scholarly journals A Novel Synergistic Flame Retardant of Hexaphenoxycyclotriphosphazene for Epoxy Resin

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3648
Author(s):  
Jiawei Jiang ◽  
Siqi Huo ◽  
Yi Zheng ◽  
Chengyun Yang ◽  
Hongqiang Yan ◽  
...  

Hexaphenoxycyclotriphosphazene (HPCP) is a common flame retardant for epoxy resin (EP). To improve the thermostability and fire safety of HPCP-containing EP, we combined UiO66-NH2 (a kind of metal-organic frame, MOF) with halloysite nanotubes (HNTs) by hydrothermal reaction to create a novel synergistic flame retardant (H-U) of HPCP for EP. For the EP containing HPCP and H-U, the initial decomposition temperature (T5%) and the temperature of maximum decomposition rate (Tmax) increased by 11 and 17 °C under nitrogen atmosphere compared with those of the EP containing only HPCP. Meanwhile, the EP containing HPCP and H-U exhibited better tensile and flexural properties due to the addition of rigid nanoparticles. Notably, the EP containing HPCP and H-U reached a V-0 rating in UL-94 test and a limited oxygen index (LOI) of 35.2%. However, with the introduction of H-U, the flame retardant performances of EP composites were weakened in the cone calorimeter test, which was probably due to the decreased height of intumescent residual char.

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 245
Author(s):  
Yong Sun ◽  
Yongli Peng ◽  
Yajiao Zhang

In this work, a flame retardant curing agent (DOPO-MAC) composed of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO and methyl acrylamide (MAC) was synthesized successfully, and the structure of the compound was characterized by FT-IR and 1H-NMR. The non-isothermal kinetics of the epoxy resin/DOPO-MAC system with 1% phosphorus was studied by non-isothermal DSC method. The activation energy of the reaction (Ea), about 46 kJ/mol, was calculated by Kissinger and Ozawa method, indicating that the curing reaction was easy to carry out. The flame retardancy of the epoxy resin system was analyzed by vertical combustion test (UL94) and limiting oxygen index (LOI) test. The results showed that epoxy resin (EP) with 1% phosphorus successfully passed a UL-94 V-0 rating, and the LOI value increased along with the increasing of phosphorus content. It confirmed that DOPO-MAC possessed excellent flame retardance and higher curing reactivity. Moreover, the thermal stability of EP materials was also investigated by TGA. With the DOPO-MAC added, the residual mass of EP materials increased remarkably although the initial decomposition temperature decreased slightly.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2205
Author(s):  
Qian Li ◽  
Yujie Li ◽  
Yifan Chen ◽  
Qiang Wu ◽  
Siqun Wang

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.


2018 ◽  
Vol 31 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Shuang Yang ◽  
Yefa Hu ◽  
Qiaoxin Zhang

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.


2013 ◽  
Vol 131 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jing Zhao ◽  
Cheng-Liang Deng ◽  
Shuang-Lan Du ◽  
Li Chen ◽  
Cong Deng ◽  
...  

2020 ◽  
pp. 096739112092780
Author(s):  
Yang Kai ◽  
Jiao Mingli ◽  
Zhang Xiaomei ◽  
Jia Wanshun ◽  
Diao Quan ◽  
...  

Phenyl molybdate-modified phenolic fibers (PMoPFs) were prepared by melt spinning from the corresponding resin which was polymerized from phenol, formaldehyde, and phenyl molybdate, followed by solution curing and then heat curing processes. The molecular structures, including characteristic groups and molecular weight, were examined by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography. The influences of the curing processes were demonstrated by mechanical properties, scanning electron microscopy, and thermogravimetric analysis characterization. PMoPF with 8 wt% molybdic acid and cured in an oven possessed a tensile strength as high as 187 MPa, initial decomposition temperature of 300°C, and a char yield under nitrogen atmosphere at 800°C as high as 66.0%, with the molybdate (MoO4 2−) groups being introduced into the phenolic main chain.


2017 ◽  
Vol 30 (10) ◽  
pp. 1229-1239 ◽  
Author(s):  
Shan Huang ◽  
Xiao Hou ◽  
Jiaojiao Li ◽  
Xiujuan Tian ◽  
Qing Yu ◽  
...  

A phosphorous/nitrogen-containing diphenylphosphine oxide (DPO) derivative (DPO-SS) was designed and synthesized via a two-step reaction of 4,4′-diaminodiphenylsulfone, 2-hydroxy-benzaldehyde, and DPO. The structure of DPO-SS was confirmed by Fourier transform infrared spectroscopy (FTIR), 1H and 31P nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS). DPO-SS was used as a flame retardant and curing agent for copolymerizing with diglycidyl ether of bisphenol-A. Thermal and flame-retardant properties of the obtained flame-retardant epoxy resin (F-EP) were investigated by thermogravimetric analysis, dynamic thermomechanical analysis, limited oxygen index (LOI) measurement, vertical burning test (UL-94), and cone calorimeter test. Results indicated that all F-EP samples exhibited excellent thermal stability and flame-retardant property. Especially for F-EP with P content of 0.7 wt% (denoted as EP/P-0.7), it achieved high LOI values (32.4%) and UL-94 V-0 rating. Compared with pure EP, all F-EP samples showed lower heat release rate, total heat release, total smoke produce, and little Tg fluctuation. In order to study the flame-retardant mechanism, the char residues were investigated by FTIR, scanning electron microscopy, and energy-dispersive spectrometer analysis. The results manifested that DPO-SS acted as flame retardant in both gas phase and condensed phase. Water absorption properties of pure EP and F-EP were also compared through immersion experiments. Results showed that EP/P-0.7 sample had apparently lower water absorptivity than pure EP.


Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2900
Author(s):  
Linyuan Wang ◽  
Yue Wei ◽  
Hongbo Deng ◽  
Ruiqi Lyu ◽  
Jiajie Zhu ◽  
...  

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.


10.6036/10327 ◽  
2022 ◽  
Vol 97 (1) ◽  
pp. 98-103
Author(s):  
XIAN WANG ◽  
JINLONG ZHUO ◽  
TIANQING XING ◽  
Xingran Wang

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


Sign in / Sign up

Export Citation Format

Share Document