JOURNAL OF MEMBRANE SCIENCE
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2024
·
IF 8.4
Zhiguang Zhang,Xiaolong Ren,Guolong Huo,Xiaowei Zhou,Hao Chen,Hongjun Zhang,Shuanyan Kang,Xiuling Chen,Nanwen Li
6FDA-based polyimide air-dehumidification membrane has been considered as one of the most advanced technologies for the energy-saving heating, ventilation, and air-conditioning systems due to their excellent solubility and processing. Nevertheless, there are few reports about the effect of free volume and hydrophilic groups on dehumidification performance. Herein, we propose to tune the free volume and hydrophilicity of 6FDA-based polyimides by tuning the hydrophilicity/hydrophobicity of diamines and/or introducing of hydrophilic carboxylic acid groups, and thus to develop a system that would support high H 2 O/N 2 separation performance for dehumidification and retain excellent mechanical properties. It is found that 6FDA/mPDA membrane shows much higher H 2 O/N 2 separation performance (i.e., H 2 O permeability 12480 Barrer and H 2 O/N 2 separation factor of 13867) than that of the 6FDA/TFDB and 6FDA/DAM membranes even though its lower FFV. It is suggested that the FFV had a negligible effect on the H 2 O/N 2 separation performance. Although the introduction of highly hydrophilic –COOH groups could significantly increase the H 2 O/N 2 separation performance of hydrophobic 6FDA/TFMB and 6FDA/DAM membranes, the performance is still lower than that of 6FDA/mPDA membrane with similar hydrophilicity. In addition, we found that more –COOH groups to polymers can lead to the possible formation of hydrophilic/hydrophobic separation in membrane which will result in the rapid water vapor condensation and thus unstable air-dehumidification. Thus, the excessive hydrophilicity of 6FDA/mPDA-DABA showed a decreased H 2 O/N 2 separation performance compared with 6FDA/mPDA membrane. These results indicated that the excellent H 2 O/N 2 separation performance mainly depends on reasonable hydrophilicity of polyimide membrane without excessive hydrophilic groups and high FFV.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Qiaoran Zhang,Tengrui Wang,Ran Du,Jiayi Zheng,Hongliang Wei,Xiaoyu Cao,Xianhu Liu
Passive radiative cooling technology without electric consumption is an emerging sustainability technology that plays a key role in advancing sustainable development. However, most radiative cooling materials are vulnerable to outdoor contamination and thermal/UV exposure, which leads to decreased performance. Herein, we report a hierarchically structured polyimide/zinc oxide (PINF/ZnO) composite membrane that integrates sunlight reflectance of 91.4% in the main thermal effect of the solar spectrum (0.78–1.1 μm), the mid-infrared emissivity of 90.0% (8–13 μm), UV shielding performance, thermal resistance, and ideal hydrophobicity. The comprehensive performance enables the composite membrane to yield a temperature drop of ∼9.3 °C, compared to the air temperature, under the peak solar irradiance of ∼800 W m–2. In addition, the temperature drop of as-obtained composite membranes after heating at 200 °C for 6 h in a nitrogen/air atmosphere can be well maintained at ∼9.0 °C, demonstrating their ideal radiative cooling effect in a high-temperature environment. Additionally, the PINF/ZnO composite membrane shows excellent chemical durability after exposure to the outdoor environment. This work provides a new strategy to integrate chemical durability and thermal resistance with radiative cooling, presenting great potential for passive radiative cooling materials toward practical applications in harsh environments.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2024
·
IF 2.5
Yuntao Fu,Haichao Meng,Fenglin Wang,Huawei Zou,Yinfu Luo,Mei Liang,Peng Xie
Polyimide (PI) hollow microspheres possess lightweight and excellent thermal resistance, which are widely used in microreactors, catalysis, adsorption separation, high-temperature insulation, and so on. In this manuscript, PI hollow microspheres are fabricated by constructing a crosslinked structure combined with gradient heating. The formation of PI hollow microspheres includes gas nucleation, expansion, and imidization. The PI hollow microspheres size is controlled by adjusting polyester ammonium salts size, and microspheres size is distributed in 309–956 µm. PI hollow microspheres have lightweight, excellent heat resistance and carbonization performance, bulk density, initial decomposition temperature, and weight residue at 800 °C is 87.3–178.6 kg m −3 , 533.6 °C and 59.8%. The PI hollow microspheres have potential applications in high-temperature resistant and multifunctional composite materials preparation. Moreover, this method is simple, efficient, and highly operable, which can be used for large-scale production of PI hollow microspheres.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Xi Chen,Yanyan Wang,Kang Zheng,Chao Xiao,Meng Xue,Lin Chen,Yi Gong,Xingyou Tian,Xian Zhang
