Polymers
·
2021
·Vol. 13
·期 9
·1363
·
IF 4.329
Xu Han,Xiaohua Zhang,Ying Guo,Xianyuan Liu,Xiaojuan Zhao,Heng Zhou,Songli Zhang,Tong Zhao
The cage and ladder structured phosphorus-containing polyhedral oligomeric silsesquioxanes (DOPO-POSS) have been synthesized through the hydrolytic condensation of 9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide (DOPO)-vinyl triethoxysilane (VTES). The unique ladder and cage–ladder structured components in DOPO-POSS endowed it with good solubility in vinyl epoxy resin (VE), and it was used with tetrabutyl titanate (TBT) to construct a phosphorus-silicon-titanium synergy system for the flame retardation of VE. Thermal stabilities, mechanical properties, and flame retardancy of the resultant VE composites were investigated by thermal gravimetric analysis (TGA), dynamic mechanical analysis (DMA), three-point bending tests, limiting oxygen index (LOI) measurement, and cone calorimetry. The experimental results showed that with the addition of only 4 wt% DOPO-POSS and 0.5 wt% TBT, the limiting oxygen index value (LOI) increased from 19.5 of pure VE to 24.2. With the addition of DOPO-POSS and TBT, the peak heat release rate (PHRR), total heat release (THR), smoke production rate (SPR), and total smoke production (TSP) were decreased significantly compared to VE-0. In addition, the VE composites showed improved thermal stabilities and mechanical properties comparable to that of the VE-0. The investigations on pyrolysis volatiles of cured VE further revealed that DOPO-POSS and TBT exerted flame retardant effects in gas phase. The results of char residue of the VE composites by SEM and XPS showed that TBT and DOPO-POSS can accelerate the char formation during the combustion, forming an interior char layer with the honeycomb cavity structure and dense exterior char layer, making the char strong with the formation of Si-O-Ti and Ti-O-P structures.Keywords:vinyl epoxy resin;flame retardant;thermal stability;mechanical properties
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yin Lu,Jiamei Liu,Wenqian Zhao,Kan Zhang
The frequent fire accidents and sustainable development concerns have called for more durable and safer flame retardant polymeric materials produced from natural renewable resources. Herein, we successfully developed a molecular design strategy by incorporating oxazine ring substituents into bio-benzoxazine monomers to achieve highly thermally stable and intrinsically flame retardant thermosets. The polybenzoxazine derived from a small-molecule bio-benzoxazine resin, 3-(furan-2-ylmethyl)-3,4-dihydro-2 H -benzo[ e ] [1] , [3] oxazine ( PH-fa ), was found to reveal a very high glass transition temperature of 317 °C. However, it was thermally unstable during the polymerization process and easy to ignite without self-extinguishing characteristic. 9,10-Dihydro-9-oxa-10-phosphaphenathrene-10-oxide (DOPO) was incorporated into PH-fa to obtain an oxazine ring substituted bio-benzoxazine ( PH-fa-[4]DOPO ) possessing non-ignitable capability, which reached the V-0 rating of UL-94 test. Unfortunately, a trade-off between the thermal stability and flame retardancy was discovered through the DOPO modification. Further incorporating renewable benzaldehyde into PH-fa -[4] DOPO generated a 2,4-substituted bio-benzoxazine ( PH-fa-[2]ph[4]DOPO ) with ideally enhanced flame retardancy as well as remained higher thermal stability. These results highlight the utility of sustainable molecular design and provide molecular-level insights into roles of oxazine ring substituents in thermal and fire-related properties of polybenzoxazines, as well as a new angle for the design of non-ignitable and high-performance bio-thermosets based on benzoxazine chemistry.
