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1.
Diglycidyl ether of bisphenol fluorene (DGEBF) and 9,9‐bis(4‐aminophenyl) fluorene (BPF) were synthesized to introduce more aromatic structures into an epoxy system, and their chemical structures were characterized with Fourier transform infrared spectroscopy, NMR, and mass spectrometric analysis. The dynamic curing behavior of the DGEBF/BPF system was investigated with differential scanning calorimetry. DGEBF was cured with BPF, diaminodiphenylsulfone (DDS), and diaminodiphenylmethane (DDM), and E‐44 (bisphenol A epoxide) was also cured with BPF for comparison. The thermal properties of the obtained polymers were evaluated with dynamic mechanical thermal analysis and thermogravimetric analysis. The cured DGEBF/BPF system showed a remarkably higher glass‐transition temperature, better thermal stability and lower moisture absorption in comparison with the general bisphenol A epoxy resin/BPF system but approximated the heat resistance of the DGEBF/DDS and DGEBF/DDM systems. Such properties make this epoxy system very promising for heat‐resistant applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

2.
A phosphorus‐containing epoxy resin, 6‐H‐dibenz[c,e][1,2] oxaphosphorin‐6‐[2,5‐bis(oxiranylmethoxy)phenyl]‐6‐oxide (DOPO epoxy resin), was synthesized and cured with phenolic novolac (Ph Nov), 4,4′‐diaminodiphenylsulfone (DDS), or dicyandiamide (DICY). The reactivity of these three curing agents toward DOPO epoxy resin was found in the order of DICY > DDS > Ph Nov. Thermal stability and the weight loss behavior of the cured polymers were studied by TGA. The phosphorus‐containing epoxy resin showed lower weight loss temperature and higher char yield than that of bisphenol‐A based epoxy resin. The high char yields and limiting oxygen index (LOI) values as well as excellent UL‐94 vertical burn test results of DOPO epoxy resin indicated the flame‐retardant effectiveness of phosphorus‐containing epoxy resins. The DOPO epoxy resin was investigated as a reactive flame‐retardant additive in an electronic encapsulation application. Owing to the rigid structure of DOPO and the pendant P group, the resulting phosphorus‐containing encapsulant exhibited better flame retardancy, higher glass transition temperature, and thermal stability than the regular encapsulant containing a brominated epoxy resin. High LOI value and UL‐94 V‐0 rating could be achieved with a phosphorus content of as low as 1.03% (comparable to bromine content of 7.24%) in the cured epoxy, and no fume and toxic gas emission were observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 353–361, 1999  相似文献   

3.
A novel phosphorus‐containing epoxy resin (EPN‐D) was prepared by addition reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) and epoxy phenol‐ formaldehyde novolac resin (EPN). The reaction was monitored by epoxide equivalent weight (EEW) titration, and its structure was confirmed by FTIR and NMR spectra. Halogen‐free epoxy resins containing EPN‐D resin and a nitrogen‐containing epoxy resin (XT resin) were cured with dicyandiamide (DICY) to give new halogen‐free epoxy thermosets. Thermal properties of these thermosets were studied by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), thermal mechanical analyzer (TMA) and thermal‐gravimetric analysis (TGA). They exhibited very high glass transition temperatures (Tgs, 139–175°C from DSC, 138–155°C from TMA and 159–193°C from DMA), high thermal stability with Td,5 wt % over 300°C when the weight ratio of XT/EPN‐D is ≥1. The flame‐retardancy of these thermosets was evaluated by limiting oxygen index (LOI) and UL‐94 vertical test. The thermosets containing isocyanurate and DOPO moieties showed high LOI (32.7–43.7) and could achieve UL‐94 V‐0/V‐1 grade. Isocyanurate and DOPO moieties had an obvious synergistic effect on the improvement of the flame retardancy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

4.
A novel epoxy resin modifier, phosphorus‐containing epoxide siloxane (DPS) with cyclic phosphorus groups in the Si O network, was prepared from the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) with polyhedral‐oligomeric siloxanes, which was synthesized by the sol–gel reaction of 3‐glycidoxypropyltrimethoxysilane. DPS was confirmed by Fourier transform infrared and 29Si NMR measurement, and then was employed to modify epoxy resin at various ratios, with 4,4‐diaminodiphenyl‐methane as a curing agent. In order to make a comparison, DOPO‐containing epoxy resins were also cured under the same conditions. The resulting organic–inorganic hybrid epoxy resins modified with DPS exhibited a high glass transition temperature (Tg), a good thermal stability, and a high limited oxygen index. In addition, the tensile strength of cured products was also rather desirable. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers  相似文献   

