RSC Advances
·
2015
·Vol. 5
·期 84
·68476-68484
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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
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化学工程
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Yuan Liu,Yunyan Peng,Jun Luo,Jingkai Liu,Xiaoqing Liu
A bridging group is an indispensable element for the preparation of diphenol-based benzoxazines, and inevitably, its electronic features will affect the H-bond formation of obtained benzoxazine, which is a crucial factor that not only makes a difference on curing behaviors of benzoxazine but also poses significant influence on the performances of cured resins. However, systematical investigation about the effects of the bridging group on the H bonds in benzoxazine is still in a barren state. Herein, we bridge the gap with three high-purity model benzoxazine monomers. The results showed that electron-donating bridge groups made the benzoxazine monomers tend to start the curing reaction earlier, whereas the electron-withdrawing bridging groups had the opposite effect. In addition, it was also confirmed that the H bonds in polybenzoxazine could be readily tailored by carefully selecting the bridge groups of aromatic diphenols. In this work, some basic characteristics about benzoxazine have been revealed, which are helpful for us to understand its structure–properties relationship more deeply.
研究领域:
材料科学
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化学
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DOI
高影响因子
RSC Advances
·
2016
·Vol. 7
·期 12
·6981-6987
·
IF 3.289
Jiheng Ding,Wanjun Peng,Ting Luo,Haibin Yu
The anhydride curing agent of 3,6-enodro-1,2,3,6-tetrahydrophthalic anhydride (OBPA) and the reactive epoxy diluent of furfuryl glycidyl ether (FGE) were prepared and characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The curing reaction kinetics process of an EP/OBPA/FGE epoxy system was studied by non-isothermal DSC methods. The parameters of the kinetics were calculated using the Kissinger model, Crnae model, Ozawa model and β–T (temperature–heating speed) extrapolation, respectively. In addition, the effect of FGE on the thermomechanical properties (glass transition temperature) and mechanical properties (flexural strength and the tensile strength) in the EP/OBPA/FGE were studied, indicating that when the content of FGE was 10 wt% the epoxy system reaches the best mechanical properties.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2020
·
IF 4.032
Xian He,Shenjun Liao,Menghao Chen,Renke Li,Yao Liu,Bo Liang,Jianghuai Hu,Ke Zeng,Gang Yang
Tyrosine derived cyclic peptide (TCP) was employed to promote the curing reaction of a phthalonitrile monomer 1,3-bis(3,4-dicyanophenoxy) (3BOCN). Differential scanning calorimetry (DSC) and rheological analysis were used to study the curing behaviors of the TCP/3BOCN blend and confirmed a relatively high curing efficiency. Fourier transform infrared spectrometer (FT-IR) and two-dimensional infrared vibrational echo spectroscopy suggested the cyclic peptide reactive site was responsible for the unique curing behavior. Isoindolin, phthalocyanine and triazine were confirmed as curing products. Thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) were used to measure the thermal and thermomechanical properties of the cured resin. The results firstly revealed the excellent thermal stability and high glass transition temperature (T g ) of this resin even under a moderate post-curing condition.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
ChemSusChem
·
2013
·Vol. 7
·期 2
·555-562
·
IF 7.475
Songqi Ma,Xiaoqing Liu,Libo Fan,Yanhua Jiang,Lijun Cao,Zhaobin Tang,Jin Zhu
Graphical An epoxy on both your houses! A trifunctional bio-based epoxy resin (denoted TEIA) is synthesized from itaconic acid. Its curing reaction with poly(propylene glycol) bis(2-aminopropyl ether) (D230) and methyl hexahydrophthalic anhydride (MHHPA) is investigated. As a result of high epoxy value and low viscosity, TEIA shows high performance and good processability. A bio-based epoxy resin (denoted TEIA) with high epoxy value (1.16) and low viscosity (0.92 Pa s, 25 °C) was synthesized from itaconic acid and its chemical structure was confirmed by 1 H NMR and 13 C NMR spectroscopy. Its curing reaction with poly(propylene glycol) bis(2-aminopropyl ether) (D230) and methyl hexahydrophthalic anhydride (MHHPA) was investigated. For comparison, the commonly used diglycidyl ether of bisphenol A (DGEBA) was also cured with the same curing agents. The results demonstrated that TEIA showed higher curing reactivity towards D230/MHHPA and lower viscosity compared with DGEBA, resulting in the better processability. Owing to its high epoxy value and unique structure, comparable or better glass transition temperature as well as mechanical properties could be obtained for the TEIA-based network relative to the DGEBA-based network. The results indicated that itaconic acid is a promising renewable feedstock for the synthesis of bio-based epoxy resin with high performance.
