JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2014
·Vol. 117
·期 2
·603-610
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IF 2.206
Liu Jialin,Li Jingrui,Fan Mengjin,Zhang Junying,Cheng Jue
Aromatic amine curing agent with flexible unit in backbone, 1,4-bis (4-diaminobenzene-1-oxygen) n -butane (DDBE), was synthesized, and the structure was confirmed by FT-IR and 1 H NMR. The curing kinetics of tetraglycidyl methylene dianiline (TGDDM, or AG80) using DDBE and 4,4′-bis-(diaminodiphenyl) methane (DDM) as curing agents, respectively, were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TG, respectively. The results showed that the activation energy of AG80/DDBE system was slightly higher than that of AG80/DDM system. Šesták-Berggren model can generally simulate well the reaction rates of these two systems. DMTA measurements showed that the storage modulus of cured AG80/DDBE is similar to that of cured AG80/DDM at the temperature below glass transition temperature ( T
g ) and lower than that of cured AG80/DDM at the temperature above glass transition temperature, while T
g of cured AG80/DDBE is lower than that of cured AG80/DDM. TG showed that the thermal stabilities of these two cured systems are similar.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2023
·
IF 3.8
Guoxin Ding,Chenfeng Sun,Meiyi Wang,Guojun Cheng,Jun Liu,Yuexiang Hu
The construction of multihollow lightweight wave absorbing materials is a future goal. Layered double hydroxides (LDHs) offer a great potential for electromagnetic wave absorption given their lamellar texture and tunable bimetallic composition. In this study, CoFe–LDH was grown on 4,4'-diaminodiphenylmethane-modified reduce graphene oxide (RGO) surfaces through a hydrothermal method, and composites with different morphologies and wave-absorbing properties were obtained at varying molar ratios of Fe to Co in CoFe–LDH. When Fe: Co=5:5, CoFe–LDH flakes grew uniformly on the RGO surface, and the composite exhibited an excellent microwave absorption performance with a minimum reflection loss of –60.0 dB and effective absorption bandwidth (EAB) of 4.4 GHz. When Fe: Co=3:7, the composite can obtain a maximum EAB of 5.12 GHz at a matched thickness of 1.82 mm.
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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
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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
·
高分子化学
·
可持续材料
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DOI
PubMed
高影响因子
Journal of Materials Chemistry B
·
2022
·Vol. 11
·期 2
·335-344
·
IF 7.571
Yuqing Lei,Jiajia Xu,Mengqi Pan,Yadong Chen,Xiaojun Li,Weipu Zhu,Chang Shu,Tianxiang Fang,Hongbing Liao,Qiaojie Luo,Xiaodong Li
Dentin bonding is the most common form of human tissue repair among tissue-biomaterial adhesions, concerning billions of people's oral health worldwide. However, insufficient adhesive infiltration in the demineralized dentin matrix (DDM) always produces numerous defects in the bonding interface termed the hybrid layer, which causes high levels of bacteria-related secondary dental diseases, and less than 50% of the bonding lasts more than 5 years. Therefore, it is urgent and vital to construct an antibacterial low-defect hybrid layer to solve the durability-related problems. A DDM with a hydrogel-like surface formed by the hydration of highly-anionic non-collagenous proteins (NCPs) is firstly used as a template to electrostatically assemble polyethyleneimine (PEI). The formation of a stable antibacterial polyelectrolyte complex of PEI/NCPs rapidly eliminates NCP hydration capacity and significantly improves the infiltration of various adhesives. Simultaneously, both the PEI during the assembly and the PEI-assembled DDM can directly destroy a biofilm of S. Mutans on the DDM. Consequently, a long-term antibacterial and low-defect hybrid layer is successfully created, which greatly improves the bonding effectiveness. This helps to improve the clinical treatment of bacteria-based dental diseases and the tooth-restoration repair effect and prevent secondary dental diseases, having significance in clinical dentistry and providing insights for other tissue-biomaterial adhesions.
研究领域:
牙科学
·
生物材料
·
组织工程
·
材料科学
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产品关联
DOI
PubMed
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2023
·
IF 5.1
Xiangkai Zhang,Zhimin Wang,Jianqiang Xie
A novel fluorinated diamine curing agent (AFPCO) was synthesized from natural isoflavone daidzein , used to cure hydrogenated epoxy resin (DGEHBPA) and tested against commercially available DGEHBPA cured with 4,4′-diaminodiphenylmethane (DDM). The results show that the non-isothermal curing reaction kinetics study found AFPCO to be less reactive than DDM. Compared to DDM, the AFPCO cured material increases the energy storage modulus , impact strength and flexural strength by 34%, 51% and 12% respectively. The AFPCO cured material performs worse in terms of decomposition temperature , but the residual carbon rate exceeds that of DDM/DGEHBPA by 230% and the flame retardancy reaches VL-94 V-1 level. In contrast to the hydrophilic nature of the material after DDM curing, the introduction of fluorine in AFPCO gives the material a water contact angle of 92.19°, which meets the criteria for hydrophobic materials. In contrast to low dielectric constant resins prepared with conventional fluorinated curing agents, AFPCO/DGEHBPA has a high dielectric constant , but still exhibits a low numerical value of 0.0338 in dielectric loss.