5.
A liquid silicon/phosphorus containing flame retardant (DOPO–TVS) was synthesized with 9,10‐dihydro‐9‐oxa‐10‐phosphapheanthrene‐10‐oxid (DOPO) and triethoxyvinylsilane (TVS). Meanwhile, a modified epoxy resin (IPTS–EP) was prepared by grafting isocyanate propyl triethoxysilane (IPTS) to the side chain of bisphenol A epoxy resin (EP) through radical polymerization. Finally, the flame retardant (DOPO–TVS) was incorporated into the modified epoxy resin (IPTS–EP) through sol–gel reaction between the ethyoxyl of the two intermediates to obtain the silicon/phosphorus containing epoxy resin. The molecular structures of DOPO–TVS, IPTS–EP and the final modified epoxy resin were confirmed by FTIR spectra and 1H‐NMR, 31P‐NMR. Thermogravimetric analysis (TGA), differential scanning calorimetry, and limiting oxygen index were conducted to explore the thermal properties and flame retardancy of the synthesized epoxy resin. The thermal behavior and flame retardancy were improved. After heating to 600°C in a tube furnace, the char residue of the modified resin containing 10 wt % DOPO–TVS displayed more stable feature compared to that of pure EP, which was observed both by visual inspection and scanning electron microscope (SEM). Moreover, the mechanical performance testing results exhibited the modified epoxy resins possessed elevated tensile properties and fracture toughness which is supported by SEM observation of the tensile fracture section. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42788.  相似文献   

6.
Diglycidyl ether of 9,9‐bis(4‐hydroxyphenyl) fluorene (DGEBF) was synthesized to introduce more aromatic structures into an epoxy resin system. The structure of DGEBF was characterized with Fourier transform infrared and 1H‐NMR. 4,4′‐Diaminodiphenylmethane (DDM) was used as the curing agent for DGEBF, and differential scanning calorimetry was applied to study the curing kinetics. The glass‐transition temperature of the cured DGEBF/DDM, determined by dynamic mechanical analysis, was 260°C, which was about 100°C higher than that of widely used diglycidyl ether of bisphenol A (DGEBA). Thermogravimetric analysis was used to study the thermal degradation behavior of the cured DGEBF/DDM system: its onset degradation temperature was 370°C, and at 700°C, its char yield was about 27%, whereas that of cured DGEBA/DDM was only 14%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

7.
A new reactive phosphorus‐containing curing agent with imine linkage called 4, 4′‐[1, 3‐phenyl‐bis(9, 10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl)dimethyneimino)]diphenol (2) was synthesized both via two‐pot and one‐pot procedure. The chemical structure of this curing agent was confirmed by FTIR, 1H, 13C, and 31P NMR spectra. A series of thermosetting systems were prepared by using conventional epoxy resins (E51), 4, 4′‐diaminodiphenyl methane (DDM) and (2). Resins with different phosphorus contents were obtained by changing the DDM/(2) molar ratios. Their dynamic mechanical thermal, thermal and flame‐retardant properties were evaluated by dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and limiting oxygen index (LOI), respectively. All samples had a single Tg, which showed that these epoxy resins were homogeneous phase. Both the two char yields under nitrogen and air atmospheres increased with increasing content of (2) and the LOI values increased from 24.5 for standard resin to 37.5 for phosphorus‐containing resin, which indicated that incorporation of (2) could impart good thermal stability and excellent flame retardancy to the conventional epoxy thermosets. POLYM. ENG. SCI., 56:441–447, 2016. © 2016 Society of Plastics Engineers  相似文献   

