Synthesis of Nitrogen-Phosphous Flame Retardants and Their Flame Retardant Applications in Epoxy Resins

doi:10.19894/j.issn.1000-0518.240324

Chinese Journal of Applied Chemistry ›› 2025, Vol. 42 ›› Issue (2): 212-221.DOI: 10.19894/j.issn.1000-0518.240324

• Full Papers • Previous Articles Next Articles

Synthesis of Nitrogen-Phosphous Flame Retardants and Their Flame Retardant Applications in Epoxy Resins

Ao-Tian ZHANG, Jun-Jie SHI, Qian-Huo CHEN(), Hong-Zhou LI()

College of Environmental and Resources，Engineering Research Center of Polymer Green Recycling of Ministry of Education，Fujian Normal University Fuzhou 350007，China

Received:2024-10-16 Accepted:2024-12-27 Published:2025-02-01 Online:2025-03-14
Contact: Qian-Huo CHEN,Hong-Zhou LI
About author:lihongzhou@fjnu.edu.cn
qhchen@fjnu.edu.cn；
Supported by:
the National Natural Science Foundation of China(22478073);the Natural Science Foundation of Fujian Province(2021J01198)

Abstract

Abstract:

In this study， a novel multielemental synergistic flame retardant （DAI） was successfully synthesized in two steps using 9，10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide （DOPO）， 2-aminobenzothiazole （ABZ）， and indole-3-carboxaldehyde （I3C）， which was verified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy （NMR）. Epoxy resin/DAI-3 （EP/DAI-3）， EP/DAI-5 and EP/DAI-7 were prepared by blending them with epoxy resin using the thermosetting method， and the flame retardant properties and residual carbon properties after combustion of the prepared EP composites were investigated. The results showed that the prepared EP composites had excellent smoke suppression and flame retardant properties， especially the 7% DAI-added EP， which showed significant reductions of 34.5%， 32.3% and 42.2% in pHRR， pCOPR and pCO₂PR， respectively. Compared with pure EP， EP/DAI-7 achieved a LOI value of 32.6% and a V-0 rating in UL-94 test. The residual carbon analysis shows that the prepared EP/DAI-7 has a denser and stronger residual carbon than pure EP， with an I_D/I_G value of 2.03， which had the highest degree of graphitization.

Key words: Epoxy resin, 9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2-Aminobenzothiazole, Indole-3-carboxaldehyde, Multi-element synergistic flame retardant

CLC Number:

O632

Ao-Tian ZHANG, Jun-Jie SHI, Qian-Huo CHEN, Hong-Zhou LI. Synthesis of Nitrogen-Phosphous Flame Retardants and Their Flame Retardant Applications in Epoxy Resins[J]. Chinese Journal of Applied Chemistry, 2025, 42(2): 212-221.

Figures/Tables 9

Table 1 Formula of EP/DAI flame retardant composite

Sample	w（EP）/%	w（DDM）/%	w（DAI）/%	w（P）/%	w（N）/%
EP	80.00	20.00	0.00	0.00	0.00
EP/DAI-3	77.60	19.40	3.00	0.19	0.26
EP/DAI-5	76.00	19.00	5.00	0.31	0.43
EP/DAI-7	74.40	18.60	7.00	0.44	0.60

Fig.1 （A） Schematic diagram of synthesized DAI；（B） FT-IR spectra of DAI and DOPO， I3C and ABZ；（C） 1H NMR spectrum of DAI

Fig.2 （A） TG and （B） DTG curves at N2 atmospheres of EP， EP/DAI-3， EP/DAI-5 and EP/DAI-7

Table 2 Data of TGA test

Sample	Char residue at 800 ℃/%	T_5%/℃	T_10%/℃	Maximum mass loss rate/（%·℃^-1）
EP	16.4	370.8	376.5	2.20
EP/DAI-3	19.8	354.8	363.8	1.61
EP/DAI-5	18.9	350.2	361.3	1.50
EP/DAI-7	19.0	352.7	361.2	1.54

