EUROPEAN POLYMER JOURNAL
·
2020
·
IF 3.862
Xunzheng Su,Zhen Zhou,Jingcheng Liu,Jing Luo,Ren Liu
In this paper, a high-performance epoxy resin was synthesized from vanillin , and the polyimine-epoxy cross-linked network was prepared via in-situ formation of the Schiff base structure. The chemical structures, thermal and mechanical properties of vanillin-based epoxy resin (DADE) and diglycidyl ether of bisphenol A epoxy resin (DGEBA) were characterized by fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectra ( 1 H NMR), differential scanning calorimetry (DSC), and dynamic thermomechanical analysis (DMA). The results indicated that the DADE showed better thermal and mechanical properties than DGEBA after cured by the same primary amine (D230). The prepared DADE-D230 showed higher Tg (106℃), tensile strength (57.4 MPa) and elongation at break (3.1%) than DGEBA-D230 (98℃, 45.1 MPa, and 2.4%, respectively). Moreover, it can be recycled at a hot pressing, and the reprocessed samples showed a comparable performance with DGEBA.
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
POLYMER DEGRADATION AND STABILITY
·
2022
·
IF 5.204
Zhenyan Ji,Fan Zhang,Hongbing Chen,Weirong He,Zhe Xing,Guozhong Wu
Although epoxy resins in nuclear facilities may be exposed to elevated temperatures and gamma irradiation, changes in the chemical structures and mechanical properties of a diglycidyl ether of bisphenol-A (DGEBA)/methyl hexahydrophthalic anhydride (MeHHPA) epoxy resin under these conditions have not been reported yet. In this study, we aim to understand the accelerated aging of the DGEBA/MeHHPA epoxy resin under simultaneous thermal heating and gamma irradiation. Samples were irradiated at ambient temperature and 70 °C with a dose rate of 2 kGy/h and a total dose of up to 1000 kGy. Various characterizations were performed to investigate the changes in their chemical structures and mechanical properties. The results showed that the relative oxygen content of the resin increased near the surface owing to the degradation of the main macromolecular chains, which was accompanied by a decrease in the thermal stability and glass transition temperature ( T g ). Under gamma irradiation at room temperature, the tensile strength increased with the absorbed dose up to 500 kGy and then decreased with higher doses. This trend indicated that thermal heating at 70 °C significantly enhanced the degradation of the DGEBA/MeHHPA epoxy resin upon gamma irradiation.
研究领域:
材料科学
·
核工程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2023
·
IF 4.1
Xinxin Fang,Xin Guo,Weilin Tang,Qun Gu,Yue Wu,Hua Sun,Junfei Gao
In this work, a bio-based epoxy resin, protocatechuic acid diester epoxy resin, (PDEP), was synthesized using protocatechuic acid. The structure and properties of PDEP have been characterized by 1H NMR, 13C NMR, and Fourier transform infrared. After different contents of PDEP were added to diglycidyl ether of bisphenol A (DGEBA), the modified epoxy resins were cured by 4,4′-diaminodiphenylmethane (DDM). With the addition of a flexible long-chain bio-based monomer to improve toughness, the impact strength was 50 kJ·m–2 with only 5.0 wt % PDEP; compared with pure DGEBA, the impact strength was 27 kJ·m–2. Further, an increase in Tg should be confirmed from the mechanical cross-linking density and rigidity group content. The single Tg proved the homogeneous phase structure of the PDEP-cured resin. Morphology exhibiting the ductile fracture of the cured resin was confirmed by scanning electron microscopy. Overall, this work demonstrates the utilization of renewable protocatechuic acid as an effective modifier for epoxy resin, which reflects its potential application.
