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Effect of Hyperbranched Polyester on Modification of Epoxy Resins Cured with Anhydride 被引量:1
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作者 Xiu Xia WANG Zhi Gang JIANG Yi Feng ZHANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第1期125-128,共4页
The synthesis and characterization of hyperbranched polyester (HBP) with different molecular weight are studied. The effect of HBP on the modification of epoxy resins cured with anhydride is mainly discussed. The ch... The synthesis and characterization of hyperbranched polyester (HBP) with different molecular weight are studied. The effect of HBP on the modification of epoxy resins cured with anhydride is mainly discussed. The characteristics of HBP and the morphologies of cured system are determined by nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and scanning electron microscope (SEM). The impact strength of cured system is detected and Fourier transform infrared (FTIR) measurements were used to pursue the curing process. The investigation shows that HBP can improve the toughness by forming copolymer networks between epoxy resins, HBP and anhydride. Moreover, when the molecular weight of HBP is 1342g/mol the toughening effect is the best, and the changes of toughness are small with the increase of molecular weight of HBP to 3500 g/mol. 展开更多
关键词 Hyperbranched polyester epoxy resins MODIFICATION toughness.
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ULTRASONIC BEHAVIOR OF EPOXY RESINS/POLY (ETHYLENE OXIDE) BLENDS CURED WITH PHTHALIC ANHYDRIDE
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作者 郑思珣 王海千 +4 位作者 罗筱烈 张乃斌 马德柱 朱长飞 胡建恺 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第1期20-27,共8页
By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found... By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased. 展开更多
关键词 Pulse-echo method Ultrasonic velocity Attenuation coefficient (α) epoxy resins /poly (ethylene oxide)blends Crosslinking network
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COMPARISON OF THE E44 EPOXY RESINS IN DIFFERENT CONTENTS OF CURING AGENT BY MICROWAVE AND THERMAL CURING METHODS 被引量:2
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作者 周健 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2000年第2期35-39,共5页
This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent. The technology of microwave curing E44 epoxy resins is inves... This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent. The technology of microwave curing E44 epoxy resins is investigated, the mechanical properties of cured epoxy resin samples in different contents of curing agent by microwave and thermal curing methods are measured respectively, and then some experimental results for which are obtained. At last, this paper analyses why microwave curing can improve mechanical property of epoxy resin. 展开更多
关键词 microwave curing thermal curing epoxy resin mechanical property
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Mechanical properties of short carbon/glass fiber reinforced high mechanical performance epoxy resins 被引量:1
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作者 张竞 黄培 《Journal of Chongqing University》 CAS 2009年第4期222-230,共9页
To research the relationship between epoxy and fiber inherent property and mechanical properties of composite,we prepared a series of composites using three kinds of high mechanical performance epoxy resins as matrice... To research the relationship between epoxy and fiber inherent property and mechanical properties of composite,we prepared a series of composites using three kinds of high mechanical performance epoxy resins as matrices and reinforced by the same volume fraction(5%)of short carbon and glass fiber.Their mechanical properties were investigated from the perspective of chemical structure and volume shrinkage ratio of epoxy.We analyzed their tensile strength and modulus based on the mixing rule and Halpin-Tsai eq... 展开更多
关键词 epoxy resin MATRIX fibers COMPOSITES mechanical properties
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MODIFICATION OF EPOXY RESINS WITH PHENOLIC HYDROXYL-TERMINATED POLYSILOXANE 被引量:1
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作者 侯庆普 黄英 余云照 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第3期235-243,共9页
Phenolic hydroxyl-terminated polysiloxanes were incorporated into epoxy resins to reduce the internal stress owing to the mismatch in coefficient of thermal expansion (CTE). Polysiloxane-epoxy resin block copolymers w... Phenolic hydroxyl-terminated polysiloxanes were incorporated into epoxy resins to reduce the internal stress owing to the mismatch in coefficient of thermal expansion (CTE). Polysiloxane-epoxy resin block copolymers were made by a pre-reaction step prior to the curing. In the cured resin, the domain size of the polysiloxane phase depended on the structure of the phenolic hydroxyl-terminated polysiloxane. It was found that the modulus of the cured resin depended largely on the level of the modifier, while the CTE was affected greatly by the structure of the polysiloxane. By means of incorporating a few percent of methylphenylsiloxane unit into the polydimethylsiloxane chain, or by introducing; more compatible end-capping groups, the compounds of more effective low stress modifiers were synthesized. 展开更多
关键词 epoxy RESIN POLYSILOXANE INTERNAL STRESS
