COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2023
·
IF 8.7
Meng Sun,Zhengyu Guo,Wenting Zhang,Enjie Ding,Xiang Li,Ming Yin,Chuyang Luo,Liying Zhang
The aviation industry requires advanced aerogels that combine both electromagnetic wave (EM) attenuation and thermal insulation capabilities. This work involved the fabrication of Ti 3 C 2 T x MXene/polyimide nanofibrous (PINF) aerogels through freeze-drying and thermal imidization. The hierarchical microporous architecture was formed by the interconnected primary pores induced by the removal of ice crystals and secondary pores from the PINF web. The unique highly porous 3D network of the nanofibrous aerogel provided well-matched impedance and enhanced multiple reflections and scattering of EM waves. The polar functional groups and defects on MXene induced dipole polarization, and the heterointerfaces between the PINFs and MXene enhanced the interfacial polarization. Consequently, the MXene/PINF aerogels exhibited efficient microwave absorption, showing a minimum reflection loss ( RL min ) of −37.9 dB and an effective absorption bandwidth ( EAB ) of 3.3 GHz. Moreover, nanofibrous aerogels also exhibited low thermal conductivity and remarkable compression properties, making them suitable for utilization in complex environments.
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2023
·
IF 9.1
Ke Zhao,Siyu Wei,Ming Cao,Meng Wang,Pengfei Li,Hao Li,Xianglin Zhang,Yuanyuan Zhang,Yingbo Chen
With the continuous development of electronic technology, polymer-based thermal management materials (TMMs) with insulation, high thermal conductivity (TC), and low dielectric performance are urgently needed for electronic devices. Nevertheless, balancing above expected properties is still a daunting challenge because of phonon scattering and interfacial polarization . Here we put forward a simple and useful method for preparing polyimide (PI) composites. First, the alignment of modified boron nitride nanosheet (MBN) along the fiber was controlled by electrospinning, while silver nanowire (AgNW) was utilized for electrostatic spraying to overlap the AgNW with MBN. Finally, a hybrid network oriented along the horizontal direction was formed by hot-pressing. The in-plane TC of the PI composites was up to 8.38 W/mK due to the formation of thermal conduction pathways along the hybrid network. The PI composites also had a series of merits, such as electrical insulation of over 2.40 × 10 14 Ω cm, low dielectric constant (3.84), low dielectric loss (<0.01) at 10 6 Hz, excellent thermal stability (T HRI = 299.3 °C), and heat dissipation capability. These PI composites with satisfactory comprehensive properties have great application potential in electronic devices, particularly in flexible electronic devices or circuits that demand electrical insulation and high TC.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Peng Wei,Yang Sui,Dong Huang,Bensheng Zhu,Xiaoyu Meng,Qiong Zhou
Sulfonated poly ether ether ketone (SPEEK) was used to fabricate proton exchange membrane (PEM) due to its adaptable proton conductivity. However, PEM cannot simultaneously enhance its conductivity and stability. To solve the problem mentioned above, phosphotungstic acid (HPW) with strong inherent proton conductivity was chosen to add to the SPEEK matrix, but it still faces the leaky problem. NH 2 -UiO-66 (NU6) with a large surface area and chemical stability was synthesized in situ on the surface of polyimide (PI) nanofiber to create NU6@PI nanofiber, which can be used to anchor HPW. Meanwhile, the stability of proton transport channel may be further enhanced by the sandwich structure, which may be advantageous for proton transport. The NU6@PI/SPEEK + HPW-20 exhibited a conductivity of 174.9 mS·cm −1 and a swelling ratio of 19 % at 60 °C and 100 % RH. After 6 weeks of testing, its conductivity decreased to 151.2 mS·cm −1 which was 24 % higher than that of SPEEK, while the swelling ratio increased to 31 % which was lower than that of SPEEK. The outcome demonstrates that the sandwich-structure NU6@PI/SPEEK + HPW membrane may really boost proton conductivity and stability at the same time. By using XPS and TEM, it is possible to confirm the acid-base interaction and acid-rich layer that exist at the interfaces of NU6@PI nanofiber and HPW/SPEEK matrix. After 6-weeks of usage, the sandwich-structure composite membrane with nanofiber at both the top and bottom of PEM can still maintain high proton conductivity and high stability, offering a novel research idea for resolving the issue that PEM cannot simultaneously achieve significant proton conductivity as well as elevated stability.
