Materials
·
2023
·Vol. 16
·期 4
·1620
·
IF 3.4
Yihong Zhang,Yong Wu,Puyu Zhou,Zhiyuan Song,Yayun Jia,Weiyi Ouyang,Rafael Luque,Yang Sun
Aluminum sulfate was employed as the main accelerator in order to explore new non-chloride and alkali-free cement accelerators. Acrylic acid, aluminum fluoride, or alkanolamine were used as regulators to further accelerate cement setting. The setting time, compressive, and flexural strengths in cement early strength progress were detected, and both the cement (raw material) and hydrated mortar were fully characterized. The cement setting experiments revealed that only loading acrylic acid as the regulator would decrease the setting time of cement and increase the compressive and flexural strengths of mortar, but further introduction of aluminum fluoride or alkanolamine improved this process drastically. In the meantime, structural characterizations indicated that the raw material (cement) used in this work was composed of C3S (alite), while hydrated mortar consisted of quartz and C3A (tricalcium aluminate). During this transformation, the coordination polyhedron of Al3+was changed from a tetrahedron to octahedron. This work puts forward a significant strategy for promoting the activity of aluminum sulfate in cement setting and would contribute to the future design of new non-chloride and alkali-free cement accelerators.Keywords:aluminum sulfate;accelerator;setting time;mortar;strength
研究领域:
材料科学
·
土木工程
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产品关联
DOI
PubMed
高影响因子
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
·
2025
·
IF 3.1
Chenyuan Teng,Yichao Ding,Yuanxiang Zhou,Lei Zhao,Yunxiao Zhang,Haoran Chen,Youbing Zhang
The curing formula is vital to the performance of epoxy resin impregnated paper (RIP) material. This work explored the effect of curing agents and accelerator contents on the thermal and electrical properties of RIP material. It was found that the RIP material cured with 1phr accelerator has the optimal glass transition temperature, electrical conductivity, dielectric loss and DC breakdown strength compared with RIP material cured by 0.5phr, 2phr, and 3phr accelerator. The RIP material cured with MEHHPA has better thermal and insulating properties compared with the RIP material cured with METHPA. The existence of the crepe paper amplifies the influence of accelerator and curing agent for the hydroxyl groups affect the curing process as well as the chain segment arrangement. This study provides the research support for the design of the curing formula for RIP insulation used in DC bushing.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2022
·Vol. 13
·期 5
·4343-4351
·
IF 4.05
Liu Wei,Na Haining,Hu Changhui,Zhou Fang,Zhang Zhenyu,Guo Zhuo,Li Mian,Zhu Jin
With the aim to exhibit the advantages of catalytic accelerator in enhancing the selective hydrolysis of cellulose to sugar, cellulose is hydrolyzed in low acid aqueous system with catalytic accelerator. And then sugar products are extracted and fermented by yeast. By the assistance of catalytic accelerator, cellulose conversion rate and total reducing sugar yield are 95.7% and 90.9%. And the glucose yield is as high as 73.6%. The sugar products with high glucose content can be easily extracted from cellulose hydrolysate. Low toxicity of the sugar products to yeast is found during yeast fermentation. The glucose in cellulose hydrolysate can be fully consumed after 12 h. A highly actual ethanol yield is exhibited, which is equal to the actual yield level of standard glucose solution. The important role of catalytic accelerator in aqueous hydrolytic system to produce fermentable sugar is clearly reflected. Furthermore, a simple but effective way is established to efficient utilization of cellulose as an applicable carbon source for the conversion of more value-added chemicals and materials.
