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1.
To obtain a more efficient flame‐retardant system, the extra‐triazine‐rich compound melamine cyanurate (MCA) was coworked with tri(3‐9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide‐2‐hydroxypropan‐1‐yl)?1,3,5‐triazine‐2,4,6‐trione (TGIC–DOPO) in epoxy thermosets; these were composed of diglycidyl ether of bisphenol A (DGEBA) epoxy resin and 4,4′‐diaminodiphenyl methane (DDM). The flame‐retardant properties were investigated by limited oxygen index measurement, vertical burning testing, and cone calorimeter testing. In contrast to the DGEBA/DDM (EP for short) thermoset with a single TGIC–DOPO, a better flame retardancy was obtained with TGIC–DOPO/MCA/EP. The 3% TGIC–DOPO/2% MCA/EP thermoset showed a lower peak heat‐release rate value, a lower effective heat of combustion value, fewer total smoke products, and lower total yields of carbon monoxide and carbon dioxide in comparison with 3% TGIC–DOPO/EP. The results reveal that MCA and TGIC–DOPO worked jointly in flame‐retardant thermosets. The dilution effect of MCA, the quenching effect of TGIC–DOPO, and their joint action inhibited the combustion intensity and imposed a better flame‐retardant effect in the gas phase. The 3% TGIC–DOPO/2% MCA/EP thermoset also exhibited an increased residue yield, and more compositions with triazine rings were locked in the residues; this implied that MCA/TGIC–DOPO worked jointly in the condensed phase and promoted thermoset charring. The results reveal the better flame‐retardant effect of the MCA/TGIC–DOPO system in the condensed phase. Therefore, the joint incorporation of MCA and TGIC–DOPO into the EP thermosets increased the flame‐retardant effects in both the condensed and gas phases during combustion. This implied that the adjustment to the group ratio in the flame‐retardant group system endowed the EP thermoset with better flame retardancy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43241.  相似文献   

2.
A P/N-containing flame retardant (PPT) constructed by phosphaphenanthrene, phosphonate, and triazole groups was successfully synthesized and used as a reactive co-curing agent for epoxy resin (EP). The curing behavior, thermal property, combustion behavior, and flame retardant mechanism of EP thermosets were comprehensively investigated. According to the analysis of DSC and TGA, PPT accelerated the crosslinking reaction and enhanced the charring ability for EP thermosets at high temperature. The results of combustion test indicated that PPT endowed epoxy thermoset with outstanding flame retardancy. When the phosphorus content was 0.71 wt%, EP/DDS/PPT-2 achieved a LOI value of 33.2% and passed V-0 rating in UL-94 test, and its peak heat release rate and total heat release were decreased by 63.7 and 30.5%, respectively, relative to EP/DDS. Moreover, the FIGRA of EP/DDS/PPT-2 was reduced from 9.7 to 3.5 kW m−2 s−1, manifesting the significantly improved fire safety of EP thermoset. The flame retardant mechanism was summarized as two parts: (a) the barrier effect of continuous phosphorus-rich char layers in condensed phase, (b) the quenching effect of phosphorous radicals and diluting effect of nonflammable gases in gaseous phase.  相似文献   

3.
A novel functionalized graphene oxide (f‐GO) decorated with phosphorus/nitrogen (P/N)‐containing molecules is fabricated using a facile water‐based procedure. The chemical structure and micro‐morphology are well characterized by a combination of experimental and theoretical methods. Reactive force field‐based molecular dynamics simulations reveal at the atomic level that the GO sheets are successfully functionalized with P‐N flame‐retardant molecules by means of hydrogen bonds. Subsequently, f‐GO with extremely low loading is introduced into epoxy resin (EP) for reducing its flammability. Thermogravimetric analysis suggests that f‐GO significantly reduces the maximum mass loss rate of EP and enhances the char‐yield during heating. Combined with the results of a microscale combustion calorimeter and limiting oxygen index, EP/f‐GO2 shows better flame retardancy than the other nanocomposites. Furthermore, the presence of 2 wt% f‐GO substantially reduces the fire hazard of EP, resulting in 29.3% decline in the peak heat release rate, as well as 73% and 65% reduction in total smoke production and rate of smoke release, respectively, according to cone calorimetric tests. Based on the analyses of the char layers, f‐GO is determined to promote the formation of a more protective phosphorus‐containing char barrier for EP during combustion, indicating an effective condensed phase flame‐retardant mechanism.  相似文献   

