COMPOSITE STRUCTURES
·
2023
·
IF 6.3
Xiaofei Wang,Yang He,Xinli Xiao,Wei Zhao,Jinsong Leng
In order to enhance the thermal conduction property and shorten response time of shape memory polyimide (SMPI), “spot-plane” directional thermally conductive acidified graphene/AlN/SMPI composites were prepared, in which AlN nanoparticles were used as “thermal conduction spots” and acidified graphene was used as two-dimensional “thermal conduction planes”. The SMPI composite doped with 6 wt% AlN and 0.8 wt% acidified graphene had good heat conducting properties (the in-plane thermal conductivity of 5.90 W m −1 K −1 ), excellent mechanical propertied (the tensile strength of 134.5 MPa, and Young’s modulus of 3.8 GPa), high shape memory transition temperature (at 419 ℃), and great thermal stability and shape memory properties. Compared with SMPI resin matrix, the response time of the acidified graphene/AlN/SMPI composite was shortened by 140 s, only 20 s, and it can be applied in flexible electronics, intelligent response structures and active deformation structures in high-temperature environment.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Feidong Yang,Lei Li,Junyuan Hua,Jintao He,Xiaohua Ma,Jianxin Li
To meet the growing demand for lithium resources, it is ideal to develop a green and efficient approach for recovering lithium resources from discarded lithium-ion batteries. In this work, nanofiber membranes of 14-crown-4-ether polyimide (14C4PI) (M n = 33 kDa) with the crown ether loading of 1.38 mmol g −1 in the main chain were fabricated by electrospinning and the structure of the nanofiber membrane was regulated by tuning the electrospinning parameters. The selectivity adsorption of 14C4PI nanofiber membrane was investigated in the simulated extract of discarded lithium-ion batteries. The results showed that the 14C4PI-12 nanofiber membrane with a high specific surface area of 41.27 m 2 /g and a diameter of 122.7 nm was successfully prepared under the operating conditions (polymer concentration of 12 wt%, voltage of 30 kV, flow speed of 1 mL h −1 , tip-to-collector of 100 mm). The 14C4PI-12 nanofiber membrane displayed a high equilibrium adsorption capacity for Li + (Q m = 40.17 mg g −1 ). The adsorption of Li + onto the membrane was proven to be monolayer chemical adsorption confirmed by adsorption kinetics and isotherm models. The calculated equilibrium adsorption rate (EAR) was up to 70 % and the complex-ratio of crown ether in 14C4PI to Li + was 1.46:1, whose theoretical value is 1:1. Meanwhile, the selective separation factor of Li + to Na + , K + , Mn 2+ , Co 2+ , and Ni 2+ were up to 52.3, 54.97, 48.82, 41.05 and 35.04, respectively, which were much higher than that obtained from other selective adsorption method reported in literatures. The density functional theory (DFT) calculations confirm that the superior selectivity of 14C4PI to Li + is attributed to the higher Gibbs free energy change of 14C4PI-Li + complexation (−113.99 kcal mol −1 ). To sum up, this work provides an efficient method to fabricate crown ether functional polymer nanofiber membrane for recycling lithium resources.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 47
·e54705
·
IF 3
Wanli Yue,Ying Cao,Ruikai Han,Libing Ren,Simeng Liu,Fan Liu,Jianxin He,Weili Shao,Li Chen
