JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Jinxue Cheng,Qinglin Huang,Yan Huang,Shiwen Yu,Changfa Xiao,Quan Hu
In this research, a novel poly(tetrafluoroethylene) (PTFE) membrane with regular geometric pore structure fabricated by near-field electrospinning (NFES) method was firstly utilized in the preparation of water-in-oil (W/O) emulsion through membrane emulsification process. Effects of NFES PTFE membranes’ pore aspect ratio (length-width ratio of rectangle pore structure) on the water-in-oil droplet size, droplet size distribution, and uniformity of water-in-oil emulsion was investigated respectively. Results showed that the increase of pore aspect ratio would bring about a smaller water-in-oil droplet size. The average water-in-oil droplet size decreased from 234.9 nm (M-1) to 167.8 nm (M-4) when the pore aspect ratio increased from 1 to 4. Compared with conventional mechanical agitation, the water-in-oil emulsion formed by membrane emulsification process showed not only more uniform water-in-oil droplet size, but also higher long-term stability (remained homogeneous after 30 days). In addition to showing the excellent membrane emulsification performance in harsh environment, the NFES PTFE membrane also exhibited excellent water-in-oil emulsion separation performance. Compared with other NFES PTFE membranes, M-1 membrane showed the highest oil flux (33.4 L m -2 h -1 , -0.02 MPa) and water rejection rate (94.4%) in the separation of water-in-oil emulsion formed by membrane emulsification process.
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
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Junqing Ren,Pao Yang,Zhijian Peng,Xiuli Fu
Nowadays, microwave dielectric substrate materials have been extensively investigated to meet the requirements of rapid development in modern communications. Among them, the composites of ceramic powder filled polytetrafluoroethylene (PTFE) have been a hot topic. However, the compatibility and connectivity between the surface of ceramics and PTFE molecular chains in the samples are usually low. Herein novel PTFE based composites with different contents of Al 2 Mo 3 O 12 (20–60 wt%) modified by C 14 H 19 F 13 O 3 Si (F8261) coupling agent were designed and prepared. The coupling agent F8261 has been successfully grafted to the surface of Al 2 Mo 3 O 12 powders, effectively promoting the densification and dielectric properties of the composites. As the content of the modified Al 2 Mo 3 O 12 powders increases from 20 to 60 wt%, the ε r value increases from 3.4 to 4.2, and tanδ almost remains constant at the beginning and increases with much more Al 2 Mo 3 O 12 added. The Al 2 Mo 3 O 12 -PTFE composites filled with 30 wt% Al 2 Mo 3 O 12 present the optimal dielectric properties of ε r = 3.6 and tanδ = 0.0018 with a high density of 95.6%. In addition, the electromagnetic and multiphysic simulation of a 24 GHz substrate integrated waveguide filter on the basis of the 30 wt% Al 2 Mo 3 O 12 - 70 wt% PTFE composite was carried out. It was revealed that the filter presented high stability on the electrical parameters caused by self-heating and dimension deformation due to the good microwave dielectric , thermal and mechanical properties of the substrate. These results indicate that the as-prepared 30 wt% Al 2 Mo 3 O 12 - 70 wt% PTFE composite would be a promising candidate for high-performance microwave dielectric substrates.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Chaowen Dai,Wei Sun,Xianfu Chen,Peng Xu,Wei Ke,Tao Wang,Qi Zhang,Minghui Qiu,Kaiyun Fu,Yiqun Fan
The surface wettability and pore structure of membranes play crucial roles in determining their separation efficiency. Innovating ceramic membranes with hydrophobic surfaces holds considerable promise for broadening their applications. Owing to the remarkable hydrophobic properties and robustness of PTFE materials, this study suggests the fabrication of PTFE/ceramic composite membranes utilizing a solid-state sintering of PTFE nanoparticles. Polyvinyl alcohol (PVA) was employed as a binding agent to facilitate the formation of a uniform PTFE membrane layer on the porous ceramic substrate. A comprehensive investigation was conducted into the influence of various factors, including PVA addition, emulsion concentration, dip-coating duration, and sintering temperature, on the morphology and performance of these composite membranes. The results showed that the incorporation of PVA effectively mitigated the back-diffusion of PTFE particles and ensured the structural integrity of membrane. The resulting PTFE/ceramic membrane exhibited a finer and more uniform pore structure than the commercial PTFE membrane. The composite membrane boasted a water contact angle of 133°, an average pore size of 78 nm, and a membrane layer thickness of 3.8 μm. These characteristics contributed to its exceptional separation performance when utilized in the ultrafiltration of polystyrene nanoparticle suspensions and the androstenedione-contained water-in-oil emulsion.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 27