4.
三聚氰胺包覆聚磷酸铵阻燃环氧树脂的研究   总被引:1,自引:0,他引:1  
研究了三聚氰胺包覆聚磷酸铵(MPP)与季戊四醇(PER)阻燃环氧树脂的燃烧性能。通过热重分析初步探讨了MPP/PER阻燃剂对环氧树脂的阻燃机理。结果表明:MPP/PER对环氧树脂具有很好的阻燃作用,能有效提高环氧树脂的氧指数和垂直燃烧性能,降低环氧树脂的热释放速率,使燃烧过程变得稳定,降低环氧树脂的火灾危险性。热重分析表明:添加了阻燃剂以后,环氧树脂的初始分解温度降低,残炭量显著增加,阻燃剂发挥了凝聚相阻燃的作用。  相似文献   

5.
To obtain epoxy resins with satisfactory thermal, flame retardant, and mechanical properties, a novel multi‐element synergistic flame retardant (PPVSZ) is synthesized through the reaction between P? H of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and C?C of polysilazane (PVSZ) and utilized as a multi‐element synergistic flame retardant for epoxy resins. The flame retardant mechanism is explored by XPS and SEM, confirming that the excellent flame‐retardance efficiency owes itself to an optimal flame retardant way which jointly exerts the flame‐retardant effects in the gaseous and condensed phase. The thermal properties deduced from DSC, TGA, and DMA, indicate the glass transition temperature, maximum weight loss rate, and char yields at 700 °C for EP‐2 increase by about 5.0 °C, 8.4 °C and 8.8%, respectively. Furthermore, mechanical properties such as impact strength, tensile strength, and flexural strength are also increased by 45.38%, 14.16%, and 17.43%, respectively, which show that the incorporation of PPVSZ does not deteriorate the mechanical properties of modified resin. All the results demonstrate that epoxy resins modified by PPVSZ not only have good effect on the flame retardance, but also have good improvement on thermal and mechanical properties, indicating the potential for applications in many fields requiring fire safety.  相似文献   

6.
The combination of gas‐phase and condensed‐phase action will contribute to high quality flame retardant. A novel 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO)‐based flame retardant (DOPO‐DOPC), which contains carbon source was synthesized in favor of conducting the effect of gas‐phase as well as promoting the char formation in condensed‐phase. The chemical structure of DOPO‐DOPC was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). DOPO–DOPC was used as an additive in poly(ethylene terephthalate) (PET) and epoxy resin (EP). The flame retardancy of PET/DOPO‐DOPC and EP/DOPO‐DOPC composites were studied by limiting oxygen index (LOI) and UL‐94 test. The results showed that the incorporation of DOPO–DOPC into PET or EP could obviously improve their flame retardancy. The LOI values of modified PET or EP, which contained 10 wt % DOPO‐DOPC reached 42.8 and 31.7%, respectively. The thermogravimetric analysis (TGA) results revealed that DOPO–DOPC enhanced the formation of char residues. The Laser Raman spectroscopy (LRS) was used to investigate the carbon structure of thermal oxidation residues. Because of the combination of the gas phase flame retardant effect of DOPO moiety and the promoting formation of char residues in condensed phase, the PET and EP composites exhibited significant improvement toward flame retardancy. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44639.  相似文献   