With the emerging of advanced flexible electronic, the PI film with excellent thermally conductive, flexible, lightweight, electrically insulating qualities is in high demand as a potential substrate and encapsulation material. Conventional thermally conductive fillers such as ceramic, metal and carbon material with high hardness, high density or electrical conductivity are unsuitable to prepare the advanced PI film. Furthermore, the confined loading of thermally conductive filler in PI matrix limited by its film-forming property is another obstacle to optimizing the thermal conductivity of PI film. In this work, the development of novel filler (carbon nitride in-plane grafted by two-dimensional carbon material, C ring -C 3 N 4 ) with intrinsic thermal conductivity and a design of three-layer structure for the introduction of high filler loading have dramatically improved the thermal conductivity of PI film. Benefitting by the planar heterostructure construction of g-C 3 N 4 and C ring , the existence of C ring increases the phonon transfer rate in g-C 3 N 4 , and the presence of g-C 3 N 4 prevents the electron movement in the facet of C ring -C 3 N 4 endowing its excellent electrical insulation property. The design of three-layer structure in which the first and third layers served as mechanical support layers with a fixed filler content (20 wt%). The second layer has the higher filler content to enhance the quantity of thermally conductive filler in PI film. Resultantly, the maximum out-of-plane thermal conductivity of the PI/C ring -C 3 N 4 composite film is 1.35 Wm −1 K −1 , which is 10 times higher than the pure PI film. In addition, the PI/C ring -C 3 N 4 composite film exhibit excellent photothermal conversion ability in which the saturation temperature of PI/C ring -C 3 N 4 can reach 283.6 °C under 0.75 W/cm 2 laser radiation being 6 times higher than that of the corresponding PI film. After the incorporation of C ring -C 3 N 4 , the PI composite film still has excellent thermal stability, low CTE, electrical insulation and mechanical properties. This work provides a novel idea for the preparation of advanced high thermal conductivity PI film.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Shihao Fu,Chang Sun,Lixin Han,Zhiqiang Li,Shuai Guo,Guangbin Li,Zhu Long
High-performance thermal insulation is critically needed in applications where heat transfer must be substantially minimized. Traditional insulating materials, whether organic or inorganic, often suffer from thermal instability or mechanical fragility. Herein, we introduce a series of lightweight, highly porous polyimide/aluminum oxide cluster (PI/AlOC) composite aerogels that exhibit superior thermal insulation properties, achieved through freeze-drying and thermal imidization processes. The aluminum oxide clusters serve as cross-linking agents, enhancing the interaction between polyimide molecular chains and endowing the composite with improved structural integrity and mechanical robustness, as evidenced by a compression modulus of 8.7 MPa, six-fold greater than that of pure PI aerogels. Moreover, the high porosity, reduced pore size, and three-dimensional network structure of the PI/AlOC composite aerogel confer exceptional thermal insulation performance, particularly at elevated temperatures, surpassing that of commercial thermal insulation materials. Thus, the PI/AlOC composite aerogels, with their high mechanical strength and outstanding thermal insulation, are promising for practical applications in thermal insulation.
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GIANT
·
2024
·
IF 5.4
Hong Li,Weiyi Jin,Weiyu Zhang,Jie Li,Jiaqi Ji,Yi Tang,Tianqi Yang,Shujiang Zhang,Haixia Yang,Chenliang Gong
Low-dielectric, transparent, and high-heat-resistant polyimide (PI) films are vital for flexible electronics and high-frequency communication devices. However, balancing these properties within intrinsic polyimides remains a significant challenge. In this work, a nonplanar diamine monomer, 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9-bis(4-nitrophenyl)-9H-fluorene (BTFDA), containing a Cardo structure and four trifluoromethyl groups, was synthesized and copolymerized with commercial monomers to produce a series of polyimides (CPI-X). These CPI-X exhibit exceptional heat resistance, with glass transition temperatures ( T g ) exceeding 350 °C, decomposition temperatures ( T d5 % ) above 530 °C, and low thermal expansion coefficients (CTE < 20.8 ppm/K). Additionally, they have excellent optical properties with over 92 % transparency at 450 nm and low birefringence (Δ n = 0.00042). They also demonstrate good hydrophobicity with low water absorption ( M a % = 0.04 %) and high-water contact angles ( C a = 97.6°). Most importantly, the CPI-X films show excellent dielectric properties ( D k = 2.25, D f = 0.00365 at 1 MHz, D k = 2.13, D f = 0.0065 at 10 GHz). Such intrinsic PI films with low D k values may be ideal candidates for next-generation interlayer media.