8.
In this study, bisphenol A epoxy resin (DGEBA) was chemically modified by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), and the molecular structure of the modified epoxy resin was characterized by Fourier transform infrared spectra. The effects of DOPO on liquid oxygen compatibility of DGEBA were calculated using mechanical impact method. The results indicated that epoxy resin (EP‐P1)/4,4‐diaminobisphenol sulfone (DDS) was compatible with liquid oxygen. When compared with EP/DDS, differential scanning calorimetry and thermogravimetry analyses showed that EP‐P1/DDS and EP‐P2/DDS had much higher glass transition temperatures and char yield. X‐ray photoelectron spectroscopic analysis suggested that phosphorus atoms on the surface of EP‐P1/DDS and EP‐P2/DDS could act in the solid phase to restrain the incompatible reaction, which was in accordance with the flame‐retardant mechanism of phosphorus‐containing compounds. The compatibility mechanism of EP‐P1/DDS was further proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40848.  相似文献   

9.
In an attempt to improve thermal and flame‐retardant properties of epoxy resins efficiently, a new reactive phosphorus‐containing curing agent called 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl‐(phenylimino)‐(4‐hydroxyphenyl)me‐thane (DOPO‐PHM) was synthesized and was combined with 4,4′‐diaminodiphenyl methane (DDM) to co‐cure epoxy resins (E51), which covalently incorporated halogen‐free DOPO organ groups into the epoxy networks. The chemical structure of this curing agent was confirmed by FTIR, 1D, and 2D NMR spectra. A reaction mechanism during the preparation was proposed, and the electron effect on the stabilization of the carbocation was discussed. Various DDM/DOPO‐PHM molar ratios were used to get the materials with different phosphorus contents. Their dynamic mechanical, thermal, and flame‐retardant properties were evaluated by dynamic mechanical thermal analysis, thermogravimetric analysis, and limiting oxygen index (LOI) respectively. All samples had a single Tg, showing that these epoxy resins were homogeneous phase for long‐term use in spite of adding DOPO‐PHM. Both char yields (under nitrogen and air atmospheres) increased with the increasing of phosphorus content and the LOI values increased from 24.5 for standard resin to 33.5 for phosphorus‐containing resins, indicating the significant enhancement of thermal stability and flame retardancy. POLYM. ENG. SCI., 54:1192–1200, 2014. © 2013 Society of Plastics Engineers  相似文献   

10.
Polymethyl(3‐glycidyloxypropyl)siloxane (PMGS) was synthesized as a flame‐retardant additive, which were cocured with diglycidyl ether of bisphenol‐A (DGEBA) using 4,4′‐diaminodiphenylsulfone as a curing agent. The structure of PMGS was confirmed through Fourier transform infrared and 1H‐NMR spectra. The cured products were characterized with dynamic mechanical thermal analysis, thermogravimetric analysis, and oxygen index analyzer. With PMGS incorporated, the cured epoxy resin showed better thermal stability, higher limited oxygen index, and higher char yield. At moderate loading of PMGS, the storage modulus and glass transition temperature of the cured epoxy resin based on neat DGEBA were obviously improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

11.
Novel phosphorus‐containing binaphthyl epoxy DGEBN (diglycidyl ether of 2,2′‐hydroxy‐1,1′‐binaphthalene) with high thermal performance was obtained from the addition reaction of DGEBN and diethyl phosphite. The modified binaphthyl epoxy was characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopy. The dynamic mechanical property of the cured epoxy polymer was investigated by dynamic mechanical thermal analysis. The result revealed that the cured polymer with lower phosphorus content displayed higher value of the storage modulus when the networks reached rubbery state (above the glass transition temperature Tg). The Tgs decreased slightly with increasing phosphorous content. The thermal degradation was studied with thermogravimetric analysis and the evolved gas was analyzed using thermogravimetric analysis/Fourier transform infrared technique. The influence of phosphorus content and the chemical structure on the degradation behavior was discussed. The P‐modified binaphthyl epoxy polymers exhibited higher thermal stability than the P‐modified diglycidyl ether of bisphenol A polymer. Flammability measurements were performed by the examination of limited oxygen index and UL‐94 test. Compared with unmodified DGEBN, P‐containing epoxy polymers displayed higher limited oxygen index values and exhibited better flame retardance. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers  相似文献   