7.
以来自自然界储量第二的木质素作为膨胀型阻燃剂的基体,通过接枝氮、磷元素成功合成碳源、酸源、气源三位一体的木质素基膨胀型阻燃剂(Lig-T),实现了良好的阻燃性能。将Lig?T按照不同含量添加到环氧树脂(EP)中制备EP/Lig-T复合材料,以锥形量热测试考察复合材料的热稳定性能和阻燃性能,并重点考察复合材料在接近真实火灾事故时的热释放和烟释放规律。结果表明,当Lig-T含量为20 %(质量分数,下同)时,复合材料的热释放速率峰值为1 374 kW/m2、热释放总量为41.63 MJ/m2、烟释放总量为1 634 m2/m2,与EP参比试样的数值相比,均呈现下降的趋势,燃烧结束的残炭率从4.26 %增至10.01 %。基于气相和凝聚相的协效阻燃机理,木质素作为膨胀型阻燃剂的碳源使得复合材料在高温条件下具备更好的成炭效果,在燃烧过程中形成稳定且致密的炭层结构,在实现高效阻燃的同时减少有毒烟气的释放,降低火灾的危害。  相似文献   

8.
A novel technology was developed to prepare microencapsulated red phosphorus (RP) with a coating of melamine cyanurate (MCA) serving as both a nitrogen‐containing flame retardant and as a solid lubrication agent. We took advantage of the self‐thickening effects during the MCA self‐assembly process to realize effective encapsulation on the surface of predispersed RP powder. The technology described in this article can overcome several drawbacks of current microencapsulation processes including (1) relatively complicated preparation processes, (2) use of formaldehyde or other noxious modifiers, and (3) poor compatibility with flame retardant fillers and polymer matrix resulting in poor physical properties. Additionally, this novel technology can also modify various properties of RP with regard to lubrication performance, ignition point, moisture absorption ratio, and color. As a composite system of flame retardant phosphorus encapsulated by a nitrogen‐containing flame retardant, the microencapsulated RP showed nitrogen‐phosphorus (N‐P) synergism with further improved flame retardancy. The action and mechanisms of the microencapsulated RP flame retardant polyamide 6 (PA6) were investigated by limiting oxygen index, vertical burning experiment (UL94), thermogravimetric analysis, and scanning electron microscope observations. The results indicated that the flame retardant PA6 possessed desired flame retardancy because of effective char‐formation of the condensed phase and it also showed satisfactory mechanical properties as the result of the good compatibility between flame retardant and PA6 resin. POLYM. ENG. SCI., 46:1548–1553, 2006. © 2006 Society of Plastics Engineers  相似文献   

9.
Microcapsulated red phosphorus (MRP), with a melamine–formaldehyde resin coating layer, was prepared by two‐step coating processes. The physical and chemical properties of MRP were characterized by Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) and other measurements. The flame retardant action and mechanism of MRP in the halogen‐free flame retardant (HFFR) polyolefins (PO) blends have been studied using cone calorimeter, limiting oxygen index (LOI), thermogravimetric analysis (TGA) and dynamic FTIR spectroscopy. The results show that the MRP, which is coated with melamine–formaldehyde resin, has a higher ignition point, a considerably lower amount of phosphine evolution and of water absorption compared with red phosphorus (RP) itself. The data observed by cone calorimeter, LOI and TGA measurements from the PO/HFFR blends demonstrated that the MRP can decrease the heat release rate and effective heat of combustion, and increase the thermostability and LOI values of PO materials. The dynamic FTIR results revealed the flame‐retardant mechanism that RP can promote the formation of charred layers with the P–O and P–C complexes in the condensed phase during burning of polymer materials. Copyright © 2003 Society of Chemical Industry  相似文献   

