ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Mingchen Jia,Yongjun Li,Chunqing He,Xiaoyu Huang
High durability of low-k value is a desired property for dielectrics serving under humid conditions, because absorbing a small amount of moisture by the material can considerably increase the k value so as to result in function deterioration. Aiming to develop a dielectric polymer with superior durability of low-k value and high thermal stability, a perfluorocyclobutyl (PFCB) biphenyl ether-based polyimide, PFCBBPPI, was synthesized. This polymer possesses a Tg of 310.3 °C and a 5% weight loss temperature of 510.5 °C. PFCBBBPPI exhibited an extremely low water uptake of 0.065 ± 0.018%, representing the best water resistance in polyimides. The increasing percentage in k value was below 2% for PFCBBPPI film exposed to moisture under various humidity conditions for 6 h. PFCBBPPI film equilibrated at 75% R.H. for 2 weeks still kept its k value below 2.50, remarkably outperforming the Kapton film. The remarkable water resistance and resulting high durability of low-k property displayed by PFCBBPPI are originated from the hydrophobic nature and small free volume fraction of the polymer, as confirmed by contact angle test and positron annihilation lifetime spectroscopy results. The outstanding moisture resistance and overall performance of PFCBBPPI make it a suitable candidate for dielectric applications under both dry and humid conditions.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
Sheng Xu,Yan Wang
In this work, two novel carboxyl-containing polyimides , 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride-4,4′-diaminodiphenylmethane/3,5-diaminobenzoic acid (6FDA-MDA/DABA, FMD) and 3,3′,4,4′-benzophenone tetracarboxylic dianhydride-4,4′-diaminodiphenylmethane/3,5-diaminobenzoic acid (BTDA-MDA/DABA, BMD), are synthesized via chemical and thermal imidization methods, respectively, and employed as pervaporation membranes for ethanol dehydration. Chemical structures of the two polyimides are examined by FTIR and TGA to confirm the successful synthesis. A post thermal treatment of the polyimide membranes with the temperature range of 250 to 400 °C is applied, and its effects on the membrane morphology and separation performance are studied and characterized by FTIR, TGA, WXRD, solubility and sorption test. It is believed that the thermal treatment of the carboxyl-containing polyimide membrane at a relative low temperature only leads to the physical annealing, while it may cause the decarboxylation-induced cross-linking at a higher temperature. In addition, the operation temperature in pervaporation is also varied and shown to be an important factor to affect the final membrane performance. Performance benchmarking shows that the developed polyimide membranes both have superior pervaporation performance to most other flat-sheet dense membranes. This work is believed to shed useful insights on polyimide membranes for pervaporation applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2015
·
IF 1.286
Peijiang Liu,Zhengjun Yao,Jintang Zhou
Graphene oxide (GO) sheets have captured the attention of the scientific community because of its excellent performance and applicability. Hence, studying its reinforcing effects on polyimide (PI) resin is an important research topic. In this study, samples of GO-reinforced PI resin were prepared by hot pressing. The effects of GO as nanofiller on the structure and morphology as well as on the mechanical, thermal, and dielectric properties of the GO/PI resin composites were investigated carefully to provide a practical strategy for the use of the polymer-based composites. The GO nanosheets were dispersed uniformly into the PI matrix by ultrasonication, as illustrated by scanning electron microscopic images (SEM). Compared with pure PI, the GO/PI resin composite loaded with 1 wt% GO showed improved tensile strength by 38.9%, flexural strength by 24.8%, and impact strength by 40.7%. Dynamic mechanical analysis test showed that the addition of GO (1 wt%) increased the glass transition temperature by nearly 9.1°C. In addition, the thermal stability and the dielectric constant were also enhanced by adding only a small amount of GO. This approach provides a strategy for developing simple and cost-effective GO-polymer resin composite materials.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 6
