scholarly journals Effects of APP/SiO2polyelectrolyte composites on wood-plastic composite

2019 ◽  
Vol 275 ◽  
pp. 01004
Author(s):  
He Chen ◽  
Shuai Zhang ◽  
Xin Cai ◽  
Mingzhu Pan
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Cationic Polyelectrolyte ◽  
Carbon Layer ◽  
Limit Oxygen Index ◽  
Crystalline Cellulose ◽  
Plastic Composite

This paper was aimed to evaluate process of APP/SiO2, which used Nano-crystalline cellulose (NCC) modified ammonium polyphosphate (APP) as anionic polyelectrolyte (a-APP), and cationic polyethyleneimine (PEI) modified Nano–SiO2as cationic polyelectrolyte (c-SiO2). The flame retardant system was built due to the reaction of a-APP and c-SiO2. Polyelectrolyte composite of a-APP/c-SiO2were then assembled on the surface of wood powder and HDPE composites. The effect of polyelectrolytes on wood-plastic composites (WPC) were investigated and the results showed that the flame-retardant property of WPC treated by polyelectrolyte was the best. The average heat release rate was 152.8kW/m2, the peak heat release rate was 352.2kW/m2, the total heat release was 108.5kW/m2, the limit oxygen index reached the maximum was 27.5%, compared with the WPC treated by APP, the elongation at break increased by 60.4%. After anionic and cationic polyelectrolyte treatment, making anionized a-APP and cationized c-SiO2due to the charge interaction, in the WPC combustion process to form a dense, uniform WPC carbon layer, thereby reducing the heat transfer to the material inside, and increasing the flame retardancy of WPC composites.

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.

Synthesis of a phosphorus–nitrogen-containing flame retardant and its application in epoxy resin

2018 ◽  
Vol 31 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Shuang Yang ◽  
Yefa Hu ◽  
Qiaoxin Zhang
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Heat Release Rate ◽  
Flame Retardancy ◽  
Release Rate ◽  
Epoxy Resins ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Cone Calorimeter Test

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.

Simultaneous Imaging of OH* Chemiluminescence and Flame Luminosity of Diesel and Biodiesel Spray Combustion

2011 ◽  
Author(s):  
Ji Zhang ◽  
Tiegang Fang
Keyword(s):  
Ambient Temperature ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Combustion Process ◽  
Spray Combustion ◽  
Chemiluminescence Intensity ◽  
High Temperature Reaction ◽  
The Impact

The research on the spray combustion of diesel and biodiesel is vital to the understanding of emission formation and optimal utilization of fuel. This paper studies the biodiesel and diesel spray combustion in a constant volume chamber under different simulated diesel engine conditions. The ambient temperature at fuel injection varied from 800K to 1200K, while the ambient oxygen concentration was maintained at 21%. Simultaneous high speed imaging of OH* chemiluminescence and flame luminosity was employed to visualize the whole combustion process. Heat release rate was analyzed based on the measured combustion pressure. The apparent heat release rate analysis shows that biodiesel has a shorter ignition delay time than diesel, and biodiesel has a smaller cumulative heat release value due to its lower heating value. The overlaying image of OH* chemiluminescence and flame luminosity clearly identifies the high temperature reaction regions and soot formation regions. The line-of-sight images agree with the published observation that the hydroxyl radical is formed on the lean side of the flame edge. Decreasing ambient temperature greatly reduces the OH* chemiluminescence intensity of the diesel combustion, while the impact is smoother and milder for biodiesel combustion. Biodiesel shows a significantly lower level of flame luminosity than diesel under all conditions. These combined observations lead to a speculation that the soot oxidation process may serve as an important contributor to OH* chemiluminescence intensity for late stage combustion, and biodiesel shows a tendency to produce less soot than diesel under the investigated conditions.