10.
In this article, a novel flame retardant (coded as BNP) was successfully synthesized through the addition reaction between triglycidyl isocyanurate, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and phenylboronic acid. BNP was blended with diglycidyl ether of bisphenol‐A to prepare flame‐retardant epoxy resin (EP). Thermal properties, flame retardancy, and combustion behavior of the cured EP were studied by thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the flame retardancy and smoke suppressing properties of EP/BNP thermosets were significantly enhanced. The LOI value of EP/BNP‐3 thermoset was increased to 32.5% and the sample achieved UL94 V‐0 rating. Compared with the neat EP sample, the peak of heat release rate, average of heat release rate, total heat release, and total smoke production of EP/BNP thermosets were decreased by 58.2%–66.9%, 27.1%–37.9%, 25.8%–41.8%, and 21.3%–41.7%, respectively. The char yields of EP/BNP thermosets were increased by 46.8%–88.4%. The BNP decomposed to produce free radicals with quenching effect and enhanced the charring ability of EP matrix. The multifunctional groups of BNP with flame retardant effects in both gaseous and condensed phases were responsible for the excellent flame retardancy of the EP/BNP thermosets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45291.  相似文献   

11.
Phosphorus-containing flame retardant (HBAEA-DOPO) for epoxy resin was synthesized by addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with bis[2-(4-hydroxybenzylideneamino)ethyl]amine (HBAEA) that was synthesized via 4-hydroxybenzaldehyde with diethylenetriamine. HBAEA-DOPO was mixed with 4,4′-diaminodiphenyl sulfone to co-cure the epoxy resin of diglycidyl ether bisphenol A. The silane modified nano-silica (nano-SiO2) was used to reinforce the epoxy resin. Thermal stability and dynamic mechanical properties of the cured epoxy materials were studied with the use of thermogravimetric analysis and dynamic mechanical thermal analysis. Flame retardance and burning behavior were evaluated by the limiting oxygen index (LOI), vertical burning test, and the cone calorimetry. The cured epoxy materials have excellent thermal stability, and the temperatures at the maximum weight loss rate are over 384.0°C. The characteristic temperature corresponding to 5.00 wt% of thermal decomposition reaches 341.5°C as 1.00 wt% of phosphorus content is loaded. Flame retardant grade meets the V-0 level. The fire residue mass gradually increases with HBAEA-DOPO and nano-SiO2. The characteristics of high flame retardance and smoke suppression of HBAEA-DOPO and nano-SiO2 on the cured epoxy composites have been demonstrated to be related to char formation and intumescent flame retardance in the condensed phase.  相似文献   

12.
An efficient flame retardant (1,4‐methylenephenylphosphinic acid) piperazine (MPPAP) is successfully synthesized. The application of MPPAP in epoxy (EP) thermosets increases limited oxygen index values of composites to 30.2% and 6 wt% or more loading makes the materials get through UL94 V‐0 rating. The investigation of the combustion process indicates that MPPAP clearly changes the combustion behavior of EP composites, forms a char layer on the surface of the composites, and presents an effective flame inhibition effect, consequently resulting in clear reduction of the flammability and smoke production. The thermal degradation process of MPPAP/EP indicates that MPPAP promotes the matrix to decompose earlier and increases the char‐forming ability of composites. The morphology and structure of the final char shows MPPAP can promote the formation of cross‐linking structures and increase the graphitization degree of char residues acting as an excellent barrier. Furthermore, the flame‐retardant mechanism illuminates that MPPAP can reduce the generation of volatile fuels, and the pyrolysis products of MPPAP contain PO and PO2, which exert free radical quenching effect in the gas phase. Therefore, MPPAP is a terrific flame retardant for epoxy thermosets which manifests a flame retarding action in the gas phase and condensed phase.  相似文献   

13.
Ultrafine dispersion of flame retardants in polymer matrices favors improving the performance of flame‐retardant polymers, but is still a challenge on most occasions. In the present research, an efficient method was employed to realize satisfactory dispersion of a nitrogen flame retardant, melamine cyanurate (MCA), in epoxy resin (EP) composites, and meanwhile integrated the synthesis of MCA with the preparation of the flame‐retardant composites. In the conventional technology, EP pre‐polymer glue with added MCA powder (synthesized in water, then dried and pulverized) is used to coat glass fabrics, which are compressed into laminated boards. Here, MCA was synthesized in a good solvent for EP, and then EP pre‐polymer was directly dissolved in the MCA suspension to obtain the in situ synthesized flame‐retardant glue. In this way, MCA could keep perfect dispersion whether in the glue or cured resin. Compared with the conventional addition system easily resulting in the aggregation of MCA particles, the in situ synthesized MCA flame‐retardant system exhibited much better stability of the coating glue, and markedly improved flame retardancy and mechanical properties. © 2016 Society of Chemical Industry  相似文献   