研究领域:
材料科学
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高分子化学
·
可持续材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 40
·51183
·
IF 3.125
Yushun Zhao,Ziyang Zhang,Song Zhang,Hongli Dou,Kerong Yang,Wei Yang
Increases in rated voltage and power density of high voltage gas insulated switchgears (GIS) impose stringent requirements on the diglycidyl ether of bisphenol A (DGEBA)-anhydride thermoset, which is widely used as insulation materials for high GIS, for higher mechanical and heat-resistant properties. In this paper, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (AOO) was copolymerized with DGEBA -anhydride system to increase the mechanical and thermal properties of the thermosets. Based on the molecular dynamics simulation method, the coefficient of thermal expansion, glass transition temperature ( T g ), and modulus of AOO copolymer-modified DGEBA-anhydride thermosets were calculated. The AOO copolymer-modified DGEBA-anhydride thermosets specimens were further experimentally prepared and subjected to differential scanning calorimeter test, TGA test, tensile bending test, and dielectric test. The results of simulation and experiment simultaneously indicated that the T g and modulus of the DGEBA-anhydride thermoset are enhanced after AOO modification. This is mainly due to the decrease in free volume percentage and mean square displacement of the epoxy cross-linked network structure after the introduction of AOO molecules, which makes the structure more compact and the cross-link density increased. Additionally, the dielectric performances of the thermoset was enhanced by AOO. The excellent thermal, mechanical and dielectric properties of AOO modified DGEBA-anhydride thermoset make it a promising application in the field of high voltage GIS.
研究领域:
材料科学
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高分子化学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2021
·
IF 13.273
Xin Wang,Haoxin Niu,Wenwen Guo,Lei Song,Yuan Hu
The development of high-performance thermosetting polymers has spawn extensive research interest over the past decade because of increasing awareness of environmental protection and sustainable policy. In this work, three cardanol-derived epoxy monomers named after CFGE, ECF, and ECFGE were synthesized, and ECFGE was selected to be further treated by flame-retardant owing to its superior thermal stability and mechanical strength. ECFGE was subsequently combined with cardanol-derived phosphate (DPP-CFR) to obtain flame-retardant bio-based epoxy materials as diglycidyl ether bisphenol A (DGEBA)-type epoxy substitutes. The chemical structure of CFGE, ECF, ECFGE, and DPP-CFR was well characterized by nuclear magnetic resonance and elemental analysis. The influence of DPP-CFR on the curing kinetics of the ECFGE/DDM system was investigated by the non-isothermal DSC . The addition of DPP-CFR imparted excellent flame-retardancy to the cured ECFGE/DDM system. Specifically, the cured ECFGE/DDM system with 15 wt% of DPP-CFR exhibited UL-94V-0 classification and LOI value of 31.0%, and its peak heat release rate was declined by 48% and 72%, respectively, compared to the cured ECFGE/DDM and DGEBA/DDM. Additionally, the cured ECFGE/DDM system with 15 wt% of DPP-CFR also showed better tensile strength and toughness than the cured DGEBA/DDM counterpart. This study demonstrates that cardanol can be utilized as a versatile platform for the fabrication of high-performance bio-based thermosetting polymers with excellent comprehensive properties.
研究领域:
材料科学
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聚合物化学
·
可持续化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 38
·期 8
·867-876
·
IF 3.154
Chen Qi,Wang Shun,Qin Feng,Liu Kuan,Liu Qian,Zhao Qing,Wang Xing-Yi,Hu Yan-Hong
Polyimide (PI) synthesized from aromatic diamine and dianhydrides via two-step poly-condensation method was highly soluble in TGDDM (MY-720) and DGEBA (E-51) at desirable temperature. TGDDM-PI (M-PI) and DGEBA-PI (E-PI) composites within 0.5%-3% PI loading could be prepared without organic solvent. On the cryogenically fractured surfaces of M-PI and E-PI composites, no obvious heterogeneous phase was observed by SEM. The mechanical properties were promoted significantly by PI, especially for impact strength. Adding 2% PI-2W into MY-720 and E-51 composites, the impact strength increased to 21 and 51 kJ/m 2 , the tensile strength increased by 62% and 19%, and the flexural strength by 18% and 13%, respectively, with slight increases in tensile modulus. These results were related to the promotion in plasticity of composites and changes in fragile→ductile fracture mode. Moreover, T g and thermal stability of M-PI and E-PI were increased effectively.