·e02663
·
IF 2
Mehedi Hasan,Baojiang Sun,Litao Chen
Graphical The impact of PTFE grain size and curing temperature on hydrophobicity is investigated in this work. Hydrophobic surfaces are developed using doctor blades, a simple coating technique for complicated structures like oil and gas pipelines. Samples dried at 100–120 °C showed the highest hydrophobicity levels, based on hydrophobicity indicators. The hydrophobic properties of polytetrafluoroethylene (PTFE), a synthetic fluoropolymer, are widely recognized. Numerous applications exist in the field of hydrophobic, self-cleaning coatings. Researchers used different types of PTFE and heaters to dry the surface at varying temperatures. According to this viewpoint, the study's goal is to investigate how drying temperature and grain size affect the hydrophobicity of surfaces coated with epoxy, fluorosilicone, and PTFE. The coated surfaces that dried at temperatures of 50, 70, 100, 120, and 150 °C, and atmospheric temperature were developed using different grain sizes of PTFE at different concentrations. The hydrophobicity-indicating parameters, like contact angles, real-time contact angles, adhesion work, and adhesion tension, were measured. The results of the study showed that the hydrophobicity of the surface is influenced by the kind of liquid, drying temperature, PTFE content, and grain size. Better results were obtained with a PTFE coating containing 200 nm nanoparticles than with one containing 0.5–1.5 µm microparticles. The samples that were dried between 100 and 120 °C exhibited the highest levels of hydrophobicity, based on the hydrophobicity indicators. Researchers and entrepreneurs are able to develop surfaces that are hydrophobic to clean themselves by employing the research data.
研究领域:
材料科学
·
表面工程
·
高分子科学
·
化学工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Membranes
·
2021
·Vol. 11
·期 6
·420
·
IF 4.106
Tianshu Liu,Xiaoji Zhou,Yizhuo Sun,Renbi Bai
In this study, PVDF/PTFE composite membranes were prepared by adding a PTFE nanoemulsion to a PVDF solution and casting it through the conventional non-solvent-induced phase separation method. The objective was to explore the effectiveness of using a simple and economical method to modify PVDF membranes with PTFE to enhance their anticorrosion performance, especially under highly acidic or alkaline conditions. PTFE nanoparticles (of around 200 nm in size) in nanoemulsion form were blended with PVDF at a mass ratio of PTFE:PVDF in the range of 0–0.3:1. The obtained membranes were examined to determine the effect of the added PTFE nanoparticles on the structure of the modified PVDF membranes as well as on their mechanical strength and surface characteristics. The membranes were then immersed in various concentrations of acidic or alkaline solutions for varied durations ranging from a few days up to as long as 180 days (6 months). The impacts of by the corrosive solutions on the tensile strength, surface roughness, and water flux of the membranes with different exposure times were quantified. The results showed that although a certain extent of change may occur with extended immersion times, greatly enhanced anticorrosion performance was obtained with the prepared PVDF/PTFE membranes compared with the unmodified PVDF membrane. For example, after being immersed in 5 mol-H+··L−1H2SO4, HCl, and HNO3solutions for 6 months, the tensile strength at breaking point remained at up to 69.70, 74.07, and 71.38%, respectively, of the initial strength for the PVDF/PTFE (M30) membrane. This was in contrast to values of only 55.77, 70.43, and 61.78% for the unmodified PVDF membrane (M0). Although the water flux and surface roughness showed a change trends to the tensile strength, the PVDF/PTFE (M30) membrane had much higher stability than the PVDF (M0) membrane. In a continuous filtration experiment containing H2SO4at 0.01 mol-H+·L−1for 336 h (14 days), the PVDF/PTFE membrane showed a maximum flux change of less than 30%. This was in comparison with a change of up to 50% for the PVDF membrane. However, the PVDF/PTFE membranes did not seem to have a greatly enhanced anticorrosion performance in the alkaline solution environment tested.Keywords:PVDF/PTFE composite membrane;PTFE nanoparticle;polymer blending;non-solvent induced phase separation method;anticorrosive performance