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Influence of Matrixes on Microstructure and Properties of CTBN Toughened Epoxy Resins 被引量:1
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作者 余剑英 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2001年第2期17-20,共4页
The influence of the type of epoxy resins(E-51, F-51)on themechanical properties and mi- crostructure of carboxyl-terminatedbutadiene nitrile rubber(CTBN)toughened epoxy resins investigated bydetermination of adhesive... The influence of the type of epoxy resins(E-51, F-51)on themechanical properties and mi- crostructure of carboxyl-terminatedbutadiene nitrile rubber(CTBN)toughened epoxy resins investigated bydetermination of adhesive strength and toughness as well asobservation of scanning electron microstructure (SEM). The resultsindicate that the adhesive strength of CTBN toughened E-51 system issuperior to CTBN toughened F-51 system. However, CTBN toughened E-51system is inferior to CTBN toughened F-51 system in the toughness. 展开更多
关键词 epoxy resin CTBN mechanical properties
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STUDIES ON EPOXY RESINS MODIFIED WITH POLY (BUTYLENE TEREPHTHALATE)-b-POLY (TETRAMETHYLENE GLYCOL)
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作者 王霞 赵炳燚 +1 位作者 李贞宜 余云照 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1997年第1期84-91,共8页
Poly(butylene terephthalate)-b-poly(tetramethylene glycol) (PBT-b-PTMG) was used as rheology modifier for the epoxy resin. The segmental copolymer formed spherulites in the epoxy medium. This copolymer was very effect... Poly(butylene terephthalate)-b-poly(tetramethylene glycol) (PBT-b-PTMG) was used as rheology modifier for the epoxy resin. The segmental copolymer formed spherulites in the epoxy medium. This copolymer was very effective in endowing yield stresses to the liquid resin. The PTMG segment brought in a lowering of the dissolution temperature of the spherulites in the epoxy gel. The cured resin with PBT-b-PTMG as modifier was two-phase materials. The rheology modifier improved the mechanical properties of the cured resin as well. The flexible PTMG segments, however, were not in favour of the toughening effect of the modifier. This was attributed to the large domain size of the dispersed phase. 展开更多
关键词 epoxy resin PBT-b-PTMG yield stress gel toughening
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RHEOLOGICAL MODIFICATION OF EPOXY RESINS WITH NANO SILICA PREPARED BY THE SOL-GEL PROCESS
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作者 Xia Wang Jiang Li +1 位作者 Cheng-fen Long Yun-zhao Yu PCLCC Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China PCLCC is the Polymer Chemistry Laboratory, Chinese Academy of Sciences and China Petro-Chemica Corporation 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第3期253-257,共5页
Nano silica-modified epoxy resins were synthesized by the sol-gel process, The materials have the morphological structure of nano particales dispersed in the epoxy matrix. The dispersed phase formed a physical network... Nano silica-modified epoxy resins were synthesized by the sol-gel process, The materials have the morphological structure of nano particales dispersed in the epoxy matrix. The dispersed phase formed a physical network in the resin and thus influenced the rheological behavior greatly. However, the nano silica did not show a significant influence on the mechanical properties of the cured resins. 展开更多
关键词 epoxy resin nano silica mechanical properties RHEOLOGY sol-gel process
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PROMOTION EFFECT OF MELAMINE ON FLAME RETARDANCY OF EPOXY RESINS CONTAINING CAGED BICYCLIC PHOSPHATE
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作者 Jing-ping Hu Dao Li Yan Qin Xing-yi Wang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2007年第6期581-588,共8页
Caged bicyclic phosphate (CBP) and its dimelamine salt (PDS) were synthesized and added to epoxy resins to obtain the flame retarded epoxy resin composites. The flammability of the composites was characterized by ... Caged bicyclic phosphate (CBP) and its dimelamine salt (PDS) were synthesized and added to epoxy resins to obtain the flame retarded epoxy resin composites. The flammability of the composites was characterized by the limiting oxygen index (LOI) and cone calorimeter tests. The LOI values of flame retarded composites increase consistently with the increase of flame retardant amounts, and they are almost the same when the loading of CBP is the same as that of PDS, although the phosphorus content of PDS is much lower than that of CBP. The total heat release increases in the order of CBP30/ER 〈 PDS30/ER 〈 PDS15/ER 〈 CBPI5/ER, whereas that of specific extinction area is CBP15/ER 〉 CBP30/ER 〉 PDS30/ER ≌ PDS15/ER. PDS exhibits more effective inhibition of oxidation of combustible gases. In the tests of thermogravimetric analyses (TG) and Fourier transform infrared spectroscopy (FT-IR), it is found that the degradation of the composites is influenced greatly by the addition of flame retardants. By scanning electron microscopy (SEM), a thick and tight char-layer is observed for PDS30/ER, resulting from the interaction of nitrogen species with phosphorus species. Therefore, the combination of CBP with melamine in the flame retarded system can improve the flame retardancy greatly. 展开更多
关键词 Flame retardancy Thermal degradation MELAMINE Caged bicyclic phosphate epoxy resin.