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Advanced Materials Interfaces
·
2019
·Vol. 7
·期 2
·1901490
·
IF 4.713
Yixing Zhan,Yating Wang,Ming Wang,Xiaoqing Ding,Xinlong Wang
The nano metal–organic framework particles (nano ZIF-8) are grafted onto the surface of short carbon fibers (SCFs) by a facile in situ growth method in order to functionalize SCFs. The morphology, crystal structure, and chemical element composition of modified SCFs (ZIF-8@SCFs) are investigated. The grafted nano-ZIF-8 could remarkably enhance the roughness, polarity, and wettability of SCFs surface and promote the curing reaction of epoxy composites. The tensile strength, flexural strength, elastic modulus, toughness, and impact strength of the epoxy composites with 1 wt% ZIF-8@SCFs are increased by 25%, 31%, 51%, 28%, and 42% compared to that of the composites with 1 wt% SCFs, respectively. Furthermore, the storage modulus ( E ′) and glass transition temperature ( T g ) are enhanced from 2558 MPa and 108.2 °C to 3000 MPa and 147.6 °C. The significant improvement in mechanical and thermomechanical properties of the prepared composites could be ascribed to the ameliorated wettability, enhanced mechanical interlock, and increased chemical bonding induced by ZIF-8@SCFs.
研究领域:
材料科学
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复合材料
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纳米技术
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产品关联
DOI
高影响因子
RSC Advances
·
2022
·Vol. 12
·期 50
·32448-32458
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IF 4.036
Yanli Dou,Shixiang Sun,Shanshan Lu,Weiguo Yao,Dongbo Guan
Conductive carbon black (CCB) is an important filler in stretchable conductive silicone rubber (CSR) composites. However, due to the active oxygen-containing groups on CCB, introducing it into silicone rubber (SR) may cause SR to not completely cure. Surface modification of CCB may ease the problem but at the cost of reducing the electrical conductivity of pristine CCB. In this work, the curing and crosslinking performance of CCB/SR is detected in detail, the hydroxyl groups (–OH) carried by CCB can react with the silicon–hydrogen group (Si–H) with the existence of Pt catalyst, causing insufficiency of the hydrosilylation reaction thus hindering the solidifying process of silicon rubber. To take advantage of this reaction, more hydrogen silicone oil (PHMS) possessing silicon–hydrogen bonds is introduced into the system to improve the curing degree as well as fix the CCB in the crosslinked network. Due to the lock-in effect of CCB, the resistance of CSR samples is stable after several hundred bending cycles, and the composite's tensile strength is three times that of the pure SR samples. Besides, the size of the composites can expand to dozens of centimeters or even a few meters with uniform electric conductivity. This composite has resistance as low as 10.20 Ω and is suitable to make electroplating mold, and a rapid plating rate of 2.4 mm/24 h can be achieved. Meanwhile, the overall properties make this CSR composite have potential applications in mold manufacture, flexible electronics, and other related fields.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 7
·1-12
·
IF 2.8
Zhang Xinle,Chi Qingguo,Tang Chao,Li Hua,Zhang Changhai,Li Zhonghua,Zhang Tiandong
The rapidly growing third-generation wide-band-gap semiconductor electronic device industry urgently requires high-temperature-resistant packaging materials. However, the epoxy molding compound materials cannot suffer the high-temperature working condition due to the intrinsic molecular chain structure of epoxy materials (EP). In this paper, bisphenol A-type cyanate (BADCy) with triazine ring structure was introduced into EP to improve its heat resistance. The curing reaction as well as the curing mechanism has been clearly revealed for BADCy/EP with different contents of BADCy according to the Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) results. In the whole copolymer system, the copolymer at higher BADCy concentration (50–60 mol%) achieved the highest crosslink density (12.8 × 10 –3 mol/cm 3 ), thus, showing excellent glass transition temperature (> 200 °C) and thermal decomposition temperature( T 5% > 400 °C). The heat resistance and electrical insulation property of BADCy/EP system have been systematically investigated, and a balance between high heat resistance and good electrical insulation are achieved at 66 mol% BADCy content, where the glass transition temperature reaches 215 °C, which is 73 °C higher than that of the EP system of anhydride copolymer. The volume resistivity of 1.5 × 10 15 Ω·m and dielectric constant of 3.3 is obtained, indicating excellent electrical insulation and dielectric properties of BADCy/EP. This work provides a facile and efficient strategy to improve the overall properties of EP by optimizing the molecular chain structure.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2013
·Vol. 52
·期 3
·375-382
·
IF 3.543
Chun Hua Zhao,Shun Jiang Wan,Lu Wang,Xiang Dong Liu,Takeshi Endo
