Polymers
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2019
·Vol. 11
·期 7
·1122
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IF 3.164
Mengmeng Zhao,Qaiser Mahmood,Chuyang Jing,Liang Wang,Guangqian Zhu,Xianhui Zhang,Qinggang Wang
A series of vanadium complexes bearing iminopyridine bidentate ligands with various electronic and steric properties:V1[CH2Ph],V2[CMe2CH2CMe3],V3[Ph] andV4[2,6-iPr2Ph] were prepared and characterized by IR spectroscopy and microanalytical analysis. The catalytic capacity of all the complexes has been investigated for isoprene polymerization and was controlled by tuning the ligand structure with differentN-alkyl andN-aryl groups. Activated by methylaluminoxane (MAO), the aryl-substituted complexV3[Ph] exhibited highcis-1,4 selectivity (75%), and the resultant polymers had high molecular weights (Mn= 6.6 × 104) and narrow molecular weight distributions (PDI = 2.3). This catalyst showed high activity up to 734.4 kg polymer (mol V)−1h−1with excellent thermostability even stable at 70 °C. Compared to the traditional VCl3/MAO catalytic system, iminopyridine-supported V(III) catalysts displayed higher catalytic activities and changed the selectivity of monomer enchainment fromtrans-1,4 tocis-1,4.Keywords:polyisoprene;iminopyridine ligands;vanadium complexes;VCl3/MAO;Ziegler-Natta polymerization
研究领域:
化学
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材料科学
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DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 137
·期 17
·48620
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IF 2.188
Jianfeng Liu,Lu Shao,Xiu Feng,Sheng Xu,Puke Mi
In this article, four constrained geometry complexes 4a [(η 5 -C 5 H 4 )CH 2 (α-C 4 H 3 N)]Ti(NMe 2 ) 2 , 7a [(η 5 -C 9 H 6 )CH 2 (α-C 4 H 3 N)]Ti(NMe 2 ) 2 , 4b [(η 5 -C 5 H 4 )CH 2 (α-C 4 H 3 N)]Zr(NEt 2 ) 2 , 7b [(η 5 -C 9 H 6 )CH 2 (α-C 4 H 3 N)]Zr(NEt 2 ) 2 with pyrrole-bridged fragment were synthesized and characterized by 1 H NMR, 13 C NMR, MASS, and EA. When combined with MAO, complex 4b given the highest activity, the activity of copolymerizing ethylene and 1-hexene reached 2.48 × 10 6 g polymer/mol·M·h. The effects of temperature, pressure, and ratio of Al/Metal on the polymerization reaction and properties of polymers had been investigated. The polymers with these complexes were characterized by 13 C NMR and DSC, and the results shown that polymer with 4a had the highest α-olefin incorporation, the incorporation of 1-hexene reached up to 9.81 mol%, and the 1-octene was 8.84 mol%. Actually, there was no [HH] or [OO] sequence in the copolymer, according to the formula of reactivity ratio, rE • rH = 0, all these results suggested that the copolymerization mode is alternating copolymerization. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48620.
研究领域:
高分子化学
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催化化学
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DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
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2024
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IF 5.3
Guoqing Wang,Lingxiang Guo,Yuling Ruan,Gai Zhao,Xianlong Zhang,Yuzhen Liu,Dae-Eun Kim
Aluminum alloys, which are vital in various industries, are susceptible to corrosion and wear. Although the micro-arc oxidation (MAO) method addresses these issues, it introduces microporosity, which undermines the integrity of the alloy. In this study, MAO coatings are enriched via plasma-enhanced chemical vapor deposition (PECVD) using hexamethyldisilane, specifically SiCOx and SiOx. The assessment of the mechanical, tribological, and corrosion-resistant characteristics of these composite coatings reveals substantial enhancements in the aluminum alloy properties post-PECVD treatment. Surface morphology observations highlight the reduced pore size and area of the PECVD-coated surfaces, particularly in SiCOx coatings, which are known for their superior gap-filling properties. Scratch tests demonstrate superior adhesion of SiCOx coatings, showed a higher scratch resistance of approximately 17.8 N compared to 15.9 N for SiOx coatings. The wear rate of the SiCOx coating significantly decreased compared to the MAO coating owing to higher hardness, dropping from 3.57 × 10 −5 mm 3 /N·m to 2.04 × 10 −5 mm 3 /N·m. SiCOx-coated surfaces show higher corrosion potential (−0.0078 V ) than MAO-only coating (−0.0212 V), indicating enhanced corrosion resistance. These innovative coatings provide an advanced surface treatment strategy and are suitable for a wide range of industrial applications owing to their enhanced surface attributes.