·期 12
·125358
·
IF 1.929
Chao Huang,Fangfang Niu,Guangxia Xie,Jinhui Li,Changqing Li,Ying Wang,Fei Ji,Guoping Zhang,Rong Sun,Ching-Ping Wong
Polyimide (PI) with excellent mechanical, thermal, dielectric properties which has been widely applied in electronics, automotive, high-speed rail and chemical industrie. However, the high curing temperture has limited its application in the micro-electronic areas. To address this issue, quinoline (QL) with uique catalytic effect was employed in low temperature curable PI. The changes in chemical structure of the PI films at different temperature was confirmed by FTIR spectroscopy with controlled addition of QL. The effects of QL content on the electrical, thermal and mechanical properties of polyimide were discussed as well. It was found that PI-1.5 has been proved with the best property which exhibited high imidization rate of 99.6% at 200 °C, dielectric constant of 3.20 and a dielectric loss of 5.06 × 10−3 (1 MHz). Besides, the Young's modulus of as much as 1.66 GPa, elongation at break of more than 145% with high tensile strength about 134 MPa have been achieved. Moreover, the T5 is more than 545 °C and the glass transition temperature is higher than 376 °C. The developed low temperature curable PI is expected to be applied in the advanced electronic packaging such as fan-out wafer package, insulation, interlayer dielectric and so forth.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
TALANTA
·
2018
·
IF 4.244
Xi-Ming Wang,Zhi-Yong Guo,Yue Zhang,Ming-Li Chen,Jian-Hua Wang
Fe x O y and ZrO 2 nanoparticles co-doped layered porous polyimide , polyimide-Fe x O y -ZrO 2 is prepared with a one-step strategy, shortly termed as PI-Fe x O y -ZrO 2 . The layered and porous structure of the polymer offers a supported platform for metallic oxide anchoring, exhibiting a mesopore size of 3.93 nm and providing a surface area of 198.47 m 2 g −1 . The metallic oxides were uniformly and highly dispersed in the PI-Fe x O y -ZrO 2 nanocomposite with percentages of 15.81 and 20.53 wt% for Fe and Zr, respectively. The magnetic Fe x O y provides driving force for rapid separation. The high doping of ZrO 2 facilitates effective enrichment of phosphopeptides, even at a very low mass ratio of 1:1000 for tryptic digest of phosphopeptides/non-phosphopeptides, e.g., β-casein/BSA in this particular case. In addition, the PI-Fe x O y -ZrO 2 nanocomposite exhibits better adsorption performance to phosphopeptides with respect to commercial titanium dioxide nanoparticles . The effectiveness of low-abundant phosphopeptides isolation and enrichment from human serum is further identified and demonstrated by means of MALDI-TOF MS and LC-ESI-MS/MS.
研究领域:
生物化学
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材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
·
2021
·Vol. 36
·期 12
·125008
·
IF 2.352
Junshuai Gong,Zhiliang Wang,Huiwen Qu,Dingyong Cang
A coplanar waveguide flexible filter based on the polyimide substrate was fabricated by self-metallization technology. The measured results indicate that the central frequency of the proposed filter is 2.5 GHz, the minimum insertion loss is −0.71 dB and the return loss is better than −20 dB. To test the conformal characteristics of the filter, bending and folding tests were performed. The test results show that the measured and simulated results are basically the same when the filter is bent and folded. The flexible filter fabricated by self-metallization technology is expected to be one of the components of future flexible wireless communication systems.