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MECHANICAL RELAXATION AND INTERMOLECULAR INTERACTION IN EPOXY RESINS/POLY (ETHYLENE OXIDE) BLENDS CURED WITH PHTHALIC ANHYDRIDE
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作者 罗筱烈 郑思珣 +1 位作者 马德柱 胡克良 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第2期144-153,共10页
The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechani... The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger. 展开更多
关键词 CROSS-LINKED BLEND OF epoxy RESIN MISCIBILITY MECHANICAL RELAXATION CURING REACTION INTERMOLECULAR INTERACTION
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Influence of aliphatic epoxy monomer on the blowing-out effect in the flame retardant epoxy resins
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作者 ZHANG Wen-chao SONG Ting-lu YANG Rong-jie 《Journal of Beijing Institute of Technology》 EI CAS 2016年第3期418-428,共11页
An aliphatic epoxy monomer"polypropyleneglycol-diglycidylether(PPGDGE,YF878)"is loaded in the epoxy resins(EP)to evaluate the influence of epoxy structure on the blowing-out effect,which is caused by 9,10-dihydr... An aliphatic epoxy monomer"polypropyleneglycol-diglycidylether(PPGDGE,YF878)"is loaded in the epoxy resins(EP)to evaluate the influence of epoxy structure on the blowing-out effect,which is caused by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)and octaphenyl silsesquioxane(OPS).The flame retarding properties of these EP composites were tested using the LOI and UL-94 procedures.The pyrolytic gases produced and the thermal stability of the EP composites with different flame retardants were detected by TGA-FTIR in air.The negative effect of YF878 was detected from the TTI,HRR,and p-HRR results after the cone calorimeter test.The char produced by the EP composites after the cone calorimeter test was investigated by FTIR.It is proposed that the aliphatic chain of the YF878 is easy to break down and produce combustible gases,so it does not easily form a crosslinked structure in the condensed phase.These results are very helpful for investigation of the conditions under which the blowing-out effect in epoxy resins can be caused by synergy of phosphorous and silicon. 展开更多
关键词 epoxy resin silicon phosphorus flame retardancy blowing-out effect
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Phosphorylated Salicylic Acid as Flame Retardant in Epoxy Resins and Composites
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作者 Lara Greiner Philipp Kukla +1 位作者 Sebastian Eibl Manfred Döring 《Journal of Renewable Materials》 SCIE EI 2022年第7期1931-1950,共20页
A novel,versatile flame retardant substructure based on phosphorylated salicylic acid(SCP)is described and used in the synthesis of new flame retardants for HexFlowRTM6,a high-performance epoxy resin used in resin tr... A novel,versatile flame retardant substructure based on phosphorylated salicylic acid(SCP)is described and used in the synthesis of new flame retardants for HexFlowRTM6,a high-performance epoxy resin used in resin transfer molding processes as composite matrix.The starting material salicylic acid can be obtained from natural sources.SCP as reactive phosphorus chloride is converted with a novolak,a novolak containing 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide(DOPO)substituents or DOPO-hydroquinone to flame retardants with sufficient thermal stability and high char yield.Additionally,these flame retardants are soluble in the resin as well as react into the epoxy network.The determined thermal stability and glass transition temperatures of flame retarded neat resin samples as well as the interlaminar shear strength of corresponding carbon fiber reinforced composite materials showed the applicability of these flame retardants.Neat resin samples and composites were tested for their flammability by UL94 and/or flame-retardant performance by cone calorimetry.All tested flame retardants decrease the peak of heat release rate by up to 54%for neat resin samples.A combination of DOPO and SCP in one flame retardant shows synergistic effects in char formation and the mode of action adapts to neat resin or fiber-reinforced samples,so there is efficient flame retardancy in both cases.Therefore,a tailoring of SCP based flame retardants is possible.Additionally,these flame retardants efficiently reduce fiber degradation during combustion of carbon fiber-reinforced epoxy resins as observed by scanning electron microscopy and energy dispersive X-ray spectroscopy. 展开更多
