SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Zhaofeng Wang,Panyi Chen,Yang Liu,Hanxiang Guo,Nan Sun,Qiqi Cai,Yueying Yu,Fangbo Zhao
In this study, a new kind of aromatic diamine monomer named as 1,4-bis(4-aminophenyl)piperazine (BANPZ) was particularly designed and synthesized, and then the novel zwitterionic polyimide (ZPI) was prepared through a two-step process including polycondensation and quaternary amination reaction. The chemical structures of the prepared monomer and polymers were identified by FTIR and 1 H NMR measurements, respectively. Meanwhile, the inherent viscosities, molecular weights, solubility behaviors and thermal properties of two obtained polymers were thoroughly characterized. Compared with the control polyimide (PI) membrane, the presence of zwitterionic groups considerably improve the hydrophilicity of the ZPI membrane, thereby enhancing the water permeability to some extent without obviously affecting the rejection ratio. Based on the static protein adsorption and dynamic cycle ultrafiltration experiments, the ZPI membrane exhibited persistent antifouling property, which was demonstrated by the flux decline ratio and filtration resistance. In particular, the water flux recovery ratio of the ZPI membrane was retained at 96.0% after a three-cycles of BSA solution filtration, which was much higher than that of the PI membrane (76.7%), suggesting excellent long-term performance stability. This new approach provided a valuable strategy of combining polymer chemical structure optimization and mature non-solvent induced phase separation (NIPS) method, which could greatly drive the development and application range of separation membranes.
研究领域:
材料科学
·
膜技术
·
聚合物化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2014
·Vol. 5
·期 2
·1301-1308
·
IF 3.708
Youfang Zhang,Wei Fan,Yunpeng Huang,Chao Zhang,Tianxi Liu
Carbon aerogels with hierarchical porous structures are highly promising for developing novel electrode materials for supercapacitors due to their substantial active sites for ion and electron transfer. Herein, a new type of graphene/carbon aerogels with multimodal pores have been facilely synthesized via carbonization of graphene crosslinked polyimide aerogels. Compared to most carbon aerogels based on organic aerogels reported previously, this preparation process is facilitated by the exclusion of harmful formaldehyde. Moreover, graphene is demonstrated as a powerful crosslinking agent, allowing acceleration of the gelation process, improvement of the porous structures inside carbon aerogels, and enlargement of specific surface area and conductivity of carbon aerogels. SEM observation shows the multimodal pores and three-dimensional nano-network of carbon aerogels, which provide short diffusion lengths for both charge and ion transport and high electroactive regions. With graphene involved, the as-prepared carbon aerogels possess high specific surface area up to 998.7 m2 g−1 and specific capacitance up to 178.1 F g−1 at a current density of 1 A g−1, which is much higher than that of pure carbon aerogels (193.6 m2 g−1 and 104.2 F g−1). This work provides a new and facile avenue for fabricating high performance carbon aerogels with hierarchical structures and broadens the potential applications of polyimide.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
JOURNAL OF CELLULAR PLASTICS
·
2020
·
IF 1.925
Jianwei Li,Ni Yu,Yuanqing Ding,Tianle Xu,Guangcheng Zhang,Zhanxin Jing,Xuetao Shi
Polyimide (PI) foams have been developed for decades and widely used as thermal insulation materials. However, the limited mechanical and thermal properties continually being a serious problem that restrict their further applications. In this study, a series of rigid PI foams with excellent mechanical and thermal performance were fabricated by the reaction of benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA) with two diamines of 2–(4-aminophenyl)-5-aminobenzimidazole (BIA) and 4,4'-diaminodiphenyl ether (ODA) with various molar ratios, and the cis-5-norbornene-endo-2,3-dicarbox-ylic acid (NA) was introduced as end-capping and foaming agent. The results demonstrate that the foaming degree decreases with increasing the BIA molar ratio in the polymer chains owing to the elevated melt viscosity of precursor. Furthermore, the prepared rigid PI foams exhibit excellent thermal and mechanical properties. When the BIA contend up to 40 mol%, the glass transition temperature (Tg) and the temperature at 10% of weight loss (Td10%) of PI foam increased ∼80°C and ∼35°C in comparison with the pristine PI-0, respectively. In addition, the compressive strength and modulus at 10% strain of PI-4 reached to 5.48 MPa and 23.8 MPa, respectively. For the above-mentioned advantages, the prepared rigid PI foams are promising candidates as thermal insulation and structure support composite materials in the aerospace and aviation industries.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Chemistry-An Asian Journal
