JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
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2021
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IF 2.569
Yuejia Li,Wei Pan,Fenghua Zhang,Jinsong Leng
Shape memory polymers (SMPs) are smart materials that can be programmed to change shape under external stimuli, whereas the low storage modulus limit the application of them. Herein, carbon fabric (CF) reinforced shape memory polyimide composites (SMPICs) with high storage modulus were manufactured via hot pressing molding process. Firstly, we synthesized one kind of thermoplastic shape memory polyimide (SMPI) with glass transition temperature of 205°C by the two-step high-temperature solution polycondensation. In addition, the triamine was added in the SMPI system as a crosslinking agent to form the thermosetting SMPI with different crosslinking degree. In order to improve the storage modulus of SMPI, the CFs with three layers were embedded in thermosetting SMPI matrix. The storage modulus of the obtained SMPICs was as high as 26 GPa. The glass transition temperature and thermal decomposition temperature of SMPICs were up to 213°C and 505°C, respectively. Moreover, the shape fixation rate and recovery rate of SMPICs were both more than 94%. These SMPICs with high storage modulus is of great significance, proving more application potential in many fields such as aerospace.
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Nature Communications
·
2023
·Vol. 14
·期 1
·1-10
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IF 16.6
Xue Tiantian,Zhu Chenyu,Yu Dingyi,Zhang Xu,Lai Feili,Zhang Longsheng,Zhang Chao,Fan Wei,Liu Tianxi
Polyimide aerogel fibers hold promise for intelligent thermal management fabrics, but their scalable production faces challenges due to the sluggish gelation kinetics and the weak backbone strength. Herein, a strategy is developed for fast and scalable fabrication of crosslinked polyimide (CPI) aerogel fibers by wet-spinning and ambient pressure drying via UV-enhanced dynamic gelation strategy. This strategy enables fast sol-gel transition of photosensitive polyimide, resulting in a strongly-crosslinked gel skeleton that effectively maintains the fiber shape and porous nanostructure. Continuous production of CPI aerogel fibers (length of hundreds of meters) with high specific modulus (390.9 kN m kg −1 ) can be achieved within 7 h, more efficiently than previous methods (>48 h). Moreover, the CPI aerogel fabric demonstrates almost the same thermal insulating performance as down, but is about 1/8 the thickness of down. The strategy opens a promisingly wide-space for fast and scalable fabrication of ultrathin fabrics for personal thermal management.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Tianqi Zhang,Jian Yin,Ying Pan,Enhua Liu,Dongxia Liu,Jianqiang Meng
Synthesis of cyclic carbonates via cycloaddition of CO 2 to epoxides is an important strategy for CO 2 valorization. However, efficient and easy-to-handle catalytic system for this type of reaction at mild conditions is still rare. In this work, we present a polyimide-based catalytic membrane with hierarchical pore structure for flow through synthesis of cyclic carbonates at mild conditions. The membrane was fabricated by incorporating a porous and metallized poly-melamine-formaldehyde (Zn@PMF) into phase inversed polyimide (PI) matrix. Upon in-situ crosslinking with tris(2-aminoethyl)amine, the solvent-resistant PI membrane can not only facilitate the CO 2 adsorption and immobilize the catalysts, but also promote mixing by flow-through operations. As a result, the nanocomposite membrane exhibited an excellent catalytic performance with a maximum TOF value of 3362 h −1 at ambient conditions. This catalytic activity is not only higher than the Zn@PMF particle but also is the highest among reported catalysts under the similar reaction conditions. Its high catalytic performance was also confirmed in CO 2 cycloaddition in a synthetic flue gas stream.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
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IF 3.573
Xuhua He,Yuechuan Wang
Multifunctional polymer composites with high thermal conductivity are beneficial as thermal management materials for advanced electronics and technologies because of their design flexibility. However, conventional polymer composites do not possess all of the desirable material properties. Here, using the binary fillers graphene oxide (GO) nanosheets and hexagonal boron nitride (BN) platelets, we fabricated flexible polyimide (PI) composite films with high thermal conductivity and excellent thermal and electrical insulating properties. For the resultant PI composite films, a maximum thermal conductivity of 11.203 W/(m K) was achieved at a low filler loading of 1 wt % GO and 20 wt % BN, approximately 50 times higher than that of neat PI films. Theoretical models demonstrated that this synergistic enhancement resulted from the interactions of the binary fillers. The PI composite films also showed improved thermal mechanical properties and thermal stability and retained electrical insulation, moderate dielectric permittivity, and low dielectric loss.