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2023
·Vol. 415
·期 27
·6785-6798
·
IF 4.3
Lu Zongyan,Guo Hao,Wang Mingyue,Yang Zeyun,Wei Xiaoqin,Liu Yinsheng,Hui Yingfei,Yu Zhiguo,Yang Wu
The development of a simple and sensitive electrochemical sensing platform for levofloxacin (LVF) analysis is of great significance to human health. In this work, a covalent organic framework (TP-COF) was in situ grown on the surface of Sn-MoC nanospheres with nanoflower-like morphology through a one-pot method to obtain the TP-COF@Sn-MoC composite. The prepared composite was used to modify a glassy carbon electrode (GCE) to realize the sensitive detection of levofloxacin. TP-COF was formed by polycondensation of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and pyromellitic dianhydride (PMDA), in which C = O and C = N groups served as double active centers for the recognition and electrocatalytic oxidation of the target molecule. Meanwhile, the introduction of Sn-MoC improved the conductivity of the electrode. The TP-COF@Sn-MoC composite produced a strong synergistic effect and showed a high electrocatalytic ability toward levofloxacin oxidation. The linear range of LVF was 0.6–1000 μM and the limit of detection (LOD) was 0.029 μM ( S / N = 3). In addition, the sensor has been successfully applied for the analysis of LVF in human urine and blood serum samples with acceptable recovery rates, demonstrating that the sensor was promising in practical applications. Graphical Abstract
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Meng Chen,Xihui Cheng,Jiwei Li,Na Wang
A multi-use fibrous filter medium composed of an electrospun polyimide (PI) nanofiber layer and a functional zeolitic imidazolate framework-8 (ZIF8) nanofilm layer was successfully fabricated to cope with the complex environmental pollution issues. The nanofilm layer consists of the anti-microbial ZIF8 converted from non-toxic zinc oxide (ZnO) nanocoating on PI fibers. One-step magnetron sputtering is utilized to deposit the ZnO nanocoating for the sake of desired functionality conformally onto the PI nanofibrous membrane without sacrificing its bulk structure and mechanical performance. The as-prepared PI/ZIF8 nanofibrous filter medium showed conspicuous biocidal efficacy and excellent interception ratio against gram-negative Escherichia coli (>99.9%) and gram-positive Staphylococcus aureus (>99.9%) within 20 min contact. Besides, compared with commercial media, the bilayer PI/ZIF8 fibrous medium showed exceptional thermal-wet comfortability due to the high porosity that could realize effective heat and humidity conduction. Moreover, the PI/ZIF8 30 NFM still present a high filtration efficiency of 99.6% towards PM 0.3 even after treated at 300 °C for 1 h. Furthermore, the PI/ZIF8 30 NFM with a fiber basis weight of 1.8 g/m 2 was endowed with a permeate flux of 17,279.2 L/m 2 /h and a high oil/water separation efficiency of > 99.6% because of the hydrophobicity and superoleophilicity. We envision that the antimicrobial, thermal-wet comfort, multi-use fibrous membrane will serve as a core-medium of environmentally-friendly platform for bioprotective equipment against future pathogen threats or oily wastewater treatment .
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Zhongji Qu,Yu Wang,Wei Wang,Dan Yu
The fabrication of flexible microwave absorbers with high-performance has become an arduous challenge for applications of anti-electromagnetic pollution and radar stealth technology. Herein, a series of FeCoNiOx-PDA-rGO absorbers were prepared and coated on the surface of pretreated polyimide (PI) fabric with PDA-rGO, and finally by screen printing FeCoNiOx-PDA-rGO/WPU for acquiring robust microwave absorption performance, in which the first layer of treated PI fabric was used as the microwave-reflection layer, the medium microwave absorbing powder and water-based polyurethane (WPU) hybrid coating served as the microwave-absorbing layer, and the outside hydrophobic polydimethylsiloxane (PDMS) layer was utilized as the microwave-transmission layer. The well-designed microwave absorption fabric exhibits excellent performance in the X-band (8.2–12.4 GHz). The minimum reflection loss (RL min ) value of the designed fabric can reach −74.70 dB with a thickness of 3.97 mm. Meantime, almost in the entire X-band, the sample can absorb more than 99% (RL < -20 dB) of incident electromagnetic waves. Besides, the performance can be adjusted by changing the load rate of each microwave absorbing layer to obtain lighter and thinner samples in practical applications. We believe this work will bring new inspiration to the design of flexible and wearable microwave absorbers.
