The Experts below are selected from a list of 4767 Experts worldwide ranked by ideXlab platform
Lei Song - One of the best experts on this subject based on the ideXlab platform.
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Highly Effective P–P Synergy of a Novel DOPO-Based Flame Retardant for Epoxy Resin
Industrial & Engineering Chemistry Research, 2017Co-Authors: Yan Zhang, Lei Song, Bibo Wang, K.m. Liew, Chengming WangAbstract:A novel flame retardant (FR) DOPO-PEPA, which was synthesized via Atherton–Todd reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane (PEPA), was used as an additive-type FR in epoxy resin (EP). The results of the limiting oxygen index (LOI), vertical burning test, and cone calorimeter test indicated that the flame retardance of FR-EP composites is dependent on the chemical structure of phosphorus-based FRs. EP/DOPO-PEPA shows pretty good mechanical properties and a relatively high degree of cross-linking. Furthermore, the synergy as DOPO-PEPA was more efficient than that of DOPO or PEPA alone to flame retardant EP. When the FR additives were 9.1%, the EP/DOPO-PEPA acquired a LOI value of 35%, UL94 V-0 rating, and the lowest peak of heat release rate (PHRR) of 595 kW/m2. Furthermore, its continuous and firm Char Residue layer also reinforced this kind of action.
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Flammability and carbonization of high-impact polystyrene/α-zirconium phosphate nanocomposites
Iranian Polymer Journal, 2015Co-Authors: Dandan Yang, Lei Song, Jingrong Wang, Jiarong ChenAbstract:High-impact polystyrene (HIPS)/organophilic alpha-zirconium phosphate (organophilic α-ZrP, OZrP) nanocomposites were prepared by melt blending method. The XRD and high-resolution transmission electronic microscopy results showed that an intercalated/exfoliated structure of nanocomposites was formed. The thermal degradation behaviors indicated that the HIPS/OZrP nanocomposites displayed similar thermo-oxidative stability with that of HIPS, and α-ZrP could promote the formation of Char Residue of the nanocomposites. The combustion behaviors revealed that the addition of α-ZrP could reduce the value of peak heat release rate (HRR) and mass loss rate (MLR) of the nanocomposites. The peak HRR value of HIPS/OZrP nanocomposites with 3 wt% OZrP was 17 % lower than that of pure HIPS. The trends of MLR were the same as those of the HRR, which indicated that the mechanism of the observed reduction both in HRR and MLR by addition of the layered phosphate depended mainly on the condensed phase flame-retardant process instead of the gas phase flame-retardant process. It could be observed that HIPS left no Residues after burning, whereas the HIPS/OZrP nanocomposites left the consistent and compact Char Residues. Moreover, graphite sheets and carbon nanotubes were observed in the Char Residues of nanocomposites. The experimental results suggested that polymers would have improved fire performance with the high crystallization of Char Residue in the presence of α-ZrP.
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Fabrication of carbon black coated flexible polyurethane foam for significantly improved fire safety
RSC Advances, 2015Co-Authors: Wei Wang, Lei Song, Haifeng Pan, Ying Pan, K.m. LiewAbstract:Fire resistant coatings, composed of nanosized carbon black (CB) and polyurethane acrylate (PUA), were synthesized through a facile and low-cost method to improve the fire safety and thermal stability of flexible polyurethane foam (FPU). Scanning electron microscopy and total reflection Fourier transform infrared analysis results demonstrated the successful deposition of the coating on the surface of FPU foam and the morphology change of FPU with different concentrations of CB. Thermogravimetric analysis results revealed that the thermal stability of the coated FPU foams was significantly improved. The Char Residue of FPU/CB 8% was increased to 28.4% from 4.0 wt% of pure FPU. The coated FPU foam with a CB concentration of 8 wt% exhibited a great reduction of 80% in peak heat release rate (pHRR), attributing to the physical barrier effect of the CB filled coating. The observation of the Char Residue indicated that FPU/CB 4% exhibited the best shape Char Residue without collapse and cracking. Simultaneously, the SEM images of the Char Residues of the coated FPU foams showed that carbon black based coating promoted the generation of a compact Char layer, suggesting a good physical blocking effect. Raman spectroscopy also confirmed that the graphitization degree of Char Residue FPU/CB 4% was the lowest, with the more stable structure. The coated FPU foam also has a certain inhibitory effect on the smoke release.
