POLYMER
·
2022
·
IF 4.432
Xiaohong Li,Minyan Wang,Nafeesa Mushtaq,Guofei Chen,Guohua Li,Xingzhong Fang,Anjiang Zhang
In this study, two series of polyimides (PI) were synthesized from one step solution polycondensation of two diamines containing sulphonyl group with aromatic and aliphatic dianhydrides. These PIs showed good organosolubility and were casted into films with high transparency of T 500 >86%, and cutoff wavelength in the range of 295–370 nm. Optical birefringence (0.0020–0.0127) of these PIs was lower than that of traditional aromatic PI. PI films demonstrated out-of-plane retardation ( R th ) in the range of 42–279 nm, indicating low optical anisotropy of these films. All PIs also exhibited high thermal stability with glass transition temperatures ranging from 200 to 339 °C. PI- 1c derived from bis[4-(3-aminophenoxy)phenyl] sulfone ( m -BAPS) and 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) showed the lowest birefringence and good transparency.
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
·
2014
·Vol. 4
·期 102
·58252-58259
·
IF 3.708
Peng Yan,Bin Zhou,Ai Du
Polyimide cross-linked silica gels with different weight percentages of solid precursors and different volumes of MTMS were prepared by using bis(trimethoxysilylpropyl)amine (BTMSPA) cross-linked polyamide acid, synthesized by 4,4′-oxydianiline (ODA), p-phenylenediamine (PPDA) and biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA), compounding with a silica network which was hydrolysed by MTMS, then supercritically dried to produce a hybrid aerogel. The obtained aerogels exhibit striking properties such as low density (as low as 90 mg cm−3), a large surface area (up to 582 m2 g−1), lower shrinkage (up to 20%) and are more easily accessible than those previous reported. Formulations made of 8.7% and 11.72% solid precursors never collapsed under compression. Furthermore, the latter shows the maximum modulus (up to 17 MPa) and a higher sound absorption coefficient (more than 0.8) with a thickness of 3 cm in a specific range of frequencies.
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
DYES AND PIGMENTS
·
2017
·
IF 3.473
Haiwei Tan,Hongyan Yao,Ying Song,Shiyang Zhu,Huaxuan Yu,Shaowei Guan
In this work, a novel tetra-amine, bis (4-(3, 5-bis (4-amino-2-(trifluoromethyl) phenoxy) phenoxy) phenyl) methanone, was synthesized and then utilized to produce hyperbranched polyamic acids via polycondensation with 4, 4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The resulting hyperbranched polyamic acids underwent termination by (4-amino) phenyl ferrocene and imidization, leading to ferrocene-terminated hyperbranched polyimide (HBPI-Fc). The resulting HBPI-Fc displayed superior solubility in conventional organic solvents and excellent thermal stability. A memory device with a configuration of indium tin oxide (ITO)/HBPI-Fc/Al was fabricated, in which the HBPI-Fc acted as the active layer. The device exhibited bistable electrical conductivity switching and nonvolatile bipolar write-once-read-many-times memory character with two threshold voltages of 2.2 V and −2.6 V, respectively, during positive and negative voltage sweep. The device exhibited an ON/OFF current ratio of 10 4 under a constant bias of −1.0 V and good stability in both ON- and OFF-state during the test period of 10 4 s. The revealed electrical bistability of the HBPI-Fc was found mainly due to the effective charge trapping effect of the electroactive terminal ferrocene groups.
研究领域:
材料科学
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电子工程
·
有机化学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Haitao Huang,Jiayu Yu,Hanxiang Guo,Yibo Shen,Fan Yang,Han Wang,Rong Liu,Yang Liu
On the basis of the outstanding fouling resistance of zwitterionic polymers, an antifouling ultrafiltration membrane was fabricated through phase inversion induced by immersion precipitation method, directly using the novel zwitterionic polyimide (Z-PI), which was synthesized via a two-step procedure including polycondensation and quaternary amination reaction, as membrane material. The chemical structure and composition of the obtained polymer were confirmed by using FTIR, 1 H NMR and XPS analysis, and its thermal stability was thoroughly characterized by TGA measurement, respectively. The introduction of zwitterionic groups into polyimide could effectively increase membrane pore size, porosity and wettability, and convert the membrane surface from hydrophobic to highly hydrophilic. As a result, Z-PI membrane displayed significantly improved water permeability compared with that of the reference polyimide (R-PI) membrane without having an obvious compromise in protein rejection. According to the static adsorption and dynamic cycle ultrafiltration experiments of bovine serum albumin (BSA) solution, Z-PI membrane exhibited better fouling resistant ability, especially irreversible fouling resistant ability, suggesting superior antifouling property and long-term performance stability. Moreover, Z-PI membrane had a water flux recovery ratio of 93.7% after three cycle of BSA solution filtration, whereas only about 68.5% was obtained for the control R-PI membrane. These findings demonstrated the advantages of Z-PI membrane material and aimed to provide a facile and scalable method for the large-scale preparation of low fouling ultrafiltration membranes for potential applications.
