Polymers
·
2022
·Vol. 14
·期 24
·5391
·
IF 4.967
Shiyang Zhang,Xiaochuang Lu,Mingwei Cai,Zhi Wang,Zhenjing Han,Zhiyin Chen,Rongtao Liu,Kaixin Li,Yonggang Min
Polyimide (PI) membrane is an ideal gas separation material due to its advantages of high designability, good mechanical properties and easy processing; however, it has equilibrium limitations in gas selectivity and permeability. Introducing nanoparticles into polymers is an effective method to improve the gas separation performance. In this work, nano-attapulgite (ATP) functionalized with KH-550 silane coupling agent was used to prepare polyimide/ATP composite membranes by in-situ polymerization. A series of characterization and performance tests were carried out on the membranes. The obtained results suggested a significant increase in gas permeability upon increasing the ATP content. When the content of ATP was 50%, the gas permeability of H2, He, N2, O2, CH4, and CO2reached 11.82, 12.44, 0.13, 0.84, 0.10, and 4.64 barrer, which were 126.87%, 119.40%, 160.00%, 140.00%, 150.00% and 152.17% higher than that of pure polyimide, respectively. No significant change in gas selectivity was observed. The gas permeabilities of membranes at different pressures were also investigated. The inefficient polymer chain stacking and the additional void volume at the interface between the polymer and TiO2clusters leaded to the increase of the free volume, thus improving the permeability of the polyimide membrane. As a promising separation material, the PI/ATP composite membrane can be widely used in gas separation industry.Keywords:polyimide;attapulgite;gas separation;permeability;selectivity
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
POLYMER
·
2022
·
IF 4.432
Yinfu Luo,Long Ni,Lu Shen,Tong Sun,Mei Liang,Pengbo Liu,Huawei Zou,Shengtai Zhou
Rigid polyimide foams (PIFs) with excellent mechanical and thermal properties were fabricated by thermal foaming of active cross-linkable units terminated polyester ammonium salts (PEAS) precursor powders. The active cross-linking strategy was realized by breaking C C bonds in maleic anhydride under heating treatment. Results showed that the formation of cross-linked structure before complete imidization effectively resisted matrix shrinkage and endowed PIFs with outstanding mechanical properties . The room temperature compressive strength and modulus of PIFs with four repeating units reached as high as 2.34 and 56.1 MPa, respectively. Moreover, the PIFs exhibited excellent thermal properties with onset decomposition temperatures ranging from 490 to 550 °C and the glass transition temperatures exceeding 290 °C. The PIFs displayed better thermal insulation , and the values of thermal conductivity fell within a range of 0.056–0.090 W m −1 K −1 , which demonstrates potential application as high temperature resistant structural materials in aerospace and energy sectors.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2021
·Vol. 28
·期 4
·1155-1165
·
IF 2.496
Liu Sha,Chen Weiwang,Zhou Xiaomeng
Polyimide (PI) aerogels with crosslinked structure are promising for diverse applications owing to their nano-porous nature and superior properties in many aspects. However, the crosslinkers used for preparing crosslinked PI aerogels are always laboriously available and expensive. The economical melamine therefore was chosen as a substitute in this study. It was proved that the use of melamine was indeed a viable strategy for effectively crosslinking PI chains. The resultant melamine-crosslinked PI (MPI) aerogels were tested to have relatively low shrinkage (as low as 9.96 vol%), ultralight bulk densities (0.084–0.116 g cm −3 ) and low thermal conductivity (< 40.0 mW m −1 K −1 ), together with considerable thermal stability (onset temperature to decompose up to 503 ℃) and acceptable compressive strength (Young’s modulus of 1.12–10.04 MPa). Meanwhile, the morphology and properties of MPI aerogels can also be tailored by regulating the proportion of hybrid diamines as well as the polymer concentration of pristine solution. Given all of these, MPI aerogels using melamine as an economical yet effective crosslinker will have a broad prospect in many fields including thermal insulation.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Shan Xu,Xiaolong Ren,Ning Zhao,Lei Wu,Zhiguang Zhang,Yanfang Fan,Nanwen Li