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MATERIALS CHEMISTRY AND PHYSICS
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2019
·
IF 2.781
Ming Yang,Chunhong Zhang,Guangdong Su,Yanjun Dong,Tadele Daniel Mekuria,Qingtao lv
A polyimide (PI) oligomer end-capping with 4-phenylethynyl anhydride was successfully synthesized to prepare a series of thermosetting PI composites containing solid lubricant fillers MoS 2 , SiO 2 , Si 3 N 4 , or graphite via hot-press-molding technique. Friction and wear tests were carried out under dry friction condition and the effects of friction and wear properties of PI containing difference solid fillers were also investigated. The results indicated that the type and content of the incorporation fillers played an important role in the wear resistance properties of PI composites. Among the prepared composites, PI/MoS 2 -20 wt% composites showed the lowest friction coefficient (0.11), which was decreased by 47.6% compared to pure PI. While PI/graphite-20 wt% composites showed the least wear loss of 0.864 mg, which was a 90.4% decrease compared to pure PI. Furthermore, the tensile strength of PI/graphite-20 wt% composites showed an increase of 18.7% compared to pure PI. Moreover, the thermal stability and thermal conductivity of PI was improved with the incorporation fillers. The wear type of worn surfaces gradually changed from adhesion wear and fatigue wear of pure PI into abrasive wear of PI composites. The resultant PI composites exhibited good wear resistance, mechanical, thermal conductivity and thermal stability properties, suggesting their potential applications as high-performance friction materials .
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MICROCHEMICAL JOURNAL
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2019
·
IF 3.206
Kai Hu,Jingyi Qiao,Weixia Zhu,Xiaohui Chen,Chunhong Dong
A facile and rapid method was reported for the preparation of magnetic nanocomposite of naphthalene-based polyimide polymer modified Fe 3 O 4 (Fe 3 O 4 @NPI), which was characterized and explored as sorbents for extraction of Sudan dyes (Sudan I, II, III and IV) in chili sauce prior to their HPLC determination. Some potential parameters influencing the MSPE efficiency were optimized using response surface methodology (RSM). Under the optimal experimental conditions an approach for the analysis of Sudan dyes was developed by coupling with high performance liquid chromatography-diode array detector (HPLC-DAD). Good linearity ( r > 0.9932) with linear range of 0.05–50 ng L −1 was obtained. The enrichment factors, LODs and LOQs for the proposed method were found to be in the ranges of 80.9–88.9, 0.02–0.05 ng g −1 and 0.07–0.17 ng g −1 , respectively. The method was utilized to analyze target Sudan dyes in real chili sauce samples, and sufficient recoveries ranged from 92.6 to 98.6% were obtained with RSDs <5.8%. These results indicate that the prepared Fe 3 O 4 @NPI is an effective sorbent for the extraction of Sudan dyes prior determination.
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iScience
·
2024
·
IF 4.6
Jianjun Wang,Tingting Wu,Xianlong Wang,Jiaqi Chen,Minyi Fan,Zhichun Shi,Jiao Liu,Liang Xu,Yu Zang
The rapid development of nuclear energy posed a great threat to the environment and human health. Herein, two hydroxyl-functionalized hyper-crosslinked polymers (PIHCP-1 and PIHCP-2) containing different electron active sites have been synthesized via Friedel-Crafts alkylation reaction of the polyimides. The resulting polymers showed a micro/mesoporous morphology and good thermal and chemical stability. Rely on the high porosity and multi-active sites, the PIHCPs show an ultrahigh iodine uptake capacity reached 6.73 g g −1 and the iodine removal efficiency from aqueous solution also reaches 99.7%. Kinetic analysis demonstrates that the iodine adsorption on PIHCPs was happened on the heterogeneous surfaces in the form of multilayer chemisorption. Electrostatic potential (ESP) calculation proves the great contribution of hydroxyl groups on the iodine capture performance. In addition, the iodine capture efficiency of both adsorbents can be maintained over 91% after four cyclic experiments which ensures their good recyclability for further practical applications.