关键词 epoxy resin COMPOSITE fiber protection bio-based flame retardant
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Synthesis and Characterization of Modified Epoxy Resins by Silicic Acid Tetraethyl Ester and Nano-SiO_2
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作者 李海燕 张之圣 《Transactions of Tianjin University》 EI CAS 2004年第2期105-108,共4页
A kind of modified epoxy resins was obtained by condensation of epoxy resin with silicic acid tetraethyl ester(TEOS) and nano-SiO2. The reactions were performed with hydrochloric acid as a catalyst at 63 ℃. The str... A kind of modified epoxy resins was obtained by condensation of epoxy resin with silicic acid tetraethyl ester(TEOS) and nano-SiO2. The reactions were performed with hydrochloric acid as a catalyst at 63 ℃. The structure, thermal stability and morphological characteristics of the modified epoxy resins were studied through infrared spectra(FT-IR) analysis, thermogravimetric(TG) analysis and scanning electron microscopy respectively. It has been found from the IR and TG study that modified epoxy resins have greater thermal stability than epoxy resins, and its thermal stability has been improved by the formation of inter-crosslinked network structure. The modified epoxy resins exhibit heterogeneous morphology and heterogeneity increases with more TEOS feeding, which in turn confirms the formation of inter-crosslinked network structure in modified epoxy resins. 展开更多
关键词 epoxy resin silicic acid tetraethyl ester(TEOS) nano-SiO_2 IR thermogravimetric analysis
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Synthesis, Characterization and Flame-retardant Properties of Epoxy Resins and AACHH Composites
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作者 秦麟卿 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第5期763-767,共5页
Flame retardant epoxy resins were prepared by a simple mixed method using ammonium aluminum carbonate hydroxy hydrate (AACHH) as a halogen-free flame retardant. The prepared samples were characterized by X-ray diffr... Flame retardant epoxy resins were prepared by a simple mixed method using ammonium aluminum carbonate hydroxy hydrate (AACHH) as a halogen-free flame retardant. The prepared samples were characterized by X-ray diffraction, thermogravimetric and differential scanning calorimetry, scanning electron microscope and limiting oxygen index(LOI) experiments. Effects of AACHH content on LOI of epoxy resins/AACHH composite and flame retardant mechanism were investigated and discussed. Results show that AACHH exhibites excellent flame-retardant properties in epoxy resin(EP). When the content of AACHH was 47.4%, the LOI of EP reached 32.2%. Moreover, the initial and terminal decomposition temperature of EP increased by 48 ℃ and 40 ℃, respectively. The flame retarded mechanism of AACHH is due to the synergic flame retardant effects of diluting, cooling, decomposition resisting and obstructing. 展开更多
关键词 epoxy resin(EP) flame retardant ammonium aluminum carbonate hydroxy hydrate (AACHH) composite
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CTBN-TOUGHENED EPOXY RESINS——EFFECT OF CURING MECHANISM ON NETWORK STRUCTURE OF THE RUBBER PHASE
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作者 宋爱腾 余云照 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1990年第2期183-187,共5页
Epoxy resins toughened with carboxyl-terminated butadieneacrylonitrile copolymers (CTBN) are two-phase thermosets. The network of the in situ formed rubber particles depends upon the curing mechanism of the resin. Whe... Epoxy resins toughened with carboxyl-terminated butadieneacrylonitrile copolymers (CTBN) are two-phase thermosets. The network of the in situ formed rubber particles depends upon the curing mechanism of the resin. When a primary polyamine such as triethylene tetramine was used as curing agent, the network of the rubber phase was quite incomplete, whereas a perfect rubber network was formed with 2-ethyl-4-methyl imidazole as the curing agent. 展开更多
关键词 epoxy resin TOUGHENING liquid rubber.