Fig.3 UL-94 test of （A） EP，（B） EP/DAI-3，（C） EP/DAI-5 and （D） EP/DAI-7

Fig.4 LOI values of EP， EP/DAI-3， EP/DAI-5 and EP/DAI-7

Fig.5 （A） HRR，（B） THR，（C） SPR，（D） TSP，（E） COPR，（F） CO2PR curves of EP， EP/DAI-3， EP/DAI-5 and EP/DAI-7

Table 3 CCT data of EP， EP/DAI-3， EP/DAI-5 and EP/DAI-7 composites

Samples	TTI/s	pHRR/（kW·m^-2）	THR/（MJ·m^-2）	pSPR/（m²·s^-1）	TSP/m²	pCOPR/（g·s^-1）	pCO₂PR/（g·s^-1）
EP	115	1004.7	81.1	0.28	26.5	0.034	0.64
EP/DAI-3	90	992.8	61.7	0.26	21.8	0.040	0.63
EP/DAI-5	96	763.7	65.7	0.34	26.8	0.039	0.45
EP/DAI-7	80	657.2	67.7	0.23	29.1	0.023	0.37

Fig.6 （A） Digital photographs，（B） SEM photographs and （C） Raman spectra of the char residues of EP， EP/DAI-3， EP/DAI-5 and EP/DAI-7

