Chen X.,Beijing University of Chemical Technology |
Zhang S.,Beijing University of Chemical Technology |
Xu G.,Beijing Technology and Business University |
Zhu X.,Heilongjiang Hongyu New Material of Short Fiber Ltd Company |
Liu W.,Sichuan Fire Research Institute
Journal of Applied Polymer Science | Year: 2012
In this article, we report the mechanical and thermal properties, together with the crystallization and flammability behaviors, of pure polypropylene (PP) and PP/aramid fiber (AF) composites with AF loadings of 5, 10, 20, 30, and 40 wt %. The mechanical properties of the samples were evaluated by tensile and izod notched impact tests, and the results show that the tensile strength of the composites could reach up to 67.8 MPa and the izod notched impact strength could rise to 40.1 kJ/m 2. The structure and morphology were observed by scanning electron microscopy and polarized optical microscopy, respectively. This demonstrated that a solid interface adhesion between the matrix and fibers was formed. The thermal and crystalline behaviors of the PP/AF composites were also investigated by thermogravimetric analysis and differential scanning calorimetry analysis, and the results show that the char residue of the PP/AF composites improved greatly with increasing AF loading, and the highest value could reach up to 23.7% in the presence of 40 wt % AF. The supercooling degree, initial crystallization temperature, and crystallization percentage were used to characterize the crystallization behavior of the PP/AF composites, and the results indicate that the AFs had positive effects on the promotion of PP nucleation, which can usually improve the mechanical properties of composites. Moreover, the flammability analysis of the PP/AF composites demonstrated that the presence of AFs could significantly decrease the peak heat release rate and the total heat release and reduce the melt-dripping of the PP/AF composites. Copyright © 2012 Wiley Periodicals, Inc.
Richard Horrocks A.,University of Bolton |
Liu W.,Sichuan Fire Research Institute
Materials China | Year: 2015
Almost 50 years ago, the 1950-1960 period witnessed the development of the chemistry underlying most of today's successful and durable flame retardant treatments for fibres and textiles. In today's more critical markets in terms of environmental sustainability, chemical toxicological acceptability, performance and cost, many of these are now being questioned. "Are there potential replacements for established, durable formaldehyde-based flame retardants such as those based on tetrakis (hydroxylmethyl) phosphonium salt and alkyl-substituted, N-methylol phosphonopropionamide chemistries for cellulosic textiles?" is an often-asked question. "Can we produce char-forming polyester flame retardants?" and "Can we really produce effective halogen-free replacements for coatings and back-coated textiles?" are others. These questions are addressed initially within the context of a historical review of research undertaken in the second half of the twentieth century which is the basis of most currently available, commercialised flame retardant fibres and textiles. Secondly, research reported during the first decade of the twenty first century and which primarily addresses the current issues of environmental sustainability and the search for alternative flame retardant solutions, the need to increase char-forming character in synthetic fibres and the current interest in nanotechnology are critically discussed. The possible roles of micro- and nano-surface treatments of fibre surfaces and their development using techniques such as plasma technology and layer-by-layer and sol gel chemistries are also reviewed. ©, 2015, Materials China. All right reserved.
Huang T.,Southwest Jiaotong University |
Wang Z.,Southwest Jiaotong University |
Zhang Z.-J.,Sichuan Fire Research Institute
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2012
High performance concrete was burned at high temperatures in a custom made pressure test set. The deterioration of the concrete was studied at different temperatures and a quantitative relationship between residual compressive strength and temperature was obtained. The results show that higher grade, high performance concrete had poorer fire resistance. The residual compressive strength of the high performance concrete decreases under constant high temperatures or with natural cooling. A minor increase in compressive strength was noticed at 300°C. The residual compressive strength decreases as the temperature increases for water spray cooling. The residual compressive strength of the concrete at high temperature is slightly higher than after natural cooling; The residual strength after water spray cooling was lowest of the three conditions.
Liu C.,Chongqing University |
Zhang Y.,Chongqing University |
Huang X.,Sichuan Fire Research Institute
Fuel Processing Technology | Year: 2014
Five possible pyrolytic pathways of guaiacol were proposed with an emphasis on the reactivity of the methoxy group. Pathway 1 is about the homolysis of OCH3. Pathways 2-4 focus on the demethoxylation of guaiacol. Pathway 5 concerns the OCH3 rearrangement. Standard thermodynamic and kinetic parameters of each reaction pathway were calculated at different temperatures based on density functional theory methods by using Gaussian 03 package at B3LYP/6-31G++(d,p) level. According to the calculation results, the five reaction pathways were ranked as Path 3, Path 1, Path 4, Path 2 and Path 5, in descending order of reactivity. Kinetic analyses results of the three demethoxylation reaction pathways (Path 2, Path 3 and Path 4) indicate that coupling a hydrogen radical to the carbon atom to which the methoxyl group bond can effectively lower the reaction energy barrier that existed in the process of demethoxylation. Pathway 5 demonstrates the possible formation mechanism of o-quinonemethide which is the key polymerization intermediate during lignin pyrolysis process. © 2014 Elsevier B.V.
Gao W.,University of Tokyo |
Zhong S.,Northeastern University China |
Mogi T.,University of Tokyo |
Liu H.,Northeastern University China |
And 2 more authors.