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synthesis of a novel triazine based hyperbranched Char foaming agent and the study of its enhancement on flame retardancy and thermal stability of polypropylene
Industrial & Engineering Chemistry Research, 2013Co-Authors: Weiyi Xing, Yongqian Shi, Panyue Wen, Xiaofeng Wang, Xiaming Feng, Gang Tang, Lei SongAbstract:A novel hyperbranched Char foaming agent (HCFA), successfully synthesized via the polycondensation of 2-chloro-4,6-di-(2-hydroxyethylamino)-s-triazine (CHT), was combined with ammonium polyphosphate (APP) to endow polypropylene (PP) with flame retardance. The study of thermal stability of various PP composites showed that HCFA/APP system could effectively improve the thermal degradation and thermal-oxidative stability of the Char Residues, and PP3 containing 30 wt % APP/HCFA with a 3/1 weight ratio left the highest amount of Char Residue at 700 °C. The results of flammability revealed that PP3 had the most effective flame retardancy and lowest fire hazards. The investigation of structure and morphology of Char Residues indicated that the compact and foaming Char layer, as a good barrier against the transmission of heat and volatiles, was formed for PP3 during combustion.
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functionalized lignin for halogen free flame retardant rigid polyurethane foam preparation thermal stability fire performance and mechanical properties
Journal of Polymer Research, 2013Co-Authors: Weiyi Xing, Yuan Hu, Haixia Yuan, Ping Zhang, Hongyu Yang, Lei SongAbstract:Halogen-free flame retardant rigid polyurethane foams (RPUF) were synthesized by substituting a part of polyther polyol with polyol-modified lignin and filled with phenolic encapsulated ammonium polyphosphate (PFAPP). Lignin was chemically modified with flame retardant elements, phosphorous, via a three-step reaction. The foams maintained a regular cell structure and had even smaller average cell size than pure foam. The effects of lignin polyol and PFAPP on the apparent density, compressive strength were discussed. The thermal stability, flame retardant properties and mechanical properties of the foams are improved. Compared with pure foam (0.2 % Char Residue at 700 °C), modified foam with lignin and PFAPP exhibits much higher Char formation (42.7 % Char Residue at 700 °C). The FR properties of these modified foams were evaluated by cone calorimeter and limiting oxygen index (LOI). The modified lignin in foam system further reduces the heat release rate and shows the combustion process. The addition of 15 % PFAPP and 10 % modified lignin into RPUF led to a considerable increase of the compressive strength with respect to the neat RPUF.
Yuan Hu - One of the best experts on this subject based on the ideXlab platform.
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An infiltration method to synthesize thermoplastic polyurethane composites based on size-controlled graphene foams
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: Lijin Duan, Yuan HuAbstract:Abstract Graphene foams (GFs) with different sizes were prepared and applied to design thermoplastic polyurethane (TPU)/GF nanocomposites by infiltration method. Size-controlled GFs were successfully synthesized with variable concentration of graphene oxide (GO). Stable framework of GFs contributed to uniformity of composites and endowed them preferable thermal and mechanics performance. Results of TGA and MCC manifested that thermostability and flame retardancy of composites were superior to pure polymer, which was contributed to laminar barrier effect of GFs. Compression modulus of composite reached up to 2041.29 kPa, which was much higher than GFs. Due to porous structure, both GFs and TPU/GF composites exhibited quite low value of thermal conductivity. Char Residue of TPU/GF composites not only remained original shape, but withstood certain pressure, which decreased potential fire risk. Polymeric materials design, based on GFs, is a feasible scheme to obtain composite with good integrated performance.
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functionalized lignin for halogen free flame retardant rigid polyurethane foam preparation thermal stability fire performance and mechanical properties
Journal of Polymer Research, 2013Co-Authors: Weiyi Xing, Yuan Hu, Haixia Yuan, Ping Zhang, Hongyu Yang, Lei SongAbstract:Halogen-free flame retardant rigid polyurethane foams (RPUF) were synthesized by substituting a part of polyther polyol with polyol-modified lignin and filled with phenolic encapsulated ammonium polyphosphate (PFAPP). Lignin was chemically modified with flame retardant elements, phosphorous, via a three-step reaction. The foams maintained a regular cell structure and had even smaller average cell size than pure foam. The effects of lignin polyol and PFAPP on the apparent density, compressive strength were discussed. The thermal stability, flame retardant properties and mechanical properties of the foams are improved. Compared with pure foam (0.2 % Char Residue at 700 °C), modified foam with lignin and PFAPP exhibits much higher Char formation (42.7 % Char Residue at 700 °C). The FR properties of these modified foams were evaluated by cone calorimeter and limiting oxygen index (LOI). The modified lignin in foam system further reduces the heat release rate and shows the combustion process. The addition of 15 % PFAPP and 10 % modified lignin into RPUF led to a considerable increase of the compressive strength with respect to the neat RPUF.
Weiyi Xing - One of the best experts on this subject based on the ideXlab platform.
