Soft Matter
·
2011
·Vol. 7
·期 18
·8516-8524
·
IF 4.457
Wei Xiong,Hanfu Wang,Yanchun Han
The synthesis and characterization of oligoaniline-containing dendron-rod-dendron dumbbell shape block oligomer (14G3A7) are presented. The unusual surface morphological evolution from fibrils to flat single-layer film and to a porous network is observed for 14G3A7 simply by oxidizing the block oligomer in solution. Based on the analysis of cryo-TEM as well as comparative studies on solution concentration and substrate properties, the series of changes in the surface morphology are explained through aniline conformational transition during oxidation. The network self-assembled from oxidized 14G3A7 contains a two dimensional close packing skeleton of aniline segment, which may find a wide range of applications in electronic sensitive devices.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Lubricants
·
2023
·Vol. 11
·期 6
·260
·
IF 3.5
Yong Li,Weidong Zhou,Wanan Xue,Yongwang Huang,Qiang Zhang,Jingbin Han
In this work, MgAl-layered double hydroxides (LDH) were synthesized by co-precipitation method using a colloid mill and characterized by XRD and SEM. It was found that the environmentally friendly LDHs had greater performance than the traditional antioxidant. By adding LDHs into large electric shovel grease (GRK-A) in open-pit coal mine, the service lifetime of grease was extended by 20%. With the increase in LDH addition, the grease sample attains greater activation energy, and the thermal oxidation and decomposition resistance become stronger. Comparing the energy storage modulus and flow transition index at different temperatures, adding the right amount of LDHs needs close attention for the system oxidation resistance and viscoelasticity. For the electric shovel grease, the best oxidation resistance and rheological properties can be achieved by adding 2% of LDHs. The rheological viscosity–temperature curves show that the grease samples with different ratios of solid LDHs have better low-temperature properties than the mine grease. This work outlines a simple method for creating an environmentally sustainable lubricant additive with the use of LDH. LDH serves as a novel inorganic antioxidant additive that is optimal for open gear lubrication and sliding friction.Keywords:layered double hydroxides;grease;antioxidant;oxidative induction time
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
International Journal of Applied Ceramic Technology
·
2023
·Vol. 20
·期 6
·3635-3646
·
IF 2.1
Haopeng Cai,Yinglong Wei,Baoguo Wang,Kun Jiang
It is necessary to give self-healing function to ceramic materials because of their notch sensitivity. In the past, studies on self-healing ceramics have mainly focused on the high-temperature stage, and less research has been done below 1000°C. In this study, SiC/Al 2 O 3 /TiB 2 ceramic composites were prepared by spark plasma discharge sintering, and cracks were introduced on the surface of the polished specimens. Crack healing at 600°C–800°C was investigated, and the recovery of macroscopic bending strength and the change of microscopic crack morphology after heat treatment were used to evaluate the crack-healing effect. It was found that the surface cracks of the material were completely filled and healed by oxidation products after heat treatment at 700°C for 60 min, and the highest healing efficiency exceeded 95% for both specimens with different crack lengths, and the main mechanism of crack by Si-Al-B-Na-Ca-O type glass produced by the reaction of TiB2 and a small amount of SiC with oxygen to produce oxides and glass powder. Good healing effect and fast healing speed effectively improve the service life and reliability of ceramic materials, which has very far-reaching significance for the practical application with ceramic materials.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Yue Yu,Dan Cao,Lingang Yang,Haibiao Guan,Zehao Liu,Changlong Liu,Xiaoshuang Chen,Haibo Shu
Two-dimensional (2D) layered group-IV monochalcogenides with large surface-to-volume ratio and high surface activity make that their structural and optoelectronic properties are sensitive to air oxidation. Here, we report the utilization of oxidation-induced gradient doping to modulate electronic structures and optoelectronic properties of 2D group-IV monochalcogenides by using SnS nanoplates grown by physical vapor deposition as a model system. By a precise control of oxidation time and temperature, the structural transition from SnS to SnSO x could be driven by the layer-by-layer oxygen doping and intercalation. The resulting SnSO x with a graded narrowing bandgap exhibits the enhanced optical absorption and photocurrent, leading to the fabricated SnSO x photodetector with remarkable photoresponsivity and fast response speed (<64 μs) at a broadband spectrum range of 520–1550 nm. The peak responsivity (7294 A/W) and detectivity (9.54 × 10 9 Jones) of SnSO x device are at least two orders of magnitude larger than those of SnS photodetector. Moreover, its photodetection performance can be competed with state-of-the-art of 2D materials-based photodetectors. This work suggests that the air oxidation could be utilized as an efficient strategy to engineer the electronic and optical properties of SnS and other 2D group-IV monochalcogenides for the development of high-performance broadband photodetectors.
