scholarly journals Synthesis of a Reactive Template-Induced Core–Shell PZS@ZIF-67 Composite Microspheres and Its Application in Epoxy Composites

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2646
Author(s):  
Kunpeng Song ◽  
Yinjie Wang ◽  
Fang Ruan ◽  
Weiwei Yang ◽  
Zhuqing Fang ◽  
...  

Developing superior properties of epoxy resin composites with high fire resistance, light smoke, and low toxicity has been the focus of the research in the flame-retardant field. In particular, it is essential to decrease the emissions of toxic gases and smoke particles generated during the thermal decomposition of epoxy resin (EP) to satisfy the industrial requirements for environmental protection and safety. Consequently, the PZS@ZIF-67 composite was designed and synthesized by employing the hydroxyl group-containing polyphosphazene (poly(cyclotriphosphazene-co-4,4′-dihydroxydiphenylsulfone), PZS) as both the interfacial compatibility and an in situ template and the ZIF-67 nanocrystal as a nanoscale coating and flame-retardant cooperative. ZIF-67 nanocrystal with multidimensional nanostructures was uniformly wrapped on the surface of PZS microspheres. Subsequently, the acquired PZS@ZIF-67 composite was incorporated into the epoxy resin to prepare composite samples for the study of their fire safety, toxicity suppression, and mechanical performance. Herein, the EP/5% PZS@ZIF-67 passed the V-0 rating in a UL-94 test with a 31.9% limit oxygen index value. More precisely, it is endowed with a decline of 51.08%, 28.26%, and 37.87% of the peak heat release rate, the total heat release, and the total smoke production, respectively. In addition, the unique structure of PZS@ZIF-67 microsphere presented a slight impact on the mechanical properties of EP composites at low loading. The PZS@ZIF-67 possible flame-retardant mechanism was speculated based on the analysis of the condensed phase and the gas phase of EP composites.

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 613 ◽  
Author(s):  
Liqiang Gu ◽  
Chen Qiu ◽  
Jianhui Qiu ◽  
Youwei Yao ◽  
Eiichi Sakai ◽  
...  

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.


Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3985
Author(s):  
Fangyi Wu ◽  
Xiaohui Bao ◽  
Jiangbo Wang

A novel graphene-based phosphorus/silicon-containing flame retardant (GO-DOPO-V) was obtained via one-step reduction of graphene oxide (GO) with phosphorus/silicon-containing compound (DOPO-V). The Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectrometer (XPS), Atomic force microscope (AFM) and Thermogravimetric analysis (TGA) measurements were used to confirm the structure and morphology. After incorporation of 2 wt% GO-DOPO-V, the maximum decreases of 28.8% in peak heat release rate and 15.6% in total heat release are achieved compared to that of pure epoxy resin (EP). Furthermore, TGA and Scanning electron microscopy (SEM) measurement showed that GO-DOPO-V significantly enhanced the thermal stability and residual char strength of EP. Thus, attributed to the barrier effect of GO and phosphorus/silicon layer formation by DOPO-V, GO-DOPO-V was a high-efficient flame retardant to improve the combustion behavior of EP nanocomposite.


2020 ◽  
Vol 32 (8) ◽  
pp. 871-882 ◽  
Author(s):  
Yun Peng ◽  
Mei Niu ◽  
Ruihong Qin ◽  
Baoxia Xue ◽  
Mingqiang Shao

To reduce the environmental hazard from the flame retardant, a halogen-free phosphorus-containing silicone flame-retardant poly N, N dimethylene phosphate aminopropyl siloxane (PDPSI) was prepared following the Mannich reaction. Then, PDPSI and ferric oxide (Fe2O3) were used for the preparation of synergistic flame-retardant polyethylene terephthalate (PET). The flame-retardant test results revealed that at 2% PDPSI/Fe2O3 content and 1:2 mass ratio of PDPSI to Fe2O3, the limit oxygen index value of the PDPSI/Fe2O3/PET composite material was 27.9%, reaching the flame-retardant level and passing the V-0 rating in the UL-94 test. In addition, the PDPSI/Fe2O3/PET composites had a char residue content of 17.5% at 700°C, an increase of 30.6% compared to that of the pristine PET. In the cone calorimeter test, the addition of PDPSI/Fe2O3 significantly reduced the peak heat release rate (PHRR), total heat release (THR) rate, and total smoke production (TSP) value of the resulting PET composites. PHRR and THR decreased by 66.05% and 14.3%, respectively. The TSP value decreased from 14.4 m2 to 8.1 m2, a decrease of 43.8%. The scanning electron microscopy images and Fourier-transform infrared spectra of the char residue showed a significant synergy between Fe2O3 and PDPSI, changing the structure of the carbon layer in continuous and dense form, thus the flame retardancy and smoke suppression of the PET composites improved. In addition, the tensile strength of the PET composite was 42.11 MPa, which was only 1.84% less than that of the pristine PET.


2021 ◽  
pp. 096739112110245
Author(s):  
Jiangbo Wang

A novel phosphorus-silicon containing flame-retardant DOPO-V-PA was used to wrap carbon nanotubes (CNTs). The results of FTIR, XPS, TEM and TGA measurements exhibited that DOPO-V-PA has been successfully grafted onto the surfaces of CNTs, and the CNTs-DOPO-V-PA was obtained. The CNTs-DOPO-V-PA was subsequently incorporated into epoxy resin (EP) for improving the flame retardancy and dispersion. Compared with pure EP, the addition of 2 wt% CNTs-DOPO-V-PA into the EP matrix could achieve better flame retardancy of EP nanocomposites, such as a 30.5% reduction in peak heat release rate (PHRR) and 8.1% reduction in total heat release (THR). Furthermore, DMTA results clearly indicated that the dispersion for CNTs-DOPO-V-PA in EP matrix was better than pristine CNTs.