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synthesis of a novel triazine based hyperbranched Char foaming agent and the study of its enhancement on flame retardancy and thermal stability of polypropylene
Industrial & Engineering Chemistry Research, 2013Co-Authors: Weiyi Xing, Yongqian Shi, Panyue Wen, Xiaofeng Wang, Xiaming Feng, Gang Tang, Lei SongAbstract:A novel hyperbranched Char foaming agent (HCFA), successfully synthesized via the polycondensation of 2-chloro-4,6-di-(2-hydroxyethylamino)-s-triazine (CHT), was combined with ammonium polyphosphate (APP) to endow polypropylene (PP) with flame retardance. The study of thermal stability of various PP composites showed that HCFA/APP system could effectively improve the thermal degradation and thermal-oxidative stability of the Char Residues, and PP3 containing 30 wt % APP/HCFA with a 3/1 weight ratio left the highest amount of Char Residue at 700 °C. The results of flammability revealed that PP3 had the most effective flame retardancy and lowest fire hazards. The investigation of structure and morphology of Char Residues indicated that the compact and foaming Char layer, as a good barrier against the transmission of heat and volatiles, was formed for PP3 during combustion.
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functionalized lignin for halogen free flame retardant rigid polyurethane foam preparation thermal stability fire performance and mechanical properties
Journal of Polymer Research, 2013Co-Authors: Weiyi Xing, Yuan Hu, Haixia Yuan, Ping Zhang, Hongyu Yang, Lei SongAbstract:Halogen-free flame retardant rigid polyurethane foams (RPUF) were synthesized by substituting a part of polyther polyol with polyol-modified lignin and filled with phenolic encapsulated ammonium polyphosphate (PFAPP). Lignin was chemically modified with flame retardant elements, phosphorous, via a three-step reaction. The foams maintained a regular cell structure and had even smaller average cell size than pure foam. The effects of lignin polyol and PFAPP on the apparent density, compressive strength were discussed. The thermal stability, flame retardant properties and mechanical properties of the foams are improved. Compared with pure foam (0.2 % Char Residue at 700 °C), modified foam with lignin and PFAPP exhibits much higher Char formation (42.7 % Char Residue at 700 °C). The FR properties of these modified foams were evaluated by cone calorimeter and limiting oxygen index (LOI). The modified lignin in foam system further reduces the heat release rate and shows the combustion process. The addition of 15 % PFAPP and 10 % modified lignin into RPUF led to a considerable increase of the compressive strength with respect to the neat RPUF.
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comparative study on the effect of beta cyclodextrin and polypseudorotaxane as carbon sources on the thermal stability and flame retardance of polylactic acid
Industrial & Engineering Chemistry Research, 2013Co-Authors: Xiaofeng Wang, Weiyi Xing, Lei Song, Bibo Wang, Panyue Wen, Ping ZhangAbstract:Polypseudorotaxane (PPR) prepared by the inclusion complex between beta-cyclodextrin (β-CD) and poly(propylene glycol) (PPG) was chosen as a ‘‘green’’ carbon source in intumescent flame retardants (IFRs) and exhibited more effective carbonization and higher degree of graphitic network than that of free β-CD. Its combination with ammonium polyphosphate (APP) and melamine (MA) presented the most excellent Char-forming ability whether in nitrogen or in air atmosphere. After blending IFRs into polylactic acid (PLA), the thermal stability was Characterized by thermogravimetric analysis (TGA), and their flammability was assessed by limited oxygen index (LOI), vertical combustion, and cone calorimeter. The higher LOI% value and lower total heat release (THR) of PLA2 (which contains 20 wt % APP/MA/PPR mixtures) revealed that it presented more excellent flame retardance. Besides, the results of scanning electron microscopy (SEM) exhibited the existence of more bubbles in the Char Residue of PLA2.
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effect of nickel containing layered double hydroxides and cyclophosphazene compound on the thermal stability and flame retardancy of poly lactic acid
Industrial & Engineering Chemistry Research, 2012Co-Authors: Xueying Shan, Lei Song, Weiyi XingAbstract:Hydrotalcite-like anionic clays or layered double hydroxides with dodecylbenzenesulfonate anions (NiFe, NiAl, and NiCr LDH-SDS, where SDS denotes sodium dodecyl sulfate) were prepared by the coprecipitation method. Hexaphenoxycyclotriphosphazene (HPCP) is an effective cyclophosphazene flame retardant. The HPCP molecule contains a cyclic backbone consisting of alternating phosphorus and nitrogen atoms. LDH-SDS and HPCP were first used to prepare poly(lactic acid) (PLA) composites. One goal of this work was to compare the thermal stability and flame retardancy of PLA/HPCP/LDH-SDS composites. The structures and properties of LDH-SDS materials were Characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Thermal analysis and Char Residue analysis of PLA/HPCP/LDH-SDS composites suggested that NiFe, NiAl, and NiCr LDH-SDS materials play different roles in improving the thermal stability and flame retardancy of PLA...