·
2018
·Vol. 13
·期 14
·1836-1841
·
IF 3.692
Yingyi Ma,Le Xu,Zijian Wu,Wenlong Zhang,Mingyan Zhang,Zhenfeng He
Graphical Combover : A honeycomb-patterned porous film was prepared through a microemulsion method and used as an effective coating for improving the dielectric and water-resistance properties of polyimide (PI) film without sacrificing its mechanical properties (see figure). Its comprehensive performance was regulated by tuning the structure of the coated porous film. A honeycomb-patterned porous film was conveniently prepared by means of the microemulsion method and then used as an effective coating for improving the dielectric properties and water resistance of polyimide (PI) film while maintaining its mechanical properties. The dielectric properties could be regulated by tuning the structure of the porous film through controlling its formation conditions. When suitable conditions were used, the prepared composite PI film exhibited a significant reduction of 28.3 % in its dielectric constant and 9.48–54.99 % in dielectric loss accompanied by an extremely low water uptake of 0.62 % relative to the 2.47 % of flat PI film. The composite PI film also displayed excellent durability under moist conditions, as the dielectric constant was still below 2.4 after exposure to 75 % relative humidity for more than 12 h. This provides a novel method to improve and control the dielectric properties of materials. It also suggests that this film is a suitable candidate for coating dielectric materials in high-humidity environments.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 7
·5952-5960
·
IF 2.993
Xu Le,Ma Yingyi,Xie Junwen,Zhang Wenlong,Wu Zijian,He Zhenfeng
The simultaneous improvement of dielectric, mechanical and water resistance properties of dielectric materials is extremely important for their practical use, but rarely been realized. Here, the comprehensive properties of polyimide (PI) film were enhanced through the construction of sandwich-type porous film using the microemulsion method. Due to the introduction of porous structure on both sides of PI film, apparent decreases were observed in dielectric constant (16.50%) and water absorption (82.7%), accompanied by increases in tensile strength (5.14%) and tensile modulus (41.17%), compared to flat PI film. Furthermore, excellent durability of low dielectric constant of the sandwich-type porous film under moist environment was demonstrated since 1.76% of increase was found upon exposing to 75% R.H. for 32 h. This provides a novel method to optimize the comprehensive properties of dielectric materials and also displays underlying insight for the development of functional materials in electronic and electric areas.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Jun-Qi Hu,Yue-Zhu Li,Song-Yi Liao,Xing-Wen Huang,Yi-Zhao Chen,Xiao-Kang Peng,Yi-Bin Yang,Yong-Gang Min
Currently, the thermal runaway of lithium-ion batteries (LIBs) has become one of its most concerned safety hazards. Therefore, battery cells with high safety and energy density have become the important goal for the development of LIBs. In this work, the ultralight and high thermal conductivity of the Cu@graphene-like thermal film (shortened as Cu@GTF) composite current collector with a sandwich structure was derived from polyimide and prepared by the vacuum evaporation method. Compared with the commercial copper foil, the Cu@GTF showed a smaller areal density of <7.0 mg/cm2 (vs 17.50 mg/cm2 of commercial Cu foil) and a higher thermal conductivity of >550 mm2/s (vs 164 mm2/s of Cu foil). Considering its lighter mass, higher thermal conductivity, and reasonable electrical conductivity, the Cu@GTF as a current collector may become a favorable competitor of the commercial Cu foil to meet people’s needs for high safety, energy, and performance of LIBs.