研究领域:
材料科学
·
化学工程
·
可持续发展
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 46
·e54674
·
IF 3
Yingting Yin,Mao Feng,Wei Li,Jinbo Yao,Jiarong Niu
To improve the flame retardancy and solid content of waterborne polyurethane (WPU), AOT, and AOD series of WPU were synthesized and characterized. Carboxylic acid/nonionic composite units were used as hydrophilic groups, and OP550/THPO and OP550/DOPO-HQ combinations were used as flame retardant modifiers, respectively. The results revealed that the flame retardant-modified WPU emulsions still had excellent dispersion, stability, and fluidity. The UL-94 rating of modified WPU could reach V-0, and the AOD series samples had better flame retardancy than the AOT series, where AO 10 D 3 -WPU containing 3% DOPO-HQ had an limiting oxygen index value up to 30.5%. Besides, the peak heat release rate and total heat release of AO 10 D 3 -WPU were respectively decreased by 32% and 34%, compared with the control sample in the conical calorimetric test. The TGA, TG-IR, and SEM-EDS exhibited that the flame retardants functioned in the condensed phase by promoting carbon formation. The tensile strength of AOT series samples was excellent with a range of 15.84–27.47 MPa, while the elongation at break of AOD series samples was relatively high with a distribution of 850.8%–913.11%, which could be selected to suit the needs of different application scenarios.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Bin Zou,Ziyan Qian,Zixuan Zhang,Weiyi Xing,Shangshang Zhong,Jiajun Li,Fukai Chu,Yongchun Kan,Jie Chen,Yuan Hu
Fire hazards are a primary concern in aircraft accidents, and controlling combustible materials is pivotal in managing cabin fire risks. This work aims to elucidate the impact of widespread measures that introduce phosphorus-based flame retardants (PFRs) on the fire safety of carbon fiber epoxy composites (CF/EP). Firstly, the hazardous indicators for flame retardant CF/EP composites exhibit two categories of optimization and degradation, which are caused by the intrinsic feature, pyrolysis characteristics and chemical valence states of PFRs. Secondly, the fire hazards of composites are assessed by fusing the analytic network process and information weights guided by Nash Equilibrium theory. The method combines the merits of subjective and objective weights from dimensions of intrinsic hazards, interrelationships and data dispersion of indicators. Finally, the assessed fire hazard rankings under 35 and 65 kW/m 2 both are EP > CF/EP16%DOPO-HQ > CF/EP > CF/EP7%DPO. In conclusion, DOPO-HQ (+1) primarily increases the fire hazard of CF/EP due to gas-phase flame-retardant effects, while DPO (+3) predominantly reduces the fire hazard of CF/EP by contributing to condensed-phase effects. This work highlights the contradictory effects of PFRs on the fire safety of CF/EP composites due to structure and thermal stability. The proposed ANP and IW hybridization method provides a theoretical foundation for selecting flame retardants and assessing material fire hazards comprehensively.
研究领域:
航空工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2022
·
IF 5.204
Shuang-Lin Hu,Ying-Ming Li,Wen-Juan Hu,Jose Hobson,De-Yi Wang
Unsaturated polyester resin (UPR) composites with excellent flame retardancy and high mechanical property is a great challenge to its widely application. In present work, a highly efficient flame retardant (MA-DOPO) containing nitrogen, sulfur and phosphorus elements was designed via a nucleophilic substitution reaction of amino and aldehyde groups. For the UPR/MA-DOPO 15 composites, its tensile strength was 28.3 MPa, which was 19.9 % higher than that of neat UPR attributing to the formation of hydrogen bonds with UPR. It should be noted that tensile strength of UPR/MA-DOPO 20 composites reached the highest 39.6 MPa, showing a growth trend with the enhancement of incorporation amount of MA-DOPO. Meanwhile, the UPR/MA-DOPO 15 composites passed the UL-94 V-0 rating with a LOI of 27.0%, and the peak heat release rate (PHRR) and total heat release rate (THR) were reduced by 35.1% and 41.6% in cone calorimeter (CC) test comparing to that of neat UPR respectively. Moreover, the detailed flame-retarding mechanism of MA-DOPO was investigated by the thermogravimetric infrared spectroscopy (TG-IR), Raman spectrum, X-ray photoelectron spectroscopy (XPS) and pyrolysis-gas chromatography/mass spectrometry (PY-GC/MS), in which the releasement of inert gas in gas-phase and the catalytic carbonation in condensed phase jointly taking effect.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2017
·
IF 2.942
Hong Yan,Zhilei Zhao,Yuanhang Wang,Qing Jin,Xinyu Zhang
As one of the important flame retardants , ammonium polyphosphate (APP) usually needs surface modification or microencapsulation to lower its solubility in water and to improve its compatibility with polymers before being applied to the flame retardant system. Herein, we reported a new way to obtain highly water-resistant hydrophobic APP by introduction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) into its molecular structure. The contact angle of obtained DOPO-modified APP is 105°, and its solubility in water at 25 and 80 °C was 0.08 and 0.2 g·100 mL − 1 H 2 O, respectively, lower than that of the commercial microencapsulated APP (0.2 and 0.4 g·100 mL − 1 H 2 O). The hydrophobic mechanism of DOPO-modified APP was discussed in detail. For PP loaded with 30% of DOPO-modified APP or commercial APP, the former could pass V0 rating (1.6 mm) at the vertical burning test (UL-94), while the latter failed. The LOI value of the former increased to 30.1% and that of the latter was only 24.2%. Moreover, cone calorimeter (CC) testing results also indicated that the former exhibited better flame retardant performance.