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A Study on a Magnesium-Based Layered Composite Used as a Flame Retardant for Phenolic Epoxy Resins
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作者 Hongxiang Liu Neng Xiong +2 位作者 Songli Wang Wei Zhang Bo Yong 《Fluid Dynamics & Materials Processing》 EI 2022年第3期549-561,共13页
The effects of a magnesium-based layered composite on the flammability of a phenolic epoxy resin(EP)are studied.In order to produce the required composite material,first,magnesium hydroxide,aluminum salt and deionized... The effects of a magnesium-based layered composite on the flammability of a phenolic epoxy resin(EP)are studied.In order to produce the required composite material,first,magnesium hydroxide,aluminum salt and deionized water are mixed into a reactor according to a certain proportion to induce a hydrothermal reaction;then,the feed liquid is filtered out using a solid-liquid separation procedure;finally,the material is dried and crushed.In order to evaluate its effects on the flammability of the EP,first,m-phenylenediamine is added to EP and vacuum defoamation is performed;then,EP is poured into a polytetrafluoroethylene mold,cooled to room temperature and demoulded;finally,the magnesium-based layered composite is added to EP,and its flame retardance is characterized by thermogravimetric analysis,limiting oxygen index and cone calorimetry.The X-ray diffraction patterns show that the baseline of magnesium-based layered composite is stable and the front shape is sharp and symmetrical when the molar ratio of magnesium to aluminium is 3.2:1;with the addition of magnesium-based layered composite,the initial pyrolysis temperature of EP of 10%,15%and 30%magnesium-based layered composite decreases to 318.2°C,317.9°C and 357.1°C,respectively.After the reaction,the amount of residual carbon increases to 0.1%,3.45%and 8.3%,and the limiting oxygen index increases by 28.3%,29.1%and 29.6%,respectively.The maximum heat release rate of cone calorimeter decreases gradually.The optimum molar ratio of Mg:Al for green synthesis is 3.2:1,and the NO_(3)-intercalated magnesium-based layered composite has the best flame retardance properties. 展开更多
关键词 Phenolic epoxy resin layered composite green synthesis flame retardance anion intercalation
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Statistical deduction and experimental verification on kinetic equations for the curing reactions of epoxy resins/amines
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作者 陈平 吕祖舜 +1 位作者 余大书 胡立江 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2005年第1期11-16,共6页
Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations)... Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations) was presented to explain the uniformity and relationship among the three different kinetic mechanisms of the reactions. The presented macro-equations were deduced from the kinetic micro-equations by the statistics method. And the constitutive equations were verified by experimental data at different reaction times and temperatures (95°C, 60°C and 39°C), taking diglycidyl ether of bisphenol A (DGEBA) /ethyleneamine (EA) as a model. 展开更多
关键词 epoxy resin AMINE unified kinetic equations curing reaction
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Study on effect of crosslink structure on decomposition of epoxy resins in nitric acid
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作者 刘宇艳 李犁 +1 位作者 吴松全 唐宇攀 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第4期19-25,共7页
One chemical approach using nitric acid as the solvent to decompose thermosetting epoxy resin was discussed. The samples were prepared by using different kinds of curing agents, namely polyamide (PA651), isophorone di... One chemical approach using nitric acid as the solvent to decompose thermosetting epoxy resin was discussed. The samples were prepared by using different kinds of curing agents, namely polyamide (PA651), isophorone diamine (IPDA), 4,4'-diaminodiphenylmethane (DDM) and 2-ethyl-4-methy-imidazole (EMI-2,4) and different kinds of epoxy resins, namely bisphenol-A epoxy resin(E-44), bisphenol-A epoxy resin(E-51), N,N,N',N' teraglycidy 4,4' diaminodiphenyl methane (AG-80) and diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate (TDE-85). Their effects on decomposition rate were investigated and the decomposition products were analyzed by Infra-red (IR) spectra, and Gas Chromatography-Mass Spectrometry (GC-MS). Based on conclusions drawn from experiments, the mechanism of degrading thermosetting epoxy resin with nitric acid was envisaged tentatively. 展开更多