References 36

1	WANG G F， LI H F， SHAO Y R， et al. Preparation method of biogenic phytic acid and chitosan-related epoxy resin flame retardant： a review［J］. J Polym Res， 2023， 30（7）： 269.
2	MATHEWS L D， CAPRICHO J C， PEERZADA M， et al. Recent progress and multifunctional applications of fire-retardant epoxy resins［J］. Mater Today Commun， 2022， 33： 104702.
3	XIAO Z T， WU G L， YANG T M， et al. Sustainably sourced and DOPO-derived triols as hardeners for epoxy thermosets： a promising solution to synchronously improve flame retardancy， mechanical strength and toughness‍［J］. Chem Eng J， 2024， 498： 155484.
4	ZHANG Y B， YAN H X， FENG G P， et al. Non-aromatic Si， P， N-containing hyperbranched flame retardant on reducing fire hazards of epoxy resin with desirable mechanical properties and lower curing temperature‍［J］. Compos Part B， 2021， 222： 109043.
5	ZHOU C Y， WU K X， ZHANG Y， et al. Alginic acid derivatives/DOPO modified epoxy resins： excellent flame retardancy， mechanical properties， chemical resistance［J］. Polym Degrad Stab， 2024， 225： 110778.
6	YU Y Y， TANG S， FENG D， et al. Non-covalently functionalized black phosphorene to efficient flame retardant EVA with improved mechanical properties［J］. Polym Degrad Stab， 2024， 225： 110777.
7	PHAM L H， NGUYEN N T， NGUYEN D M， et al. Effective non-halogen flame-retardants combined with nSiO₂ particles to improve thermal stability and fire resistance of high-performance polyurethane nanocomposite foams‍［J］. J Mater Sci Technol， 2024， 203： 1-13.
8	RAD E R， VAHABI H， DE ANDA A R， et al. Bio-epoxy resins with inherent flame retardancy‍［J］. Prog Org Coat， 2019， 135： 608-612.
9	WANG P， CHEN L， XIAO H， et al. Nitrogen/sulfur-containing DOPO based oligomer for highly efficient flame-retardant epoxy resin［J］. Polym Degrad Stab， 2020， 171： 109023.
10	林渊，陈嘉炼，李红周. 单宁酸/聚乙烯醇的阻燃性能［J］. 应用化学， 2023， 40（1）： 69-78.
	LIN Y， CHEN J L， LI H Z. Flame retardant properties of tannic acid/poly（vinyl alcohol）‍［J］. Chin J Appl Chem， 2023， 40（1）： 69-78.
11	KANDOLA B K， MAGNONI F， EBDON J R. Flame retardants for epoxy resins： application-related challenges and solutions［J］. J Vinyl Addit Technol， 2022， 28（1）： 17-49.
12	CHEN Q， WANG S， LI S X， et al. Highly efficient phosphorous-containing flame retardant for transparent epoxy resin with good mechanical properties［J］. J Polym Res， 2023， 30（1）： 32.
13	YANG Y X， WANG D Y， JIAN R K， et al. Chemical structure construction of DOPO-containing compounds for flame retardancy of epoxy resin： a review［J］. Prog Org Coat， 2023， 175： 107316.
14	史俊杰，史哲航，李红周. 磷系阻燃剂插层镁铝型水滑石复合物的制备及其在热塑性聚氨酯中的阻燃应用［J］. 应用化学， 2023， 40（9）： 1288-1301.
	SHI J J， SHI Z H， LI H Z. Preparation of magnesium aluminum-type hydrotalcite compounds intercalated with phosphorus flame retardants and their flame retardant application in thermoplastic polyurethane［J］. Chin J Appl Chem， 2023， 40（9）： 1288-1301.
15	WANG P， CHEN L， XIAO H. Flame retardant effect and mechanism of a novel DOPO based tetrazole derivative on epoxy resin［J］. J Anal Appl Pyrolysis， 2019， 139： 104-113.
16	ZOU Y B， SHI J J， CUI W Q， et al. Isopropanolamine-modified ammonium polyphosphate for improved flame retardancy of epoxy resin［J］. J Appl Polym Sci， 2024， 141（25）： e55526.
17	KIM H H， SIM M J， LEE J C， et al. The effects of chemical structure for phosphorus-nitrogen flame retardants on flame retardant mechanisms［J］. J Mater Sci， 2023， 58： 6850-6864.
18	YUAN Y， SHI Y Q， YU B， et al. Facile synthesis of aluminum branched oligo（phenylphosphonate） submicro-particles with enhanced flame retardance and smoke toxicity suppression for epoxy resin composites‍［J］. J Hazard Mater， 2020， 381： 121233.