研究领域:
材料科学
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环境工程
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生物医学工程
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DOI
高影响因子
Energy Technology
·
2017
·Vol. 6
·期 2
·326-332
·
IF 2.789
Ailian Wang,Hao Xu,Fulin Liu,Xu Liu,Shi Wang,Qian Zhou,Jie Chen,Shiyong Yang,Liaoyun Zhang
A new solid polymer electrolyte composed of a polyimide matrix, an ionic liquid additive (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [Bmim][TFSI]), and a lithium salt (lithium bis(trifluoromethanesulfonyl)imide, LiTFSI) is fabricated by the solution-casting technique. The obtained self-standing polyimide (PI)-based polymer electrolyte (PI-100 %BmimTFSI-60 %LiTFSI) membranes show a great flexibility, transparency, and infiltration ability. As a result of the high thermal stability of the polyimide matrix, the thermal decomposition temperature of the electrolyte is high (420 °C). The ionic conductivity can be up to 1.73×10 −5 S cm −1 at room temperature and reaches 1.26×10 −3 S cm −1 at 80 °C. In addition, the PI-100 %BmimTFSI-60 %LiTFSI electrolytes have a wide electrochemical stability window of 4.8 V, a general lithium ion transference number of 0.12, and good interfacial stability and compatibility. In particular, the assembled LiFePO 4 /Li half cells made from this polyimide-based electrolyte can light up a light-emitting diode lamp at room temperature.
研究领域:
材料科学
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电化学
·
能源存储
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产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Zheng Lu,Jiang-Huai Hu,Chang Chen,Wei-Feng Peng,Zheng-Zhou Liu,Yang Liu,Ke Zeng,Gang Yang
To broaden the application of polyimide materials, adenine-based polyimide/nano-silica hybrid films were prepared via sol-gel method without using coupling agents. Adenine-based diamine, 9,10-bis(4-aminopheny)adenine ( p -APA), was introduced to polymerize with 3,3′,4,4′-tetracarboxydiphthalic ether dianhydride (ODPA) to synthesize polyimide (API) matrix. The compatibility between the polymer matrix and silica was improved by hydrogen bonding between NH group in p -APA and Si OH group in silica. Systematic studies showed that API hybrid films possess high transparency and outstanding thermal properties even though the doping content was up to 20 wt% (glass transition temperature ( T g ): 328 °C, maximum decomposition occurring temperature ( T max ): 603 °C (N 2 ), coefficient of thermal expansion (CTE): 16.60 ppm/ o C).
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
COMPOSITES PART B-ENGINEERING
·
2018
·
IF 4.92
Xiaomin Li,Juying Wu,Changyu Tang,Zhoukun He,Ping Yuan,Yong Sun,Woon-ming Lau,Kai Zhang,Jun Mei,Yuhong Huang
Boron carbide (B 4 C) is an important type of neutron radiation shielding material with relatively high efficiency due to the high content of 10 B element. Incorporation of B 4 C particles into polymer to prepare high-performance neutron radiation shielding material has become more and more important for the safe operation of nuclear power in the defense industry and nuclear power plant . The polyimide/B 4 C composite films with different micro-sized B 4 C contents were successfully prepared by in-situ polymerization. Silane coupling agent KH550 was employed to functionalize B 4 C particles to improve the dispersion of B 4 C particles in the polyimide matrix with strengthened interfacial interaction . As shown that the micro-sized B 4 C functional particles can be well dispersed in the BPDA/ODA polyimide matrix. With the B 4 C content increase, thermal stability of the polyimide/B 4 C composite films can be significantly improved, even mechanical properties partly declined. Meanwhile, the polyimide/B 4 C composite films exhibit good thermal neutron radiation shielding properties. The neutron permeability I/I 0 changes exponentially with the change of B 4 C content. When the B 4 C content is increased to 30 wt%, the polyimide/B 4 C composite films show optimum properties combination with thermal decomposition temperature (T d 10 ) of 622 °C, neutron permeability ( I/I 0 ) of 0.24 (800 μm in thickness), and tensile strength of 406 MPa. The composite thus shows great potential for use in applications which require materials with high thermal stability and neutron radiation shielding ability, such as fusion reactor system and nuclear waste disposal.
研究领域:
材料科学
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核工程
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产品关联
DOI
高影响因子
NEW CARBON MATERIALS
·
2021
·
IF 1.905
Ze-zheng Yuan,Wei Chen,Yun-kai Shi,Xiao-dong Chu,Zheng-hong Huang,Lin Gan,Jia Li,Yan-bing He,Bao-hua Li,Fei-yu Kang,Hong-da Du
Aromatic polyimide (PI)-based graphite nanofibers were obtained from the graphitization of graphene oxide (GO)-doped electrospun PI nanofibers. GO improves the PI molecular orientation, crystalline structure and thermal conductivity of the resulting nanofibers. The degree of PI molecular orientation in the nanofibers is increased by the GO during fiber preparation. This improvement in molecular orientation produces an increase in the thermal conductivity of the graphite nanofibers, and the addition of only 0.1% GO has a significant effect. The GO not only affects the thermal conductivity, but improves the PI molecular orientation and its role as nucleation centers during graphitization. This approach and the resulting high thermal conductivity materials show great potential for practical applications.