The CO 2 -induced plasticization effects impose detrimental effects on polymeric membranes separation performance. To address this issue, a high-performance crosslinked brominated 6FDA-based polyimide (BMPI) is developed in this work, exhibiting highly suppressed plasticizing effects. The permeability and selectivity of polyimide precursor membranes are tuned by introducing bromine atoms into the polyimide structure, creating a best performing membrane with bromination degree of 60%. The membrane CO 2 permeability reaches 395 Barrer, and the selectivity of CO 2 /CH 4 increases from 22.0 for a non-brominated analogue to 26.0. The debromination induced crosslinked BMPI membranes are achieved upon thermal treatment within the temperature range of 150 °C–350 °C with varied crosslinking degree, resulting in large differences for the membrane separation performance. The completely crosslinked BMPI treated at 350 °C for 10 h demonstrates high CO 2 permeability of 483.6 Barrer and the CO 2 /CH 4 selectivity of 26.0. Most importantly, the crosslinking reaction greatly stabilizes the membrane performance against plasticization under high CO 2 feed pressure. Compared with the non-crosslinked membranes with a plasticizing pressure of 150 psia, the plasticization for the crosslinked membrane occurs at high CO 2 pressure of 600 psia. This study provides a facile approach for the preparation of high-performance gas separation polymeric membranes with enhanced plasticization resistance.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
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2023
·Vol. 30
·期 4
·1-10
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IF 2.8
Li Tao,Zhang Yang,Sun Yu,Dai Haiyang,Chen Jing
Ultra-low permittivity ( κ ) materials have broad application prospects in the microelectronic fields. In this study, we prepared microporous polyimide-based composite membranes with ultra-low permittivity by incorporating a trace of cage-like Phenyl-POSS (POSS) into fluorinated polyamic acid (PAA).The effects of POSS incorporation on their dielectric properties correlated with the characteristics of the free volume defects of composite membranes have been investigated by positron annihilation technique. Incorporating POSS with hollow core into PI can effectively improve the free volume size and the relative volume fraction of composite membranes, which optimizes their low dielectric properties, but reduces their dielectric breakdown strength. The membrane with 3 wt % POSS presents an ultra-low permittivity ( κ = 1.77 at 10 4 Hz) and maintains excellent mechanical properties . As POSS-doping amount reaches 5wt% , POSS agglomerates in composite membranes, resulting in a rebound in its permittivity. The incorporation of POSS reduces the tensile strength of composite membranes, which can be attributed to the fact that the rigid phenyl-POSS dispersing in the matrix weakens the interaction between the molecular chains of PI. The experimental results can provide valuable information for improving the dielectric properties of polyimide-based membranes in future.
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
Science China-Technological Sciences
·
2023
·Vol. 66
·期 10
·2797-2807
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IF 4.6
Jiang Miao,Xiao Chao,He XuSheng,Du HuiChao,Wang YanYan,Ding Xin,Zhang Xian,Li XiaoFei,Zheng Kang,Liu XiangLan,Chen Lin,Tian XingYou
In hot environments, the human body shows an efficient capability to maintain a stable temperature by benefiting from sweating behavior. Inspired by this skin perspiration strategy, in this study, we demonstrated an innovative polyimide foam (PIF)-based mimetic skin with excellent cooling capability by integrating a silver coating and reusable hydrogel for the first time. Because of the hybrid thermal dissipating system, the successive silver coating quickly transferred heat to the inside of the polyacrylamide hydrogel. Meanwhile, the hydrogel absorbed a large amount of heat due to its large enthalpy and effectively dissipated heat to the environment through the evaporation of moisture, similar to the sweating of skin. Thus, the temperature of the skin-like film was reduced by 25.4°C compared with pure PIF under a high-power laser heating source. Identical and remarkable cooling effects were also obtained in mobile phone and battery applications, far better than commercially available thermally conductive polyimide (PI). This outstanding performance paves a new way for the thermal management application of PI in wearable electronics, microprocessors, and flexible electronics.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
npj Materials Degradation
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2024
·Vol. 8
·期 1
·1-12
·
IF 6.6