研究领域:
材料科学
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表面工程
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DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
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2023
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IF 5.4
Weizhou Li,Quanzhi Chen,Deli Shen,Ruixia Yang,Xiuhai Zhang
In order to decrease defects and improve protective performance, micro-arc oxidation (MAO) coating was modified by adding SiO 2 particles to form a composite coating on TA2 alloy via laser treatment. The microstructural morphology, phase structure, cohesive strength and corrosion resistance of the composite coatings were investigated and analyzed by using SEM, XRD , thermal cycle, and electrochemical testing, respectively. The results showed that SiO 2 particles were firstly adsorbed onto the MAO surface with the aid of ultrasonic treatment and then sealed micro-pores of the MAO coating after laser treatment. The composite coating mainly consisted of R-TiO 2 , A-TiO 2 and SiO 2 phases and exhibited a dense multilayer structure with a rich Si element in the outer layer. After subjecting the coatings to 300 thermal cycles, clacking or marked spalling zones could not be observed in the composite coating; nevertheless, an obvious destruction appeared in the single MAO coating without SiO 2 particles. The corrosion potential ( E corr ) and pitting potentials ( E pit ) of the composite coating were −0.303 V and 1.765 V compared to that of −0.682 V and 1.401 V for the single MAO coating. Additionally, the corrosion rate decreased to 1.40 × 10 −4 A·cm −2 with the highest resistance (76,788.67 Ω·cm 2 ) from2.19 × 10 −4 A·cm −2 , indicating a stronger corrosion resistance in the composite coating. The results of simulation from Comsol Multiphysics demonstrated that a laser power as 80 W was appropriate for melting SiO 2 particles into the MAO coating to form a dense and cohesive composite coating.
研究领域:
材料科学
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表面工程
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腐蚀与防护
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2024
·
IF 6.3
Shun Hu,Hua-yun Du,Hao Huang,Ying-hui Wei,Li-feng Hou,Qian Wang,Huan Wei,Xiao-da Liu,Yan Zhou,Hong-wei He
Micro arc oxidation-Polydopamine (MAO-PDA) composite coating is a functional corrosion resistant coating formed on the surface of magnesium alloy by combining MAO to form a porous ceramic layer and the spontaneous oxidation polymerization characteristics of PDA. The MAO-PDA coating is environmentally friendly and modifiable, providing a basic film layer for achieving self-warning, self-healing, conductivity and other modification functions, which has attracted widespread attention. A new type of MAO-PDA composite coating with good corrosion resistance was deposited on the surface of magnesium alloy by photocatalysis, which expanded the application range of magnesium alloy MAO surface treatment. Surface morphology, coating adhesion and corrosion resistance of the composite coating are characterized. Combined with Density functional theory (DFT) calculation, the possible mechanism is explored. The results indicate that the MAO layer containing Mg 2 TiO 4 exhibits fewer pores and can better deposit PDA under ultraviolet (UV) light conditions, forming a magnesium alloy MAO-PDA composite coating with good corrosion resistance and modification friendliness. Band structure calculations confirm the photocatalytic effect of Mg 2 TiO 4 under UV irradiation. As a result of the photocatalytic effect, reactive oxygen species (ROS) were generated in the pores and on the surface of the MAO sample, thus accelerating the local deposition of PDA.
研究领域:
材料科学
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表面工程
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腐蚀与防护
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产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
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2025
·
IF 6.1
Gai Zhao,Zhiyuan Guo,Jingfu Song,Guoqing Wang,Yanbo Zhao
Micro-arc oxidation (MAO) is a widely utilized surface modification technique for aluminum alloys, but its inherent porosity compromises both wear and corrosion resistance in aggressive environments. This study addresses these limitations by integrating a photocurable polyurethane acrylate (PPUA) coating with different surface textures onto the MAO-treated aluminum alloy using 3D printing. Mercury intrusion porosimetry revealed that the PPUA coating significantly reduced porosity and total intrusion volume, leading to a denser and less permeable surface. Tribological evaluations demonstrated that surface texture plays a critical role in friction and wear behavior. The flat surface exhibited the highest friction coefficient and the highest wear rate. Square textured surface displayed a moderate friction coefficient but suffered from severe plastic deformation and debris accumulation, contributing to an increased wear rate. Meanwhile, circular textured surface exhibited the lowest friction coefficient and wear rate. Potentiodynamic polarization tests confirmed that the PPUA coating significantly enhanced corrosion resistance by increasing the corrosion potential and reducing the corrosion current density, effectively limiting electrolyte infiltration. These findings suggest that the combination of MAO with a tailored photocurable polymer coating offers a promising approach to optimizing the mechanical durability and corrosion protection of aluminum alloys for advanced engineering applications.
