scholarly journals A Novel POSS-Based Copolymer Functionalized Graphene: An Effective Flame Retardant for Reducing the Flammability of Epoxy Resin

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 241 ◽  
Author(s):  
Min Li ◽  
Hong Zhang ◽  
Wenqian Wu ◽  
Meng Li ◽  
Yiting Xu ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Photoelectron Spectroscopy ◽  
Diglycidyl Ether ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Limiting Oxygen Index ◽  
X Ray ◽  
Grafting Reaction ◽  
Trade Name

In this study, a novel copolymer, PbisDOPOMA-POSSMA-GMA (PDPG), containing methacryloisobutyl polyhedral oligomeric silsesquioxane (POSSMA), reactive glycidyl methacrylate (GMA), and bis-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide methacrylate (bisDOPOMA) and derivative functionalized graphene oxide (GO) were synthesized by a one-step grafting reaction to create a hybrid flame retardant (GO-MD-MP). GO-MD-MP was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Flame-retardant epoxy resin (EP) composites were prepared by adding various amounts of GO-MD-MP to the thermal-curing epoxy resin of diglycidyl ether of bisphenol A (DGEBA, trade name E-51). The thermal properties of the EP composites were remarkably enhanced by adding the GO-MD-MP, and the residue char of the epoxy resin also increased greatly. With the incorporation of 4 wt % GO-MD-MP, the limiting oxygen index (LOI) value was enhanced to 31.1% and the UL-94 V-0 rating was easily achieved. In addition, the mechanical strength of the epoxy resin was also improved.

Investigation of nickel ammonia phosphate with different morphologies as a new high-efficiency flame retardant for epoxy resin

2019 ◽  
Vol 32 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Weiwei Zhang ◽  
Hongjuan Wu ◽  
Weihua Meng ◽  
Jiahe Li ◽  
Yumeng Cui ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Flame Retardancy ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Ammonium Phosphate ◽  
Cone Calorimetry ◽  
Limiting Oxygen Index ◽  
X Ray ◽  
The Matrix

Nanowires, nanosheets, and microflowers of nickel ammonium phosphate (NiNH4PO4·H2O) were synthesized by a mixed solvothermal method and used to improve the flame retardancy of epoxy resin (EP). The solvent concentration and surfactant content were found to play a key role in nucleation and growth of NiNH4PO4·H2O. The structure of NiNH4PO4·H2O was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The flame retardancy, thermostability, mechanical properties, and flame retardancy mechanism of EP/NiNH4PO4·H2O composites were analyzed using the limiting oxygen index (LOI), cone calorimetry (Cone), mechanical property tests, thermogravimetric analysis, and thermogravimetric–Fourier transform infrared spectroscopy. The results indicated that NiNH4PO4·H2O has proper thermal stability and greatly improves the flame retardancy of EP. The nanosheets outperformed the other morphologies; the EP/5% NiNH4PO4·H2O nanosheets have an LOI of 35.2%, which exceeds that of pure EP (24.7%). Furthermore, Cone showed that these nanosheets have the lowest peak heat release rate and peak smoke production rate, which are 69.1% and 36.5% lower than those of pure EP, respectively. NiNH4PO4·H2O can promote the formation of a stable char layer and release nonflammable gases, thus protecting the matrix by preventing heat and oxygen transfer and reducing the concentration of combustible gas. NiNH4PO4·H2O is expected to serve as a new high-efficiency flame retardant for EP.

scholarly journals Synthesis of K-Carrageenan Flame-Retardant Microspheres and Its Application for Waterborne Epoxy Resin with Functionalized Graphene

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1708 ◽  
Author(s):  
Wang ◽  
Teng ◽  
Yang ◽  
You ◽  
Zhang ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Oxygen Index ◽  
Functionalized Graphene ◽  
Limiting Oxygen Index ◽  
Gas Source ◽  
Waterborne Epoxy ◽  
Emulsion Polymerizations ◽  
Flame Retardant Properties ◽  
Waterborne Epoxy Resin

