Preparation and Properties of Halogen-Free Flame Retardant Epoxy Resins with Aryl Phosphinate Dianhydride Hardener

2011 ◽  
Vol 328-330 ◽  
pp. 1335-1338 ◽  
Author(s):  
Bing Liang ◽  
Tie Zhu Bao ◽  
Jun Cao ◽  
Xiao Dong Hong

Two halogen-free flame retardant epoxy resins were prepared by diglycidyl ether of bisphenol A (DGEBA) epoxy with two compound hardeners. The aryl phosphinate dianhydride BPAODOPE was used as a hardener and flame retardant when coupled with two curing agents, such as methylhexahydrophthalic anhydride (MeHHPA) and maleic anhydride (MA). The effect of the BPAODOPE contents on the fire resistance, thermal properties and mechanical properties of halogen-free flame-retardant epoxy resins were investigated in detail. The results showed that the phosphorus-containing epoxy resin composites had a higher UL-94 grade and char yield, furthermore, the flame retardation and the char yield of the cured epoxy resins increased with an increase of the phosphorus content, the phosphorus content of 1.75% was enough to achieve UL-94 V-1 grade and the best combination properties for the two composites with different hardeners.

2009 ◽  
Vol 62 (6) ◽  
pp. 829-841 ◽  
Author(s):  
Jiapei Ding ◽  
Zhiqiang Tao ◽  
Xiaobiao Zuo ◽  
Lin Fan ◽  
Shiyong Yang

2012 ◽  
Vol 466-467 ◽  
pp. 495-499 ◽  
Author(s):  
Ming Gao ◽  
Ying Juan Sun

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.


Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 317 ◽  
Author(s):  
Liang Li ◽  
Zaisheng Cai

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.


2012 ◽  
Vol 560-561 ◽  
pp. 563-568 ◽  
Author(s):  
Ming Gao ◽  
Ying Juan Sun

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.


2015 ◽  
Vol 18 (4) ◽  
pp. 16-22
Author(s):  
Linh Thi Thuy Pham ◽  
Hien Thi Thu Nguyen ◽  
Quy Thi Dong Hoang

In order to improve the fire performance of composite materials, halogen-free flame retardant (diamonium hydrogen phosphate- DAP) was studied in an attempt to obtain UL-94 ratings for composite PVC-wood flour (PVC-WF). The fire behaviors and thermal stability properties were evaluated using UL- 94 vertical test, LOI test and thermogravimetric analysis (TGA). The UL- 94 test results show that V-0 rating is achieved at 1.5 wt% of DAP loading. The incorporation of halogene-free flame retardant (FR) increases the flame retardant properties as well as the amounts of charred residues protecting the mixture from further degradation. This assertion can be accepted when observing that the char residual of PVC-WF/DAP mixture at 600 oC is much higher than that of neat PVC-WF. The char layer may limit the amount of fuel available and insulate the underlying composite material from the flame and, thus, inhibit further degradation. This FR is a promising candidate that could replace the halogenbased flame retardant.


2011 ◽  
Vol 197-198 ◽  
pp. 1346-1349 ◽  
Author(s):  
Fa Chao Wu

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.


RSC Advances ◽  
2021 ◽  
Vol 11 (49) ◽  
pp. 30943-30954
Author(s):  
Wei Peng ◽  
Yu-xuan Xu ◽  
Shi-bin Nie ◽  
Wei Yang

Phosphorus-containing flame retardants have received huge interest for improving the flame retardant behavior of epoxy resins (EP) over the past few decades.


Author(s):  
Zhenwei Miao ◽  
Dongpeng Yan ◽  
Xiaodong Wang ◽  
Xinfang Zhang ◽  
Wenqi Zhou ◽  
...  

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 380 ◽  
Author(s):  
Wei Zhao ◽  
Yongxiang Li ◽  
Qiushi Li ◽  
Yiliang Wang ◽  
Gong Wang

The flame retardant modification of epoxy (EP) is of great signification for aerospace, automotive, marine, and energy industries. In this study, a series of EP composites containing different variations of phosphorus-containing polysulfone (with a phosphorus content of approximately 1.25 wt %) were obtained. The obtained EP/polysulfone composites had a high glass transition temperature (Tg) and high flame retardancy. The influence of phosphorus-containing compounds (ArPN2, ArPO2, ArOPN2 and ArOPO2) on the thermal properties and flame retardancy of EP/polysulfone composites was investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), a UL-94 vertical burning test, and cone calorimeter tests. The phosphorus-containing polysulfone enhanced the thermal stability of EP. The more stable porous char layer, less flammable gases, and a lower apparent activation energy at a high degree of conversion demonstrated the high gas inhibition effect of phosphorus-containing compounds. Moreover, the gas inhibition effect of polysulfone with a P–C bond was more efficient than the polysulfone with a P–O–C bond. The potential for optimizing flame retardancy while maintaining a high Tg is highlighted in this study. The flame-retardant EP/polysulfone composites with high thermal stability broaden the application field of epoxy.


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