Polymers
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2021
·Vol. 13
·期 8
·1329
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IF 4.329
Maijun Li,Zhibo Zheng,Zhiguang Zhang,Nanwen Li,Siwei Liu,Zhenguo Chi,Jiarui Xu,Yi Zhang
To improve the interfacial compatibility of mixed matrix membranes (MMMs) for gas separation, microporous polyimide particle (AP) was designed, synthesized, and introduced into intrinsic microporous polyimide matrix (6FDA-Durene) to form “all polyimide” MMMs. The AP fillers showed the feature of thermal stability, similar density with polyimide matrix, high porosity, high fractional free volume, large microporous dimension, and interpenetrating network architecture. As expected, the excellent interfacial compatibility between 6FDA-Durene and AP without obvious agglomeration even at a high AP loading of 10 wt.% was observed. As a result, the CO2permeability coefficient of MMM with AP loading as low as 5 wt.% reaches up to 1291.13 Barrer, which is 2.58 times that of the pristine 6FDA-Durene membrane without the significant sacrificing of ideal selectivity of CO2/CH4. The improvement of permeability properties is much better than that of the previously reported MMMs, where high filler content is required to achieve a high permeability increase but usually leads to significant agglomeration or phase separation of fillers. It is believed that the excellent interfacial compatibility between the PI fillers and the PI matrix induce the effective utilization of porosity and free volume of AP fillers during gas transport. Thus, a higher diffusion coefficient of MMMs has been observed than that of the pristine PI membrane. Furthermore, the rigid polyimide fillers also result in the excellent anti-plasticization ability for CO2. The MMMs with a 10 wt.% AP loading shows a CO2plasticization pressure of 300 psi.Keywords:mixed-matrix membranes;compatibility;microporous polyimide particle;polyimide matrix;permeability
研究领域:
材料科学
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化学工程
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DOI
PubMed
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2013
·Vol. 24
·期 6
·600-608
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IF 1.635
Zhenxun Huang,Jianqing Zhao,Yanchao Yuan,Shijing Yan,Shumei Liu,Xingtao Zan
In this study, amino derivative of pure silica zeolite nanocrystal (A-PSZN) was dispersed into polyimide (PI) matrix to prepare PI/A-PSZN hybrid films, and their thermal and mechanical properties, as well as hydrophobicity, were characterized scientifically. The test results show that PI/A-PSZN hybrid films possess higher glass transition temperature, higher thermal stability and lower in-plane coefficient of thermal expansion than pristine PI. The mechanical property data suggest that the incorporation of A-PSZN results in an increase in Young's modulus and tensile strength of the hybrid films, but as its content exceeds the critical value (maybe 5 wt%), its enhancement effect on the hybrid's strength and toughness gets weaker. Furthermore, liquid dripping imaging analysis results indicate that the film's hydrophobicity is clearly improved by the introduction of A-PSZN. As compared with PSZN, A-PSZN exhibits better effect on enhancing the overall performance of pristine PI films. A comparison with other studies suggests that PI/A-PSZN is a hybrid film with superior comprehensive properties. Copyright © 2013 John Wiley & Sons, Ltd.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
SOFT MATERIALS
·
2021
·
IF 2.429
Dongxu Pei,Bing Lv,Jianhua Wang,Shengli Qi,Guofeng Tian,Dezhen Wu
In order to better understand the influences of polyimide (PI) skeleton structure and freeze-drying process on the properties of PI aerogel materials, PI molecular chains (ODPA-ODA, BPDA-ODA, BPDA-PPDA) with different stiffnesses and flexibilities were designed and a series of PI aerogels were accordingly fabricated by freeze-drying technique. The aerogels produced featured light weight (density of 0.01–0.16 g/cm3) and high flexibility, and their density, pore structure, and compress recovery performance could be well controlled by delicately tuning the molecular chain structure and solid contents of the poly (amic acid) salt solution. In addition, a hard PI aerogel with enhanced compressive strength was obtained by quick-freezing in liquid nitrogen.
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 Physical Chemistry C
·
2019
·
IF 4.309
Yu Lin,Shani Hu,Guozhang Wu
A continuing challenge in polymer nanocomposites (PNCs) is to control nanoparticle (NP) dispersion and understand its role in property enhancements. Previous studies have been focused on the flexible polymer chain systems. In this study, we report the structure, glass transition behavior, segmental dynamics, and mechanical properties of polyimide (PI) nanocomposites that consisted of either bare or PI-grafted silica NPs to discriminate the role of grafted rigid chains in polymer–NP interactions and dynamic response of such hybrids. Silica NPs are well dispersed in the poly(amic acid) (the precursor of PI) nanocomposites. After thermal imidization, the aggregate structure and self-assembled small clusters of NPs are observed in ungrafted and grafted silica NP-filled PI composites, respectively. The glass transition temperature (Tg) shifts to high temperature by the addition of silica NPs resulting from strong polymer–NP interactions and steric hindrance, and Tg deviation is more visible with increasing the molecular weight of grafted PI chains. The α-relaxation dynamics are suppressed in PI nanocomposites, but there is no interfacial layer relaxation detected because of the rigid chain characteristic of PI. The accelerated Maxwell–Wagner–Sillars polarization process is noted in the presence of PI-grafted silica NPs with high molecular weight. PI-grafted silica NPs are effective in improving polymer–NP interfacial adhesion, resulting in superior mechanical properties to those of the bare silica NP-filled composites. Moreover, high molecular weight grafted PI chains are beneficial in the mechanical enhancement of the resulting PI nanocomposites. These findings provide new insight into the fundamental understanding of chain packing and relaxation dynamics of PNCs with rigid polymer chains and therefore provide guidance in designing such materials with desired macroscopic properties.