研究领域:
材料科学
·
电化学
·
电池技术
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Xiaolei Wang,Kunlong Zhao,Wenxin Cao,Dongchao Ji,Zhijie Ye,Zhenhua Su,Ge Gao,Zhuochao Wang,Chunqiang Sun,Yingqi Liu,Lan Zhang,Tianyu Zhang,Feiran Li,Jiaqi Zhu
High-performance aerogels are highly desirable in the fields of thermal barriers, drug delivery, and mechanical cushions; however, most of the reported aerogels are limited by complex preparation processes and single functionality. To address such issues, in this study, we prepare a series of aramid nanofiber (ANF)/polyimide (PI) multifunctional composite organic aerogels via a facile polyimide-coating-on-aramid nanofiber (PCoA) strategy. This strategy utilizes PI to coat on the surface of ANFs and construct numerous mesopores within the ANF three-dimensional network skeleton to make the ANF/PI composite aerogels exhibit superior multifunctional properties, such as outstanding thermal and acoustic insulation, mechanical strength, thermal stability, flame retardancy, and hydrophobicity. In particular, the as-prepared composite aerogels with a PI content of 20 wt% exhibit a thermal conductivity of 23.20 mW/mK, which is lower than that of air, and their specific Young’s modulus reaches 32.57 MPa/(g/cm 3 ), the highest among all previously reported organic aerogels, at a density of only 14.86 mg/cm 3 . The composite aerogels are destined to be extremely valuable as they can combine so many remarkable properties in a single package. Currently, the composite aerogels have been available in the form of ultrathin thermal insulation films at a thickness of only 100 μm, which can provide effective heat protection in microelectronic devices, and remain a terrific ability to operate under extreme conditions. Owing to these superior multifunctional properties, the ANF/PI composite aerogels show enormous potential for application in numerous fields, such as thermal management, environmental governance, catalysis, and energy storage.
研究领域:
材料科学
·
化学工程
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2025
·
IF 7.3
Sihao Bi,Tong Zhao,Jinghui Tuo,Xiaolong Wang,Ying Sun,Yuantao Zhang
Polyimide (PI) has been widely utilized as an insulating coating material in electrical and electronic packaging applications. Doping fluorinated graphene (FG) into PI can result in a composite insulating coating that combines a high thermal conductivity with a low dielectric constant. To explore the mechanism of the physical property evolution under extreme conditions such as high temperatures, intense electric fields, oxygen-rich, and high-humidity environments, PI neat and PI/FG composite systems were constructed, and molecular dynamics simulations were conducted under the reactive force field (ReaxFF). The results demonstrated that compared with the PI neat system, doping FG into the PI/FG composite significantly increased the thermal conductivity and free volume fraction by 164.7 % and 18.4 %, respectively. Furthermore, FG effectively mitigated the degradation of PI molecules under high temperatures and intense electric fields, reducing the generation of small-molecule degradation products such as CO, CO 2 , H 2 O, and H 3 N. Additionally, FG doping reduced the binding energy with O 2 and H 2 O onto PI molecules, thereby preventing erosion of PI by these species. Finally, a comparative analysis with other studies revealed excellent agreement between the experiments and simulations. This study provides valuable theoretical insights for designing insulating coating materials with enhanced durability and reliability.
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
Journal of Energy Storage
·
2024
·
IF 8.9
Shiyu Qin,Jinhui Song,Hongmei Qin,Yuheng Fu,Man Liu,Siyu Yu,Ling Zhou,Chuanxi Xiong,Shan Wang
High-temperature energy storage performance of traditional polymer dielectrics is insufficient due to the mutual constraints of glass transition temperature ( T g ) and bandgap ( E g ), making them challenging to meet the demands of harsh environmental applications. In this work, in conjunction with density functional calculations (DFT), we employed the trifluoromethyl (CF 3 ) substituent strategy to develop a heat-resistant aromatic polyimide dielectric (6FDA/TFMB) with a high T g of 329 °C of and a large E g of 3.6 eV. The introduction of the CF 3 group, reducing molecular conjugation and increasing intermolecular spacing, renders the solution-cast 6FDA/TFMB film colorless and transparent. It exhibits remarkable Weibull breakdown strength ( E b ) values of 578 MV m −1 and 452 MV m −1 at 150 °C and 200 °C, respectively. Moreover, 6FDA/TFMB achieves an energy density ( U e ) of 3.21 J/cm 3 with an efficiency ( η ) of 84 % at 150 °C and a U e of 2.42 J/cm 3 with an η of 82 % at 200 °C, which outperforms most existing heat-resistant polymer dielectrics . Additionally, 6FDA/TFMB demonstrates excellent fatigue resistance and self-healing ability. This study provides a promising and cost-effective approach for developing high-performance flexible dielectrics capable of withstanding extreme thermal and electric field conditions.