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
APPLIED THERMAL ENGINEERING
·
2024
·
IF 6.1
Jiewen Xiong,Minqi Zhang,Wentao Wan,Yanbokang Shu,Shengji Li,Xuefeng Huang
This paper prepared aluminum@polytetrafluoroethylene (Al@PTFE) composite fuels with different PTFE contents and evaluated the effect of PTFE content on the thermal and combustion characteristics via multiple characterization methods. The scanning electron microscopy (SEM) and thermogravimetry–differential scanning calorimetry (TG-DSC) results showed that the PTFE was well coated on the surface, and the higher the PTFE content, the faster the oxidation reaction rate. Al@PTFE_8% fuel demonstrated more stable thermal performance and higher weight gain. Al@PTFE_15% had a weak endothermic peak at 337.2 °C, while the other two fuels did not appear. The nanosecond pulsed laser-induced plasma ignition (LIPI) test showed that compared to pure Al counterpart, Al@PTFE fuels could effectively shorten the ignition delay and promote the energy release, for Al@PTFE_8% with a reduction of 41.9% in ignition delay and an increase by 17.1 % in combustion temperature. The self-sustaining burn time decreased as the PTFE content increased. The gas-phase combustion of Al@PTFE fuels were more pronounced, and their AlO spectral signal intensity were stronger. The Al@PTFE combustion residues showed lots of cracks and holes, and the mass fraction of O was increased from 22.96 % (Al) to 30.53 % (Al@PTFE_8%). The proposed combustion mechanism reveals that PTFE destroyed the alumina film that hindered combustion, significantly promoting the combustion of Al particles. This study provides guidance for laser-induced plasma ignition of this material under ultrahigh heating rates.
研究领域:
材料科学
·
燃烧学
✓ 已验证
DOI
高影响因子
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
·
2022
·Vol. 29
·期 6
·2190-2198
·
IF 2.509
Feipeng Wang,Zijian Yang,Jingliang Huang,Yuyang Yan,Jian Li
Insulating oil is indispensable cooling impregnation and isolation agent for oil-filled electrical equipment, such as power transformers. The aging byproducts, i.e., water and organic acids, impose a serious threat to these expensive transformers. Insulating oil reclamation is a complicated process. In this article, a polyvinylidene fluoride (PVDF) polymer with polytetrafluoroethylene (PTFE) additive composite nanofiber membrane is synthesized for insulating oil reclamation with high efficiency. The reclamation and dielectric performance of the PVDF/PTFE nanofiber membrane is evaluated by the acid value, microwater (MW) contents, and ac breakdown voltage of the treated oil. The results show that the nanofiber membrane filtration rate toward acetic acid and MW is 69.4% and 76.0%, respectively. Moreover, the dielectric loss factor and relative permittivity of treated oil decrease significantly at low frequencies, and the breakdown voltage is increased from 21.8 to 65.2 kV. The PVDF/PTFE composite nanofiber membrane has removed organic acid and MW effectively, and it provides a more practical method for insulating oil reclamation.
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
FUEL
·
2024
·
IF 6.7
Shuai Ma,Hongyu Huang,Haoming Zou,Xijuan Lv,Shuai Zhao,Ting Zhang,Qinghai Shu
The study focuses on resolving moisture-induced oxidative deactivation and Mg/PTFE interfacial bonding challenges in reactive materials by utilizing polydopamine (PDA) to bridge magnesium (Mg) and polytetrafluoroethylene (PTFE). Initially, a 5 % PDA content was set based on FIB-SEM and specific surface area results, yielding a surface area of 18.2794 m 2 /g for Mg@5%PDA. The contact angle reached 76.91°, a 19.62° increase over raw Mg, signifying improved hydrophobicity. Subsequently, analysis of the thermal and combustion behavior of Mg@PTFE indicated continuous improvement with increasing PTFE content, reaching an inflection point at 8 % PTFE. The DSC peak temperature of Mg@PTFE increased with higher PTFE content, indicating enhanced stability. However, the DSC heat release reaches its maximum of 5806 J/g at 8 % PTFE. Meanwhile, ignition delay minimized to 117 ms at 8 % PTFE, a 53.01 % reduction compared to 4 % PTFE. Additionally, the contact angle of Mg@8%PTFE was 96.12°, a 38.83° rise from raw Mg, further improving hydrophobicity. Finally, optimal PTFE content was determined to be 8 %. Hence, the Mg@5%PDA@8%PTFE dual-core shell structure was successfully fabricated, with hydrophobicity tests showing a contact angle of 108.54°, a significant 51.25°increase over raw Mg, demonstrating exceptional hydrophobicity.