19	SHEN J J， LIANG J W， LIN X F， et al. The flame-retardant mechanisms and preparation of polymer composites and their potential application in construction engineering［J］. Polymers， 2022， 14（1）： 82.
20	QIN C L， CHEN J， RUAN S S， et al. Theoretical study on the effect of oxidation states of phosphorus flame retardants on their mode of action［J］. Polym Degrad Stab， 2024， 223： 110735.
21	PENG W， NIE S B， XU Y X， et al. A tetra-DOPO derivative as highly efficient flame retardant for epoxy resins‍［J］. Polym Degrad Stab， 2021， 193： 109715.
22	GUO W W， YU B， YUAN Y， et al. In situ preparation of reduced graphene oxide/DOPO-based phosphonamidate hybrids towards high-performance epoxy nanocomposites［J］. Compos Part B， 2017， 123： 154-164.
23	SHI Z H， LUO F B， LI H Z， et al. Synthesis of a graft-functionalized flame retardant based on DOPO and its application on the surface of terylene/cotton fabrics［J］. J Appl Polym Sci， 2024， 141（8）： 54976.
24	HUO S Q， SAI T， RAN S Y， et al. A hyperbranched P/N/B-containing oligomer as multifunctional flame retardant for epoxy resins［J］. Compos Part B， 2022， 234： 109701.
25	CAI H P， HUANG W Y， LI B L， et al. A multi-element flame retardant for rail transit to improve the flame retardant performance of epoxy resin while reducing smoke density［J］. J Appl Polym Sci， 2024， 141（4）： e54841.
26	LU J Y， CHEN L P， LUO Z L， et al. A vanillin-containing DOPO-based compound for improving the flame retardancy of epoxy resin simultaneously with comparable transparency and mechanical property［J］. J Appl Polym Sci， 2023， 140（9）： e53556.
27	KIM H H， SIM M J， LEE J C， et al. The effects of chemical structure for phosphorus-nitrogen flame retardants on flame retardant mechanisms［J］. J Mater Sci， 2023， 58： 6850-6864.
28	WAN C， DUAN H J， ZHANG C H， et al. A P/N/S-containing compound toward enhanced fire safety epoxy resin with well-balanced performance［J］. Polym Degrad Stab， 2021， 192： 109698.
29	杨雪艳，史俊杰，周勇军，等. 磷系阻燃剂插层镁铝水滑石增强环氧树脂的阻燃性能［J］. 应用化学， 2024， 41（8）： 1154-1167.
	YANG X Y， SHI J J， ZHOU Y J， et al. Enhanced flame retardancy of epoxy resins by intercalation of magnesium-aluminum hydrotalcite with phosphorus-based flame retardants［J］. Chin J Appl Chem， 2024， 41（8）： 1154-1167.
30	WEI Z B， CHEN X L， JIAO C M. Thermal degradation and flame retardancy of fumaric acid in thermoplastic polyurethane elastomer［J］. Polym Adv Technol， 2019， 30（2）： 475-482.
31	HUANG G B， CHEN W， WU T， et al. Multifunctional graphene-based nano-additives toward high-performance polymer nanocomposites with enhanced mechanical， thermal， flame retardancy and smoke suppressive properties‍［J］. Chem Eng J， 2021， 410： 127590.
32	LIU C， WU W， SHI Y Q， et al. Creating MXene/reduced graphene oxide hybrid towards highly fire safe thermoplastic polyurethane nanocomposites［J］. Compos Part B， 2020， 203： 108486.
33	LIU Y， ZHAO J， DENG C L， et al. Flame-retardant effect of sepiolite on an intumescent flame-retardant polypropylene system［J］. Ind Eng Chem Res， 2011， 50（4）： 2047-2054.
34	LI W J， LUO F B， DAI Y M， et al. Fabrication of highly efficient flame-retardant and biocompatible ramie fabrics through covalent bonding and layer-by-layer assembly methods［J］. Cellulose， 2024， 31（14）： 9025-9042.
35	ZOU Y B， CUI W Q， CHEN D L， et al. In situ-generated heat-resistant hydrogen-bonded organic framework for remarkably improving both flame retardancy and mechanical properties of epoxy composites［J］. ACS Appl Mater Interfaces， 2023， 15（40）： 47463-47474.
36	WANG X， WU T， HONG J， et al. Organophosphorus modified hollow bimetallic organic frameworks： effective adsorption and catalytic charring of pyrolytic volatiles［J］. Chem Eng J， 2021， 421： 129697.