Influence of the Spatial and Temporal Interaction Between Diesel Pilot and Directly Injected Natural Gas Jet on Ignition and Combustion Characteristics

2017 ◽  
Author(s):  
Georg Fink ◽  
Michael Jud ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Gas Jet ◽  
Injection Timing ◽  
Release Rates ◽  
Temporal Interaction ◽  
The Impact

In this paper, pilot-ignited high pressure dual-fuel (HPDF) combustion of a natural gas jet is investigated on a fundamental basis by applying two separate single-hole injectors to a rapid compression expansion machine (RCEM). A Shadowgraphy system is used for optical observations, and the combustion progress is assessed in terms of heat release rates. The experiments focus on the combined influence of injection timing and geometrical jet arrangement on the jet interaction and the impact on the combustion process. In a first step, the operational range for successful pilot self-ignition and transition to natural gas jet combustion is determined, and the restricting phenomena are identified by analyzing the shadowgraph images. Within this range, the combustion process is assessed by evaluation of ignition delays and heat release rates. Strong interaction is found to delay or even prohibit pilot ignition, while it facilitates a fast and stable onset of the gas jet combustion. Furthermore, it is shown that the heat release rate is governed by the time of ignition with respect to the start of natural gas injection — as this parameter defines the level of premixing. Evaluation of the time of gas jet ignition within the operability map can therefore directly link a certain spatial and temporal interaction to the resulting heat release characteristics. It is finally shown that controlling the heat release rate through injection timing variation is limited for a certain angle between the two jets.

scholarly journals Flame-Retardant and Thermal Degradation Mechanism of Caged Phosphate Charring Agent with Melamine Pyrophosphate for Polypropylene

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xuejun Lai ◽  
Jiedong Qiu ◽  
Hongqiang Li ◽  
Xingrong Zeng ◽  
Shuang Tang ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Heat Release ◽  
Flame Retardant ◽  
Heat Release Rate ◽  
Release Rate ◽  
Degradation Mechanism ◽  
Limiting Oxygen Index ◽  
Thermal Degradation Mechanism ◽  
Charring Agent ◽  
Ul 94

An efficient caged phosphate charring agent named PEPA was synthesized and combined with melamine pyrophosphate (MPP) to flame-retard polypropylene (PP). The effects of MPP/PEPA on the flame retardancy and thermal degradation of PP were investigated by limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimetric test (CCT), and thermogravimetric analysis (TGA). It was found that PEPA showed an outstanding synergistic effect with MPP in flame retardant PP. When the content of PEPA was 13.3 wt% and MPP was 6.7 wt%, the LOI value of the flame retardant PP was 33.0% and the UL-94 test was classed as a V-0 rating. Meanwhile, the peak heat release rate (PHRR), average heat release rate (AV-HRR), and average mass loss rate (AV-MLR) of the mixture were significantly reduced. The flame-retardant and thermal degradation mechanism of MPP/PEPA was investigated by TGA, Fourier transform infrared spectroscopy (FTIR), TG-FTIR, and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDXS). It revealed that MPP/PEPA could generate the triazine oligomer and phosphorus-containing compound radicals which changed the thermal degradation behavior of PP. Meanwhile, a compact and thermostable intumescent char was formed and covered on the matrix surface to prevent PP from degrading and burning.

scholarly journals Enhanced Thermal Insulation and Flame-Retardant Properties of Polyvinyl Alcohol-Based Aerogels Composited with Ammonium Polyphosphate and Chitosan

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
MinYi Luo ◽  
Jiayou Xu ◽  
Shu Lv ◽  
XueFeng Yuan ◽  
Xiaolan Liang
Keyword(s):  
Polyvinyl Alcohol ◽  
Heat Release ◽  
Flame Retardant ◽  
Thermal Insulation ◽  
Heat Release Rate ◽  
Flame Retardancy ◽  
Release Rate ◽  
Ammonium Polyphosphate ◽  
Composite Aerogel ◽  
Composite Aerogels