研究领域:
生物化学
·
可再生资源利用
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DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2020
·Vol. 144
·期 3
·721-728
·
IF 2.731
Li Heping,Liang Daolun,Liu Jianzhong
Nano-materials are potential substitutes for micro-sized solid propellant ingredients for improving energy density and reaction activity. So far, several nano-carbides act as accelerants for boron (B) oxidation reaction but their promotive effects and corresponding action mechanisms have rarely been reported. In this work, four nano-carbides [nano-boron carbide (nB 4 C), nano-titanium carbide (nTiC), nano-zirconium carbide (nZrC), and nano-silicon carbide (nSiC)] were evaluated by thermogravimetric differential scanning calorimetry-combined thermal analysis system and thermodynamic software FactSage 6.2. Among the four nano-carbides, nTiC ranked as the best accelerant by reducing the initial oxidation temperature of B by 10.7% and increasing heat release by 16.0%. By comparison, nB 4 C and nZrC were ranked as second and third best accelerants with abilities of decreasing the initial oxidation temperature (by 5.4% and 3.3%, respectively) and raising heat release (both by 6.2%). On the other hand, though nSiC slightly decreases the initial oxidation temperature of B, heat release of B + nSiC was lower than that of original B. The action mechanisms of nano-carbides were found complex, and one nano-carbide can accelerate B oxidation following one or several approaches. First, the nano-carbide can be oxidized before B to offer extra heat and induce the oxidation of B. The produced gaseous oxidation product CO 2 by nano-carbide may then help break down the liquid oxide film deposited on B particle surface. Third, the reaction between nano-carbide and B would generate borides, which may diminish accumulated liquid oxide film at low temperatures. Finally, the corresponding oxide will be produced to catalyze the oxidation of B. Overall, these findings look promising for future performance improvement of B-based solid propellants.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Xin Liu,Dining Li,Mingqi Li,Hui Xie,Xiaohan Yu,Haochuan Wang,Wei Wang,Jinxiang Hong,Zuhua Zhang,Pan Feng
Magnesium salts are key components of liquid alkali-free accelerator; however, their influence on the setting and hardening of accelerated cement pastes remains unclear. This study systematically investigates the role of different magnesium salts by preparing and examining aluminum sulfate (AS)-based accelerators at different dosages. The effects of the accelerators on the setting and early age mechanical properties of the cement pastes were comparatively studied. Results revealed that the type and dosage of magnesium salts significantly affected these properties. Specifically, MgSiF 6 substantially accelerated the cement paste setting, albeit at the expense of early age mechanical strength, owing to its considerable delay in C 3 S hydration. Conversely, both Mg(NO 3 ) 2 and MgSO 4 slightly shortened the setting time while improving the 6 h compressive strength, which was attributed to the facilitation of C 3 S hydration and refinement of the cement pore structure. Further analysis of ettringite formation, growth and chemical composition indicated that the low pH environment induced by MgSiF 6 promoted the incorporation of magnesium and fluoride ions into ettringite, leading to the formation of higher-aspect-ratio crystals. This morphological change enhanced the percolation network, thus accelerating cement setting. These findings advance our understanding of the setting and hardening mechanisms of accelerated cement pastes and offer valuable guidelines for optimizing accelerator formulations.
研究领域:
材料科学
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土木工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2021
·Vol. 33
·期 2
·610-626
·
IF 3.665
Haolan Gou,Yingying Zhao,Yanglong Zhou,Wei Wei,Xiaoma Fei,Xiaojie Li,Xiaoya Liu
For the molding compounds used in electronic packaging, curing accelerators play a significant effect on the curing behavior of thermosetting resins, thus the cross-linked structure and performance of the cured product. In this study, nine commercially available imidazole compounds, divided into three types, were introduced into a polyfunctional epoxy resin (E 1 )/XYLOK phenolic resin (P 1 )/MDA benzoxazine (B 1 ) ternary system to reduce the curing temperature for molding processing. To understand the cross-linked structure of the cured product, the ternary system was divided into unitary system and binary system, and the curing behavior and chemical structure of each system was monitored by differential scanning calorimetry and Fourier transform-infrared systematically. Due to the nucleophilicity of tertiary amines influenced by the steric hindrance effect, it was discovered that the reaction activity of epoxy resin initiated by nine imidazole compounds, was significantly different. However, the ring opening of benzoxazine occurs at a high temperature, even catalyzed with imidazoles, and its curing behavior was nearly the same owing to the unique ring-opening mechanism initiated by active hydrogen of imidazole. In addition, phenolic resin elevates reaction activity for both epoxy resin and benzoxazine. The cross-linked structure of E 1 P 1 B 1 ternary system was proposed based on the experimental results from each system. It suggested that the formed network of the E 1 P 1 B 1 cured product with Type I and II imidazoles is mainly IPN structure, while the cured products of E 1 P 1 B 1 + Type III is the copolymerization of epoxy, phenolic and benzoxazine. This paper systematically illustrated the ideal chemical structures of epoxy resin/phenolic resin/benzoxazine ternary system with different imidazole compounds, which is valuable for industrial application of resin-based materials.