研究领域:
材料科学
·
化学工程
·
高分子化学
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DOI
高影响因子
CARBON
·
2020
·
IF 8.821
Lijun Cao,Shuairu Zhu,Baohai Pan,Xinyan Dai,Weiwei Zhao,Yuan Liu,Weiping Xie,Yongbo Kuang,Xiaoqing Liu
The stability and durability of laser-induced graphene (LIG) patterns embedded in polymer substrates are significant for their practical application. However, most of currently reported LIG precursors are facing the dilemma of weak structural controllability, poor resistance to acid/base, or bad processability . In this work, we efficiently converted the synthesized poly (Ph-ddm) into LIG using a straightforward CO 2 laser, aiming to find a potential LIG precursor with excellent durability under harsh conditions. The graphene structure of obtained LIG was confirmed by Raman spectra , scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Results indicated that the poly (Ph-ddm)-based LIG showed a low sheet resistance of 35 Ω/sq as well as a high specific surface area of 883 m 2 /g. And due to the superior properties of poly (Ph-ddm), the LIG patterns exhibited excellent resistance to strong acid/base solutions and high adhesion on the substrate, which ensured their stable application under severe conditions. Besides, potential application of as-prepared LIG was demonstrated in well-performed supercapacitors and electrode for water splitting in an alkaline medium . Based on the results in this work, polybenzoxazine could be a promising precursor for stable and durable LIG preparation.
研究领域:
材料科学
·
纳米技术
·
电化学
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DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Peixiao Sun,Hongjian Zhang,Xiaoli Li,Yang Leng,Bin Li,Zhao Wang,Miaojun Xu
With the rapid progress of electronics and 5 G technology, high flame retardancy and low toxicity epoxy resin have been crucial. Hence, the bio-carbon dot (CD) doped with N, P, and Mo elements was prepared by hydrothermal method using corn straw as the biomass carbon source, ethylenediamine as the nitrogen source, and phosphomolybdic acid as the phosphorus and molybdenum source. As a P-containing compound, ADP complexed with CD containing the transition metal element Mo on the surface to obtain complexes (ADP/CD). The flame retardant epoxy resin composites (EP/ADP/CD) were further prepared by ADP/CD as a flame retardant and 4,4′-diaminodiphenylmethane (DDM) as a curing substance. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the shape and chemical structure of CD. The experimental results indicate that when the additive amount of ADP/CD was 4 % (ADP: CD=3.5:0.5), the limiting oxygen index (LOI) of the EP/3.5ADP/0.5CD was 37.5 % (41.5 % higher than pure EP) and reached the UL94 V-0 rate. Cone calorimeter testing revealed a 51.4 %, 39.1 %, 19.6 %, and 70.4 % decrease in the peak heat release rate (pHRR), total heat release (THR), carbon monoxide production (COP), and carbon dioxide production (CO 2 P) of EP/ADP/CD. respectively, then with EP. Furthermore, the mechanical properties of EP/3.5ADP/0.5CD were discussed. Therefore, this work designs a flame-retardant carbon dot , providing a new scheme for creating a multifunctional epoxy resin with flame retardancy, smoke reduction, and toxicity reduction.
研究领域:
材料科学
·
化学
·
消防安全工程
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DOI
高影响因子
POLYMER TESTING
·
2020
·
IF 3.275
Weiqi Xie,Donglin Tang,Shumei Liu,Jianqing Zhao
The development of high-performance biomass-derived epoxy thermosets with excellent flame resistance is vital to various applications (i.e., composites, coatings and adhesives). Herein, a difunctional epoxy monomer bis(2-methoxy-4-(oxiran-2-ylmethyl)phenyl) phenyl phosphate (BEU-EP) was synthesized from abundant and biobased eugenol . In addition, BEU-EP was cured by 4,4′-diaminodiphenyl methane (DDM) and the cured resin diglycidyl ether of bisphenol A (DGEBA)/DDM was used as a reference. Results indicated that BEU-EP/DDM not only showed a 58.1%, 28.8% and 35.1% increase in residual char (at 700 °C), flexural and storage modulus (at 30 °C) compared with DGEBA/DDM, but also exhibited excellent flame resistance and smoke suppression. BEU-EP/DDM passed V-0 rating (in UL-94 testing) with limiting oxygen index (LOI) of 38.4% and greatly decreased the peak heat release rate (pHRR) and total smoke production (TSP) by 84.9% and 80.5%, respectively. The mechanism analysis confirmed that the phosphorus-containing group and aromatic structure from BEU-EP contributed both the gas and condensed-phase flame retardation of BEU-EP/DDM network. This work provides an efficient and scalable route for synthesizing biobased epoxy thermosets with high integrated performance and superior flame resistance.
研究领域:
材料科学
·
化学工程
·
高分子科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）