Particulate matter (PM) has a significant impact on air quality, especially the PM produced by automobile exhaust and high temperature environment. Therefore, it is of great significance to develop a technology that can effectively intercept fine PM under high temperature conditions. This study reports the construction of poly(m-phenylene isophthalamide) (PMIA) nanofiber-reinforced polyimide aerogel (PPNFAs) filters using freeze-drying and electrospinning for high temperature filtration. After 100 compression cycles, the maximum compressive stress of PPNFAs is reduced by only 15%. When the content of PMIA is 0.65 wt%, PPNFAs has a high porosity (97.35%), high specific surface area (8.87 m 2 g −1 ) and highest dust holding capacity (124.8 m 2 g −1 ). After 15 days of continuous heating test at 300°C, the filtration efficiency of PPNFAs filter for different diameter particles of impurities remained above 98%. Therefore, the PPNFAs filter prepared in this study provides a new design concept for a new generation of high temperature filters.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Zhenyuan Li,Tianliang Han,Wei Lai,Jie Ma,Yang Zhang,Qi Wu,Can Wang,Chunfa Liao,Shuangjiang Luo
Herein, we develop and investigate the performance of defect-free hollow fiber membranes (HFMs) based on a novel 6FDA-mPDA 0.65 -DABA 0.3 -TFMB 0.05 copolyimide for helium separation from multi-component natural gas. The copolyimide is synthesized using a two-step condensation polymerization, and the hollow fiber membranes are fabricated using a dry-jet/wet-quench spinning approach. Thermal crosslinking of hollow fiber membranes is conducted to enhance plasticization resistance. The crosslinked membranes exhibit improved He selectivity (α(He/CH 4 ) = 259) compared to the pristine hollow fiber membrane (α(He/CH 4 ) = 210). Gas permeation tests are performed on the pristine and crosslinked hollow fiber membranes using pure-gas and mixed-gas at various pressures. The results demonstrate that the crosslinked membranes effectively resist plasticization even under high-pressure gas feeds containing CO 2 , light hydrocarbons, and heavy hydrocarbons. In contrast, the uncrosslinked membranes experience plasticization, dramatically decreasing selectivity. The findings provide valuable insights into the plasticization behavior of different impurity compounds in hollow fiber membranes and highlight the potential of thermal crosslinking as an effective strategy to improve the plasticization resistance of HFMs for He recovery. These defect-free and plasticization-resistant membranes hold promise for efficient He recovery from mixed-gas streams, offering a viable and energy-efficient alternative to traditional separation methods.
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POLYMER COMPOSITES
·
2021
·Vol. 42
·期 6
·3000-3010
·
IF 3.171
Peng Yin,Zhicheng Shi,Liang Sun,Peitao Xie,Davoud Dastan,Kai Sun,Runhua Fan
Polymer nanocomposites with high energy-storage capability have been widely used in electronic devices. To achieve further enhanced energy density, developing nanofillers with tailored compositions and nanostructures is demonstrated to be an effective strategy. Especially, hybrid nanoparticles (NPs) with abundant internal interfaces are acknowledged as a promising candidate. Here, a class of carbon/silica hybrid nanoparticles (C/SiO 2 h-NPs) with disorderly mixed nanostructures are synthesized and employed to prepare C/SiO 2 h-NPs/polyimide nanocomposites. To reveal the influence of internal interfaces on dielectric properties, a series of comparative composites co-filled with C and SiO 2 NPs are also prepared. The breakdown strength of the C/SiO 2 h-NPs/polyimide composites can reach 303.96 kV/mm, which is over 200% that of their counterparts. It is believed that the abundant heterogeneous interfaces inside the C/SiO 2 h-NPs can effectively impede the development of conductive paths, thereby obviously enhancing breakdown strengths. Furthermore, the C/SiO 2 h-NPs/polyimide composite with 5 wt% C/SiO 2 h-NPs demonstrates a high discharged energy density of ~0.612 J/cm 3 at 150 kV/mm, which is about 2.29 times higher than pure polyimide (PI) (~0.267 @ 150 kV/mm), along with a high discharge energy efficiency of 85.9%. This work offers a practicable strategy for the design of functional NPs toward high-performance dielectric composites.