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
POLYMER DEGRADATION AND STABILITY
·
2017
·
IF 3.386
Wen-Jun Liang,Bin Zhao,Cong-Yun Zhang,Rong-Kun Jian,Dong-Yue Liu,Ya-Qing Liu
A novel flame retardant , namely bisphenol-A bridged penta(phenoxy)cyclotriphosphazene (A-BP), was synthesized and characterized successfully. Obtained A-BP was mixed in different proportions with diglycidyl ether of bisphenol-A (DGEBA) in order to prepare a series of flame retardant epoxy resins (EP). The differential scanning calorimeter (DSC) results indicated that the glass transition temperatures (T g ) of EPs containing A-BP had only a slight decrease in comparison to EP. Thermogravimetric analysis (TGA) showed that the incorporation of A-BP improves the thermal stability of EP at a high temperature. Moreover, an increase of LOI value (33.9%) was achieved for EP contained with 9 wt% of A-BP. Furthermore, such sample passed UL-94 V-0 rating. Additionally, according to the cone calorimeter tests, in the whole combustion, the EP/9% A-BP material showed lower heat release and smoke production than neat EP. To elucidate the flame retardant actions of A-BP for EP, comprehensive measurement including Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) and TG-FTIR techniques were adopted to analyze the char layers and gaseous products. As a result, a bi-phase flame retardant mechanism was proposed showing the efficiency of inert gas dilution and quenching of existed free radicals in gaseous phase and char formation action in a condensed phase, respectively.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2023
·
IF 5.1
Hao Guan,Zhiyong Li,Qinlong Xu,Jingjing Meng,Kai Guo
The epoxy resin made from petroleum-based bisphenol A has clear shortcomings both in raw material sustainability and the heat resistance as well as mechanical properties of polymers, which limits its use in high-performance products. A multifunctional epoxy resin was derived from sustainable resveratrol and phloroglucinol via a solvent-free procedure. The matrix showed its advantages in phase transition temperature ( T g , 247.5°C), storage modulus (4.14GPa), flexural strength (184.70 MPa), tensile modulus (6.14 GPa), and lap shear strength (28.15 MPa). Besides, the thermal conductivity (0.151 W/m•K), and coefficient of thermal expansion (84 ppm/°C) suggested its outstanding structural stability and dimensional stability below 250 °C. Moreover, it also possessed an intrinsic flame retardancy. The highly extended performances implied its promising applications in lightweight, fireproof, and heat insulation engineering.
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
RSC Advances
·
2015
·Vol. 5
·期 84
·68476-68484
·
IF 3.84
Qinqin Luo,Yanchao Yuan,Chunlei Dong,Shumei Liu,Jiangqing Zhao
5,10-Dihydro-phenophosphazine-10-oxide (DPPA) served as a co-curing agent for 4,4′-diaminodiphenylmethane in the curing reaction of bisphenol A diglycidyl ether (DGEBA) epoxy resin (EP). 1H NMR tracking the reaction of DPPA with DGEBA revealed that the P–H bond in DPPA had a higher reactivity with the epoxy group than the N–H bond. DPPA could promote the curing reaction of DDM with DGEBA. DPPA endowed the epoxy resin with a high flame-retardant efficiency due to the unique combination of phosphorus and nitrogen in the phenophosphazine ring. The cured epoxy resin could achieve a V-0 rating in the UL-94 test with a limiting oxygen index (LOI) of 33.6% at only 2.5 wt% DPPA. The reduced peak heat release rate and total heat release, and increased char yield further verified the excellent flame retardancy of EP. The flame-retardant mechanism of the epoxy resin was investigated by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscopy, elemental analysis and FTIR spectrometry. The results indicated that DPPA catalyzed the formation of the rigid intumescent char and the generation of the blowing-out effect in the epoxy resin matrix.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2016
·
IF 2.567
Qinqin Luo,Yanchao Yuan,Chunlei Dong,Haohao Huang,Shumei Liu,Jianqing Zhao
The flame retardancy, thermal, and mechanical properties of the cured epoxy resins are difficult to be simultaneously improved. In the present work, a novel DPPA-based curing agent, 10-[(4-hydroxyphenyl)(4-hydroxyphenylimino)methyl]-5,10-dihydrophenophosphazine 10-oxide (H-DPPA), is successfully synthesized to serve as a co-curing agent of 4, 4′-diaminodiphenylmethane (DDM) for bisphenol A diglycidyl ether (DGEBA) epoxy resin. With the aid of 3.0 wt % of H-DPPA, the cured epoxy resin, in which the phosphorus content is as low as 0.22%, passes V-0 rating of UL-94 test with limiting oxygen index (LOI) of 31.8%. The high flame retardancy of epoxy resin modified by H-DPPA originated mainly from the formation of intumescent char layer during combustion. This new type of flame retardant containing both phosphine oxide structure and nitrogen moieties provides epoxy resins with excellent integrated performances.