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
COMPOSITES SCIENCE AND TECHNOLOGY
·
2020
·
IF 7.094
Kaizheng Zhu,Yu Liu,Heliang Wang,Xiwei Guo,Shuangquan Liao,Zhifen Wang,Lin Fang
Reinforcing agents and accelerators are the most important auxiliaries for rubber industry. In this paper, ceric ammonium nitrate (CAN), for the first time, worked as a catalyst for hydroxyl groups in silica to prepare silica grafted sodium xanthate (SSX), which was used as an in-situ modified multifunctional rubber additive in this work. Compared with sodium isobutyl xanthate (SIBX), SSX has enhanced the initial and final degradation temperatures, achieving the improvement of 103 °C and 277 °C, respectively. Notably, owing to the powerful interaction between each component, SSX can be homogeneously dispersed in the natural rubber (NR) matrix in contrast to the seriously aggregated silica. Meanwhile, NR/SSX composites exhibited superior curing properties and showed an increase of 29.1% and 33.4% in the tensile strength and tear strength , respectively, compared to that of traditional 2-mercaptobenzothiazole (MBT) system. Since high-performance rubber composites can be obtained by introducing SSX, we believe that this work can provide a novel and facile approach to prepare natural silicate minerals-based vulcanization accelerators.
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
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2019
·
IF 4.978
Bowen Zhang,Yingying Zhao,Xin Sun,Xiaoma Fei,Wei Wei,Xiaojie Li,Xiaoya Liu
Organic-inorganic hybrid microcapsules encapsulating 2-phenylimidazole (2-PhIm) were prepared by Pickering emulsion polymerization of styrene and divinyl benzene using methacryloyloxy silane-modified silica particles as the stabilizer, and served as a thermal latent curing accelerator for diglycidylether of bisphenol A epoxy/anhydride system. The one-component curing composition containing 5 wt% of the microcapsules exhibited an excellent storage stability. The pot life at room temperature was as long as 30 days, while which of 2-PhIm curing system was only 2 days. At elevated temperature, the encapsulated 2-PhIm could be released from microcapsules effectively, and instantly accelerated the curing reaction. Meanwhile, the addition of microcapsules did not cause an adverse effect on the thermomechanical performance of the epoxy thermosets . In addition, the latency and curing behavior could be facilely regulated at a wide range of temperature by adjusting monomer ratios of the polymer matrix, to match different process temperatures. The microcapsules with robust cross-linked polystyrene matrix structure also showed good resistance to shearing forces, indicating their feasibility for high-speed mixing or kneading process in practical applications. It is suggested that the novel latent curing accelerator is potential for high-performance one-pot epoxy formulations, particularly recommended for application in electronic packaging fields.
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 INTERNATIONAL
·
2021
·Vol. 70
·期 12
·1680-1691
·
IF 2.99
Haolan Gou,Bowen Zhang,Wei Wei,Xiaoma Fei,Xiaojie Li,Xiaoya Liu
Latent curing accelerators are essential for application to one-component epoxy systems in various industries, such as coatings, adhesives and electronic packaging. Herein, we developed organic–inorganic hybrid microcapsules encapsulating triphenylphosphine (TPP) by Pickering emulsion polymerization of styrene and methoxyethyl methacrylate with dimethoxydiphenylsilane-modified silica nanoparticles as emulsifiers. The microcapsules were further surface-modified by epoxy silane and employed as a thermal latent curing accelerator for an epoxy/anhydride system. Good dispersibility and interfacial bonding of the hybrid microcapsules with the resin matrix were observed. Compared with TPP, the microcapsule-type accelerator endowed the one-component epoxy curing system with significantly enhanced storage stability at room temperature of 25 °C (a pot life of 20 days) and a comparable curing activity at high temperature. The activity of the encapsulated accelerator can be blocked and released rapidly and effectively with increasing temperature to trigger the segmental motion of the polymeric microcapsules. Furthermore, the addition of microcapsules increased the glass transition temperature and thermal stability of the epoxy thermosets owing to the organic–inorganic hybrid character. Moreover, the toughness of the cured resin was also improved. Therefore, the latent curing accelerator demonstrated a promising prospect for application in high-performance one-pot epoxy formulations. © 2021 Society of Industrial Chemistry.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Hongyu Lu,Xinyuan Zhan,Zhengbo Yue,Zhilin Xie,Pengcheng Zhao,Wei Wang,Xiao He,Jin Wang
The large accumulation of superfine iron tailings (SIT) as solid waste may lead to significant environmental and safety risks, urgently requiring resource utilization. The preparation of geopolymers using SIT is high-valued and environmentally friendly method. Therefore, a low-cost, alkali-containing solid carbonate series accelerator (CSA) was used to accelerate the early geopolymerization process of coal fly ash (CFA)/SIT-based three-dimensional printed geopolymers (CS-3DPG). The optimal addition time and content of CSA were 25 min and 6 %, respectively, which significantly shortened the setting time of CS-3DPG to 9 min and increased its early compressive strength to 24.18 MPa. The addition of CSA enhanced the rheological properties of CS-3DPG, improving its printability and buildability. These results provide assurance for achieving rapid prototyping of CS-3DPG. Combined with microscopic characterization, selective chemical extractions (SCE) and isothermal conduction calorimetry (ICC), CSA effectively promoted the CS-3DPG geopolymerization reaction process, transitioning from interactions at the phase boundary (I) to diffusion (D). Additionally, the CO 2 emissions of CS-3DPG were reduced by 76 % compared to Ordinary Portland Cement (OPC). This study successfully reveals the role and impact mechanism of CSA in 3DPG, providing an important theoretical reference for regulating 3DPG buildability.