Xi Le,Lv Yadong,Feng Jiabao,Huang Yanyan,Huang Yajiang,Yang Qi,Li Guangxian,Kong Miqiu
Due to their excellent mechanical properties and intrinsic flexibility, polyimides (PIs) are promising candidates for optoelectrical applications under harsh conditions such as flexible organic solar cells as well as flexible smart windows, etc. Much progress has been made on their optical transmittance; however, there remain significant concerns about their environmental stability, particularly their UV resistance. Herein, 4 types of colorless polyimides (CPIs) with different molecular structures containing trifluoromethyl, ethers, or fluorenes are carefully designed, and the dependence of their UV resistance on structures is explored systematically. It is found that the introduction of isopropylidene, ethers and fluorenes effectively enhances the UV resistance of CPI and its initial performance (optical transparency, thermal stability, and toughness) simultaneously as a result of the subtle manipulation of the conjugation structures. Specifically, the optimized polyimide film shows decent optical properties ( \({T}_{550{\rm{nm}}}\) ~ 88%, yellowness index ~3.26), and thermal stability ( \({T}_{5 \% }\) ~ 503 °C in N 2 atmosphere, \({T}_{{\rm{g}}}\) ~ 312 °C). Moreover, after high-intensity UV irradiation, CPI not only maintains over 90% of mechanical properties but also retains excellent optical properties ( \({T}_{550{\rm{nm}}}\) ~ 88%) and thermal stability ( \({T}_{5 \% }\) ~ 506 °C). The design strategy paves the way for enhancing the durability of PIs for energy conversion and electronic applications resisting harsh conditions.
研究领域:
材料科学
·
光电子学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Jun Lin,Jianwei Li,Yutong Song,Wei Chu,Wen Li,Fei Liu,Xinhai He,Qiangli Zhao,Hang Zhao
The fabrication of carbon aerogels with ultralow density, high electrical conductivity, and ultraelasticity still remains substantial challenges. This study utilizes electrospun polyimide aerogel as the source to fabricate flexible carbon nanofibrous aerogel (PI-CNA) capable of multifunctional applications. The lightweight PI-CNA based piezoresistive sensor shows a wide linear range (0–217 kPa), rapid response/recovery time, and fatigue resistance (12,000 cycles). More importantly, the superior pressure sensing enables the PI-CNA for all-range healthcare sensing, including pulse monitoring, physiological activity detection, speech recognition, and gait recognition. Moreover, the EMI SE and the A coefficient of the PI-CNA reach 45 dB and 0.62, respectively, indicating the outstanding absorption dominated EMI shielding effects due to the multiple reflections and absorption. Furthermore, PI-CNA exhibits satisfying Joule heating performance up to 120 °C with rapid response time (10–30 s) under low supply voltages (1.5–5 V) and possesses sufficient heating reliability and repeatability in long-term repeated heating/cooling cycles. The fabricated PI-CNA shows significant potential applications in wearable technologies, energy conversion, electronic skin, and artificial intelligence.
研究领域:
材料科学
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传感技术
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能源转换
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人工智能
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jianhong Guo,Leyan Zhang,Chunhua Zhang,Dandan Zhong,Weihao Long,Jieyao Qin,Zhuan Fu,Sijie Zhou,Junyao Gong,Heng Pan,Hua Ji,Lixin Du,Liangjun Xia
Water is the source of life and the largest energy carrier on Earth. Various excellent hydrovoltaic technologies have been proposed, but still suffer from issues such as intermittent output, material limitations, and poor flexibility. Here, we proposed a method for fabrication of a hydrovoltaic generator using the flexible polyimide fabric. Carbon black was deposited on the polyimide fabric surface using a simple method of candle flame burning. On the basis of water transport in the fabric and charge separation induced by negatively charged carbon black channels, sustainable hydrovoltaic power generation was achieved by the generator. A single carbon deposited polyimide fabric (CBP) could generate a continuous voltage output of nearly 260 mV by dripping a water drop on one side. Multiple CBP devices were connected in series and parallel to increase output power, which could be applied for the power and energy storage of small electronic devices. This work may provide a convenient strategy for fabricating sustainable flexible hydrovoltaic generators and offer insights for the development of clean power sources.