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
·
2016
·
IF 1.045
Guangliang Song,Lina Wang,Dandan Liu,Jianan Yao,Yiming Cao
A series of polyimide (PI) membranes were prepared based on three triphenylamine-based diamines, namely 4,4′-diaminotriphenylamine, 4,4′-diamino-3′′,5′′-dimethyltriphenylamine, and 4,4′-diamino-3′′,5′′-ditrifluoromethyltriphenylamine, via thermal imidization procedure. The PI membranes displayed good thermal properties, with glass transition temperatures of 279–341°C and 5% weight loss temperatures above 515°C under a nitrogen atmosphere. The gas permeation properties of the membranes were investigated and interpreted from the viewpoint of the PI backbone structure. The gas permeation coefficients increased as the substituent pendant groups at the 3′′,5′′ positions of the triphenylamine varied from –H to –CH3 and –CF3, and the permselectivity of gas pairs (including hydrogen/nitrogen (N2), oxygen/N2, carbon dioxide (CO2)/N2, and CO2/methane) decreased in this order. The diffusion coefficients and solubility coefficients were calculated, and the results revealed the variation of the substituted triphenylamine units principally influenced the diffusion coefficients, indicating that the substituted triphenylamine affected the gas transport properties by “diffusivity-controlled” modification.
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
RSC Advances
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2016
·Vol. 6
·期 22
·18279-18287
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IF 3.289
Na Yang,Chen Xu,Jun Hou,Yanmei Yao,Qingxin Zhang,Maryam E. Grami,Lianqi He,Nongyue Wang,Xiongwei Qu
Polyimide (PI) has been widely used as a preferred packaging matrix material due to its low dielectricity, outstanding insulation and excellent thermal stability. Hexagonal boron nitride (h-BN) microparticles were functionalized with a silane coupling agent, 3-glycidyloxypropyltrimethoxy silane (γ-MPS), to improve the interface action with the PI matrix. The modified h-BN (m-BN) particles were used to fabricate the PI/m-BN composites with enhanced thermal conductivity by in situ polymerization. The Fourier transform infrared (FTIR) spectra, thermo-gravimetric analysis (TGA), transmission electron microscopy (TEM) and contact angle test proved that γ-MPS coupling agent molecules had been chemically grafted onto the h-BN surface. In addition, the effects of the m-BN content on the thermal conductivity of PI/m-BN composites were investigated. The composite obtained with 40 wt% m-BN particle loading presented a thermal conductivity of 0.748 W m−1 K−1, 4.6 times higher than that of pure PI. Meanwhile, the fabricated PI/m-BN composites retained excellent electrical insulation and thermal stability. The glass transition temperature values of the PI/m-BN composites decreased slightly while the storage modulus improved with the increase of the m-BN content. These results showed that PI/m-BN composites may offer new applications in the microelectronic industry because future substrate materials require effective heat dissipation.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 7
·5918-5926
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IF 2.993
Ren Rui-Peng,Wang Zhen,Ren Jing,Lv Yong-Kang
Graphene aerogel with three-dimensional (3D) interconnected porous structure and good hydrophobicity has been extensively investigated for sorbent materials for oils and demonstrated to be effective. Herein, a 3D polyimide–graphene aerogel (PI-GA) nanocomposite has been prepared by introducing water-soluble polyimide (PI). Benefiting from the synergetic effect of PI and GA, the PI-GA nanocomposite exhibits ultralow density, excellent compressibility and hydrophobicity. When evaluated as a sorbent material for oils and organic solvent, PI-GA nanocomposite has high absorption capacity and can separate oil from water rapidly and efficiently. Furthermore, the mechanical squeezing process can be used for the recycling of the PI-GA due to its excellent compressibility. The excellent absorption performance and robust mechanical properties make the PI-GA suitable for oil cleanup and chemical leakage.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
Materials Science and Engineering B-Advanced Functional Solid-State Materials
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2022
·
IF 3.407
Tao Li,Yu Sun,Haiyang Dai,Junjie Liu,Jing Chen,Dewei Liu
Four kinds of polyimide (PI) films were prepared by polycondensation reaction using the pyromellitic dianhydride (PMDA) and 4, 4′-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA）as the dianhydride monomer, the p-phenylenediamine (PDA), 4-4′-diaminodiphenyl ether (ODA) and 4,4′-(Hexafluoroisopropylidene) bis(p-phenyleneoxy) dianiline (HFBDA) as the diamine monomer respectively. The incorporation of trifluoromethyl groups can effectively inhibit the formation of intermolecular and intramolecular charge-transfer complex (CTC), improve the energy gap and increase the free volume in PI, which leads to an improvement in the optical and dielectric properties in different degree for three fluorinated PI films compared with the Kapton film. The maximum transmittance in visible region reaches 90.5% and the dielectric constant at 10 4 Hz is close to 2.0 for PI 6FDA-HFPBDA film. The breakdown strength weakens because of the increase of free volume. The correlation between the dielectric and breakdown characteristics and their free volume has been explained with the help of positron lifetime spectra.