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 6
·1402
·
IF 3.623
Yi Zeng,Yiwu Liu,Jinghua Tan,Jie Huang,Junjie Liu,Ao Tang,Chengliang Chen,Hong Chen
In order to meet the increasingly stringent requirements for heat resistance and barrier properties in the packaging and electronic device encapsulation field. A high-barrier polyimide (NAPPI) contains naphthalene ring and amide group was prepared by polymerization of a novel diamine (NAPDA) and pyromellitic dianhydride. The structure and properties of diamine monomers and polymers were characterized. Results show that the NAPPI exhibits superior barrier properties with extremely low water vapor and oxygen transmission rate values of 0.14 g·m−2·day−1and 0.04 cm3·m−2·day−1, respectively. In addition, the NAPPI presents outstanding mechanical properties and thermal stability as well. This article attempts to explore the relationship between NAPPI structure and barrier properties by combining experiment and simulation. Studies on positron annihilation lifetime spectroscopy, Wide angle X-ray diffractograms and molecular dynamics simulations prove that the NAPPI has smaller interplanar spacing and higher chain regularity. In addition, the strong chain rigidity and interchain cohesion of NAPPI due to the presence of the rigid naphthalene ring and a large number of hydrogen bond interactions formed by amide groups result in compact chain packing and smaller free volume, which reduces the solubility and diffusibility of small molecules in the matrix. In general, the simulation results are consistent with the experimental results, which are important for understanding the barrier mechanism of NAPPI.Keywords:polyimide;naphthalene ring;amide group;barrier properties;molecular simulation
✓ 已验证
产品关联
DOI
PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
·
2020
·
IF 3.862
Xiaoping Zhou,Chenhui Ding,Chuyun Cheng,Shuwu Liu,Gaigai Duan,Wenhui Xu,Kunming Liu,Haoqing Hou
High mechanical performance electrospun polymeric nanofibers are highly desired for practical applications, especially as reinforcements for composites. However, most of the electrospun polymeric nanofibers present tensile strength < 3 GPa. To overcome such limitation, this work successfully prepared single rGO reinforced polyimide composite nanofiber with tensile strength up to 4.2 GPa (PI/rGO-1.0%) and modulus up to 121 GPa (PI/rGO-1.2%) by applying in-situ polymerization, electrospinning, and in-situ thermal conversion. These mechanical properties are higher than other polymer-based electrospun nanofibers, and 45% and 236% higher than those of neat PI single nanofiber, respectively. The in-situ strategies provide the homogeneous dispersion of rGO in single electrospun nanofibers and enhance the interfacial interaction between rGO and PI. In addition, the PI/rGO composite nanofibers also present excellent thermal stability with glass transition temperature (T g ) > 295 °C, and the 5% thermal decomposition temperature (T 5% ) > 539 °C. This work would open a new route for the preparation of high performance electrospun nanofibers for composites.
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2020
·
IF 6.289
Syed Asadullah,Shiqi Mei,Deqiang Wang,Yuan Yao,Yongkang Pan,Dongliang Wang,Han Guo,Jie Wei
To improve the surface bio-performances of polyimide (PI), tantalum pentoxide (Ta 2 O 5 )/PI composites (TPC) were prepared, and concentrated sulfuric acid was utilized to modify TPC surface. The results revealed that sulfonated TPC (STPC) exhibited microporous surface with pores size of about 3 μm, and sulfonic acid (-SO 3 H) groups were introduced onto the microporous surface. In addition, many Ta 2 O 5 submicro particles appeared on the microporous surface, which formed micro-submicro structures. Compared with PI, the surface roughness, hydrophilicity, surface energy and protein adsorption as well as apatite mineralization of STPC in simulated body fluid were obviously enhanced, which increased with Ta 2 O 5 content increasing. In addition, STPC exhibited antibacterial performances due to the presence of -SO 3 H groups and Ta 2 O 5 . Furthermore, the responses (adhesion, proliferation and differentiation) of rat bone marrow mesenchymal stem cells to STPC were remarkably promoted with the increase of Ta 2 O 5 content. In short, STPC with 50w% Ta 2 O 5 content (STPC 50) with sulfonated microporous surface contained micro-submicro structures, which exhibited antibacterial performances and stimulated cell responses. STPC50 with improved surface properties and cytocompatibility might have large potentials for bone repair applications.