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DOI
高影响因子
Materials Today Communications
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2025
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IF 4.5
Zhou Jie,Siyuan Jin,Ruizhi Wu,Xiaochun Ma,Haoran Wang,Mengyao Pang,Zhe Yu,Wang Guixiang,Jinghuai Zhang,Boris Krit,Sergey Betsofen,Neshchimenko Vitalii,Buzikov Ruslan,Min Qiu,Yurong Yang,Jiaming Chen
Due to the poor corrosion resistance of Mg-Li alloys and the limited effectiveness of single surface treatment methods, developing a composite coating is essential to significantly enhance the corrosion protection. In this study, a stable ceramic coating was fabricated on the surface of a Mg-Li alloy by micro-arc oxidation with regulation of the concentration of ZnO nanoparticles added to the electrolyte. Layered double hydroxides (LDH) was subsequently prepared on the coating surface by modulating the hydrothermal temperature, contributing to blocking the micropores and cracks to enhance the compactness of the coating. Additionally, a low-surface-energy hexadecyltrimethoxysilane (HDTMS) was selected to self-assemble on a rough micro/nano structured MAO/LDH coating to obtain a superhydrophobic surface The composite coating exhibited exceptional corrosion resistance, with the R ct value increasing by four orders of magnitude compared to the substrate and the Y 0 (CPE out ) reduced to the 10 -9 range. Furthermore, the coating keeps almost non-corrosion morphology after 7 days of immersion in 3.5% NaCl solution, which is attributed to the combined effects of the superhydrophobicity of HDTMS, the physical barrier effect and chloride ion trapping ability of LDHs, and the reduction in porosity achieved through the incorporation of nano-ZnO in MAO coating.
研究领域:
材料科学
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表面工程
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腐蚀科学
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纳米技术
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电化学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2026
·
IF 5.6
Lingjiao Zhu,Yan Liu,Dongmei Pu,Qiwen Yong,Liang Wu,Zhi-Hui Xie
A synergistic sealing protocol involving modifying micro-arc oxidation (MAO) coatings with a mixture of stearic acid (SA) and yttrium nitrate was developed to intensify the long-lasting corrosion protection. The micropore-sealing effects of two yttrium-containing solutions at different times and the corresponding morphologies and compositions of the composite coatings were investigated. The organic-inorganic SY-MAO-20 composite coating treated in the mixture for 20 minutes exhibited mostly enhanced corrosion protection, ascribed to the decreased surface porosity resulting from the sealing effect of (C 17 H 35 COO) 3 Y (Yttrium stearate) compared to the unmodified coating. The SY-MAO-20 coating possesses an extremely low corrosion current down to 10.9 nA·cm -2 and a high impedance modulus up to 6.52 MΩ·cm -2 at low frequency, which are decreased by two orders of magnitude and increased by 50 times compared to the MAO film without modification. The enhancement of the as-prepared coating in corrosion resistance is also caused by the transition of surface wettability from hydrophilicity (water contact angle: 20.4° ± 4.2°) to hydrophobicity (141.2° ± 1.2°) due to the SA modification. These results demonstrate an effective strategy to address the micropore issue in the MAO coating and thus significantly intensify the physical barrier action for achieving long-term corrosion protection for the magnesium alloy.
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DOI
高影响因子
CERAMICS INTERNATIONAL
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2026
·
IF 6
Jia Wang,Zeru Wang,Chuanyao Dong,Kan Zhang
Titanium alloys are widely used in lightweight mechanical components, but their limited mechanical and tribological properties often lead to failure under service conditions. In this study, a titanium-based micro-arc oxidation (Ti-MAO) composite coating was developed by incorporating hexagonal boron nitride (h-BN) while optimizing electrolyte composition and process parameters. Proper control of h-BN content effectively improved the high-temperature oxidation resistance and tribological properties of the Ti-MAO coating. The research results showed that h-BN could regulate the energy distribution during MAO discharge, promote coating densification, and reduce structural defects. At a concentration of 4 g/L, h-BN maintained good dispersibility. Compared with an additive-free Ti-MAO coating, the h-BN/Ti-MAO composite coating showed an 86% reduction in the oxidation rate constant at 600 °C. Due to the stable layered structure of h-BN over a wide temperature range, the composite coating maintained a friction coefficient (COF) below 0.31 from room temperature (RT) to 500 °C, reduced to below 0.21 within 300 °C. However, excessive h-BN led to particle aggregation and a decline in overall coating performance. In summary, this approach enhances the durability of titanium alloy components through improved oxidation resistance and tribological properties.
