTRIA ◽

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

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Polyurethane Hybrid Composites Reinforced with Lavender Residue Functionalized with Kaolinite and Hydroxyapatite

Materials ◽

10.3390/ma14020415 ◽

2021 ◽

Vol 14 (2) ◽

pp. 415

Author(s):

Sylwia Członka ◽

Agnė Kairytė ◽

Karolina Miedzińska ◽

Anna Strąkowska

Keyword(s):

Thermal Decomposition ◽

Compressive Strength ◽

Impact Strength ◽

Flexural Strength ◽

Flame Retardant ◽

Hybrid Composites ◽

Thermal Characteristic ◽

Flame Resistance ◽

Limiting Oxygen Index ◽

The Impact

Polyurethane (PUR) composites were modified with 2 wt.% of lavender fillers functionalized with kaolinite (K) and hydroxyapatite (HA). The impact of lavender fillers on selected properties of PUR composites, such as rheological properties (dynamic viscosity, foaming behavior), mechanical properties (compressive strength, flexural strength, impact strength), insulation properties (thermal conductivity), thermal characteristic (temperature of thermal decomposition stages), flame retardancy (e.g., ignition time, limiting oxygen index, heat peak release) and performance properties (water uptake, contact angle) was investigated. Among all modified types of PUR composites, the greatest improvement was observed for PUR composites filled with lavender fillers functionalized with kaolinite and hydroxyapatite. For example, on the addition of functionalized lavender fillers, the compressive strength was enhanced by ~16–18%, flexural strength by ~9–12%, and impact strength by ~7%. Due to the functionalization of lavender filler with thermally stable flame retardant compounds, such modified PUR composites were characterized by higher temperatures of thermal decomposition. Most importantly, PUR composites filled with flame retardant compounds exhibited improved flame resistance characteristics—in both cases, the value of peak heat release was reduced by ~50%, while the value of total smoke release was reduced by ~30%.

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