14.
A phosphorus/silicon flame retardant, MVC‐DOPO, was synthesized from 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and 2,4,6,8‐tetra‐methyl‐2,4,6,8‐tetra‐vinyl‐cyclo‐tetrasiloxane (MVC) via addition reaction. Its flame‐retardant effect on polycarbonate (PC) was investigated. The phosphorus/silicon flame retardant increased the limited oxygen index and UL‐94 rating and reduced the heat release rate and total heat release of DOPO‐MVC/PC composites during combustion, indicating the excellent flame‐retardant effect of MVC‐DOPO on PC. MVC‐DOPO inhibited the burning intensity of PC material in the gaseous phase and promoted the formation of a more viscous residue in the condensed phase. Through releasing phosphorus‐containing pieces and phenoxy radicals from the phosphaphenanthrene group, MVC‐DOPO quenched the combustion chain reaction in the gaseous phase; through promoting formation of a more viscous residue and a dense char layer from the main actions of the cyclotetrasiloxane group, MVC‐DOPO reduced fuel release and generated a barrier effect in the condensed phase. Hence, MVC‐DOPO effectively exerted a flame‐retardant effect on PC material in both the gaseous and condensed phases during combustion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45815.  相似文献   

15.
A novel phosphorus/nitrogen-containing flame retardant (DOPO-AM) was synthesized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and acrylamide (AM) and its chemical structure was characterized. DOPO-AM was added into diglycidyl ether of bisphenol-A (DGEBA) with curing agent m-xylylenediamine (MXDA)to prepare flame retarded epoxy resin to reduce the possibility of fire. The compounds with different valences sulfur respectively replace partial DGEBA resin to study the effects of sulfur valences on the flame retardance of epoxy resins. The results indicated that DOPO-AM had excellent flame retardance for epoxy resin. When phosphorus content was only 0.75%, DGEBS resin containing DOPO-AM achieved the limiting oxygen index value of 34.55% and vertical burning test (UL-94) V-0 rating. Although sulfur element is help for refractive index of epoxy resin, sulfur element in three kinds of valences all weaken the flame retardant of epoxy resin. Improving phosphorus content is help for the synergistic effect of P N and P N S. Moreover, the flame retardance is not proportional to sulfur valence, sulfide with +2 valence had the best flame retardance. However, +6 valence sulfonic with strong oxidation effect worsen the flame retardant. Simultaneous thermal analysis of thermogravimetric analyzer and differential scanning calorimeter and scanning electronic microscopy photographs verified the above conclusion.  相似文献   

16.
By curing the reaction mixture of diphenylphosphine oxide (DPO) and diglycidyl ether of bisphenol A with 4,4′‐diaminodiphenylsulfone, flame‐retardant epoxy resins (EP/DPO) were prepared. Flame‐retardant epoxy resins modified with 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) were similarly prepared (denoted as EP/DOPO). The limiting oxygen index value of pure epoxy resin, EP/DPO–P‐0.9 (with a phosphorus content of 0.9 wt%), and EP/DOPO–P‐0.9 are 23.0, 30.5, and 29.4%, respectively. EP/DPO–P‐0.9 reached a UL‐94 vertical burning test V‐0 rating, while EP/DOPO–P‐0.9 failed. The results of the cone calorimetry test, thermo‐oxidative degradation behavior study, and pyrolysis‐gas chromatography/mass spectrometry analysis indicated that both flame retardants mainly act through the gas‐phase activity mechanism. Together, the results of this study suggest that EP/DPO are high performance resins with good thermal stability, high glass transition temperature, and low water absorptivity for practical applications.  相似文献   