研究领域:
材料科学
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能源技术
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 42
·20092-20106
·
IF 3.5
Zhuo Longhai,He Lixia,Wang Yuhan,Gou Pengfei,Wang Xuechuan,Hu Guang,Xie Fan
Advanced thermal management materials play a crucial role in driving innovation and enhancing the performance of cutting-edge technologies. In this work, polyimide foams were fabricated by freeze-drying precursor polyamic acid (PAA) solutions and thermally imidization, incorporating π-electron-rich benzimidazole structures along with Cu 2 ⁺, Ca 2 ⁺, Na⁺, and K⁺ ions to form cation-π crosslinked structures. The integration of cation-π crosslinked structures notably enhanced polyimide foams, boosting its compressive strength, glass transition temperature, and thermal insulation properties. Particularly noteworthy was the superior enhancement and modification effects exhibited by Ca 2 ⁺ among the cations, followed by Cu 2 ⁺, whereas Na⁺ and K⁺ showed relatively lesser effectiveness. Specifically, the inclusion of 30 mol% Ca 2 ⁺ resulted in a remarkable 136.36% increase in compressive strength and a 320.47% increase in Young's modulus for the polyimide foams. Furthermore, a 50 mol% infusion of Ca 2 ⁺ reduced the thermal conductivity from 0.0533 to 0.0432 W m⁻ 1 K⁻ 1 compared to pristine polyimide foam, while also decreasing the surface temperature of a 15 mm thick sample from 74.1 to 55.7 °C after exposure to a 200 °C platform for 10 min. This study underscores the importance of integrating cation-π crosslinked structures into polyimide foams, leading to significant improvements in thermal insulation properties and thus advancing the field of thermal management materials. Graphical abstract
研究领域:
材料科学
·
热管理技术
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2022
·
IF 3.662
Xiaozhou Zhang,Changyu Han,Tianhui Liang,Hongge Jia,Xigao Jian,Jinyan Wang
In this study, a new polyimide film were prepared using monomers with different proportions of hexaazatriphenylene-ternary-anhydride (HAT-T). This material had higher molecular weights (M n =1.81–11.4 × 10 6 ; M w =2.32–15.5 × 10 6 ) and narrow molecular weight distribution (PDI=1.10–1.36). With the introduction of HAT-T, the glass transition temperature (T g ) of the polyimide film exceeded 300 °C, and the temperature for 5% decomposition in N 2 exceeded 520 °C. The polyimide exhibited good mechanical properties (T S = 63.39–77.81 MPa; E B = 4.50~7.72%). The polyimide film with HAT-T had a micro-crosslinked structure, and its coefficient of thermal expansion decreased by 97 ppm/K. This work has potential contributions to the study of flexible display substrate materials .
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2017
·
IF 2.572
Xin Wang,Yi Liu,Yongfeng Gong,Xinkun Suo,Hua Li
Liquid flame sprayed polyimide-copper coatings were developed for marine antifouling applications. Mixture of polyimide precursor and copper particles was prepared as the starting feedstock for making the composite coatings. Synthesis of polyimide was achieved during the spraying and polyimide acts as binder to fix copper particles. Copper particles were enwrapped by polyimide matrix and distribute evenly in the coatings. Further electrochemical testing revealed excellent corrosion resistance of the coatings in artificial seawater. The coatings resist effectively colonization of E. coli and Bacillus sp. bacteria on their surfaces, suggesting their remarkable antifouling performances. The results shed light on construction of polymer-based antifouling layers for widespread marine applications.
研究领域:
材料科学
·
海洋工程
·
生物学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）