JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
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2021
·
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.
研究领域:
材料科学
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航空航天工程
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DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2020
·Vol. 221
·期 12
·2000085
·
IF 2.335
Zhigeng Chen,Sen Zhang,Qi Feng,Yancheng Wu,Shumei Liu,Jianqing Zhao
Both the formation of insoluble salt for aliphatic diamines and the poor reactivity for aliphatic dianhydrides result in semi-aromatic polyimide (SAPI) with low molecular weight and, thereby, in highly brittle SAPI films in nature. To solve the above problems, a cyclic-olefin copolymer synthesized from norbornene and maleic anhydride is used as the third monomer (crosslinking agent) to prepare the crosslinked SAPI (cSAPI) films. The relative viscosity of the precursor solution of cSAPI is increased with the loading of cyclic-olefin copolymer, giving rise to the improvement in mechanical and thermal properties of cSAPI films. The tensile modulus, tensile strength, and elongation at break of cSAPI film with 5 wt% cyclic-olefin copolymer are increased to 4.49 GPa, 137 MPa, and 14.9% from 3.57 GPa, 111 MPa, and 7.6%, respectively, compared to those of the baseline SAPI film. Meanwhile, the glass transition temperature of cSAPI films is increased to 282 from 270 °C of the SAPI film, which is advantageous to better meet the requirement for high-temperature manufacturing processes such as lead-free solder reflowing. In addition, all cSAPI films exhibit good optical transparency in the entire visible region.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Zhiqiang Wu,Huihui Zhou,Qiang Guo,Zhenguo Liu,Lei Gong,Qiuyu Zhang,Ganji Zhong,Zhongming Li,Yanhui Chen
In this work, we prepared the polyimide (PI) nanocomposite films containing barium titanate @polydopamine (BT@PDA) nanoparticles within a core-shell structure by solution casting method. The dielectric constant of these nanocomposite films is significantly improved compared to pure PI film, and increases with the increase of BT nanoparticles. And, the breakdown strength of these nanocomposite films is better than that of untreated BT/PI films at the fixed BT content. The PI composite film containing 1 vol% of BT@PDA nanoparticles exhibits the highest energy storage density of 1.94 J/cm 3 under an electric field of 315 kV/mm, which is 42% over the pristine PI (1.37 J/cm 3 at 295 kV/mm) and about 162% greater than biaxially-oriented polypropylene (BOPP) (≈1.2 J/cm 3 at 640 kV/mm). The presence of PDA shell effectively improves the dispersion uniformity and interfacial compatibility of BT nanoparticles in the PI matrix, giving rise to lower local electric field distortion in the composites. Besides, the BT@PDA/PI nanocomposite films have excellent dielectric thermal stability in the temperature range from 25 to 200 °C and thermal stability up to 500 °C. The BT@PDA/PI composites fabricated in this work have a great potential to be used in the high-temperature film capacitors.