研究领域:
材料科学
·
环境科学
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Liangjing Wang,Xiaowei Fan,Mengsi Li,Yi Wang,Defang Liu
Herein, polyaniline (PANI) and reduced graphene oxide (rGO) as nanoprobes couple with graphitic carbon nitride to form rGO@g-C 3 N 4 -PANI nanocomposite, which exhibits good synergetic enhancement impact on the ECL signal of g-C 3 N 4 . Moreover, ZnNiO 2 nanoflowers (ZnNiO 2 NFs) are firstly used as co-reaction accelerators to remarkably enhance the ECL emission of rGO@g-C3N4-PANI in this work. In the presence of ZnNiO2 NFs, a significant ECL signal enhancement of 15780 a.u. is observed, which is 4 times stronger than that of the rGO@g-C3N4-PANI. Owing to the excellent electronic conductivity and the ability to avoid the deposition of positively charged reduction products, the ZnNiO2 NFs can effectively prevent electrode passivation , thus the rGO@g-C3N4-PANI/ZnNiO2 system emits stable and strong ECL signal. A sensitive ECL sensor has been constructed for the quantitative detection of methotrexate (MTX) of the real blood sample by quenching the ECL signal. Under the optimal conditions, the sensor exhibits a superior linear range from 1 pM to 10 μM and a low detection limit of 0.24 pM (S/N = 3). The proposed ECL signal amplification strategy can be an effective analytical tool for trace detection of targets in biological systems.
研究领域:
生物传感
·
材料科学
·
医学检测
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2022
·Vol. 18
·期 44
·2204827
·
IF 15.153
Qing Cao,Zhaoyang Cheng,Jiajun Dai,Tianxiao Sun,Guixiang Li,Lili Zhao,Jiayuan Yu,Weijia Zhou,Jianjian Lin
The rational design for transition metals-based carbon nano-materials as efficient electrocatalysts still remains a crucial challenge for economical electrochemical hydrogen production. Carbon nanotubes (CNTs) as attractive electrocatalysts are typically activated by non-metal dopant to promote catalytic performance. Metals doping or metal/non-metal co-doping of CNTs, however, are rarely explored. Herein, this work rationally designs bimetal oxide templates of ZnCo 2 O 4 for heterogeneously doping Zn and N into Co nanoparticles embedded carbon nanotubes (Co@Zn-N-CNTs). During the formation of CNTs, Zn atoms volatilize from ZnCo 2 O 4 and in situ dope into the carbon skeleton. In particular, owing to the low electronegativity of Zn, the electrons aptly transfer from Zn to carbon atoms, which generate a high electron density for the carbon layers and offer more preponderant catalytic sites for hydrogen reduction. The Co@Zn-N-CNTs catalyst exhibits enhanced hydrogen evolution reaction activity in 0.5 m H 2 SO 4 electrolyte, with a low onset potential of −20 mV versus RHE at 1 mA cm −2 , an overpotential of 67 mV at 10 mA cm −2 , a small Tafel slope of 52.1 mV dec −1 , and persistent long-term stability. This study provides brand-new insights into the utilization of Zn as electronic regulator and activity promoter toward the design of high-efficiency electrocatalysts.
研究领域:
材料科学
·
电化学
·
纳米技术
·
能源材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）