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
POLYMER DEGRADATION AND STABILITY
·
2021
·
IF 5.03
Jiali Huang,Wenwen Guo,Xin Wang,Lei Song,Yuan Hu
Petroleum-based diglycidyl ether bisphenol A (DGEBA)-type epoxy is one of the most popular thermosetting materials currently, but it suffers from brittleness, flammability and non-renewability. In this study, an intrinsically flame retardant bio-based epoxy monomer (HECarCP) was synthesized from cardanol and cyclophosphazene. Subsequently, HECarCP was cured by 4,4’-diaminodiphenyl methane (DDM) to obtain a thermosetting material. Compared to the cured DGEBA/DDM thermoset, the cured HECarCP/DDM thermoset showed lower initial decomposition temperature; however, the earlier thermal decomposition caused by cyclophosphazene core contributed to char formation in return. As well, the HECarCP/DDM exhibited slightly lower tensile strength but much higher elongation at break than the DGEBA/DDM, overcoming the drawback of brittleness of the DGEBA/DDM. More importantly, the cyclophosphazene core provided intrinsic flame retardancy to the HECarCP/DDM thermoset, which displayed a relatively high LOI value of 33.0% and UL-94 V-0 classification. In cone calorimeter measurement, the peak heat release rate, total heat release and total smoke production of the HECarCP/DDM thermoset was declined by 63%, 24% and 72%, respectively, compared to those of the DGEBA/DDM, owing to the formation of a thermally stable and insulating char layer during combustion. This study paves the way for broadening applications of cardanol in fabrication of high-performance bio-based thermosetting polymers with excellent comprehensive properties.
研究领域:
材料科学
·
化学工程
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY
·
2017
·
IF 1.073
Yuan Yin,Meihua Liu,Wei Wei,Changmei Zheng,Jian Gao,Wanxi Zhang,Chunbai Zheng,Pengyang Deng,Yue Xing
Imidazolium salts containing , , , , or ionic liquids were blended with an epoxy prepolymer, dyglycidylether of bisphenol A (DGEBA) to obtain a series of compositions. To characterize the resulting mixtures and determine the influence of the imidazolium anion on the reactivity and properties of epoxy systems, we performed the following analyses and tests: (i) differential scanning calorimetry (DSC), to determine the curing reaction characteristics, (ii) in situ fourier-transform infrared spectroscopy (FTIR), to assess chemical structure changes, (iii) mechanical property testing of the hardened epoxy material, and (iv) thermogravimetric analysis (TGA). The DSC and FTIR analyses indicate that [Hmim]BF4, and [Hmim]PF6 cannot induce the epoxy ring opening reaction and thus these materials are unable to function as epoxy curing agents. In contrast, the imidazolium ionic liquids [Hmim]FeCl4, [Hmim]N(CN)2, and [Hmim]Zn2Cl5 independently promote the epoxy ring opening reaction. TGA analyses show that the cured DGEBA/[Hmim]Zn2Cl5 system exhibits thermal stability similar to the cured DGEBA/[Hmim]FeCl4. These results can provide an essential reference not only for studying the synergistic effect of [C6mim]FeCl4/mixed-amines on the curing process of epoxy systems and the mechanism of the ring opening of epoxides with [C6mim]FeCl4/mixed-amines, but also for designing new epoxy curing systems.
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）