研究领域:
材料科学
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热传导工程
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产品关联
DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 3
·649
·
IF 4.967
Jian-Jun He,Hai-Xia Yang,Feng Zheng,Shi-Yong Yang
Fluorinated aromatic polyimide (FAPI) films with rigid polymer backbones have been prepared by chemical imidization approach. The polyimide films exhibited excellent mechanical properties including elastic modulus of up to 8.4 GPa and tensile strength of up to 326.7 MPa, and outstanding thermal stability including glass transition temperature (Tg) of 346.3–351.6 °C and thermal decomposition temperature in air (Td5) of 544.1–612.3 °C, as well as high colorless transmittance of >81.2% at 500 nm. Moreover, the polyimide films showed stable dielectric constant and low dielectric loss at 10–60 GHz, attributed to the close packing of rigid polymer backbones that limited the deflection of the dipole in the electric field. Molecular dynamics simulation was also established to describe the relationship of molecular structure and dielectric loss.Keywords:fluorinated aromatic polyimide;low dielectric loss;molecular chain orientation;molecular dynamics simulation
研究领域:
材料科学
·
物理学
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产品关联
DOI
PubMed
高影响因子
Polymers
·
2022
·Vol. 14
·期 14
·2818
·
IF 4.967
Liyao Xiong,Weijie Zheng,Shenglong Cao,Yuying Zheng
Aerogel materials are used in various fields, but there is a shortage of aerogel materials with an excellent combination of mechanical properties, thermal stability, and easy preparation. In this study, polyimide aerogel materials with superior mechanical properties, thermal stability, and low thermal conductivity were prepared by forming a double-gel system in the liquid phase. The amino-modified gel, prepared by coating SiO2nano-microspheres with GO through a modified sol-gel method (SiO2@GO-NH2), was subsequently homogeneously dispersed with PAA wet gel in water to form a double-gel system. The construction of a double-gel system enabled the PI aerogel to shape a unique honeycomb porous structure and a multi-layered interface of PI/SiO2/GO. The final obtained PI aerogel possessed effective thermal conductivity (0.0309 W/m·K) and a high specific modulus (46.19 m2/s2). In addition, the high thermal stability (543.80 °C in Ar atmosphere) and the ability to retain properties under heat treatment proved its durability in high thermal environments. The hydrophobicity (131.55°) proves its resistance to water from the environment. The excellent performance of this PI aerogel and its durability in thermal working environments make it possible to be applied in varied industrial and research fields, such as construction and energy, where heat and thermal insulation are required.Keywords:thermal insulation;hydrophobic;thermal stability;aerogel;polyimide
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
TRIBOLOGY INTERNATIONAL
·
2022
·
IF 5.62
Yang Lei,Liping Zhang,Liang Zhou,Jiaxin Yu,Gai Zhao,Lihe Guo,Ding Zhang,Huimin Qi
The effects of proton irradiation on the tribological performance of polyimide (PI) composites filled with carbon nanotubes (CNTs) were explored. The results demonstrate that incorporating CNTs into PI decreased the friction coefficients of the composites after they were exposed to proton irradiation. In particular, the addition of 1.0 wt% CNT reduces the friction coefficient by up to 58.8%, which is attributed to the generation of a protective tribofilm. Further analysis of FIB-TEM images demonstrates that polymers and hydrogenated amorphous carbon promote the tribofilm growth, and improve the lubrication properties of the composites. Whereas, the proton radiation-induced mechanical changes result in the poor wear resistance of the PI composites.
研究领域:
材料科学
·
摩擦学
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Ruoxing Liao,Yumin Guo,Liqiu Yang,Haoli Zhou,Wanqin Jin
Membrane technology , a successful technology for separating gases such as CO 2 /CH 4 mixture, has attracted much attention because of its low energy consumption, and membrane performance is an important factor affecting its industrial application. Herein, the solvent-induced microstructure of a polyimide membrane was employed to enhance its CO2/CH4 separation performance. The effect of solvents on the membrane structure and gas separation performance was investigated by using different solvents (such as tetrahydrofuran, N,N-dimethylacetamide) to dissolve a newly synthesized polyimide polymer, which was fabricated into a membrane. Various characterization methods, such as positron annihilation lifetime spectroscopy (PALs) and X-ray diffractometry (XRD), were conducted to reveal changes in the microstructure of membranes prepared with different solvents. The interaction of solvents with groups of polymer backbones was also analyzed for the explanation of the effect of solvents on the membrane performance for the separation of different gas pairs, such as CO2/CH4 mixture. The results showed that a membrane with optimal separation performance was obtained by optimizing the solvent composition, which exceeded the 2018 mixed-gas CO2/CH4 upper bound. The induced effect of solvents on the polymer membrane structure provides a new research path for the optimization of polymer membranes to enhance separation performance.
研究领域:
材料科学
·
化学工程
·
气体分离技术
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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）