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COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Xiaoshuan Pan,Xiaofei Li,Chao Xiao,Xin Ding,Kang Zheng,Xianglan Liu,Meng Xue,Lin Chen,Yi Gong,Xingyou Tian,Xian Zhang
With the development of dynamic infrared camouflage technology, photothermal infrared camouflage has attracted researchers' attention due to its remote-control capability and fast response speed. However, lots of photothermal fillers for high temperatures will break the flexibility and transparency of the polymer. In this work, transparent photothermal infrared camouflage liquid metal microspheres/colorless polyimide (LM/CPI) films with light programming were fabricated. The polydopamine-coated LM microspheres endow CPI with excellent photothermal effect, achieving a wide range of infrared camouflage from room temperature to 390 °C. Furthermore, the glass transition, residual stress, and the different thermal expansion coefficients endow the LM/CPI film with light programming and light actuation capability. The LM/CPI film can mimic the bending of an arm and the opening and closing of a hook. Combining the light programming capability with the dynamic infrared camouflage ability of the LM/CPI film proposes an infrared camouflage strategy where the position of the camouflage film is changed through light programming while conducting infrared camouflage, thereby targeting the design of deceptive, false targets or altering the camouflaged area. Therefore, the LM/CPI films open up a new strategy for dynamic infrared camouflage, sketching a promising future for them in dynamic infrared camouflage.
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APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
XingPeng Fei,Shusheng Liu,Ayush Subedi,Xinkai Ding,Enzhu Hu,Kunhong Hu
The development of biomass materials can effectively mitigate the scarcity of energy and minimize resource waste. In this work, onion-like biomass carbon nanoparticles (OLCs) were prepared using rice husk ash (RHA) which was subjected to a high-temperature graphitization reaction catalyzed by iron nitrate. OLCs/molybdenum disulfide (MoS 2 ) composite particles were prepared and incorporated into polyimide (PI), and a composite coating of OLCs/MoS 2 /PI with excellent tribological properties was successfully prepared. The tribological properties of coatings were evaluated using a controlled atmosphere tribometer (WMT-2E) under dry friction conditions. The related friction and wear mechanism of PI coatings including particles was clarified by the SEM/EDS, XPS, HRTEM and DFT theory. Results show that the wear rate of the three composite coatings of polyimide with OLC, MoS 2 , and OLC/MoS 2 particles were reduced by 52.9 %, 48.2 %, and 58.1 %, respectively. For the coefficient of friction, PI-0.20 OLC/MoS 2 coating material decreased by 16.1 %. Anti-wear and friction reduction mechanism is attributed to the presence of a transfer film on the surface of the steel balls. The addition of MoS 2 facilitated the deposition of nanoparticles, which further improved the stability and densification of the friction film, resulting in better protection of the metal surface against severe wear. Besides, the component structure changes of OLCs and MoS 2 and adsorption energy of friction products on the surface of tribo-pairs were also important reasons for clarifying the modification tribological behavior of PI coatings including three kinds of nanoparticles.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
·
IF 14.3
Yugen Wang,Jianwei Li,Yuanyuan Zhong,Jiahao Kang,Bilin Zhang,Zhonglei Ma,Qiangli Zhao
The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference (EMI) shielding and wave-absorbing materials. Hence, a densification strategy was proposed to fabricate multifunctional rigid polyimide (PI) composite foam. As a result, the composite PI foam exhibits excellent mechanical properties, with tensile and bending strengths of 4.7 and 21.1 MPa, respectively. Moreover, the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient ( A ) of 0.71, coupled with an X-band (8.2–12.4 GHz) EMI rating of 44 dB (2 mm) due to its high conductivity (20.29 ms/mm). Satisfyingly, the composite PI foam also has an optimal reflection loss (RL) of up to −46.4 dB and an effective absorption bandwidth (EAB) (RL < −10 dB) that covers the entire X-band. Meanwhile, the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages (3–9 V) and rapid response time (within 20 s) for stable and reproducible performance in long-term cycling. This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption, demonstrating great potential for aerospace, microelectronics, and energy conversion applications.