研究领域:
材料科学
·
能源化学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xianfu Chen,Chaowen Dai,Tianyu Zhang,Peng Xu,Wei Ke,Jian Wu,Minghui Qiu,Kaiyun Fu,Yiqun Fan
Membrane separation has been proven to be a promising technology for waste-oil purification. However, the efficient preparation of hydrophobic and strong membrane materials has always been one of the bottlenecks and the object of research focus in the field. Here, we developed an efficient construction method for preparing a hydrophobic membrane with a robust polytetrafluoroethylene (PTFE) top layer. The macroporous ceramic substrate was applied instead of the ceramic membrane as the support of the PTFE layer. Meanwhile, two-dimensional graphene oxide was introduced to partially pre-fill the large pores on the surface of the substrate. Resultantly, the binding depth between the membrane layer and the substrate was properly tailored. The excessive infiltration of the PTFE membrane layer was avoided, and there was a strong binding between the membrane layer and the ceramic substrate. The effects of the graphene oxide and PTFE loadings and thermal treatment on the microstructure and performance of the composite membrane were systematically studied. The optimized PTFE/alumina composite membrane exhibited a water contact angle of ∼ 135°, an average pore size of ∼ 200 nm, and a layer thickness of 6.5 μm. Additionally, the prepared composite membrane exhibited excellent separation performance for emulsified water and particle suspensions in oil.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Sustainability
·
2022
·Vol. 14
·期 9
·5353
·
IF 3.889
Kun Li,Tao Zhou,Xinqiang Xu,Changye Han,Hua Zhang,Jiang Jin
Mn-Co-based catalysts were loaded to ceramic filters element by impregnation for the coprocessing of dust and nitrogen oxide (NOx) in flue gas. The influence of the Mn/Co ratio and loading on the catalytic performance was investigated. The Mn-Co-based catalytic ceramic filter with a Mn/Co molar ratio of 2/1 can achieve 99% NO conversion by selective catalytic reduction of NOxwith NH3(NH3-SCR) in the temperature range of 100−180 °C, but its resistance to H2O was relatively poor. The filter element was modified by PTFE to improve the H2O resistance. After modification, the catalytic ceramic filter showed superior resistance to H2O and SO2at low temperatures (100–180 °C) and satisfactory self-cleaning performance.Keywords:NH3-SCR;catalytic ceramic filter;PTFE-modified;H2O resistance
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 39
·22289-22294
·
IF 3.049
Dapeng Gu,Longxiao Zhang,Suwen Chen,Kefeng Song,Deng Pan,Bingchao Yang,Shouyao Liu
Polytetrafluoroethylene/poly(methyl methacrylate) (PTFE/PMMA) composites were prepared by a self-curing method. The influence of heat treatment processes on the friction and wear behaviors of PTFE/PMMA composites against bearing steel balls were studied by a ball-on-disk tribometer. The thermal performance of PTFE/PMMA composites with heat treatment was analyzed by Thermogravimetric Analysis (TGA). The surface morphologies and element distribution of PTFE/PMMA composites in a PMMA matrix were detected by Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive Spectroscopy (EDS). The results indicated that the wear rates of PTFE/PMMA composites with different heat treatments significantly declined compared with the unheated treatment composite. The wear rate of the PTFE/PMMA composite decreased firstly and then increased with molding temperature and time increasing, and reduced with the molding pressure increasing. The main wear mechanisms of PTFE/PMMA composites with different heat treatments were fatigue wear and abrasive wear.
研究领域:
材料科学
·
机械工程
·
表面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RARE METALS
·
2018
·Vol. 42
·期 11
·3870-3876
·
IF 1.5
Ji Ruo-Nan,Liu Chen-Xu,Zhang Jin,Zhang Shu-Guang,Zhang Le,Lian Yong
Al 2 O 3 /polytetrafluoroethylene (PTFE) composite coating was prepared on titanium alloy by cathode plasma electrolytic deposition (CPED) and impregnation method, to improve the hydrophobicity and tribological properties. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analysis of the coating indicate that PTFE penetrates into the interior of the coating and is well bonded to titanium alloy substrate by cross-linking with Al 2 O 3 ceramic coating. The contact angles were measured by contact angle measurement, and the tribological properties of the composite coating were evaluated by sliding wear test. The surface of the composite coating is found to possess good hydrophobicity with a water contact angle of 140°. The results also indicate an improved tribological properties of Al 2 O 3 /PTFE composite coating at room temperature with a steady friction coefficient as low as 0.05. The self-lubricating anti-wear composite coating is expected to solve fouling problems and poor wear resistance of titanium alloys.
研究领域:
材料科学
·
表面工程
✓ 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）