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高影响因子
JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 59
·期 13
·1414-1423
·
IF 0
Aftab Ahmad,Hui Tong,Tao Fan,Ju Xu
The development of high-performance dielectric films with high energy density and temperature stability is extremely desired for modern electronics and power systems. Herein, a simple and low-cost approach is proposed to fabricate all-organic blend films prepared from poly (arylene ether urea) (PEEU) and polyimide (PI) via solution casting and thermal imidization process. The incorporation of PEEU in PI matrix significantly improved dielectric breakdown strength and dielectric constant of PI. More precisely, blend film with 15 wt% PEEU exhibited highest energy density 5.14 J/cm 3 at 495.65 MV/m, with enhanced dielectric constant of 4.73 and very low dissipation factor of 0.299%. Furthermore, the dielectric properties of the PEEU/PI blend displayed wonderful temperature stability in the range of − 50–+ 250°C, and great frequency stability between 10 and 10 6 Hz. The blend film also exhibited excellent heat resistance and presented valuable potential in thin film capacitors for high voltage direct current system. Graphical
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ACS Nano
·
2021
·
IF 15.881
Xin Li,Guoqing Dong,Zengwei Liu,Xuetong Zhang
Aerogel fibers with ultrahigh porosity, large specific surface area, and ultralow density have shown increasing interest due to being considered as the next generation thermal insulation fibers. However, it is still a great challenge to fabricate arbitrary aerogel fibers via the traditional wet-spinning approach due to the obvious conflict between the static sol–gel transition of the aerogel bulks and the dynamic wet-spinning process of aerogel fibers. Herein, a sol–gel confined transition (SGCT) strategy was developed for fabricating various mesoporous aerogel fibers, in which the aerogel precursor solution was first driven by the surface tension into the capillary tubes, then the gel fibers were easily formed in the confined space after static sol–gel process, and finally the mesoporous aerogel fibers were obtained via the supercritical CO2 drying process. As a typical case, the polyimide (PI) aerogel fiber prepared via the SGCT approach has exhibited a large specific surface area (up to 364 m2/g), outstanding mechanical property (with elastic modulus of 123 MPa), superior hydrophobicity (with contact angle of 153°), and excellent flexibility (with curvature radius of 200 μm). Therefore, the aerogel woven fabric made from PI aerogel fibers has possessed an excellent thermal insulation performance in a wide temperature window, even under the harsh environment. Besides, arbitrary kinds of aerogel fibers, including organic aerogel fibers, inorganic aerogel fibers, and organic–inorganic hybrid aerogel fibers, have been fabricated successfully, suggesting the universality of the SGCT strategy, which not only provides a way for developing aerogel fibers with different components but also plays an irreplaceable role in promoting the upgrading of the fiber fields.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Shuyu Liu,Jintao Wang
Superhydrophilic and underwater superoleophobic polydopamine/starch@polyimide mesh (PDA/starch@PIM) was successfully fabricated by a facile, inexpensive and eco-friendly approach. The coating of PDA/starch hybrid on PIM resulted in good underwater superoleophobicity and superhydrophilicity. The formation of hybrid coating was characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). The surface of PDA/starch@PIM exhibited special wettability with high oil contact angle (OCA) of about 153.8° underwater. Meanwhile, the decorated PIM showed superb durability towards various harsh conditions. In addition, the coated PIM exhibited excellent oil/water separation property and the separation efficiencies are higher than 99.5%. Even after 60 times of reuse, the coated PIM still maintained high separation efficiency. Because the proposed route is green, simple and cheap, the underwater superoleophobic PDA/starch@PIM has a wide application prospect in oil-polluted wastewater treatment.
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高影响因子
Polymer Chemistry
·
2021
·Vol. 12
·期 37
·5364-5376
·
IF 5.582
Zhenghui Yang,Haiquan Guo,Chuanqing Kang,Lianxun Gao
Three novel dianhydride monomers involving amide groups were synthesized and further polymerized with various diamines to afford a series of colorless polyimides (cPI). The resultant cPI films present outstanding optical performance, exceedingly good dimensional stability at high temperature, great film ductility and solution-processability. In particular, chemically imidized AMDA/TFDB has an ultra-low coefficient of thermal expansion value of 5.2 ppm K−A, a relatively high Tg value of 333 °C and large elongation at break of 29%, resulting from its rigid-rod backbone and the formation of hydrogen bonding (–CO⋯NH–) between adjacent molecular chains. Concurrently, it exhibits a high optical transmittance of 87% at a wavelength of 550 nm, a small haze value of 0.71 and low yellow index of 4.29 by reason that the incorporation of bulky trifluoromethyl and cyclohexyl preclude the formation of a charge transfer complex effectively. The high overall performance of the amide-containing cPI films suggests its potential application in the field of flexible OLED displays.