Journal of Loss Prevention in the Process Industries | Year: 2013
Sensitivity and severity parameters are critical for risk assessment and safety management of dust explosions. In this paper, to reveal the effects of material thermal characteristics on dust explosions parameters during monobasic alcohols dust explosions, three long chain monobasic alcohols, being solid at room temperature and similar in physical-chemical properties, were chosen to carry out experiments in different functional test apparatus according to the internationally accepted ASTM standards. As a result, it was found that the material thermal characteristics strongly affected these basic explosive parameters. On the one hand, for the sensitivity parameters, Minimum Ignition Temperature, Minimum Ignition Energy and Electrical Resistivity were the highest in the Eicosanol dust cloud, while Minimum Explosible Concentration in this cloud was the lowest. On the other hand, for severity parameters, Maximum Explosion Pressure in Eicosanol dust cloud always maintained the highest values as varying the dust concentrations. In contrast, Deflagration Index showed a complex trend. © 2012 Elsevier Ltd.
Shen X.,East China University of Science and Technology |
He X.,Sichuan Fire Research Institute |
Sun J.,Hefei University of Technology
Fuel | Year: 2015
The premixed hydrogen-air and propane-air flames in a closed duct were experimentally studied for a deep insight into the tulip distortion phenomenon. High speed schlieren photography and pressure sensors recorded the flame images and pressure dynamics at different equivalence ratios for detailed analyses and comparisons. The distorted tulip shape which was first scrutinized and distinguished as an exclusive feature in premixed hydrogen-air flame, was also observed in stoichiometric premixed propane-air flame with a similar behavior on flame shape changes. Tulip distortions are always accompanied by remarkable flame tip velocity fluctuations with near-constant amplitudes. But the pressure dynamics is totally different. There are no observable oscillation and stepped rise in pressure trajectory of stoichiometric premixed propane-air flame. The pressure wave effect is definitely not the incitation factor, but an additional enhancement of flame acceleration, deceleration and deformation. © 2015 Elsevier Ltd. All rights reserved.
Xiao H.,Sichuan Fire Research Institute |
He X.,Sichuan Fire Research Institute |
Wang Q.,Sichuan Fire Research Institute |
Sun J.,Hefei University of Technology
International Journal of Heat and Mass Transfer | Year: 2013
The premixed flame propagation in a closed duct with a 90 bend is studied using high-speed schlieren photography and numerical simulation. The investigation provides basic understanding of the influence of the bend on the premixed flame propagation. The flame undergoes four stages in the propagation. The outer flame skirt influences significantly the flame dynamics. The flame surface area reaches its minimum value after the full formation of tulip flame. The flame dynamics observed in the experiment is well reproduced by the numerical simulation. The flame behavior at the later stage is in close connection with the hydrodynamics of the combustion-generated flow. The numerical simulation indicates that a single vortex is generated near the flame tip in the burnt gas just before the formation of flame indentation. The vortex remains in the vicinity of the flame tip and changes the flow field around the flame front. As a consequence, the effects of the circulating flow create the conditions required for the formation of a tulip flame. © 2013 Elsevier Ltd. All rights reserved.
Liu W.,University of Sichuan |
Liu W.,Sichuan Fire Research Institute |
Chen L.,University of Sichuan |
Wang Y.-Z.,University of Sichuan
Polymer Degradation and Stability | Year: 2012
A novel flame retardant, poly (1,2-dicarboxyl ethylene spirocyclic pentaerythritol bisphosphonate) (PEPBP) has been synthesized by the reaction of spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride (SPDPC) with tartaric acid (TA). PEPBP was used as the flame-retardant finishing agent for cotton fabrics. The flame retardancy of the samples was characterized by limiting oxygen index (LOI) and the vertical burning test. The cotton fabric sample with 21.2 wt% of PEPBP has a LOI value of 33.8, which is 14.4 higher than that of the untreated cotton sample. The treated cotton fabrics have shorter after-glow time, shorter char length and no after-flame during the vertical burning test. The thermal decomposition behaviors of the fabrics, the chemical structures and morphologies of the residues of the fabrics were investigated using thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM), respectively, and a possible flame retardant mechanism was discussed. © 2012 Elsevier Ltd. All rights reserved.
Hu Z.-R.,Sichuan Fire Research Institute
Procedia Engineering | Year: 2013
It introduces the fire situation of China in recent years and puts forward the urgency to develop the building fire engineering technology in this study. Besides urging to compile the fire control regulations and develop the fire control engineering standards, the fire-test-based experimental techniques also advance to application of the new fire engineering techniques and products. Emphasis is given to introducing recent fire tests aiming at promoting the new fire engineering techniques and products. © 2013 The Authors. Published by Elsevier Ltd.
Zhang X.,Sichuan Fire Research Institute |
Zhang F.,Sichuan Fire Research Institute
Advanced Materials Research | Year: 2012
A novel phosphor-nitrogen intumescent flame retardant was prepared by dry method (without adding any solvent) using H 3PO 4, P 2O 5, pentaerythritol and melamine as raw materials. IR analysis found that the synthetic flame retardants had the P=O and P-O-C double-ring structures, the same to phosphate ester melamine salts. The reaction temperature, time and the ratio of raw materials had significant effect on the esterification reaction. The esterification reaction temperature should be controlled between 120°C and 130°C, and the reaction time should be 2.5 hours. The conversion rate of esterification could be improved by adding P 2O 5 to the reaction, and preferential mole rate between H 3PO 4 and P 2O 5 should be 2:1. Thermogravimetric analysis showed that the starting decomposition temperature of the flame retardant was 190°C, and at 700°C, the residual char rate was about 30%. The expansion ratio of the flame retardant after heated was about 30 to 50 times, SEM analysis found that the exteral surface of the expansion char layer was continuous and smooth, and the interior of the expansion char layer was uniformly porous structures, and the aperture size was about 150-200 μm, such porous structures could provide better adiabatic effect.