研究领域:
材料科学
·
光电技术
·
纳米科技
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2013
·
IF 2.77
Xiaofeng Wang,Weiyi Xing,Gang Tang,Ningning Hong,Weizhao Hu,Jing Zhan,Lei Song,Wei Yang,Yuan Hu
A novel sulfur-bearing secondary antioxidant with a high molecular weight of 2252 (OS-POSS), successfully synthesized via photoinitiated thiol-ene click reaction, was compared with two commercial sulfur-bearing secondary antioxidants on the stabilization of polypropylene (PP). The results of their oxidation induction time (OIT) via differential scanning calorimeter measurement (DSC) showed that the higher the molecular weight of secondary antioxidant is, the longer the OIT value, whether such sulfur-bearing antioxidant is used singly or in combination with primary antioxidant. The study of their long-term accelerated thermal aging in the air oven at 150 °C displayed that the molecular structure of sulfur-bearing secondary antioxidant, besides molecular weight, is another highly important factor determining the antioxidant efficiency, i.e., physical loss of antioxidants with the relatively low molecular weight may determine antioxidant efficiency, whereas thioether groups having neighboring ester carbonyl moieties may decompose more hydroperoxides with quicker rate.
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
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 131
·期 3
·
IF 1.395
Mingliang Xin,Yujie Ma,Kai Xu,Mingcai Chen
Octyl gallate (OG), dodecyl gallate (DG), and hexadecyl gallate (HG) were synthesized and characterized by Fourier transform infrared (FTIR) and NMR, and their thermal stability was measured by thermogravimetric analysis (TGA). The antioxidant effect of these derivatives in polypropylene (PP) was measured by oxidation induction temperature measurement on DSC, and by measurement of carbonyl groups in the polymer on attenuated total reflectance FTIR spectroscopy after they were aged at 120°C. The results indicated that the gallate derivatives could provide long-term stabilization to PP under conditions of oxidative degradation. The antioxidant performance of HG with longer alkyl chain was superior to the OG and DG, making the former a good candidate to be used as antioxidant additive in PP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 39850.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2017
·
IF 3.671
Kai Chen,Dezhan Ye,Shaojin Gu,Yingshan Zhou
Which factors are crucial to improving lignin antioxidant ability in polymers has been debated over years. Here, the structural effect of natural antioxidant from technical Kraft lignin (KL) on the oxidation induction time (OIT) of KL/polypropylene (PP) was quantitatively investigated using correlation analysis model instead of traditional linear fitting model. The correlation coefficient and significance value of their relationship clearly demonstrated the dominating role of non-condensed Phenolic OH (Ph-OH) in improving KL/PP thermal-oxidation stability, subsequently followed by M ¯ n , aliphatic OH/total Ph-OH, condensed Ph-OH and polydispersity. OIT is positive with non-condensed and total Ph-OH, while it declines with increase of the above other factors. Remarkably, the longest OIT (∼90 min) was obtained even at extreme loading (0.5 wt%), almost ∼911% and ∼201% huge increase in contrast to that of pure PP and crude KL/PP composite, respectively. Meanwhile, the mechanical properties of KL fractions/PP blends can be maintained at the same or better level than that of pure PP, due to strong interfacial adhesion strength.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2022
·Vol. 62
·期 12
·4214-4225
·
IF 2.573
Wenrong Zhao,Ming Lu,Bin Wang,Xiaoqing Liu,Shuang Wang
The effect of iron-containing substances with different forms on the properties of carbon-black filled natural rubber compound is discussed. The ionic iron substances (FeCl 2 , FeCl 3 , Fe(SA) 3 ) have a detrimental effect on the rubber. Based on the oxidation induction temperature values, the relative deteriorating effects of ionic iron substances on the rubber are in the order: Fe(SA) 3 > FeCl 3 ≈ FeCl 2 . Not only are the metal ions (Fe 2+ , Fe 3+ ) with adjacent stable oxidation states catalytically active in degrading rubber, but also the counterions have an influence on the effect of oxidation, particularly the stearic anion. Ionic iron materials can decrease the molecular weight, especially for the case of Fe(SA) 3 as measured by gel permeation chromatography. Due to the degrading effect on the rubber molecules, Fe(SA) 3 brings about a torque decrease in moving die rheometer and evident decrease of the Mooney viscosity at 100°C, which is different from the effects of Fe 2 O 3 and 304L-Fe. The insoluble iron substances behave more like hard fillers. Additionally, Fe(SA) 3 remarkably alters the bound rubber content and the tensile properties after aging via two different process (scission and crosslinking). Overall, this work has a thorough comparison of effect of iron-containing materials on rubber aging and provides useful inspiration to protect the rubber from deterioration by foreign reagents and regulating the rubber stability and degradation rate via introducing degradative metal ions.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
·
2021
·Vol. 98
·期 6
·673-682
·
IF 1.849
Changqing Miao,Yanbo Wang,Zhiying Ma,Yang Luo,Yu Miao,Pingfang Yuan,Jiao Guo,Gairong Chen,Hongbo Liu
In this study, poly( p- phenylenediamine) (PPDA) was synthesized by an enzymatic polymerization method using p- phenylenediamine as the monomer in the water phase. The PPDA structure was characterized by infrared (IR), gel permeation chromatography, and elemental analysis. The antioxidation behavior of the as-synthesized PPDA in biodegradable castor oil was investigated using a rotary oxygen bomb test and pressurized differential scanning calorimetry. A theoretical calculation was conducted to investigate its antioxidation mechanism. PPDA was found to exhibit excellent oxidation resistance in castor oil at 150 °C, which effectively prolonged the oxidation induction time of the oil. The results obtained herein suggest that as with phenolic antioxidants, PPDA with a hindered structure effectively improves the antioxidation performance of the oil by enhancing the stability of nitrogen free radicals.