This study investigates the curing of epoxidized soybean oil (ESO) using dicyandiamide (DICY) and combinations of DICY with several accelerators as curing agents. The differential scanning calorimetry (DSC) results indicated that carbonyldiimidazole (CDI) is a highly efficient accelerator for the ESO-DICY curing system. CDI accelerated ESO-DICY curing system can gel within a short period of 13 min at 190 °C. The activation energies of the ESO-DICY curing systems with and without CDI are 95 and 121 kJ mol −1 , respectively. Similar acceleration effect was observed in the ESO-diglycidyl ether of biphenyl A (DGEBA) blending formulations. When the molar part of the glycidyl epoxy groups of DGEBA was equal to the internal epoxy groups of ESO in the mixture, gelation of the DICY curing system accelerated by CDI was achieved in 3 min at 160 °C. Furthermore, the DSC results with FTIR analysis suggest that the stoichiometric curing molar ratio was 3 ESO epoxy units per 1 DICY molecule. Two epoxy units reacted with DICY to give secondary alcohols, while the other one linked to the nitrile group. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 375–382
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2017
·Vol. 131
·期 2
·1499-1507
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IF 1.953
Lyu Jiaxun,Hu Dongdong,Liu Tao,Zhao Ling
The non-isothermal curing kinetics of epoxy resin system consisting of diglycidyl ether of bisphenol A (DGEBA) and m-xylylenediamine (MXDA) were investigated by high-pressure differential scanning calorimetry at different heating rates of 5, 10, 15 and 20 K min −1 under compressed carbon dioxide (CO 2 ) of 0.1–8 MPa. The activation energies were determined by isoconversional Kissinger–Akahira–Sunose method and Vyazovkin numerical method, and the average values decreased from 53.5 to 46.8 and 54.1 to 44.5 kJ mol −1 , respectively, when the CO 2 pressure increased from 0.1 to 8 MPa. It is indicated that the curing reaction of epoxy resin occurs more easily under higher-pressure CO 2 due to the promoted molecular movement, especially in the supercritical state. The non-isothermal curing kinetics were investigated by n th-order model and two-parameter autocatalytic model (Šesták–Berggren model), and the latter one analyzed by Málek method exhibited good agreement with the experimental data except the initial and final stages of the curing reaction.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2015
·Vol. 33
·期 11
·1259-1268
·
IF 1.578
Jiapeng Li,Qihui He,Renfu Xu,Baixing Hu
In this paper silica nanoparticles with covalently grafted polymer chains were incorporated into bisphenol A dicyanate ester (BADCy) to prepare composites which resulted in improvements in the mechanical and thermal properties. Fourier-transform infrared (FT-IR) spectroscopy transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) were employed to examine the surface functionalization of silica nanoparticles. The effects of functionalized SiO 2 (F-SiO 2 ) on the curing reactivity mechanical and thermal properties of BADCy resin were investigated systematically. The curing reaction of the system was facilitated with the addition of F-SiO 2 . Meanwhile compared with the neat resin the incorporation of appropriate content of modified F-SiO 2 can enhance the mechanical properties including impact flexural strengths and fracture toughness K IC of BADCy resin. In addition the thermal stability of BADCy/F-SiO 2 nanocomposites is also superior to that of pure BADCy resin.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 19
·52132
·
IF 3.057
Jinzhao Li,Mengdi Chen,Yuechuan Wang
Demand for electronic materials with improved dielectric properties are increasing. One of the ways to reduce the dielectric constant is to incorporate fluorine atoms. In this article, a novel fluorinated epoxy resin (diglycidol ether of 2,4-bis (1,1,1,3,3,3-hexafluoroisopropyl) fluorobenzene (FB-EP)) with 45.7 wt% fluorine content was synthesized from fluorobenzene, epichlorohydrin and hexafluoroacetone. The structures of desired monomers were characterized by NMR and FTIR. The epoxy resin FB-EP was cured by copolymerization with hexahydrophthalic anhydride (HHPA) and by homopolymerization catalyzed with boron trifluoride ethylamine (BF 3 MEA), respectively. The curing reaction kinetics of the fluorinated epoxy and the properties of the cured materials were studied in comparison with those of common diglycidol ether epoxy resin (BADGE). The results of curing activation energy indicate that FB-EP is reactive as the BADGE, and the four-trifluoromethyl groups on FB-EP do not negatively affect the cationic polymerization reactivity of the epoxy groups. The cured FB-EP materials had lower moisture absorption, and especially lower dielectric constant ( D k , 2.23) and lower dielectric loss ( D f , 0.011) in the frequency range of 8.2–12.4 GHz. This article provides a base for further study of fluorinated epoxy resin as advanced electronic materials.
研究领域:
材料科学
·
电子材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）