研究领域:
电子工程
·
通信技术
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Yun Huang,Qin Wang,Jianling Zhang,Yuyan Yu,Yi Dan,Long Jiang
Polyimide photocatalysts with planar or stereo crosslinked structures are achieved by rational structure design, aiming to study structure influence on photocatalytic performance at the molecular level for better designing photocatalysts with good properties. The crosslinked structure is controlled by the configuration of two trifunctional amino monomers, 4,4′,4″-triaminotriphenylamine (TPA) and melamine (MA). 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) was chosen as the key anhydride unit to polycondense with the amino monomers for good visible light harvesting, charge-carrier mobility, and photo-stability. The structure and morphology of polyimide networks (T-PI for the TPA-NTCDA copolymer while M-PI for the MA-NTCDA copolymer) show that T-PI has a porous and amorphous texture with a specific surface area up to 70.2 m2/g, while M-PI exhibits flake-like and crystalline structure with a lower specific surface area of 20 m2/g. Interestingly, a superior performance on photo-degradation of RhB was witnessed by using M-PI as the photocatalyst, although T-PI possesses a smaller bandgap (1.65 eV), wider spectra response , and higher RhB adsorption capability under identical conditions. Combining photocatalytic activities with the stereo difference between M-PI and T-P, we rationally concluded that a planar crystalline texture could be a better choice for polyimide photocatalyst toward efficient elimination of environmental pollutants.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 7
·984
·
IF 4.7
Xin Li,Rongrong Zheng,Cheng Wang,Haiyang Chang,Shuwu Chen,Liyan Wang,Xue Cui,Yutao Liu,Junhao Li,Guangning Yu,Ji Shi
The design of high-performance polyimide (PI) films and understanding the relationship of the structure–dielectric property are of great significance in the field of the microelectronics industry, but are challenging. Herein, we describe the first work to construct a series of novel tert-butyl PI films (denoted as PI-1, PI-2, PI-3, and PI-4) based on a low-temperature polymerization strategy, which employed tetracarboxylic dianhydride (pyromellitic anhydride, 3,3′,4,4′-biphenyl tetracarboxylic anhydride, 4,4′-diphenyl ether dianhydride, and 3,3′,4,4′-benzophenone tetracarboxylic anhydride) and 4,4′-diamino-3,5-ditert butyl biphenyl ether as monomers. The results indicate that introducing tert-butyl branches in the main chain of PIs can enhance the free volume of the molecular chain and reduce the interaction between molecular chains of PI, resulting in a low dielectric constant. Particularly, the optimized PI-4 exhibits an excellent comprehensive performance with a high (5) wt% loss temperature (454 °C), tensile strength (117.40 MPa), and maximum hydrophobic angle (80.16°), and a low dielectric constant (2.90), which outperforms most of the results reported to date.
研究领域:
材料科学
·
微电子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2024
·
IF 4.1
Yifan Li,Jiahui Li,Wenhao Zhang,Qiyun Lin,Lingcheng Chen,Zhihuan Weng,Yi Xiao
The flammability and hydrophilicity of epoxy resins hinder their applications in the high-tech fields of aerospace and electronics. To break these limitations, a highly rigid and hydrophobic polyimide structure has been designed as the harder for epoxy resins. This diamine monomer polyimide (PI–OH) featured a new spiral fluorene-xanthene core doubly grafted phenolic hydroxyl units, to match the commercial bi-trifluoromethyl dianhydride monomer. The curing performance of the polyimide PI-OH was studied in a concentration gradient fashion with the epoxy resin N, N, N′, N′-tetraglycidyl-4, 4′-diaminodiphenylmethane (TGDDM), and compared to the benchmark curer 4, 4′-diaminodiphenyl sulfone (DDS). Due to the unique structural rigidity of spiral crosslinks and the compatibility of the polyimide, the cured PI-OH/TGDDM exhibited Young's modulus of 6.18 GPa and a hardness of 480 MPa, 27.7% and 42.3% higher than that of DDS/TGDDM, demonstrating excellent comprehensive performance. The introduction of PI-OH also reduced the curing temperature with higher curing activity. Resin with 40% loading of the polyimide reached a residual carbon rate of 49.0% at 700 °C (under nitrogen), presenting flame retardancy superior to DDS/TGDDM. Furthermore, the involvement of trifluoromethyl groups reduced the surface free energy and hydrophilicity, lowering the water absorption rate for the modified epoxy resin. This study opens an avenue for comprehensively improving the performance of epoxy resins at lower curing temperatures, which has broad application prospects in aerospace and motor vehicle fields.