In this article, the intumescent flame-retardant microsphere (KC-IFR) was prepared by inverse emulsion polymerizations, with the use of k-carrageenan (KC) as carbon source, ammonium polyphosphate (APP) as acid source, and melamine (MEL) as gas source. Meanwhile, benzoic acid functionalized graphene (BFG) was synthetized as a synergist. A “four-source flame-retardant system” (KC-IFR/BFG) was constructed with KC-IFR and BFG. KC-IFR/BFG was blended with waterborne epoxy resin (EP) to prepare flame-retardant coatings. The effects of different ratios of KC-IFR and BFG on the flame-retardant properties of EP were investigated. The results showed that the limiting oxygen index (LOI) values increased from 19.7% for the waterborne epoxy resin to 28.7% for the EP1 with 20 wt% KC-IFR. The addition of BFG further improved the LOI values of the composites. The LOI value reached 29.8% for the EP5 sample with 18 wt% KC-IFR and 2 wt% BFG and meanwhile, UL-94 test reached the V-0 level. In addition, the peak heat release (pHRR) and smoke release rate (SPR) of EP5 decreased by 63.5% and 65.4% comparing with EP0, respectively. This indicated the good flame-retardant and smoke suppression property of EP composites coating.

Adsorption behavior of isocyanate/ethylenediamine tetraacetic acid-functionalized graphene oxides for Cu2+ removal

2018 ◽  
Vol 78 (12) ◽  
pp. 2459-2468 ◽  
Author(s):  
Yan Yang ◽  
Yun Yu ◽  
Ning-ning Yang ◽  
Bin Huang ◽  
Ya-fei Kuang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Tetraacetic Acid ◽  
Functionalized Graphene ◽  
Graphene Oxides ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Heavy Metal Cations ◽  
Ethylenediamine Tetraacetic Acid

Abstract A special adsorption of Cu2+ removal is demonstrated using specifically functionalized graphene oxide (GO)/isocyanate (MDI) composites, on which ethylenediamine tetraacetic acid (EDTA) is grafted via amidation and carbamate reaction. The structure and morphology of GO and functionalized composites (EDTA/MDI/GO) were characterized by scanning electron microscope (SEM), Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis (TGA). This study investigated the adsorption and desorption behaviors of heavy metal cations and the effects of solution conditions such as pH on Cu2+ removal. The experimental results illustrated that after introducing EDTA and MDI into the GO, the maximum adsorption capacity reached 254.2 ± 10.4 mg/g within 180 min, obviously higher than the GO prepared without these additions (136.5 ± 7.2 mg/g). The EDTA/MDI/GO adsorption kinetics and equilibrium adsorption isotherm fitted the pseudo-second-order kinetic model (R2 = 0.995) and Langmuir isotherm model (R2 = 0.986) well, respectively. Furthermore, EDTA/MDI/GO also displayed good reusability for the efficient removal of Cu2+ after being washed with HCl, suggesting potential application in Cu2+ cleanup.

scholarly journals Preparation and Corrosion Resistance of ETEO Modified Graphene Oxide/Epoxy Resin Coating

Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 46 ◽  
Author(s):  
Chunling Zhang ◽  
Xueyan Dai ◽  
Yingnan Wang ◽  
Guoen Sun ◽  
Peihong Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Graphene Oxide ◽  
Epoxy Resin ◽  
Composite Coating ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Resin Coating ◽  
Epoxy Resin Coating

Improving the corrosion resistance of epoxy resin coatings has become the focus of current research. This study focuses on synthesizing a functionalized silane coupling agent (2-(3,4-epoxycyclohexyl)ethyl triethoxysilane) to modify the surface of graphene oxide to address nanomaterial agglomeration and enhance the coating resistance of the epoxy resin coating to corrosion by filling the coating with functionalized graphene oxide. Functionalized graphene oxide and coatings filled with functionalized graphene oxide were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The corrosion performance of each coating was studied by electrochemical impedance spectroscopy and a salt spray test. Results showed that the incorporation of functionalized graphene oxide enhances the corrosion protection performance of the epoxy composite coating, and the composite coating exhibited the best anticorrosion performance when the amount of functionalized graphene oxide was 0.7 wt %.