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
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Tingting Jia,Zhen Fan,Shuai Zheng,Haoran Zhou,Hao Chen,Ning Ma,Changwei Liu
In recent years, as the electronics industry has driven the development of human civilization, flexible responsive materials have become highly favored in sensing applications. However, most flexible materials are not stable under high-temperature conditions, so only a few flexible responsive materials are suitable for high-temperature and high-strength applications. In this paper, multi-walled carbon nanotubes (MWCNTs) were added as conductive material into poly(amic acid) ammonium salt (PAAS) solutions to prepare MWCNTs/polyimide aerogel-based papers (CPs) by a simple method. The introduction of MWCNTs into the ordered multilayer folded structure of the CPs provided a conductive pathway and improved their thermal stability. When the multilayer folded structure was deformed, the MWCNTs between the layers contacted each other, increasing the number of electron transport channels and providing a larger contact area for the conductive network. When the deformation was removed, the MWCNTs in the interlayer contact zone rapidly separated, providing stable and excellent responsiveness at high temperatures (CP-2: ΔR/R 0 value of up to −0.45 at 300 °C) and favorable stability after 1000 cycles (CP-2: RV retention of 92.4 % at 25 °C and 80.5 % at 300 °C). Therefore, the prepared CPs have great application prospects in the fields of high-temperature mechanical device monitoring, sensing, and alarms.
研究领域:
材料科学
·
传感器技术
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Small Structures
·
2024
·
IF 13.9
Renhao Li,Yan Bao,Ruyue Guo,Lu Gao,Wenbo Zhang,Chao Liu,Haihang Zhao
The rational use of efficient thermal insulation materials is one of the effective strategies for energy management. However, existing thermal insulation materials often exhibit poor stability, suboptimal thermal insulation performance, and weak mechanical properties in some extreme environments. Herein, this work develops an easy and scalable strategy for creating hollow polyimide (PI) nanofibers through coaxial electrospinning and high-temperature template removal technology, in which the internal hollow structure is precisely controlled. A large amount of air is filled in the hollow structure within the nanofibers and the voids between the nanofibers, giving PI nanofibers low density (23.3 mg cm −3 ) and high porosity (98.2%). This characteristic also effectively suppresses the heat transfer of PI nanofibers, resulting in an ultralow thermal conductivity (20.6 mW m −1 K −1 ). Meanwhile, PI nanofibers also exhibit excellent mechanical properties with a stress and strain of 5.52 MPa and 62.7%, respectively. In addition, compared to other commercial thermal insulation materials, PI nanofibers demonstrate superior extreme temperature tolerance (from −196 to 350 °C) and flame retardancy (limit oxygen index of 30.8%). Given these advantages, this work provides inspiration for the structural design of nanofiber materials with efficient thermal insulation.
研究领域:
材料科学
·
能源管理
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Maijun Li,Yubo Long,Zhibo Zheng,Xu Hu,Siwei Liu,Zhenguo Chi,Nanwen Li,Jiarui Xu,Yi Zhang
Chemical modification of polyimide membranes is employed to achieve “trade-off” breakthrough or improve the plasticization resistance in CO2 separation. However, harsh reaction conditions restrict the application of traditional chemical modifications. In this work, a simple chemical modification method─the coordination cross-linking between hydroxyl groups on polyimide (6FSPI) and Zn(II)─was investigated. Because of the reversible complexation of Zn(II) in the modified membrane as a transport carrier with CO2, and the addition of Zn(II) disrupts coiled chain of spiro moiety or intrachain cross-linking to induce more quantities of ultrafine micropores, the CO2 permeability coefficient of the modified membrane is 2.97 times that of the pristine 6FSPI. Simultaneously, there is improvement in diffusion selectivity of the modified membrane, resulting in the CO2/CH4 selectivity improvement. The overall CO2/CH4 separation performance of the modified membrane reaches up to the 2008 Robeson limit. In addition to serving as facilitated transport carriers, Zn(II) can also be used as cross-linking points. The modified membrane maintains a stable CO2 permeability coefficient beyond 4000 kPa. Our work suggests that the Zn(II) coordination cross-linking is a facile chemical modification method that can enhance long-term performance and separation performance of polyimide membranes simultaneously.
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）