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 13.2
Ningning Xiao,Wei Wang,Chunyu Ding,Dongming Qi,Zhijie Chen,Yangyi Sun
F lame- r etardant w aterborne p oly u rethane (FR-WPU) combines fire resistance with the environmental benefits of waterborne systems, making it attractive for advanced textiles, transportation, and construction applications. The traditional strategy relies on covalently embedding rigid, polar flame-retardant moieties into the PU backbone, which ensures durable flame resistance, but inevitably compromises chain mobility and mechanical robustness. Here, leveraging a macromolecular rigidity-flexibility synergy strategy, we have developed a novel bio-based FR-WPU by integrating flexible c astor o il (CO) segments with a rigid 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-derived flame-retardant chain extender. By precisely tuning the CO/DOPO ratio, we construct a balanced macromolecular architecture in which flexible chains dissipate stress and enhance compatibility, while rigid phosphorus-aromatic domains form thermally stable char barriers. The resulting FR-WPU achieves a l imiting o xygen i ndex (LOI) of 29.2% (well above the 27% threshold), along with excellent mechanical properties, including a tensile strength of 34.3 MPa (35.9% higher than that of CO-free PU) and an elongation at break of 347.9% (an 11.7% improvement). When applied to m icro f iber synthetic l eather (MFL), the MFL maintains robust flame retardancy (with an LOI of 28.1%). This work highlights rigidity-flexibility synergy as a universal design strategy to overcome the trade-off between macromolecular functionality and mechanical performance, paving the way for next-generation eco-friendly, high-performance polymeric materials.
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2026
·
IF 5.4
Zhennan Wang,Hui Ge,Zongmin Zhu,Guangzhong Yin,Xiaomei Yang,Xuebao Lin
A cytosine-derived DOPO-pyrimidine flame retardant, CTD, was synthesized. • CTD endowed epoxy resin with a UL-94 V-0 rating and an LOI of 35.8%. • EP/8%CTD reduced pHRR and THR by 44.9% and 39.8%, respectively. • Compact graphitized char and gas-phase radical trapping jointly suppressed burning. • EP/6%CTD improved impact strength by 93% while retaining tensile strength. A phosphorus‑nitrogen additive denoted CTD was prepared from cytosine, terephthalaldehyde, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The resulting pyrimidine-containing compound was then introduced into epoxy resin (EP). CTD increased the flame resistance of EP while retaining favorable mechanical behavior. At 8 wt% CTD, the limiting oxygen index rose from 21.0% to 35.8%, equivalent to a 70.5% increase. This formulation also attained a UL-94 V-0 rating. Cone calorimetry gave a peak heat release rate of 562.3 kW m −2 and a total heat release of 33.08 MJ m −2 . These values were 44.9% and 39.8% below those of neat EP, respectively. The post-test residue simultaneously increased from 22.40 wt% to 39.90 wt%, supporting the enhanced carbonization induced by CTD. These findings identify CTD as an effective flame retardant for epoxy composites that combine improved fire safety with mechanical toughness. Download: Download high-res image (164KB) Download: Download full-size image
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2018
·
IF 3.193
Junjing Zhao,Xu Dong,Shan Huang,Xiujuan Tian,Liang Song,Qing Yu,Zhongwei Wang
Two phosphorus-containing flame retardants , (bis(4-hydroxyphenyl)methyl)diphenyl phosphine oxide (DPO–PHE) and 1-(bis(4-hydroxyphenyl)methyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO–PHE) were synthesized and characterized. The two target compounds both were used as a flame retardant and a co-curing agent of 4,4′-diaminodiphenylsulfone of bisphenol A diglycidyl ether to prepare flame-retardant epoxy resins (EP/DPO–PHE and EP/DOPO–PHE). The thermal and flame-retardant properties of the thermosets were investigated by thermogravimetric analysis (TGA), limited oxygen index (LOI) measurement, and UL-94 vertical burning testing (UL-94). The results indicated that both flame retardants can improve the flame retardancy of epoxy thermosets. TGA results indicated that the char yields of EP/DPO–PHE–P-0.9 and EP/DOPO–PHE–P-0.9 thermosets were increased from 19.1% of EP/P-0 to 25.3% and 27.8%, respectively. Compared with that of EP/P-0, the LOI of the EP/DPO–PHE–P-0.5 thermoset increased from 23.7% to 30.1%, and the sample reached UL-94 V-0. Meanwhile, the LOI of the EP/DOPO–PHE–P-0.7 thermoset increased from 23.7% to 28.9%, and the sample reached UL-94 V-0. Cone calorimetry test, scanning electron microscopy of burning residues, and pyrolysis–gas chromatography/mass spectrometry indicated that both flame retardants mainly act through the gas–phase mechanism. In addition, no condensed-phase activity of DPO–PHE was observed, whereas the condensed-phase activity of DOPO–PHE was negligible. Immersion experiments showed that the water absorption activity of flame retardant epoxy resins fluctuates. Compared with DOPO–PHE, DPO–PHE was more effective as a higher flame-retardant and exhibited better characteristics for improving the T g , thermal stability, and water absorption of modified resins.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2014
·
IF 2.633
Liqiang Gu,Guoan Chen,Youwei Yao
Two novel halogen-free flame retardants , DP-DDE and DP-DDS, were synthesized via a one-pot procedure based on the Pudovik reactions between 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and imines directly resulting from the condensation reactions of 3-methoxy-4-hydroxybenzaldehyde with two typical curing agents , 4,4′-oxydianiline (DDE) and 4,4′-diaminodiphenylsulfone (DDS), respectively. The fire-resistant properties of DP-DDE or DP-DDS modified epoxy resins (2,2-bis(4-glycidyloxyphenyl)propane) with 4,4′-methylenedianiline as hardener were been investigated by UL-94 vertical test. Their high flame-retarding performance has been found: the epoxy thermosets with a relatively low addition amount of DP-DDE or DP-DDS (on the account of phosphorus content of 0.75 wt.% or 0.73 wt.%) can reach UL-94 V-0 flammability rating. These thermosets demonstrated excellent thermal stability, high glass transition temperature ( T g > 135 °C) and high char yields (>22% at 800 °C). Moreover, the thermal degradation kinetics of the flame retardants and their corresponding epoxy thermosets were studied based on Kissinger, Ozawa and FWO methods by thermogravimetric analysis .