Preparation of dual-functionalized graphene oxide for the improvement of the thermal stability and flame-retardant properties of polysiloxane foam

2018 ◽  
Vol 42 (16) ◽  
pp. 13873-13883 ◽  
Author(s):  
Tianlu Xu ◽  
Chunling Zhang ◽  
Peihong Li ◽  
Xueyan Dai ◽  
Lijie Qu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Functionalized Graphene ◽  
Foam Material ◽  
Functionalized Graphene Oxide ◽  
Limiting Oxygen Index ◽  
Flame Retardant Properties ◽  
Combustible Materials

Polysiloxane foam (PSF) is a foam material with outstanding performance. However, the limiting oxygen index (LOI) of pure PSF is only 22.0 vol%, which can be attributed to combustible materials.

scholarly journals Thermal Degradation and Flame Retardant Mechanism of the Rigid Polyurethane Foam Including Functionalized Graphene Oxide

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 78 ◽  
Author(s):  
Xuexi Chen ◽  
Junfei Li ◽  
Ming Gao
Keyword(s):  
Graphene Oxide ◽  
Thermal Degradation ◽  
Flame Retardant ◽  
Polyurethane Foam ◽  
Main Stage ◽  
Rigid Polyurethane Foam ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Limiting Oxygen Index ◽  
Char Layer

A flame retardant rigid polyurethane foam (RPUF) system containing functionalized graphene oxide (fGO), expandable graphite (EG), and dimethyl methyl phosphonate (DMMP) was prepared and investigated. The results show that the limiting oxygen index (LOI) of the flame-retardant-polyurethane-fGO (FRPU/fGO) composites reached 28.1% and UL-94 V-0 rating by adding only 0.25 g fGO. The thermal degradation of FRPU samples was studied using thermogravimetric analysis (TG) and the Fourier transform infrared (FT-IR) analysis. The activation energies (Ea) for the main stage of thermal degradation were obtained using the Kissinger equation. It was found that the fGO can considerably increase the thermal stability and decrease the flammability of RPUF. Additionally, the Ea of FRPU/fGO reached 191 kJ·mol−1, which was 61 kJ·mol−1 higher than that of the pure RPUF (130 kJ·mol−1). Moreover, scanning electron microscopy (SEM) results showed that fGO strengthened the compactness and the strength of the “vermicular” intumescent char layer improved the insulation capability of the char layer to gas and heat.

Fabrication and Characterization of Poly(vinyl Alcohol)/Functionalized Graphene Oxide Nanofibers Produced by Electrospinning Method

2013 ◽  
Vol 747 ◽  
pp. 405-408
Author(s):  
Yuan Hsiang Yu ◽  
Chih Jie Jan
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Functionalized Graphene ◽  
Sem Images ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Electrospinning Method

A series of poly (vinyl alcohol) (PVA)/functionalized graphene oxide (FGO) nanofibers with low feeding ratios of FGO to PVA were fabricated by electrospinning method. In this study, the prepared PVA/FGO nanocomposites were dispersed in water phase followed by electrospinning treatment under different operational parameters (i.e., applied voltage, feeding rate and FGO contents) to give nanofibers of various diameters and morphologies. The morphology, diameter and structure of electrospun nanofibers and FGO were investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), (TGA) and differential scanning calorimetry (DSC). SEM images showed that the morphologies of the nanofibers were improved by the incorporation of FGO at a low loading content (e.g., 0.1~0.5 wt %) as compared to pure electrospun PVA. The crystallinity and thermal stability of PVA/FGO nanofibers were also studied.

scholarly journals An Electrochemical Sensor Based on Gold and Bismuth Bimetallic Nanoparticles Decorated L-Cysteine Functionalized Graphene Oxide Nanocomposites for Sensitive Detection of Iron Ions in Water Samples

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2386
Author(s):  
Na Zhou ◽  
Jing Li ◽  
Shaoxia Wang ◽  
Xuming Zhuang ◽  
Shouqing Ni ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensor ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Functionalized Graphene ◽  
X Ray Diffraction ◽  
Functionalized Graphene Oxide ◽  
Glassy Carbon Electrodes ◽  
X Ray ◽  
Seawater Samples

In this work, gold and bismuth bimetallic nanoparticles decorated L-cysteine functionalized graphene oxide nanocomposites (Au-BiNPs/SH-GO) were prepared and applied to selective detection of Fe(III) in lake and seawater samples by modifying onto glassy carbon electrodes. Bimetallic nanoparticles have various excellent properties and better catalytic properties because of the unique synergistic effect between metals. The modified electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. Under optimized conditions, current peak intensity increased linearly with increasing Fe(III) concentration over the range of 0.2–50 μM and a detection limit of 0.07 μM (S/N = 3). The Au-BiNPs/SH-GO/GCE was used for the determination of Fe(III) in lake and seawater samples with recoveries ranged from 90 to 103%. Those satisfactory results revealed the potential application of the Au-BiNPs/SH-GO electrochemical sensor for heavy metals detection in environmental monitoring.