12.
A novel phosphorus‐ and silica‐containing hybrid (DPS) was synthesized by the reaction between diethyl phosphate (DEP) and polyhedral oligomeric siloxanes (POS) formed by hydrolysis condensation of 3‐glycidoxypropyltrimethoxysilane (GPTMS). The novel phosphorus‐ and silica‐containing hybrid was characterized by the flourier transform infrared spectroscope (FT‐IR), silicon nuclear magnetic resonance, and gel permeation chromatography (GPC). Then, the determination of the activation of the reaction between epoxy resin and phosphorus‐, and silica‐containing hybrids was studied by differential scanning calorimeter (DSC). In the presence of catalyst, the activation energies of the curing reaction were 63.3 and 66.7 kJ/mol calculated by Kissinger model and Ozawa model respectively. The thermal and flame retardant properties of the cured epoxy modified by DPS were determined by differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA), and limited oxygen index (LOI). The results revealed that those properties were improved in comparison with unmodified epoxy resin. In addition, scanning electron microscopy (SEM) was used to investigate the morphology of the cured epoxy resin modified by DPS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

13.
Curing kinetics and properties of epoxy resin-fluorenyl diamine systems   总被引:1,自引:0,他引:1  
Wenbin Liu  Qihao Qiu  Zichun Huo 《Polymer》2008,49(20):4399-4405
Diglycidyl ether of bisphenol fluorene (DGEBF), 9,9-bis-(4-aminophenyl)-fluorene (BPF) and 9,9-bis-(3-methyl-4-aminophenyl)-fluorene (BMAPF) were synthesized to introduce more aromatic structures into the epoxy systems, and their chemical structures were characterized with FTIR, NMR and MS analyses. The curing kinetics of fluorenyl diamines with different epoxy resins including DGEBF, cycloaliphatic epoxy resin (TDE-85) and diglycidyl ether of bisphenol A (DGEBA) was investigated using non-isothermal differential scanning calorimetry (DSC), and determined by Kissinger, Ozawa and Crane methods. The thermal properties of obtained polymers were evaluated with dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The results show that the values of activation energy (Ea) are strongly dependent on the structures of epoxy resin and curing agent. The curing reactivity of epoxy system is restrained by the introduction of rigid fluorene into chain backbone and flexible methyl into side groups. The cured DGEBF/fluorenyl diamine systems exhibit remarkably higher glass transition temperature, better thermal stability and lower moisture absorption compared to those of DGEBA/fluorenyl diamine systems, and display approximate heat resistance and much better moisture resistance relative to those of TDE-85/fluorenyl diamine systems.  相似文献   

14.
In the present work, the hexabromocyclododecane and the antimony trioxide were introduced into the bisphenol A epoxy resin to improve its flame retardancy. The effects of hexabromocyclododecane and antimony trioxide on flame retardancy of bisphenol A epoxy resin were estimated according to ASTM D2512-95 (2008). The specimen cured by T-31, with the addition of hexabromocyclododecane, did not show any flash and explosion during the 20 times of mechanical impact, whereas slightly empyreumatic scent was detected. The explosion was observed for the other specimens. The resin particles on the surface of the specimen after the mechanical impact were more than that before the mechanical impact, which was attributed presumably to the mechanical impact at the low temperature resulted in the crushing of the resin materials. It also indicated that bisphenol A epoxy resin cured by 593 with antimony trioxide at the low temperature had low flexibility. The XPS analysis confirmed that the surface of the specimen observed explosion was readily reacted with liquid oxygen. The O/C ratios of the specimen cured by T-31, with the addition of hexabromocyclododecane, before and after the mechanical impact were statistically approximate to 0.223 and 0.238, respectively, which revealed that the specimen was compatible with liquid oxygen.  相似文献   

15.
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   

16.
The results of flame retardance and thermal stability of a reactively modified organo‐phosphorus diglycidylether of bisphenol‐A and an organo‐phosphorus tetraglycidyl diaminodiphenylmethane are reported here. The organo‐phosphorus epoxy resins were synthesized by the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and diglycidyl ether of bisphenol‐A and tetraglycidyl diaminodiphenylmethane, respectively, and then cured with a mixture of 3,5‐diethyltoluene‐2,4‐diamine and 3,5‐diethyltoluene‐2,6‐diamine. In addition to this, between 5 and 7.5% of organically modified polymeric layered silicate nano‐clay was also added to neat epoxy resin or to the phosphorus‐modified epoxy resin to investigate any synergies, or otherwise, a combination of clay and phosphorus on the flame, degradation, and thermal properties are also reported. The reaction kinetics of phosphorus‐modified and epoxy cure were studied by FTIR, 1H‐NMR, and DSC. Thermal properties and morphology of the final product were analyzed by thermogravimetric analysis, dynamic mechanical thermal analysis, X‐ray diffraction, and cone calorimetry. Improvement in flame retardance by cone calorimetry was demonstrated by the addition of only 3% phosphorus or 7.5% clay into the epoxy compared with unmodified epoxy resins, whereas no evidence of synergy for a phosphorus and clay combination was found. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1233–1253, 2004  相似文献   

