scholarly journals Preparation and Antiflame Performance of Expandable Graphite Modified with Sodium Hexametaphosphate

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hongmei Zhao ◽  
Xiuyan Pang ◽  
Zhixiao Zhai
Keyword(s):  
Layer Structure ◽  
Sodium Hexametaphosphate ◽  
Expandable Graphite ◽  
Mass Ratio ◽  
Linear Low Density Polyethylene ◽  
X Ray Diffraction ◽  
Limiting Oxygen Index ◽  
Intercalation Reaction ◽  
Graphite Oxidation ◽  
Expansion Temperature

A kind of polyphosphate modified expandable graphite (EGp) was prepared in graphite oxidation and intercalation reaction with KMnO4 as oxidant, H2SO4 as intercalator, and sodium hexametaphosphate (SHMP) as assistant intercalator. The feasible mass ratio of C : KMnO4 : H2SO4 (98%) : SHMP was determined as 1.0 : 0.3 : 4.5 : 0.6, H2SO4 was diluted to 77 wt% before intercalation reaction, and the reaction lasted for 40 min at 40°C. Expanded volume and initial expansion temperature of the prepared EGp reached 600 mL/g (at 800°C) and 151°C, respectively. X-ray diffraction spectroscopy testified the intercalation and layer structure of EGp, and Fourier transform infrared spectroscopy illuminated the intercalated functional groups. Flame retardance of the prepared EGp and the referenced EG (with only H2SO4 as intercalator) for linear low density polyethylene (LLDPE) was also investigated. Addition of 30 wt% EGp to the polymer improved the limiting oxygen index (LOI) from 17.5 to 27.3%. On the other hand, the LOI of the same amount of the referenced EG was only 24.6%. Assistant intercalation of SHMP improved the dilatability and flame retardancy.

scholarly journals Preparation of low initial expansion temperature expandable graphite and its flame retardancy for LLDPE

2013 ◽  
Vol 11 (6) ◽  
pp. 953-959 ◽  
Author(s):  
Xiuyan Pang ◽  
Yu Tian ◽  
Mingwei Duan ◽  
Meng Zhai
Keyword(s):  
Reaction Temperature ◽  
Mass Concentration ◽  
Oxygen Index ◽  
Influence Factors ◽  
Expandable Graphite ◽  
Thermal Gravimetric ◽  
Mass Ratio ◽  
Limiting Oxygen Index ◽  
Intercalation Reaction ◽  
Expansion Temperature

AbstractTo get expandable graphite (EG) flame retardant for Liner Low-Density Polyethylene (LLDPE) with low initial expansion temperature and high dilatability, the effects of various factors on dilatability were investigated including the dosages of oxidant KMnO4, intercalating reagent H2SO4, assistant intercalating reagent acetic acid (HAc) and reaction temperature. Feasible conditions were obtained according to the results of L9 (34) experiments and single factor experiments. EG with an initial expansion temperature of 160°C and expansion volume of 460 mL g−1 could be prepared according to the mass ratio of material graphite C: KMnO4: 100% H2SO4: HAc = 1.0: 0.4: 5.0: 1.0 (H2SO4 should be diluted to the mass concentration of 75% before the intercalation reaction); the reaction time was 1.0 hour at 25°C. It was found that reaction temperature and H2SO4 dosage were the most important influence factors for dilatability. The limiting oxygen index could be improved to 28.1% by adding 30% of the prepared EG to LLDPE, and the synergistic anti-flame capability of 20% EG with 10% Ammonium polyphosphate (APP) (I) can reach to 33.9%. According to thermal gravimetric and differential thermal analysis results, 70% LLDPE /10% APP (I) /20% EG synergistic anti-flame system shows higher residual carbon and thermal stability.

Preparation and Anti-Flame Capability of Expandable Graphite

2012 ◽  
Vol 560-561 ◽  
pp. 779-783 ◽  
Author(s):  
Xiu Yan Pang ◽  
Ming Kai Song
Keyword(s):  
Oxygen Index ◽  
Orthogonal Test ◽  
Expandable Graphite ◽  
Mass Ratio ◽  
Limiting Oxygen Index ◽  
Intercalation Reaction ◽  
Dta Analysis ◽  
Tg And Dta Analysis ◽  
Expansion Temperature ◽  
Single Factor Experiment

Subscript textFeasible conditions to get flame retardant expandable graphite (EG) with low initiation expansion temperature and high dilatability were obtained through orthogonal test and single factor experiment. EG with initiation expansion temperature of 148 ±2 °C and expansion volume of 550 mL/g can be prepared according to the mass ratio of C : KMnO4 : 98% H2SO4 : Na4P2O7 = 1.0 : 0.4 : 5.0 : 0.6 (H2SO4 should be diluted to thSubscript texte mass concentration of 80% before intercalation reaction), the reaction time is 40 min at 40 °C. Addition of 30% of the prepared EG to Liner Low-Density Polyethylene (LLDPE) can improve its limiting oxygen index LOI from 17.5% to 29.4%, and the synergistic anti-flame LOI of 20% EG with 10 polyphosphate (APP II) can reach to 31.2%. TG and DTA analysis was completed to discuss the anti-flame mechanism.