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DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
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2021
·
IF 5.039
Xin Wang,Hongguang Yan,Ruiqiang Hang,Huixian Shi,Lifei Wang,Jianchao Ma,Xiaoping Liu,Xiaohong Yao
A multi-functional composite coating was fabricated on magnesium (Mg) AZ31 alloy through micro-arc oxidation (MAO) combined with self-assembly technology. Polyethyleneimine (PEI) as a medium was assembled on MAO coating based on the chemical bonding and electrostatic interactions. Adhered PEI successfully mediates the self-assembly of functional silver nanoparticles (Ag NPs) with a formation of Ag NPs/PEI/MAO (APM) composite coating. The morphology and microstructure of as-prepared APM coating were characterized by using of different technologies (e.g. scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy). Its corrosion behavior in simulated body fluid and the corresponding antibacterial performance against Staphylococcus aureus ( S. aureus ) were also investigated. The potentiodynamic polarization results showed that the corrosion current density of APM coated AZ31 decreased more than three orders of magnitude in comparison with that of uncoated AZ31, indicating an enhanced anticorrosive ability. Electrochemical impedance spectroscopy results further revealed that the improvement of corrosion resistance was attributed to a synergistic effect of Ag NPs/PEI and MAO. The hydrogen evolution tests confirmed that APM coating provided AZ31 an excellent corrosion protection during a relatively long term. And the antibacterial research showed that APM coated AZ31 had a great antibacterial activity. This study presents a promising approach to fabricate a multi-functional composite coating on Mg alloy, which improves the anticorrosive performance of the substrate and endows it an antibacterial activity to meet a better demand in the applications.
研究领域:
材料科学
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生物医学工程
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产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2026
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IF 4.8
Chenchen Wang,Xiaolei Song,Diantao Chen,Junyu Su,Yong Wang,Cheng Huang,Wei Wei
Considering the irreversible nature of Alzheimer's disease (AD), early diagnosis is of great importance for AD treatment. Both β-amyloid (Aβ) and monoamine oxidase B (MAO-B) are potential biomarkers for AD. This study developed a surface-enhanced Raman scattering (SERS) sensor using gold-nanocube (OX-AuNCs) to detect Aβ42 and MAO-B. OX-AuNCs, a type of gold-nanocube with open gaps, achieved a Raman enhancement factor of 8.99 × 10 8 due to numerous hot spots. The specific affinity between Thioflavin T (ThT) and Aβ42 inhibits ThT's intramolecular rotation, reducing its SERS signal. This reduced signal showed a linear correlation with Aβ42 concentrations from 66.70 pM to 0.20 μM, achieving a limit of detection (LOD) at 44.30 pM, while also distinguishing different aggregation levels of Aβ42. Interestingly, SERS intensity of phenethylamine (PEA) also decreased significantly when interacting with MAO-B. A linear relationship was found between the change in PEA intensity and MAO-B concentration (0.01–20.00 μg mL −1 ), yielding an LOD of 5.00 ng mL −1 . The proposed SERS sensor effectively detected two potential AD biomarkers, Aβ42 and MAO-B, in artificial cerebrospinal fluid (ACSF) and human serum with satisfactory recovery rates, respectively. These results show promise for clinical diagnosis and drug screening for AD.
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DOI
PubMed
高影响因子
WEAR
·
2022
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IF 4.695
Dongya Zhang,Xin Du,Ao Bai,Liping Wang
In this study, micro-arc oxidation (MAO) coatings were fabricated and modified graphene (MGr) was used as an oil additive to enhance the tribological properties of Ti6Al4V. The results show that: the friction coefficient of Ti6Al4V is significantly reduced when lubricated by the modified oil, and the friction coefficients of the MAO coatings are much lower than those of Ti6Al4V with Polyα olefin synthetic oils that are added with modified graphene (PAO–MGr). The mainly wear form of Ti6Al4V is mainly adhesive, while that of the MAO coating is abrasive. Furthermore, the peaks of typical graphene were observed in the friction region using Raman spectroscopy . The modified graphene enters the porous structure of the MAO coating and forms a stable graphene transfer film, thereby achieving a low friction coefficient and wear.
研究领域:
材料科学
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摩擦学
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DOI
高影响因子
危险品化学品经营许可证（带存储）