研究领域:
材料科学
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电气工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
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IF 2.7
Ling Weng,Jinming Liu,Xiaorui Zhang,Hang Xu,Lizhu Guan,Yang Yu
Considering the ongoing evolution of flexible printed circuit boards and the importance of safeguarding the intellectual property of circuit designs, there exists an imperative demand for the development of a black film exhibiting exceptional electrical properties and remarkable light-shielding capabilities. Consequently, this work employs a straightforward strategy to enhance the opacity of polyimide films by incorporating carbon black (CB) and manganese dioxide (MnO 2 ) as black fillers using an in situ doping method. Rigorous tests are conducted, analyzing properties such as dielectric constant, dielectric loss, breakdown field strength, current density, and ferroelectric energy storage. The optimal ratio of CB to MnO 2 (mass fraction) is determined as 1:5, with a total powder doping amount of 6 wt%, providing the best ratio relative to the matrix resin. This ratio ensures an optimal powder dispersion state, resulting in an outstanding breakdown field of 147.4 kV/mm and ultralow dielectric constants, measuring less than 3.78 at 103 Hz. This composite film is anticipated to find applications as a cutting-edge material for electronic devices and the semiconductor industry.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 95
·93094-93102
·
IF 3.289
Ying Song,Hongyan Yao,Yunxia Lv,Shiyang Zhu,Shanyou Liu,Shaowei Guan
A novel triamine monomer, N,N′,N′′-tris(4-methoxyphenyl)-N,N′,N′′-tris(4-phenylamino)-1,3,5-benzenetriamine, was designed and synthesized. A hyperbranched polyimide (HBPI) was prepared by reacting the triamine monomer with 4,4-(hexafluoroisopropylidene)diphthalic anhydride for application in memory devices. The resulting HBPI exhibited excellent organo-solubility and high thermal stability. A memory device with a sandwich structure of indium tin oxide (ITO)/HBPI/Al was fabricated by using HBPI as an active layer. The device exhibited static random access memory (SRAM) behavior with a relatively low switching voltage of −1.90 V. Moreover, the device showed good stability in both the OFF and ON states, which could be retained as long as 1 × 104 s under a constant voltage stress of −1.00 V with an ON/OFF current ratio reaching up to 1 × 106. Molecular simulation results suggested that efficient charge transfer between the triamine moieties and hexafluoropropylidene phthalimides moieties in HBPI exist, which is responsible for the improved electrical memory performance. Such a HBPI was expected to be potentially useful in polymer memory applications.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 98
·95825-95835
·
IF 3.289
Hui Yuan,Qing liang You,Lin Jie Song,Gui ying Liao,Hua Xia,Dong Sheng Wang
The novel carbon nanotubes (CNT)/porous polyimide (PI) composites were prepared via blending and were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and nitrogen adsorption–desorption techniques. The feasibility of CNT, CNT/PI (3/1) and CNT/PI (1/1) to remove 2,4-dichlorophenol (2,4-DCP) from an aqueous solution was examined. The influence of different parameters such as pH, ionic strength, contact time and temperature has been carried out. The results showed that PI was successfully combined with CNT and formed CNT/PI composites with higher adsorption capacity and shorter equilibrium time. The adsorption capability at 298 K of CNT, CNT/PI (3/1) and CNT/PI (1/1) composites were 330.0 mg g−1, 412.5 mg g−1 and 506 mg g−1, respectively. Their kinetic experimental data were better fitted by a pseudo-second-order model, and their adsorption isotherms could be represented by the Freundlich isotherm model perfectly. A thermodynamic study showed that the adsorption of 2,4-DCP on them was spontaneous and endothermic. Discoveries in this study suggest that the CNT/PI composites are promising adsorbents for removal of 2,4-DCP from aqueous solution.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2016
·Vol. 134
·期 8
·
IF 1.866
Jianwei Li,Guangcheng Zhang,Qi Zhu,Jiantong Li,Hongming Zhang,Zhanxin Jing
In this research, a series of porous copolyimide (co-PI) films containing trifluoromethyl group (CF 3 ) were facilely prepared via a phase separation process. The co-PI were synthesized by the reaction of benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (BTDA) with two diamines of 4,4′-diaminodiphenyl ether (ODA) and 3-trifluoromethyl-4,4'-diaminodiphenyl ether (FODA) with various molar ratios. The flexible and tough porous co-PI films with about 300 μm thickness and 8∼10 μm average diameter could be obtained by solution casting conveniently. The thermal properties of the obtained porous co-PI films were excellent with a glass transition temperature at 270 °C ∼ 280 °C and only 5% weight loss in temperature from 530 °C to 560 °C under nitrogen atmosphere. In addition, the dielectric and hydrophobic properties of porous co-PI films were remarkably improved owing to the presence of trifluoromethyl groups (CF 3 ) in the polymer chains. Moreover, our synthesized porous co-PI films also showed good mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44494.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
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2016
·
IF 1.045
Yang Liu,Yuping Ai,Pengfei Huo,Haitao Huang,Jiyou Gu
In this study, a new kind of membrane material, an aromatic zwitterionic polyimide (PI) copolymer, was synthesized through a one-pot polymerization reaction by precise variation of the molar ratios of different monomers with specific groups. The zwitterionic PI ultrafiltration (UF) membrane was prepared through an immersion precipitation phase inversion method and thoroughly characterized by scanning electron microscopy, water contact angle measurement, protein adsorption measurement, and UF experiment. The zwitterionic PI membrane showed significantly improved hydrophilicity and permeability and stable antifouling property. The amount of bovine serum albumin adsorbed on the zwitterionic PI membrane was considerably lower compared with the reference PI membrane. According to the cycle UF experiment for protein solution, the zwitterionic PI membrane had a water flux recovery ratio of 86.7%, compared with only 61.1% for the reference PI membrane. Moreover, the irreversible fouling of the zwitterionic PI membrane was significantly decreased, suggesting superior antifouling property. This new approach to the preparation of a zwitterionic polymer seems promising for potential applications in separation membrane.