scholarly journals Chemical Modification of Expandable Graphite by Boric Acid and Its Flame Retarded Application in Polyethylene

2018 ◽  
pp. 34-39
Author(s):  
Ya-Fang Meng ◽  
Xiu-Yan Pang ◽  
Wei-Shu Chang
Keyword(s):  
Thermal Stability ◽  
Boric Acid ◽  
Intercalation Compound ◽  
Expandable Graphite ◽  
Linear Low Density Polyethylene ◽  
Limiting Oxygen Index ◽  
X Ray ◽  
Graphite Intercalation ◽  
Pure Matrix ◽  
Flame Retarded

The aim of this research is to get the graphite intercalation compound with high thermal stability and fire resistance. Firstly, the normal expandable graphite (EG) was prepared with potassium permanganate (KMnO4) as oxidant and sulfuric acid (H2SO4) as intercalator, respectively. Then, with (3-Aminopropyl)-trimethoxysilane (KH-550) as coupling agent, the boric acid (H3BO3) modified EG (EGB) was prepared by silane grafting method through H3BO3 bonded with EG. The analysis of X-ray powder diffractiometer and Fourier transform infrared spectroscopy testified the existence of EGB. EGB showed better thermal stability and flame retardancy for linear low density polyethylene (LLDPE) than the referenced EG. Addition of 13.0 wt% of EGB improved the limiting oxygen index (LOI) of 87.0LLDPE/13.0EGB to 24.6%, which was obviously higher than that of pure matrix of 17.5%. Whereas, the LOI of 87.0LLDPE/13EG was 22.7%. Furthermore, when EGB combined with ammonium polyphosphate (APP), the LOI and UL-94 level of 87.0LLDPE/8.7EGB/4.3APP reached 27.1% and V-0, respectively.

A New Polyethylene Corrosion Protecting Coating with Ion Selectivity

2011 ◽  
Vol 314-316 ◽  
pp. 273-278
Author(s):  
Yu Hua Dong ◽  
Ke Ren ◽  
Qiong Zhou
Keyword(s):  
Ion Selectivity ◽  
Nano Particles ◽  
Ammonium Bromide ◽  
Linear Low Density Polyethylene ◽  
X Ray Diffraction ◽  
Sulfosalicylic Acid ◽  
X Ray ◽  
Chemically Modified ◽  
Before And After ◽  
Industrial Standards

Linear low density polyethylene (LLDPE) was chemically modified with grafting maleic anhydride (MAH) monomer on its backbone by melting blending. Nano-particles SiO2 was modified by cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) and anionic surfactant sulfosalicylic acid (SSA) and added to PE coating respectively. Measurement of membrane potential showed that the coating containing modified SiO2 nano-particles had characteristic of ion selectivity. The properties of the different coatings were investigated according to relative industrial standards. Experimental results indicated that PE coating with ion selectivity had better performances, such as adhesion strength, cathodic disbonding and anti-corrosion, than those of coating without ion selectivity. Crystal structure of the coatings before and after alkali corrosion was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). Structure of the coating without ion selectivity was damaged by NaOH alkali solution, causing mechanical properties being decreased. And the structure of the ion selective coatings was not affected.

scholarly journals Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1801
Author(s):  
Rafał Oliwa ◽  
Joanna Ryszkowska ◽  
Mariusz Oleksy ◽  
Monika Auguścik-Królikowska ◽  
Małgorzata Gzik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Structure ◽  
Oxygen Index ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Ftir Analysis ◽  
Limiting Oxygen Index ◽  
Peak Heat Release Rate ◽  
Physical And Chemical ◽  
Scanning Electron

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

Syntheses, crystal structures and photoluminescence properties of two rare-earth molybdates CsLn(MoO4)2 (Ln=Eu, Tb)

2018 ◽  
Vol 233 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Dan Zhao ◽  
Fa-Xue Ma ◽  
Bao-Zhong Liu ◽  
Yun-Chang Fan ◽  
Xue-Feng Han ◽  
...  
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Layer Structure ◽  
Green Emission ◽  
Salt Flux ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Light Excitation ◽  
Rare Earth Molybdates

AbstractSingle crystals of two cesium rare-earth molybdates CsLn(MoO4)2(Ln=Eu, Tb) have been prepared using the high temperature molten salt (flux) method. Single-crystal X-ray diffraction analyses reveal that they crystallize in the orthorhombic space groupPccm(No. 49) and features a 2D layer structure that is composed of [Ln(MoO4)2]∞and [Cs]∞layers. Under near-UV light excitation, emission spectrum of CsEu(MoO4)2consists of several sharp lines due to the characteristic electronic transitions of Eu3+ions, whereas CsTb(MoO4)2exhibits characteristic green emission of Tb3+ions.