17.
A siloxane compound (MVC) and a bi‐group phosphaphenanthrene/triazine compound (TGD) were employed in epoxy thermosets to explore high‐efficiency flame retardant systems. With only 1 wt% MVC and 3 wt% TGD, an epoxy thermoset passed UL 94 V‐0 rating test and achieved a limiting oxygen index value of 34.0%, exhibiting an excellent flame retardant effect. The MVC/TGD system not only decreased the peak value of heat release rate and effective heat of combustion but also imparted an improved charring ability to thermosets, thereby outstandingly reducing the flammability of 1%MVC/3%TGD/EP. Compared with the fire performance of 4%TGD/EP and 4%MVC/EP, the MVC/TGD system showed an obvious flame retardant synergistic effect, mainly depending on the general improvement of flame inhibition, charring and barrier effects of the thermoset during combustion. Evolved gas analysis combined with condensed‐phase pyrolysis product analysis jointly revealed the details of the changed pyrolysis mode. © 2017 Society of Chemical Industry  相似文献   

18.
The action of metals on the flame retardancy of thermoplastic has aroused much interest in recent years. However, their action on thermosets is still not clear. In this work, metal‐phosphorus hybridized nanomaterials with different metal centers were prepared via hydrothermal reaction between metal hydroxide/salts with phosphinic/phosphonic acids. The loading of these hybrids in epoxy (EP) resins resulted in great change on fire resistance. Thermogravimetric analysis, solid and gas phase analysis results indicated that the flame retardant action of the hybrids perhaps didn't take place following the conventional models in condensed and gas phase. It was found that the flame retardancy was greatly correlated with the action of metal centers with EP resin, which resulted in the formation of metal‐oxygen bonds and the delayed release of flammable compounds from EP resin. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45445.  相似文献   

19.
使用无卤磷系阻燃剂二乙基次膦酸铝(ADP)和氮系阻燃剂三聚氰胺氰尿酸盐(MCA)作为阻燃剂,马来酸酐接枝聚烯烃弹性体(POE-g-MAH)为增韧剂,对聚对苯二甲酸丙二酯(PTT)进行阻燃改性,分别研究两种不同体系阻燃剂对PTT阻燃性能和力学性能的影响,并通过热失重(TG)分析仪、差示扫描量热(DSC)仪,扫描电子显微镜(SEM)对其阻燃机理进行研究。实验结果表明,添加质量分数10%的ADP时,阻燃PTT达到V–0级,极限氧指数(LOI)达到30.0%,ADP主要在凝聚相中发挥阻燃作用;添加质量分数20%的MCA时,阻燃PTT达到V–0级,LOI达到24.9%,MCA主要在气相中发挥阻燃作用;ADP与MCA的加入都降低了阻燃PTT的综合力学性能。TG和DSC测试结果说明,ADP与PTT间的相容性良好,可以有效地促进PTT成炭并提高材料的阻燃性能;MCA与PTT间的相容性较差,且MCA对PTT成炭没有影响。添加质量分数5%的ADP和10%的MCA时,阻燃PTT达到V–0级,LOI达到26.9%,说明ADP与MCA具有协效阻燃作用。  相似文献   

20.
磷氮复配无卤阻燃聚苯醚合金的研究   总被引:1,自引:0,他引:1  
采用固体阻燃剂间苯二酚双[二(2,6-二甲苯基)磷酸酯](RXP)及其与三聚氰胺氰脲酸盐(MCA)的复配阻燃剂,制备了无卤阻燃聚苯醚/高抗冲聚苯乙烯/苯乙烯-丁二烯-苯乙烯热塑性弹性体(PPE/PS-HI/SBS)合金,通过氧指数、水平垂直燃烧、扫描电子显微镜、力学性能等测试分析方法,考察了PPE/PS-HL/SBS合...  相似文献   

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