研究领域:
材料科学
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膜技术
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生物医学工程
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产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 39
·22169-22176
·
IF 2.936
Shiyang Wei,Qiaoxi Yu,Zhenguo Fan,Siwei Liu,Zhenguo Chi,Xudong Chen,Yi Zhang,Jiarui Xu
The preparation of polymeric composite materials with low filler content as well as high thermal conductivity has been an important subject for the field of polymer material research. During our recent investigation on polyimide (PI), it was found that poly(amic acid) (PAA) solution (in dimethylacetamide, DMAc) could crystallize at low temperature. When adding reduced graphene oxide (rGO) as the thermal conductive fillers in the PAA solution, it was also found that the crystallization process of PAA would impel the rGO to rearrange in order and form an aligned thermal conductive network. To retain the rGO network structure, the freeze-drying technique was used to remove the solvent. Subsequently, through a thermal imidization process the final rGO/PI films containing a 3D rGO network could be obtained. The PI composite films retain good flexibility, excellent thermal stability, and exhibit excellent thermal conductivity. When the content of rGO added is 8 wt%, the thermal conductivity of the rGO/PI film can reach a high value of 2.78 W m−1 K−1, which is about 15.4 times that of neat PI and 5.5 times that of the rGO/PI composite film prepared by the conventional two-step routine with the same content of rGO.
研究领域:
材料科学
·
热传导技术
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产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
·
2019
·
IF 1.584
Yuqi Li,Qiu Zhang,Hong Ruan,Fengan Li,Xu Xu,Xiaohua Huang,Shaorong Lu
To explore the effect of added graphene sheets (GNs) and added perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) on the tribological and mechanical performances of polyimide (PI) matrix, GNs and PTCDA reinforced PI-based composites were synthesized via the blending method. The tribological properties of GNs/PTCDA/PI (GAPI) composites with different weight ratios of GNs and PTCDA under dry sliding, deionized water lubrication, and kerosene lubrication were comparatively investigated. A synergism was found between GNs and PTCDA; this synergism endowed filled PI composites with a lower friction coefficient and showed an improved wear rate under different lubrication conditions, especially when the weight ratio of GNs and PTCDA was 1:1 (GAPI-1). Under dry sliding, deionized water lubrication, and kerosene lubrication, the friction coefficient of GAPI-1 composites decreased by 41.1%, 70%, and 35.7%, respectively, while the wear rate decreased by 39%, 50%, and 25.1%, respectively. Meanwhile, the tensile strength, tensile modulus, and the elongation at break of GAPI-1 films increased by 40.8%, 51.3%, and 49.2%, respectively, relative to those of pure PI. We anticipate that this work can be used to exploit a simple and effective method for preparing materials for bearings and transmission parts that possess good tribological properties under harsh lubrication conditions.
研究领域:
材料科学
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表面工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
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.
研究领域:
化学工程
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材料科学
·
催化反应
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产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
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 .
研究领域:
材料科学
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摩擦学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）