Jixing Xie - One of the best experts on this subject based on the ideXlab platform.
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Investigation on the thermal degradation of flexible poly(vinyl chloride) filled with ferrites as flame retardant and smoke suppressant using TGA–FTIR and TGA–MS
Polymer Degradation and Stability, 2013Co-Authors: Caihong Liu, Yunhong Jiao, Jixing XieAbstract:Abstract A series of ferrites (ZnFe 2 O 4 , MgFe 2 O 4 , NiFe 2 O 4 , and CuFe 2 O 4 ) was prepared by wet air oxidation and their structure and morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The prepared ferrites were added to flexible poly(vinyl chloride)(PVC) as flame retardants and smoke suppressants. Subsequently, thermal degradation properties of flexible PVC with ferrite additives were investigated by using TGA–DTG, TGA–FTIR, and TGA–MS. The main mechanism underlying the flame-retarding activity was shown to be caused by the catalyzed the dehydrochlorination of PVC at the first stage and breaking of the Char Residue at higher temperature. The results showed that addition of ferrites, especially MgFe 2 O 4 , at the first stage, not only decreased T 5% (defined as the temperature at which 5% of the initial weight has been lost) and increased the weight loss rate, but also promoted cross-linking and stability of Char Residue. The main gas pyrolysis products were HCl and benzene. When compared with neat PVC, PVC/MgFe 2 O 4 and PVC/CuFe 2 O 4 generated more HCl and less benzene, and consequently retained more carbon in the matrix with respect to the increased flame-retarding and smoke-suppressing. At the second stage, the weight loss of flame-retarding PVC increased obviously, with simultaneous increase in the yield of main gaseous pyrolysis products, CO 2 and aliphatic fragments. PVC/CuFe 2 O 4 generated a high yield of CO 2 , because of the cationic cracking reactions in the presence of Lewis acid, fragmenting of the Char Residue at higher temperature. Additionally, the inner surface morphology of the Char Residue derived from PVC/MgFe 2 O 4 was investigated by SEM and EDS, which showed the existence of alveolate and breakable structures, as well as needle-like structures, composed of a mixture of iron chloride and magnesium chloride.
Panyue Wen - One of the best experts on this subject based on the ideXlab platform.
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synthesis of a novel triazine based hyperbranched Char foaming agent and the study of its enhancement on flame retardancy and thermal stability of polypropylene
Industrial & Engineering Chemistry Research, 2013Co-Authors: Weiyi Xing, Yongqian Shi, Panyue Wen, Xiaofeng Wang, Xiaming Feng, Gang Tang, Lei SongAbstract:A novel hyperbranched Char foaming agent (HCFA), successfully synthesized via the polycondensation of 2-chloro-4,6-di-(2-hydroxyethylamino)-s-triazine (CHT), was combined with ammonium polyphosphate (APP) to endow polypropylene (PP) with flame retardance. The study of thermal stability of various PP composites showed that HCFA/APP system could effectively improve the thermal degradation and thermal-oxidative stability of the Char Residues, and PP3 containing 30 wt % APP/HCFA with a 3/1 weight ratio left the highest amount of Char Residue at 700 °C. The results of flammability revealed that PP3 had the most effective flame retardancy and lowest fire hazards. The investigation of structure and morphology of Char Residues indicated that the compact and foaming Char layer, as a good barrier against the transmission of heat and volatiles, was formed for PP3 during combustion.
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comparative study on the effect of beta cyclodextrin and polypseudorotaxane as carbon sources on the thermal stability and flame retardance of polylactic acid
Industrial & Engineering Chemistry Research, 2013Co-Authors: Xiaofeng Wang, Weiyi Xing, Lei Song, Bibo Wang, Panyue Wen, Ping ZhangAbstract:Polypseudorotaxane (PPR) prepared by the inclusion complex between beta-cyclodextrin (β-CD) and poly(propylene glycol) (PPG) was chosen as a ‘‘green’’ carbon source in intumescent flame retardants (IFRs) and exhibited more effective carbonization and higher degree of graphitic network than that of free β-CD. Its combination with ammonium polyphosphate (APP) and melamine (MA) presented the most excellent Char-forming ability whether in nitrogen or in air atmosphere. After blending IFRs into polylactic acid (PLA), the thermal stability was Characterized by thermogravimetric analysis (TGA), and their flammability was assessed by limited oxygen index (LOI), vertical combustion, and cone calorimeter. The higher LOI% value and lower total heat release (THR) of PLA2 (which contains 20 wt % APP/MA/PPR mixtures) revealed that it presented more excellent flame retardance. Besides, the results of scanning electron microscopy (SEM) exhibited the existence of more bubbles in the Char Residue of PLA2.