Synthesis of multielement phosphazene derivative and the study on flame-retardant properties of epoxy resin

2020 ◽  
Vol 32 (10) ◽  
pp. 1169-1180 ◽  
Author(s):  
Lurong Wang ◽  
Baoping Yang ◽  
Yongliang Guo ◽  
Yabin Zhang ◽  
Niannian Wang ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Heat Release Rate ◽  
Condensed Phase ◽  
Release Rate ◽  
Photoelectron Spectroscopy ◽  
Carbon Layer ◽  
Limiting Oxygen Index ◽  
Ep Matrix

Herein, we have successfully synthesized phosphorus/nitrogen/silicon tri-elements compound phosphazene derivative hexa-[4-( N-(3-(triethoxysilyl)propyl)acetamide)phenoxy]cyclotriphosphazene (HNTPC) from hexachlorotriphosphazenitrile, methyl 4-hydroxybenzoate, and 3-triethoxysilylpropylamine, and it was used as an additive flame retardant in epoxy resin (EP). Then, the thermal stability and flame retardancy of the composite (HNTPC/EP) were tested. Thermogravimetric analysis showed that the presence of HNTPC made EP matrix decompose at a relatively low temperature, thus promoted the formation of a stable coke layer and protected the matrix from fire. Therefore, the amount of carbon residue was markedly increased at 800°C, indicating an outstanding condensed phase flame-retardant effect. Furthermore, various combustion test data manifested that the addition of HNTPC could significantly improve the flame-retardant performance of EP. In addition, the sample could pass the vertical burning tests (UL-94) V-1 grade when the addition amount was 10% and the limiting oxygen index value was 32.6%, the peak heat release rate and total heat release rate decreased by 40.0% and 21.5%, respectively. Besides, the results of scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy also showed that HNTPC can promote the formation of carbon layer and improved the flame-retardant property of EP. Finally, the condensed phase and gas phase synergistic flame-retardant mechanism of HNTPC was proposed.

scholarly journals Functionalized Graphene Oxide Shields Tooth Dentin from Decalcification

2019 ◽  
Vol 99 (2) ◽  
pp. 182-188 ◽  
Author(s):  
M.Z.I. Nizami ◽  
Y. Nishina ◽  
T. Yamamoto ◽  
Y. Shinoda-Ito ◽  
S. Takashiba
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Dental Caries ◽  
Epithelial Cells ◽  
Photoelectron Spectroscopy ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
Silver Diamine Fluoride ◽  
X Ray ◽  
Aged Society

This in vitro study assessed the efficacy of functionalized graphene oxide (f-GO) nanocomposites on the decalcification of dentin, because dental caries of the root surface is becoming one of the new problems in aged society. Hydroxyapatite plates (HAP) and dentin slices were coated with f-GO nanocomposites by comparing them to silver diamine fluoride as a positive control, then treated with decalcification solutions such as ethylenediaminetetraacetic acid and citrate at 37°C for 24 h. Scanning electron microscopy (SEM) revealed significant protection of the surface morphology of HAP and dentin. On the other hand, a cariogenic Streptococcus mutans growth was inhibited by f-GO nanocomposites. In addition, cytotoxicity of them to epithelial cells was much less than that of povidone-iodine, which is commonly used for oral disinfectant. We synthesized 5 different f-GO nanocomposites such as GO–silver (Ag), GO-Ag–calcium fluoride (CaF2), GO-CaF2, GO-zinc, and GO–tricalcium phosphate (Ca3(PO4)2). They were standardized by evaluating under SEM, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TGA), and Raman spectra after being synthesized in an aseptic technique. The abilities of GO-Ag, GO-Ag-CaF2, and GO-CaF2 nanocomposites were most preventive for decalcification. In addition, GO-Ag and GO-Ag-CaF2 almost completely inhibited S. mutans growth. However, they did not exhibit cytotoxicity to epithelial cells except at the highest concentration (0.1 w/v%) of GO-Ag and GO-Ag-CaF2. Furthermore, these f-GO nanocomposites exhibited less or no discoloration of dentin, although commonly used silver diamine fluoride causes discoloration of dentin to black. Thus, these f-GO nanocomposites are useful to protect dental caries on the tooth root that becomes a social problem in aged society.

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