[1]	Xue-Yan YANG, Jun-Jie SHI, Yong-Jun ZHOU, Yu-Mei DAI, Hong-Zhou LI. Flame Retardancy of Epoxy Resin Enhanced by Intercalation of Magnesium Aluminum Hydrotalcite with Phosphorous Flame Retardants [J]. Chinese Journal of Applied Chemistry, 2024, 41(8): 1154-1167.
[2]	Zi-Wei LU, Yong-Fu LIU, Zhao-Hua LUO, Peng SUN, Jun JIANG. Progress on Cr³⁺-Doped Broadband Near-Infrared Phosphors [J]. Chinese Journal of Applied Chemistry, 2024, 41(3): 328-339.
[3]	Jun-Jie SHI, Zhe-Hang SHI, Hong-Zhou LI. Preparation of Magnesium Aluminum-Type Hydrotalcite Compounds Intercalated with Phosphorus Flame Retardants and Their Flame Retardant Application in Thermoplastic Polyurethane [J]. Chinese Journal of Applied Chemistry, 2023, 40(9): 1288-1301.
[4]	Meng-Yao WANG, Mei-Zhen GAO, Qi SHI, Jin-Xiang DONG. Toluene-Templated Synthesis of ZIF-93 and Its Adsorptive Separation of 1，3-Propanediol and 2，3-Butanediol [J]. Chinese Journal of Applied Chemistry, 2023, 40(9): 1302-1311.
[5]	Peng-Hui FAN, Jie LIU, Sheng-Hui LOU, Tao TANG. Research Progress on Synergists of Phosphorous Flame Retardants in Epoxy Resin [J]. Chinese Journal of Applied Chemistry, 2023, 40(5): 653-665.
[6]	Shu-Min CHEN, Zi-Quan LYU, Xuan ZOU, Shui-Qing GUI, Xue-Mei LU. Research Progress of Functional Masks Amid the Normalization of the COVID-19 Pandemic [J]. Chinese Journal of Applied Chemistry, 2023, 40(11): 1504-1517.
[7]	Zhi-Peng HAN, Chong QIN, Jin-Xiang ZHOU, Ming YU, Zhao-Bin CHEN. High Temperature Resistant Epoxy Resin-Based Composites by Casting Process for Neutron Shielding [J]. Chinese Journal of Applied Chemistry, 2023, 40(10): 1420-1429.
[8]	Jing-Hui WEN, Bing ZHAO, Wei KAN, Li-Yan WANG, Li SUN, Tian-Shu SONG, Bo SONG. Synthesis of Isomers of Distinguishable Iron（Ⅲ） Fluorescent Probes and Application in Water Samples [J]. Chinese Journal of Applied Chemistry, 2022, 39(5): 787-796.
[9]	Yong-Xin TANG, Li-Wu NIE. Effect of Epoxy Resin Content on the Performance of Luminous Resin Permeable Concrete [J]. Chinese Journal of Applied Chemistry, 2022, 39(11): 1665-1671.
[10]	Yu-Fei YAN, Ji CHEN, Kai LI, Dan ZOU, De-Qian LI. Extraction of Cerium (Ⅳ) by Primary Amine N1923 from Sulfuric Acid Medium Containing Fluorine [J]. Chinese Journal of Applied Chemistry, 2022, 39(02): 307-314.
[11]	CAI Man-Ying, LIAO Yu-Hui, XU Wei, ZHOU Dong-Fang. Research Progress on Biosafety Materials for the Prevention and Control of the Coronavirus Disease 2019 [J]. Chinese Journal of Applied Chemistry, 2021, 38(5): 498-509.
[12]	CAO Ling-Zhi, WANG Zhao-Shuo, WANG Bei. Application of Nano Biomaterials in Antiviral Vaccine Adjuvant [J]. Chinese Journal of Applied Chemistry, 2021, 38(5): 572-581.
[13]	YOU Geyun, FENG Bin, FAN Fangfang, YANG Changjie, LIANG Cong. Synthesis of Phosphorus-Nitrogen Synergistic Flame-Retardant Compounds with Imide Structure and Their Flame Retardant Effect on Epoxy Resin [J]. Chinese Journal of Applied Chemistry, 2020, 37(2): 144-154.
[14]	ZHANG Lu, WANG Haichang, LI Hua, WANG Huijun, HUI Linhai, PENG Meiling, ZHU Yutian. Progress of Recycling of Carbon Fiber/Resin Composites via Supercritical Fluid [J]. Chinese Journal of Applied Chemistry, 2020, 37(12): 1357-1363.
[15]	LIU Xide, ZHOU Di, ZHANG Zhaoshun. Wastewater Treatment and Recycle of Zinc Chloride in 1,2,3,9-Tetrahydro-4H-carbazol-4-one Production Process [J]. Chinese Journal of Applied Chemistry, 2020, 37(1): 117-122.

Synthesis of Nitrogen-Phosphous Flame Retardants and Their Flame Retardant Applications in Epoxy Resins

RichHTML

PDF

Knowledge

Abstract

Cite this article

share this article

Figures/Tables 9

References 36

Related Articles 15

Recommended Articles 0

Metrics

Comments