关键词 epoxy resin nitric acid chemical decomposition
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Nucleophilic amino acids as a renewable alternative to petrochemically-derived amines in glycerol epoxy resins
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作者 Yunyi Liang Yonghong Luo +4 位作者 Yingji Wu Xiaona Li Quyet Van Le Jianzhang Li Changlei Xia 《Journal of Bioresources and Bioproducts》 EI CSCD 2024年第2期222-232,共11页
The standard epoxy resin curing agents revealed are from unsustainable petroleum-based sources,which produce poisonous exhaust when cured.Amino acids,a bio-based epoxy curing agent with amino and carboxyl groups,are a... The standard epoxy resin curing agents revealed are from unsustainable petroleum-based sources,which produce poisonous exhaust when cured.Amino acids,a bio-based epoxy curing agent with amino and carboxyl groups,are another potential curing agent.Water-soluble epoxy resins cured with lysine(Lys),glutamic acid(Glu),leucine(Leu),and serine(Ser)as amino acids were inves-tigated.The results showed that the water-soluble epoxy resin(glycerol epoxy resins,GER)was cured with Lys and Glu after reacting.Fourier transform infrared(FT-IR)spectroscopic analysis of the GER-Lys showed that the amino and carboxyl groups of Lys primarily reacted with the epoxy groups of GER.The elongation at break of Lys-cured GER(GER-Lys)cured at 70℃ with a molar ratio of 1꞉0.75 was 75.32%.The fact that elongations at break of GER-Lys(79.43%)were higher than those of GER-Glu(17.33%),respectively supports the decrease of crosslinking density by the amino acid-cured GER reaction.The potential of Lys and Glu alternatives for petrochemical amines is demonstrated and provides promising opportunities for industrial application. 展开更多
关键词 Curing agent Amino acids Bio-based epoxy resins LYSINE Glutamic acid
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Low dielectric constant and highly intrinsic thermal conductivity fluorine-containing epoxy resins with ordered liquid crystal structures
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作者 Xuerong Fan Zheng Liu +1 位作者 Shuangshuang Wang Junwei Gu 《SusMat》 SCIE EI 2023年第6期877-893,共17页
Epoxy resins with a high dielectric constant and low intrinsic thermal conductivity coefficient cannot meet the current application requirements of advanced electronic and electrical equipment.Therefore,novel fluorine... Epoxy resins with a high dielectric constant and low intrinsic thermal conductivity coefficient cannot meet the current application requirements of advanced electronic and electrical equipment.Therefore,novel fluorine-containing liquid crystal epoxy compounds(TFSAEy)with fluorinated groups,biphenyl units,and flexible alkyl chains are first synthesized via amidation and esterification reactions.Then,4,4′-diaminodiphenylmethane(DDM)is used as a curing agent to prepare the corresponding fluorine-containing liquid crystal epoxy resins.The obtained dielectric constant(ε)and dielectric loss(tanδ)values of TFSAEy/DDM at 1 MHz are 2.54 and 0.025,respectively,which are significantly lower than those of conventional epoxy resins(E-51/DDM,3.52 and 0.038).Additionally,the intrinsic thermal conductivity coefficient(λ)of TFSAEy/DDM is 0.36 W/(m⋅K),71.4%higher than that of E-51/DDM(0.21 W/(m⋅K)).Meanwhile,the corresponding elastic modulus,hardness,glass transition temperature,and heat resistance index of TFSAEy/DDM are 5.73 GPa,0.35 GPa,213.5◦C,and 188.7℃,respectively,all superior to those of E-51/DDM(3.68 GPa,0.27 GPa,107.2℃,and 174.8℃),presenting potential application in high-heating electronic component packaging and printed circuit boards. 展开更多
关键词 epoxy resins fluorine-containing groups highly intrinsic thermal conductivity liquid crystal structure low dielectric constant
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