研究领域:
材料科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
·
2015
·
IF 2.184
Shiya Ran,Li Zhao,Ligang Han,Zhenghong Guo,Zhengping Fang
A kind of rare earth compound, ytterbium trifluoromethanesulfonate (Yb(OTf) 3 ), was introduced into high-density polyethylene (HDPE) by melt compounding to investigate the effect of Yb(OTf) 3 on the thermal and thermo-oxidative stability of HDPE. The results of thermogravimetric (TG) and differential scanning calorimetry (DSC) showed that the addition of Yb(OTf) 3 made the thermal degradation temperatures dramatically increased, the oxidative induction time (OIT) extended, and the enthalpy (Δ H d ) reduced. Very low Yb(OTf) 3 loading (0.5 wt%) in HDPE could increase the onset degradation temperature in air from 334 to 407 °C, delay the OIT from 11.0 to 24.3 min, and decrease the Δ H d from 61.0 to 13.0 J/g remarkably. Electron spin resonance spectra (ESR), thermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TGA-FTIR), rheological investigation and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) indicated that the free radicals-trapping ability of Yb(OTf) 3 was responsible for the improved thermal and thermo-oxidative stability.
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
TRIBOLOGY INTERNATIONAL
·
2025
·
IF 6.9
Yuexia Huang,Qiang Chen,Jing Yang,Pingxia Guo,Xiao Liu,Kai Feng,Meirong Cai,Feng Zhou
A novel oil-miscible hindered phenol based multifunctional lubricant additive (BHT)-NP was synthesized and its antioxidant, tribological properties were thoroughly characterized. Compared with the commercially available hindered phenolic antioxidants (ST-135), the (BHT)-NP exhibited enhanced antioxidant and wear reduction properties at room temperature or 100 ℃. Specifically, adding 4 wt% (BHT)-NP to PAO10 could prolong its oxidation induction time from 4 to 70 min, which is 2.2 times that of ST-135. Additionally, this lubricant system could also decrease the wear volume of PAO10 + 4 wt% ST-135 by 88.67 % (rt), 88.42 % (100 ℃), respectively. Subsequently, lubrication mechanism analysis results suggested that an effective protection film was fabricated on the sliding steel surface, which significantly prevented the direct contact between the sliding pairs.
研究领域:
材料科学
·
机械工程
·
化学工程
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 74
·46678-46689
·
IF 3.108
Chenyang Li,Zhenhuan Li,Maliang Zhang,Bowen Cheng
SiC-fixed organophilic montmorillonite (OMMT@SiC) hybrid particles, with various proportions of SiC, were fabricated by electrostatic self-assembly in the presence of CTAB. Then, their PPS composites were prepared by melt-compounding. The results showed that the oxidation resistance and mechanical properties of PPS/OMMT@SiC composites was enhanced. When SiC content reached 5 wt%, the oxidation induction temperature of the PPS/OMMT@SiC composite achieved its maximum 513.1 °C, which was 40.9 °C higher than that of pure PPS. Meanwhile, the oxidation induction time of the obtained composite achieved a maximum of 25.2 min. These enhancements were attributed to the existence of the SiC, which prevented the aggregation of OMMT and facilitated OMMT to be further exfoliated in the PPS matrix. The sulfur atoms of PPS formed chemical bonds with SiC, meanwhile, a part of the surface hydroxyl groups of SiC formed hydrogen bonds with PPS, thus weakening the oxidation activity. OMMT and SiC effectively postponed the thermal oxidative degradation of PPS due to synergistic effects.
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
危险品化学品经营许可证（带存储）