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2017
·Vol. 29
·期 1
·603-611
·
IF 1.907
Ting Chen,Xianming Chen,Meijie Wang,Peixin Hou,Cao Jie,Jilu Li,Yiting Xu,Birong Zeng,Lizong Dai
A novel halogen-free 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-containing co-curing agent, 6,6′-(1,4-phenylenebis(((4-(phenylamino)phenyl)amino)methylene))bis(dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (DPN) was synthesized via a simple 1-pot or 2-step procedure with yield of 86.2% and 70.8%, respectively. The molecular structures of 4,4′-((1,4-phenylenebis(methanylylidene))bis(azanylylidene))bis(N-phenylaniline) (DPN intermediate) and DPN are characterized by FTIR, NMR, and MS. TGA tests show that the char yield of DPN/EP composites raises to 30.9% when the molar ratio of DPN to 4,4-diaminodiphenyl methane(DDM) is 20:80. T g values of DPN/EP composites tested by DSC and DMA are similar to neat epoxy resin (EP), which is due to the secondary amine in DPN that participates in the cross-linking reaction of epoxy resin. The storage modulus in the rubber stage (E′-190 °C) of flame-retardant epoxy resin is close to that of neat EP, while their tanδ's are lower, which indicates the similarity of samples' cross-linking density due to the participation of DPN in the cross-linking reaction. The results show that when the molar ratio of DPN and DDM is 5:95, the epoxy has a higher T g value and better mechanical properties than other samples. The introduction of DPN efficiently improves the flame-retardant properties of epoxy resin with V-0 rating of UL-94 vertical burning test, non-dripping, 41% of limit oxygen index (LOI) value, low peak heat release rate (PHRR), and total heat release (THR).
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2019
·
IF 3.47
Peng Wang,Lei Chen,Hang Xiao
A novel highly efficient flame retardant with phosphaphenanthrene group and tetrazole ring, 6-(((1H-tetrazol-5-yl)amino)(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]oxaphosphinine 6-oxide (ATZ), was synthesized and incorporated into epoxy matrix as co-curing agent to remarkably improve the flame retardancy of epoxy resin. The curing behaviors of epoxy systems were investigated by non-isothermal differential scanning calorimetry (DSC) tests. The thermal and flame retardant properties of epoxy thermosets were studied by thermogravimetric analysis (TGA), DSC analysis, limiting oxygen index (LOI), UL-94 and cone calorimeter test. Moreover, the flame retardant mechanism was comprehensively investigated by analyzing the thermo-oxidative degradation and pyrolysis behaviors, along with the morphology and structure of residual char of epoxy thermosets. It showed that ATZ could accelerate the crosslinking reaction of epoxy system. The incorporation of ATZ resulted in the decrease of glass transition temperature ( T g ) and initial degradation temperature, while the increase of char yield at high temperature of epoxy thermoset. With the incorporation of 6 wt% ATZ, the thermoset achieved an LOI value of 33.7% and V-0 rating in UL-94 test. Moreover, the peak heat release rate (PHRR) in cone calorimetry test decreased by 26% in comparison with that of neat EP, accompanied with lower total heat release (THR) and total smoke production (TSP). The flame retardant mechanism was ascribed to the barrier effect of intumescent and compact phosphorus-rich char layers with honeycombed cavity structure inside in the condensed phase, and quenching effect of phosphorous radicals and diluting effect of nonflammable gases in the gas phase. The interesting blowing out effect observed during UL-94 test arose from the intensive release of pyrolytic gases with considerable phosphorous radicals and nonflammable gases from the surface of sealed char layers.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）