研究领域:
材料科学
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物理学
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DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2020
·
IF 4.032
Menghao Chen,Bo Liang,Yuhang Guo,Chengfeng Li,Xian He,Jianghuai Hu,Renke Li,Ke Zeng,Gang Yang
The pyrolysis mechanism and pyrolysis behavior of adenine-containing polyimide (API) were studied by thermogravimetric analyzer with Fourier transform infrared analysis and mass spectrometry (TG-FTIR-MS) and pyrolysis-gas chromatography-mass spectroscopy (Py-GC-MS). TG-FTIR-MS and Py-GC-MS were employed to continuously track the release of volatile products during the pyrolysis process. Thermogravimetric analysis (TG) indicated that API presented outstanding thermal stability. Additionally, it was observed that the volatile products were formed during the pyrolysis of API, including CO 2 , CO, HCN, benzonitrile , aniline and phenyl isocyanate . A probable pyrolysis mechanism of the API has been proposed according to the results of TG-FTIR-MS and Py-GC-MS.
研究领域:
材料科学
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化学工程
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生物分子化学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2020
·Vol. 38
·期 8
·840-846
·
IF 3.154
Hao Fu-Yao,Wang Jian-Hua,Qi Sheng-Li,Tian Guo-Feng,Wu De-Zhen
A series of polyimide (PI) films derived from pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) were prepared with the employment of chemical pre-imidization, and the pre-imidization degree (pre-ID) was found influential on structures and properties of the films obtained. Specifically, a certain degree of chemical imidization could promote the in-plane orientation of molecular chains inside the film, which then enhanced the mechanical strength and reduced the coefficient of thermal expansion (CTE) of the films. Further, such pre-imidization process could expand the internal space gap inside the films, thereby lowering their dielectric constant and glass transition temperature. Our study provides a new approach for preparing high-performance PI films through chemical imidization.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2022
·
IF 1.73
Tingting Zhang,Zhenghui Yang,Fengyu Piao,Haiquan Guo
According to the application requirements of colorless transparent polyimide (CPI) film for low coefficient of thermal expansion (CTE) in the field of OLED display, the new aromatic dianhydride monomers with amide bond structure were synthesized, namely s-ABDA, i-ABDA, EADA. Furthermore, a series of CPI films were prepared by two-step method from the reaction of as-synthesized dianhydrides with 2.2′-bis (trifluoromethyl) −4.4′-diaminobiphenyl (TFMB) or trans-1.4′-cyclohexanediamine (t-CHDA). Based on the analysis of performance results, the incorporation of amide group and biphenyl, benzene or ether bond into dianhydride monomer helped this new type of transparent polyimide film with excellent optical properties (T550 nm> 88%), great heat stability (CTE <4.4 ppm/K; Tg >314°C; Td5% >478°C) and good mechanical strength (σ > 208 MPa). The film s-ABDA/TFMB showed ultra-low CTE value at 4.4 ppm/K, aligning with the maximum birefringence, indicating that the role of hydrogen bonding was of great benefit to the regulation of thermal expansion.
研究领域:
材料科学
·
显示技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 45
·17225-17235
·
IF 8.067
Man Liu,Yiheng Song,Hongmei Qin,Ziwei Li,Yuheng Fu,Chuanxi Xiong,Feihua Liu
Polymers with both high dielectric breakdown strength and high dielectric constant are vital for a large number of applications. However, most polymer or polymer composites suffer from the problem of deteriorated breakdown strength caused either by undesired submicron voids during film processing or the addition of high dielectric constant filler. In this work, we present a facile blending strategy to fabricate polyamide-imide (PAI)/polyimide (PI) alloy. The strong interchain hydrogen bonds and electrostatic force of the PAI/PI alloy increase chain packing density and decrease possible corresponding imperfect points. The intermolecular forces are simulated and calculated via Materials Studio. It is found that the PAI/PI alloy with 50 wt% PAI possesses the strongest intermolecular forces, which is consistent with the experimental results. The PAI/PI alloy with 50 wt% PAI exhibits enhanced dielectric properties, such as 54.3% improvement in breakdown strength, 68.8% enhancement in dielectric constant and suppressed dielectric loss compared with pristine PI, leading to a high discharged energy density of 5.84 J cm−3 with an efficiency of 91.8% at 545 MV m−1. The excellent performance of the PAI/PI alloy can be attributed to the polar groups in PAI that promote the dielectric constant, strong hydrogen bonds and electrostatic force between the molecule chains in the blend that contribute to the greatly enhanced breakdown strength. This novel molecular engineering strategy is an effective way to fabricate high-performance dielectric polymers for film capacitor applications.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）