研究领域:
材料科学
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环境科学
·
核工程
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高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Baokai Zhang,Xianqiang Pei,Yanming Wang,Shanhong Wan,Juan Yang,Gai Zhao,Qihua Wang,Tingmei Wang
A novel organic coating was created by dispersing solvent-free covalent graphene oxide nanofluids (GO NFs) into a polyimide (PI) matrix. The tribological properties of GO NFs/PI composite coatings was tested against ball-on-disk tribometer. Even a low loading of GO NFs significantly improve the tribological properties of PI. MD simulation and nanoindentation tests reveal that GO NFs adsorbs the PI molecular chains, enhancing the composites' mechanical properties. Moreover, a stable tribofilm develops on the steel ball surface lubricated with the GO NFs/PI composite coating, with analyses indicating that the GO NFs promote its growth. The enhancement of mechanical properties and the formation of this tribofilm are essential for the improved tribological performance of the composite. This research aims to contribute to the development of novel PI composite coatings with superior anti-friction and wear-resistant properties. Highlights The GO NFs exhibited excellent dispersion stability and tribological properties. Novel GO NFs/PI composite coating with significantly enhanced tribological properties. A carbon-based tribofilm forms on the steel ball. The strengthening mechanisms of composites were revealed by MD simulation.
研究领域:
材料科学
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表面工程
·
计算模拟
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JOURNAL OF MEMBRANE SCIENCE
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2024
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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.
研究领域:
材料科学
·
化学工程
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JOURNAL OF APPLIED POLYMER SCIENCE
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2025
·
IF 2.8
Jintao Huang,Haoxin Lv,Xiaojun Zhao,Jong-Min Lee,Yonggang Min
Overheating of electronic devices reduces lifespan and increases safety risks. The use of graphite films with high thermal conductivity to enhance thermal dissipation in electronic equipment is of significant importance. This study used urea-choline chloride (UCC) to modify polyimide (PI) films from two different monomer systems, which were then graphitized to prepare a novel graphite film with high thermal conductivity. The direct formation of hydrogen bonds between poly(amic acid) (PAA) and UCC facilitates the ordered structure during thermal imidization, enhancing the graphitization degree and thermodynamic properties of PI films. The results indicate that the graphitization degree of PI films increased from 30% to over 59% in the 4,4′-oxydianiline-pyromellitic dianhydride (OPU) system and from 80% to over 92% in the 4,4′-diaminobenzoyltiphenylamine-3,3′,4,4′-biphenyl tetracarboxylic dianhydride (DBU) system. Notably, 4,4′-oxydianiline-pyromellitic dianhydride-3.5 wt% urea-choline chloride (OPU35) and 4,4′-diaminobenzoyltiphenylamine-3,3′,4,4′-biphenyl tetracarboxylic dianhydride-3.5 wt% urea-choline chloride (DBU35) exhibited the highest thermal conductivity in their respective systems, with coefficients of 45 and 742 W/m K, representing 200% and 47.8% improvements over pure PI-based graphite films. This provides a new material for heat dissipation in electronic devices.
研究领域:
材料科学
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热管理技术
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ACS Applied Nano Materials
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2024
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IF 5.3
Fan Xie,Qiyang Dai,Longhai Zhuo,Chaobin He,Xiyi Dai,Qiaoling Liu,Haitao Wei,Zhaoqing Lu
Inspired by the structure and production process of textiles, a zigzag aligned structural design was proposed to fabricate flexible thermally conductive nanocomposites via a facile, scalable lamination process of electrospun polyimide (PI) nanofibers. More specifically, polydopamine (PDA) was used as a modifier to functionalize boron nitride nanosheets (BNNS), and the p-BNNS/PI nanofilm was prepared using the electrostatic spinning technique. Subsequently, the nanofilm was rolled into vertically oriented cylinders, and vacuum-assisted impregnation of polydimethylsiloxane (PDMS) was carried out, resulting in the construction of p-BNNS/PI/PDMS nanocomposites. The obtained nanocomposites not only demonstrated strong anisotropy and significantly enhanced thermal conductivity but also possessed excellent electrical insulation performance. The nanocomposites with 10 wt % p-BNNS exhibited both an ultrahigh out-of-plane thermal conductivity of 1.26 W/m K and a high volume resistivity of approximately 1015 Ω cm. Additionally, the nanofilm maintained excellent flexibility and remained intact even after kneading for 60 s while exhibiting a maximum tensile strength of 29.7 MPa. This work provided an effective method to establish a continuous thermal conductive network and further expanded the thermal management applications of polymer-based nanocomposites in electronic packaging and other fields.
研究领域:
材料科学
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热传导技术
·
高分子化学
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高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
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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.
研究领域:
材料科学
·
化学工程
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