A (4,4)-connected zinc(II) coordination polymer constructed with the flexible 2-carboxy phenoxyacetate ligand: synthesis, conformation alteration and fluorescent properties

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jun-Xia Li ◽  
Tian Zhang ◽  
He-Jun Chen ◽  
Zhong-Xiang Du
Keyword(s):  
Coordination Polymer ◽  
Hydrothermal Reaction ◽  
Layer Structure ◽  
Fluorescence Emission ◽  
Phenoxyacetic Acid ◽  
X Ray Diffraction ◽  
Fluorescent Properties ◽  
Sulfate Heptahydrate ◽  
X Ray ◽  
Related Compounds

Abstract A new binary ZnII coordination polymer, [Zn(2-cpa)(H2O)] n (2D-Zn) has been prepared by a 120 °C hydrothermal reaction of zinc(II) sulfate heptahydrate and 2-carboxy phenoxyacetic acid (2-H2cpa) in the presence of potassium hydroxide. Single-crystal X-ray diffraction analysis shows that the ZnII ion is located in a deformed ZnO6 octahedron bonded by one water and three 2-carboxy phenoxyacetate (2-cpa) ligands. The 2-cpa exhibits pentadentate double bridging chelate-μ 3 coordination mode and connects adjacent ZnII ions to generate a corrugated (4,4)-connected layer structure. The structures, conformation of 2-cpa and photoluminescence spectra for 2D-Zn have been carefully analyzed and compared with its two closely related compounds ̶ 1D [Zn(2-cpa)(H2O)] n (1D-Zn) and mononuclear [Zn(2-cpa)(H2O)3] (0D-Zn). The results showed that the conformation of 2-cpa in 2D-Zn has the maximum alteration and the corresponding fluorescence emission peak of 2D-Zn has the largest red-shift of 62 nm compared with that of free 2-H2cpa.

Chemical Synthesis and Properties of Layered Co1-yNiyO2-δOxides (0≤y≤1)

2000 ◽  
Vol 658 ◽  
Author(s):  
A. Manthiram ◽  
R. V. Chebiam ◽  
F. Prado
Keyword(s):  
Layer Structure ◽  
Magnetic Data ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Ni Content ◽  
Wet Chemical ◽  
Oxide Ions ◽  
Structure Layer

ABSTRACTLayered Co1-yNiyO2-δ oxides with 0≤y≤1 have been synthesized by chemically extracting lithium from LiNi1-yCoyO2 with NO2PF6 at ambient temperature. The samples have been characterized by X-ray diffraction, wet-chemical analyses, infrared spectroscopy, and magnetic susceptibility measurements. While NiO2-δ retains the initial O3 (CdCl2 structure) layer structure of LiNiO2, CoO2-δ consists of a mixture of P3 and O1 (CdI2 structure) phases that are formed by a sliding of the oxide ions in the initial O3 structure. CoO2-δ and NiO2-δ have oxygen contents of, respectively, 1.67 and 1.95 and the oxygen content increases with increasing Ni content, y, in Co1-yNiyO2-δ. While CoO2-δ exhibits metallic conductivity as revealed by theabsence of absorption bands in the infrared spectrum, NiO2-δ exhibits semiconducting behavior due to a completely filled t2g band. Magnetic data reveal a transition from antiferromagnetic to ferromagnetic correlations as the Ni content in Co1-yNiyO2-δ increases.

The investigation of disturbed surface layer structure by the external photoeffect under X-ray diffraction conditions

1982 ◽  
Vol 71 (2) ◽  
pp. 603-610 ◽  
Author(s):  
V. G. Kohn ◽  
M. V. Kovalchuk ◽  
E. M. Imamov ◽  
B. G. Zakharov ◽  
E. F. Lobanovioh
Keyword(s):  
Surface Layer ◽  
Layer Structure ◽  
X Ray Diffraction ◽  
X Ray

X-Ray Reflectivity Studies of Pt/AlN Multilayered Films

2007 ◽  
Vol 561-565 ◽  
pp. 2095-2098
Author(s):  
Takashi Harumoto ◽  
Ji Shi ◽  
Yoshio Nakamura
Keyword(s):  
Layer Structure ◽  
Bragg Reflection ◽  
X Ray Diffraction ◽  
Multilayered Films ◽  
Sputtering Deposition ◽  
X Ray ◽  
First Order ◽  
Periodic Layer ◽  
Deposited Films ◽  
Very High

Pt/AlN multilayered films fabricated by alternative sputtering deposition were characterized by X-Ray Reflectometry and X-Ray Diffraction. As-deposited films have (111) and (001) preferred orientation for Pt and AlN, respectively. The X-Ray Reflectivity profiles are assigned to the total reflection and Bragg reflections due to periodic layer structure. The Bragg peaks are observed at the 2Theta range beyond 15 degree and the peak intensities increase after annealing. The reflectivity of the first order Bragg reflection is approximately 65% and is stable after annealing at 873K. Simulation of the reflectivity profile has shown roughnesses of the Pt/AlN interfaces are below 0.4nm. X-Ray Diffraction revealed the development of film texture and formation of superlattice by annealing. The latter indicates periodicity of film is very high.

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