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PROGRESS IN ORGANIC COATINGS
·
2025
·
IF 7.3
Zhongli Zhang,Zhensheng Wu,Shuai Zheng,Haitao Yang,Fuqiang Tian
Polyimide inorganic nanocomposites have become a major focus of research in various fields due to their excellent integrated properties. This study adopts a combination of theoretical simulations and experimental methods. Using Density Functional Theory (DFT) calculations, the microscopic properties of polyimide molecules and nano-TiO 2 and nano-Al 2 O 3 were investigated, while Molecular Dynamics (MD) simulations revealed the microscopic mechanism behind the thermal breakdown of polyimide films. Subsequently, polyimide/titanium dioxide (PI/nano-TiO 2 ) and polyimide/titanium dioxide/alumina (PI/nano-TiO 2 /nano-Al 2 O 3 ) nanocomposite films were prepared. The results showed that the breakdown strength of the PI/nano-TiO 2 film was 3.58 times that of conventional polyimide films. The surface modification of nanoparticles was achieved by adding the coupling agent KH550, which enhanced the structure, morphology, and overall properties of the composite films, significantly improving their thermal stability. Our research framework adopts a multi-scale approach, starting with insights at the microscopic level obtained from Density Functional Theory (DFT) calculations and MD simulations, followed by experimental validation, and ultimately classifying the breakdown strength through machine learning. We systematically analyzed the breakdown performance of polyimide films across multiple scales, from molecular simulations and experimental analysis to machine learning, providing theoretical support and practical reference for the design of nanocomposite films, and demonstrating the potential of this material for high-performance dielectric applications.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2017
·Vol. 56
·期 5
·505-513
·
IF 2.952
Haiwei Tan,Huaxuan Yu,Ying Song,Shiyang Zhu,Bo Zhang,Hongyan Yao,Shaowei Guan
A series of ferrocene-terminated hyperbranched polyimides (HBPI-Fcs) were synthesized from a tetra-amine, bis(4-(3,5-bis (4-amino-2-(trifluoromethyl) phenoxy) phenoxy) phenyl) methanon, and various dianhydrides, followed by termination with (4-amino) phenyl ferrocene. All the HBPI-Fcs possessed good organo-solubility and high thermal stability. The devices based on HBPI-Fcs exhibited bipolar and nonvolatile write-once-read-many times (WORM) memory performance with various threshold voltages and the same ON/OFF current ratio of 10 4 . Moreover, the devices possessed excellent bistability under a constant bias of −1.00 V during a test period of 10 4 s. The different charge trapping ability of the electron-accepting moiety endowed the devices with different the threshold voltages. Mechanism analysis showed that the switching behavior was dominated by the charge trapping effect and the charge transfer was well fitted with the space-current-limited-current (SCLC) and ohmic model. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56 , 505–513
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ChemSusChem
·
2018
·Vol. 11
·期 5
·916-923
·
IF 7.411
Zhenggong Wang,Huiting Ren,Shenxiang Zhang,Feng Zhang,Jian Jin
Graphical Just touching base : New carbon molecular sieve (CMS) membranes are fabricated with the use of a Tröger's base (TB)-based microporous polyimide as the polymer precursor, and their gas-separation performance is investigated. The comprehensive gas-separation performance of the TB–CMS membranes is improved relative to that of most state-of-the-art CMS membranes derived from common polyimides reported so far. Carbon molecular sieve (CMS)-based membranes have attracted great attention because of their outstanding gas-separation performance. The polymer precursor is a key point for the preparation of high-performance CMS membranes. In this work, a microporous polyimide precursor containing a Tröger's base unit was used for the first time to prepare CMS membranes. By optimizing the pyrolysis procedure and the soaking temperature, three TB–CMS membranes were obtained. Gas-permeation tests revealed that the comprehensive gas-separation performance of the TB–CMS membranes was greatly enhanced relative to that of most state-of-the-art CMS membranes derived from polyimides reported so far.
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