Polyvinyl alcohol- (PVA-) based aerogels have attracted widespread attention owing to their low cost, eco-friendliness, and low density. However, the applications of PVA-based aerogels are limited by their flammability. In this study, a flame retardant, ammonium polyphosphate (APP), and a biopolymer, chitosan (CS), were added to polyvinyl alcohol (PVA), and the polymer was further crosslinked using boric acid (H3BO3). In the PVA aerogels, the negatively charged APP and positively charged CS formed a polyelectrolyte complex (PEC) through ionic interaction. Cone calorimetry and vertical burning tests (UL-94) indicated that the PVA composite aerogels have excellent flame retardancy; they could decrease the heat release rate, total heat release rate, and carbon dioxide (CO2) generation. Both PVA/H3BO3 and APP-CS in the composite aerogel could be burned to carbon, and the foamed char layer could act together to impart the PVA composite aerogels with good flame retardancy. Further, the decrease in the temperature at the backside of the aerogels with increasing APP-CS content, as determined by the flame-spraying experiment, indicated that the PVA-based aerogels with APP-CS can also serve as thermal insulation materials. This work provides an effective and promising method for the preparation of PVA-based aerogels with good flame retardancy and thermal insulation property for construction materials.

scholarly journals Analysis on Pattern of Heat Release Rate in Two-Stroke Slow Speed Diesel Engine (2nd Report: Prediction of the Combustion Process)

2003 ◽  
Vol 38 (5) ◽  
pp. 303-308
Author(s):  
Takeshi Imahashi ◽  
Eiji Tomita ◽  
Sadami Yoshiyama ◽  
Kouji Moriyama
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Slow Speed

Experimental and Theoretical Optimization of Combustion Chamber and Fuel Distribution for the Low Emission DI Diesel Engine

2001 ◽  
Author(s):  
Yoshiyuki Kidoguchi ◽  
Michiko Sanda ◽  
Kei Miwa
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Combustion Chamber ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Mixture Distribution ◽  
Initial Mixture ◽  
Injection Timing ◽  
Initial Heat

Abstract This study investigated the effect of combustion chamber geometry and initial mixture distribution on combustion process in a direct-injection diesel engine by means of experiment and CFD calculation. The high squish combustion chamber with squish lip could produce simultaneous reduction of NOx and particulate emissions with retarded injection timing in the real engine experiment. According to the CFD computation, the high squish combustion chamber with central pip is effective to continue combustion under the squish lip until the end of combustion and the combustion region forms rich and high turbulence atmosphere, which reduces NOx emissions. This chamber can also reduce initial burning because combustion continues under the squish lip. The CFD computation is also carried out in order to investigate the effect of initial mixture distribution on combustion process. The results suggest that mixture distribution affects the history of heat release rate. When fuel is distributed in the bottom or wide region in the combustion chamber, burned gas tends to spread to the cavity center and initial heat release rate becomes high. On the contrary, the high squish combustion chamber with central pip produces lower initial heat release rate because combustion with local rich condition continues long under the squish lip. Diffusion burning is promoted by high swirl motion in this chamber with keeping lower initial heat release rate.

scholarly journals Non-Chloride in Situ Preparation of Nano-Cuprous Oxide and Its Effect on Heat Resistance and Combustion Properties of Calcium Alginate

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1760 ◽  
Author(s):  
Peiyuan Shao ◽  
Peng Xu ◽  
Lei Zhang ◽  
Yun Xue ◽  
Xihui Zhao ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Heat Release ◽  
Hybrid Materials ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cuprous Oxide ◽  
Calcium Alginate ◽  
Combustion Process ◽  
Protective Layer ◽  
Combustion Properties

With Cu2+ complexes as precursors, nano-cuprous oxide was prepared on a sodium alginate template excluded of Cl− and based on which the calcium alginate/nano-cuprous oxide hybrid materials were prepared by a Ca2+ crosslinking and freeze-drying process. The thermal degradation and combustion behavior of the materials were studied by related characterization techniques using pure calcium alginate as a comparison. The results show that the weight loss rate, heat release rate, peak heat release rate, total heat release rate and specific extinction area of the hybrid materials were remarkably lower than pure calcium alginate, and the flame-retardant performance was significantly improved. The experimental data indicates that nano-cuprous oxide formed a dense protective layer of copper oxide, calcium carbonate and carbon by lowering the initial degradation temperature of the polysaccharide chain during thermal degradation and catalytically dehydrating to char in the combustion process, and thereby can isolate combustible gases, increase carbon residual rates, and notably reduce heat release and smoke evacuation.

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