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高影响因子
POLYMER COMPOSITES
·
2019
·Vol. 41
·期 2
·740-747
·
IF 2.268
Xuhua He,Xin Yu,Yuechuan Wang
Highly thermally conductive polymer composites are urgently required for effective heat dissipation in advanced electronic devices. Rational matching of thermal conductive fillers and proper preparation method are important for obtaining a highly thermally conductive composites at low filler content. Here we report polyimide (PI) composites filled with graphene flakes (GF) and polyhedral aluminum nitride (AlN), which simultaneously exhibit high thermal conductivity, improved thermal mechanical properties, and excellent thermal stability. PI composite films were readily prepared by in situ polymerization at the presence of fillers that are dispersed with sonication. The thermal conductivity of PI composite films reached 11.19 Wm −1 K −1 at the low content of 1 wt% GF and 10 wt% AlN, which is ascribed to the construction of synergistically enhanced heat transfer pathways by the combination of the hybrid fillers. The PI composite films with hybrid fillers also showed lower electrical conductivity than that of the PI composite films with single GF filler. This study provides an effective method for preparation of high-performance thermal management materials.
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高影响因子
Journal of Environmental Sciences
·
2018
·
IF 3.12
Yanyang Liu,Haijian Ou,Shangqing Li,Qingliang You,Huixian Liu,Guiying Liao,Dongsheng Wang
A novel polyimide-inlaid amine-rich porous organic block copolymer (PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine (MA)/terephthalaldehyde (TA)/pyromellitic dianhydride (PMDA), at molar ratios of 4/3/1, 4/2/2 and 4/1/3. The copolymer contained both aminal groups belonging to ARPOP and imide groups belonging to PI, and the bonding styles of the monomers and growth orientations of the polymeric chains were diversiform, forming an excellent porous structure. Notably, MA/TA/PMDA (4/2/2) had a surface area and pore volume of 487.27 m 2 /g and 1.169 cm 3 /g, respectively. The adsorption performance of the materials towards 2,4-dichlorophenol (2,4-DCP) in ultra-pure water was systematically studied. The pH value of 7 was optimal in aqueous solution. Na + and Cl − ions did not negatively affect the adsorption process, while humic acid (HA) slightly decreased the capacity. The equilibrium time was 40 sec, and the maximum adsorption capacity reached 282.49 mg/g at 298 K. The removal process was endothermic and spontaneous, and the copolymer could maintain its porous structure and consistent performance after regeneration by treatment with alkali. Moreover, to further assess the practical applicability of the material, the adsorption performance towards 2,4-DCP in river water was also investigated. This paper demonstrated that the PI-b-ARPOP can be an efficient and practical adsorbent to remove chlorophenols from aqueous solution.
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PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 15
·11104-11115
·
IF 2.993
Wei Chenjie,Cheng Qi,Lin Ligang,He Zhifu,Huang Kai,Ma Sisi,Chen Li
A novel one-step strategy is proposed for the recyclable polyimide nanofiltration (PI-NF) membranes. By designing the chain structure, the soluble polyimide polymer with coexisted imide rings and flexible pendant groups are fabricated. With the polyimide polymer as matrix, the NF membranes with integrally skinned asymmetric architecture were obtained by a phase inversion method. The structure evolution was demonstrated by scanning electron microscope and atomic force microscope analyses. The rejections of prepared PI-NF membrane for Rose Bengal, PEG 1000 and typical salts under optimized conditions were 92, 91.78, 98.68%, respectively. The rejections of NF membranes for different salts followed the order: Na 2 SO 4 > MgSO 4 > NaCl > MgCl 2 . Furthermore, the fabricated polyimide-based NF membranes show a stable performance during long-time filtration process and exhibit a confirmed excellent recyclable property.
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高影响因子
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