2021 ◽  
Vol 2 (1) ◽  
pp. 24-48
Author(s):  
Quoc-Bao Nguyen ◽  
Henri Vahabi ◽  
Agustín Rios de Anda ◽  
Davy-Louis Versace ◽  
Valérie Langlois ◽  
...  

This study has developed novel fully bio-based resorcinol epoxy resin–diatomite composites by a green two-stage process based on the living character of the cationic polymerization. This process comprises the photoinitiation and subsequently the thermal dark curing, enabling the obtaining of thick and non-transparent epoxy-diatomite composites without any solvent and amine-based hardeners. The effects of the diatomite content and the compacting pressure on microstructural, thermal, mechanical, acoustic properties, as well as the flame behavior of such composites have been thoroughly investigated. Towards the development of sound absorbing and flame-retardant construction materials, a compromise among mechanical, acoustic and flame-retardant properties was considered. Consequently, the composite obtained with 50 wt.% diatomite and 3.9 MPa compacting pressure is considered the optimal composite in the present work. Such composite exhibits the enhanced flexural modulus of 2.9 MPa, a satisfying sound absorption performance at low frequencies with Modified Sound Absorption Average (MSAA) of 0.08 (for a sample thickness of only 5 mm), and an outstanding flame retardancy behavior with the peak of heat release rate (pHRR) of 109 W/g and the total heat release of 5 kJ/g in the pyrolysis combustion flow calorimeter (PCFC) analysis.


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.


2020 ◽  
pp. 073490412093408
Author(s):  
Wei Yan ◽  
Pu Xie ◽  
Zhengwei Yang ◽  
Guangjin Luo ◽  
Weijiang Huang ◽  
...  

Aluminum phosphates coated sepiolite nanocomposite was fabricated via a simple one-pot heterogeneous precipitation strategy, and the effects of aluminum phosphates on the morphology of aluminum phosphates coated sepiolite were investigated. Moreover, the effect of aluminum phosphates coated sepiolite on the flame-retardant behavior, mechanical properties, and thermal stability of epoxy resin have been discussed. The results indicated that the introduction of only 20 wt% aluminum phosphates coated sepiolite in epoxy resin increased the limited oxygen index from 21.8% to 30.1%, thus the material met the UL-94 V-0 rating. Thermogravimetric analyses revealed that char yield increased in the presence of aluminum phosphates coated sepiolite form thermally stable carbonaceous char. Aluminum phosphates–coated sepiolite could improve the mechanical performance, thermal stability of epoxy resin.


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.


2016 ◽  
Vol 30 (2) ◽  
pp. 255-272 ◽  
Author(s):  
Xilei Chen ◽  
Lili Huo ◽  
Jianbo Liu ◽  
Chuanmei Jiao ◽  
Shaoxiang Li ◽  
...  

Flame-retardant polyurethane elastomers (PUEs) have been prepared using trichloroethyl phosphate (TCEP) as flame retardant. The combustion performances and thermal decomposition properties of PUEs were studied using cone calorimetry test and thermogravimetric analysis, respectively. Kissinger method and Flynn–Wall–Ozawa (FWO) method were adopted to discuss the pyrolysis kinetics of PUEs. The experimental results showed that TCEP has good flame-retardant effect for PUE. With the increase of TCEP, the peak heat release rate and total heat release values decrease. A good diagram of linear regression can be obtained from both Kissinger and FWO methods. The activation energy values of flam- retardant PUE can be calculated from FWO method at different conversion rates.


2017 ◽  
Vol 31 (10) ◽  
pp. 1352-1370 ◽  
Author(s):  
Wufei Tang ◽  
Hongfei Li ◽  
Sheng Zhang ◽  
Jun Sun ◽  
Xiaoyu Gu

Kaolinite has often been intercalated before being introduced into polymers to improve its dispersibility; however, the conventional intercalation usually reduces the flame retardancy of the composite. This work reports our recent efforts on improving both the flame retardant efficiency and dispersibility of kaolinite in polypropylene (PP) by intercalating with ammonium sulfamate (AS). The intercalation had been performed through three steps: dimethyl sulfoxide was firstly introduced into kaolinite layers under supersonic wave, then it was replaced by potassium acetate-aqueous (KAc), and finally the intercalated KAc was replaced by AS to obtain AS-intercalated kaolinite. The structure of intercalated kaolinite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and thermogravimetric analysis (TGA). The flammability evaluation by limit oxygen index, vertical burning test (UL-94), cone calorimeters test (CONE), and TGA indicated that the fire resistance, thermal stability, and physical properties of PP can be effectively enhanced by the introduction of AS-intercalated kaolinite. The peak heat release rate (pHRR) value of PP composite containing only 1.5 wt% intercalated kaolinite (1169 kW m−2) had been reduced 13.2% compared with that of the sample containing 1.5 wt% raw kaolinite (1346 kW m−2). The morphology analysis from scanning electron microscope images and XRD patterns demonstrated that the compatibility and dispersibility of kaolinite in PP had been significantly improved by intercalation. The flame retardant mechanism of AS-intercalated kaolinite in PP was proposed.


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