✓ 已验证
产品关联
DOI
高影响因子
Membranes
·
2021
·Vol. 11
·期 8
·618
·
IF 4.106
Haojie Li,Shan Xu,Bingyu Zhao,Yuxiu Yu,Yaodong Liu
Blending and heat-treatment play significant roles in adjusting gas separation performances of membranes, especially for incorporating thermally labile polymers into carbon molecular sieve membranes (CMSMs). In this work, cellulose acetate (CA) is introduced into polyimide (PI) as a sacrificial phase to adjust the structure and gas separation performance from polymer to carbon. A novel result is observed that the gas permeability is reduced, even when the immiscible CA phase decomposes and forms pores after heat treatment at 350 °C. After carbonization at 600 °C, the miscible CA has changed without contribution, while the role of the immiscible CA phase has changed from original hindrance to facilitation, the composite-based CMSM at a CA content of 10 wt.% shows highest performances, a H2permeability of ~5300 Barrer (56% enhancement) with a similar H2/N2permselectivity of 42. The structural analyses reveal that the chain interactions and phase separation behaviors between CA and PI play critical roles on membrane structures and gas diffusion, and the corresponding phase structural evolutions during heat treatment and carbonization determine gas separation properties.Keywords:cellulose acetate;polyimide;chase separation behavior;carbon molecular sieve membranes
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Mechanical Behavior of Biomedical Materials
·
2021
·
IF 3.902
Syed Asadullah,Shiqi Mei,Kong Yang,Xinglong Hu,Fan Wang,Baoqing Yu,Zhaoying Wu,Jie Wei
Surface characteristics of the biomaterials have significant effects on response of osteoblast and formation of new bone tissue. In this study, to improve the bio-performance of polyimide (PI) as an implantable material for bone substitute, concentrated sulfuric acid suspension with tantalum (V) oxide (vTO) submicro-particles of 10w% (PIST10) and 15w% (PIST15) was utilized to modify PI surface. After sulfonation , microporous coatings including vTO particles were created on PI (PIST10 and PIST15) while microporous coating without vTO particles was also created on PI (PIS). Results showed that surface roughness , hydrophilicity and protein adsorption of PIST15 was remarkably higher than PIST10 and PIS. Furthermore, after soaking into simulated body fluid (SBF), no apatite mineralization on PIS was found, while PIST15 with high vTO content exhibited better apatite mineralization compared with PIST10. Moreover, PIS showed low antibacterial property , while PIST15 with high vTO content revealed better antibacterial property compared with PIST10. In addition, cellular response (such as adhesion, proliferation and alkaline phosphatase activity) of bone marrow stromal cells (BMSC) of rat to PIST15 was higher than PIST10 and PIS. In conclusion, the microporous coating of PIST15 including vTO submicro-particles possessed good antibacterial property and bioactivity , which significantly promoted the responses of BMSC. Therefore, PIST15 has potential application prospects for bone substitute.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Kang Sun,Fan Wang,Wenke Yang,Hu Liu,Caofeng Pan,Zhanhu Guo,Chuntai Liu,Changyu Shen
The development of flexible MXene-based multifunctional composites is becoming a hot research area to achieve the application of conductive MXene in wearable electric instruments. Herein, a flexible conductive polyimide fiber (PIF)/MXene composite film with densely stacked “rebar-brick-cement” lamellar structure is fabricated using the simple vacuum filtration plus thermal imidization technique. A water-soluble polyimide precursor, poly(amic acid), is applied to act as a binder and dispersant to ensure the homogeneous dispersion of MXene and its good interfacial adhesion with PIF after thermal imidization, resulting in excellent mechanical robustness and high conductivity (3787.9 S/m). Owing to the reflection on the surface, absorption through conduction loss and interfacial/dipolar polarization loss inside the material, and the lamellar structure that is beneficial for multiple reflection and scattering between adjacent layers, the resultant PIF/MXene composite film exhibits a high electromagnetic interference (EMI) shielding effectiveness of 49.9 dB in the frequency range of 8.2–12.4 GHz. More importantly, its EMI shielding capacity can be well maintained in various harsh environments (e.g., extreme high/low temperature, acid/salt solution, and long-term cyclic bending), showing excellent stability and durability. Furthermore, it also presents fast, stable, and long-term durable Joule heating performances based on its stable and excellent conductivity, demonstrating good thermal deicing effects under actual conditions. Therefore, we believe that the flexible conductive PIF/MXene composite film with excellent conductivity and harsh environment tolerance possesses promising potential for electromagnetic wave protection and personal thermal management.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）