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
POLYMER COMPOSITES
·
2024
·
IF 4.8
EnZhi Feng,Yu Wang,Ling Sun,Wenlong Yang,Hongguo Sun
Tailoring the interfacial structure is a critical approach for modulating the dielectric characteristics of nanocomposites. Herein, the energy storage properties of polyimide/silica (PIS) were improved by grafting 4-carboxyphenyl ( PhCOOH), 4-aminophenyl, isocyanate, phenyl and amino groups on the interfaces. The results demonstrated that the PhCOOH groups not only optimized the interfacial structures, but also enhanced both the relative dielectric permittivity ( ε r ) and dielectric strength ( E b ) of PI-based films. The PhCOOH endowed the PI-based films with high ε r by elevating the intrinsic polarization and suppressing the relaxation polarization. Moreover, the PhCOOH elevated charge injection barriers and reduced carrier hopping distances, resulting in a lower current density. Molecular simulations revealed that the PhCOOH raised the SiO 2 electron affinity and the trap depth of PIS composites, achieving the enhancement of E b . The PIS-PhCOOH films with high ε r (7.57, 10 3 Hz) and E b (421 kV⋅mm −1 ) exhibited superior discharge energy density (6.20 J⋅cm −3 ) and energy storage efficiency (88.80%), which was 119.08% higher than that of PIS (2.83 J⋅cm −3 , 75.91%). This work provides insights into interface engineering to synergistically improve dielectric permittivity and dielectric strength of polymer-based composites, paving the way for fabricating high-performance dielectrics. Highlights Polarization response were modulated by interface modification. Both permittivity and dielectric strength of PI-based films were enhanced. PI-based films showed an energy density as high as 6.20 J⋅cm −3 .
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
Materials Today Physics
·
2024
·
IF 10
Ying Li,Chunlei Dong,Sijia Wang,Peng Zhang,Dongyi Lei,Binbin Yin,Zhichun Chen,Xiaodong He,Chengkan Liu,Jiaxin Liu
Two-dimensional transition metal carbides and nitrides (MXenes) which enriched with surface functional groups, defects, and considerable interlayer spaces, demonstrate promising prospects in microwave absorption due to that significantly contribute to dielectric loss. However, their limited gelation ability in aqueous solutions and propensity for self-stacking restrict their applications. Addressing this, a lightweight Ti 3 C 2 T x MXene/Polyimide (MP) aerogel nanocomposites without magnetic materials has been developed through a straightforward freeze-drying method, where ‘PI chains’ anchor the MXene layers, inhibiting self-stacking and enhancing interactions between the Ti 3 C 2 T x nanosheets. The prepared composite aerogels with different MXene contents exhibit exceptional microwave absorption performance. When the thickness of the MP30% is 1.92 mm, the minimum reflection loss (RL min ) is −49.36 dB at 16.28 GHz, and the effective absorption bandwidth (EAB) reaches 6.9 GHz with a matching thickness of 2.5 mm. At 3.8 mm, MP45% achieves an RL min of −80.4 dB. Additionally, MP aerogels have a notable role in fire protection and insulation. The microwave absorbing mechanism of lightweight MP aerogels from the perspectives of chemical composition and physical structure was deeply explored, which is helpful to the preparation of MXene/PI based aerogels with better microwave absorbing ability in the future. Furthermore, the radar cross section (RCS) reduction value of the optimized MP30% aerogel is simulated as high as 34.775 dBm 2 when the scattering angle is 90 o using the computer simulation technology (CST). The prepared MP aerogel with extraordinary radar attenuation ability could potentially be applied as efficient absorber candidates in practical applications.
研究领域:
材料科学
·
电磁材料
·
复合材料
·
微波工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 3
·393
·
IF 4.7
Xiaoyu Du,Shijun Zhao,Yanqing Qu,Hongge Jia,Shuangping Xu,Mingyu Zhang,Guoliang Geng
Imidazole ionic liquids (ILs) have good affinity and good solubility for carbon dioxide (CO2). Such ionic liquids, combined with polyimide membrane materials, can solve the problem that, today, CO2is difficult to separate and recover. In this study, the ionic liquid (IL) of 1-ethyl-3-methylimidazolium tetrafluoroborate (IL1), 1-pentyl-3-methylimidazolium tetrafluoroborate (IL2), 1-octyl-3-methylimidazolium tetrafluoroborate (IL3), and 1-dodecylimidazolium tetrafluoroborate (IL4) with different contents were added to a polyimide matrix, and a series of polyimide membranes blended with ionic liquid were prepared using a high-speed mixer. The mechanical properties and gas separation permeability of the membranes were investigated. Among them, the selectivity of the PI/IL3membrane for CO2/CH4was 180.55, which was 2.5 times higher than the PI membrane, and its CO2permeability was 16.25 Barrer, which exceeded the Robeson curve in 2008; the separation performance of the membrane was the best in this work.
研究领域:
材料科学
·
环境工程
✓ 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）