17.
A simple imide compound, 4‐amino‐phthalimide (APH), was synthesized as a curing agent for epoxy resin. APH was prepared from the hydration of 4‐nitro‐phthalimide, which was prepared from the nitration of phthalimide. The chemical structure of APH was verified by IR and 1H‐NMR spectra. The thermal properties and dielectric constant (ε) of a phosphorus‐containing novolac epoxy resin cured by APH were determined and compared with those of epoxy resins cured by either 4,4′‐diamino diphenyl methane (DDM) or 4,4′‐diamino diphenyl sulfone (DDS). The results indicate that the epoxy resin cured by APH showed better thermal stability and a lower ε than the polymer cured by either DDM or DDS. This was due to the introduction of the imide group of APH into the polymer structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

18.
The effects of functionalized multi‐walled carbon nanotubes (MWCNTs) on thermal and chemorheological behaviors of an epoxy‐based nanocomposite system were investigated. Chemical functionalization of MWCNTs by acid modification (A‐MWCNTs) and chemical amidation (D‐MWCNTs) was confirmed using Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found that the D‐MWCNTs had a significant effect on the chemorheological behaviors of the epoxy‐based nanocomposite. Compared to the epoxy/A‐MWCNT nanocomposite, the epoxy/D‐MWCNTs nanocomposite showed a significant increase in gel time, as obtained from isothermal rheology measurements. Also, the storage modulus of the diglycidylether of bisphenol F (DGEBF)/D‐MWCNTs nanocomposite was higher than that of the DGEBF/D‐MWCNTs nanocomposite and gradually increased with an increase of frequency. This could be interpreted by the relatively strongly interconnected structure of the D‐MWCNTs in the DGEBF epoxy resin, which arises from the functionalized alkyl groups of the D‐MWCNTs in dispersion phases with the DGEBF epoxy resin. Copyright © 2012 Society of Chemical Industry  相似文献   

19.
将玉米秸秆木质素与双酚A环氧树脂混合,于100℃下预处理1 h,以改善环氧树脂的性能。对预处理后环氧树脂的黏度进行了测试,对改性环氧树脂与聚酰胺固化后材料的力学性能、动态力学性能、热稳定性以及燃烧性能进行了综合测试,考察了不同质量分数的玉米秸秆木质素对改性环氧树脂性能的影响。结果表明:以固化体系的总质量为基准,在w(木质素)=0~7%的范围内,与未添加木质素的环氧树脂相比,随着木质素质量分数的增加,改性环氧树脂22℃下的黏度从1 220 m Pa·s增大到13 220 m Pa·s;改性环氧树脂固化物的弯曲强度随木质素质量分数的增加先升高后降低,在w(木质素)=3%时达到最大值83.2 MPa,但其冲击强度下降,由20.7 MPa降低为13.6 MPa;改性环氧树脂固化物的玻璃化转变温度(Tg)随木质素质量分数的增加而增加,w(木质素)=5%时Tg提高了4.8℃;改性环氧树脂固化物的热稳定性有所改善,w(木质素)=7%时热失重50%的温度提高13℃,同时木质素的加入能够改善环氧树脂的阻燃性能。  相似文献   

20.
以9,9-双[4-4-氨基苯氧基苯基]芴(BAOFL)作为固化剂,采用非等温DSC技术,研究了BAOFL/环氧树脂(E-51、TDE-85和芴基环氧树脂)体系的固化反应动力学,利用动态热机械分析仪(DMA)和热重分析仪(TGA)测试了固化树脂的力学性能和热稳定性。结果表明,固化反应活化能与环氧树脂和固化剂的结构密切相关,芳醚的引入提高了氨基与环氧基的反应性,固化树脂呈现出优良的热性能和力学性能,其玻璃化转变温度(T)达到206~248℃,贮能模量为2.54~2.94 GPa,初始热分解温度312~375℃,700℃g时的残炭率达到15.2%~31.7%。()  相似文献   

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