EUROPEAN POLYMER JOURNAL
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2019
·
IF 3.621
Haoran Zhou,Shuai Zheng,Chunyan Qu,Dezhi Wang,Changwei Liu,Yiying Wang,Xupeng Fan,Wanbao Xiao,Hongfeng Li,Daoxiang Zhao,Jiaying Chang,Chunhai Chen,Xiaogang Zhao
The development of wearable devices , soft robots, and electronic skin requires strain sensors that integrate multiple functionalities, such as being stretchable, self-healing, and biocompatible. In this work, we prepared a fully aromatic polyamic acid salt (PAAs) hydrogel using a novel and simple approach. This study describes an environmentally friendly and green synthetic method for synthesizing. The obtained PAAs hydrogel exhibits excellent stretch ability and has an elongation rate of about 1350%. It can also rapidly complete self-healing and return to the original mechanical strength without needing any external stimuli. In addition, the PAAs hydrogel has excellent temperature responsiveness. When used as a strain sensor, the PAAs hydrogel has a sensitive electrical resistance response even after 200 cycles and adhesiveness to various surfaces, especially human skin. To the best of our knowledge, this is the first time to prepare a high-performance polyimide (PI) precursor hydrogel that can be used as a raw material for PI aerogel . Because of its superb overall performance, low preparation cost, efficient preparation, and environmentally friendliness, the PAAs hydrogel is highly suitable for use as sensitive strain sensors for applications in motion detection.
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Journal of Materials Chemistry A
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2019
·Vol. 7
·期 7
·3170-3178
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IF 10.733
Mei-Ling Liu,Jia-Lin Guo,Susilo Japip,Tian-Zhi Jia,Dan-Dan Shao,Sui Zhang,Wen-Jie Li,Jue Wang,Xue-Li Cao,Shi-Peng Sun
The practical application of graphene oxide (GO)/polymer composite membranes requires addressing the poor long-term stability caused by exfoliation of GO laminates from the substrate, solvent dissolution of the substrate and fouling by organic pollutants. This study describes the concurrent cross-linking of GO laminates, a polyimide substrate and their interface through a single filtration step with multifunctional triethylenetetramine (TETA). The new strategy features the following advantages: (1) the improved free volume and tunable charge characteristic of GO laminates lead to higher acetonitrile permeance with precise molecular sieving properties over state-of-art organic solvent nanofiltration (OSN) membranes; (2) the covalent bonding formed at the GO/polyimide interface and polyimide substrate endows the membrane with significantly enhanced stability in harsh environments; (3) the photocatalytic properties hold great potential for fouling reduction and dye decolorization.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 22
·19956-19965
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IF 2.195
Chi Qingguo,Wang Bo,Zhang Tiandong,Zhang Changhai,Zhang Yongquan,Wang Xuan,Lei Qingquan
The energy density of the capacitors is determined by the breakdown strength and the relative dielectric constant. Polyimide (PI) has high breakdown strength, linear polarization property and high energy efficiency. However, due to the low dielectric constant of PI, its energy storage density is not high enough to satisfy the requirement. Therefore, seeking a method to improve the dielectric constant while ensuring its breakdown strength is the key to solve the problem of the low energy storage of PI. In this study, the core–shell structured barium zirconate titanate calcium (BCZT) and silica (SiO 2 ) composited fibers (SiO 2 @BCZT) have been constructed and modified by silane coupling agent (KH550), the SiO 2 @BCZT inorganic fillers are beneficial to improve the dielectric constant of the PI-based composites. In order to further improve the breakdown strength of the composites, the sandwich-structured composite films have been designed, where the PI filled with SiO 2 @BCZT films act as dielectric reinforced top and bottom layers, and the PI filled with hydroxylated boron nitride nanosheet (BN) films serve as breakdown strength enhanced inter-layer. The microstructure and electrical properties of the composite films have been systematically investigated. For the sandwiched composite films, the discharged energy density and energy storage efficiency reach to 3.37 J/cm 3 and 84.89%, respectively. This study provides an effective way to improve the energy storage properties for PI-based composite films.
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POLYMER JOURNAL
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2015
·Vol. 48
·期 2
·169-175
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IF 1.653
Wu Qi,Pan Lili,Wang Haijiang,Deng Wenxiu,Yang Guangjie,Liu Xikui
Polymeric aerogels have great potential in numerous fields because of their unique combination of thermal and electrical properties, and lightweight porous structures. However, the laborious supercritical CO 2 drying method required for making these aerogels limits their commercial availability. Here we demonstrate a green and scalable method for preparing high-performance polyimide (PI) aerogels using a low-boiling-point solvent mixture of tetrahydrofuran/methanol, and especially using sublimation drying instead of laborious supercritical CO 2 drying. The monolithic and powder polyamic acid aerogels can be prepared easily; after thermal imidization, PI aerogels with nanofibrous morphology, low density and high thermal stability can be obtained. This green, scalable and cost-effective process will facilitate the application of high-performance PI aerogel materials in many fields, in particular those in which high-temperature resistance is important.
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APPLIED SURFACE SCIENCE
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2017
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IF 3.387
Tao Yang,Enlin Han,Xiaodong Wang,Dezhen Wu
A new methodology to decorate the surface of polyimide (PI) fiber with carbon nanotubes (CNTs) has been developed in this study. This surface decoration was carried out through a surface alkali treatment, a carboxylation modification, surface functionalization with acyl chloride groups and then with amino groups, and a surface graft of CNTs onto PI fiber. Fourier -transform infrared and X –ray photoelectron spectroscopic characterizations confirmed that CNTs were chemically grafted onto the surface of PI fiber, and scanning electron microscopic observation demonstrated the fiber surface was uniformly and densely covered with CNTs. The surface energy and wettability of PI fiber were improved in the presence of CNTs on the fiber surface, which made a contribution to enhance the interfacial adhesion of PI fiber with other inorganic matrices when used as a reinforcing fiber. The application of CNTs-decorated PI fiber for the reinforcement of phosphoric acid-based geopolymers was investigated, and the results indicated that the geopolymeric composites gained a noticeable reinforcement. Compared to unreinforced geopolymer, the geopolymeric composites achieved a remarkable increase in compressive strength by 120% and in flexural strength by 283%. Fractography investigation demonstrated that the interaction adhesion between the fibers and matrix was enhanced due to the surface decoration of PI fiber with CNTs, which contributed to an improvement in fracture-energy dissipation by fiber pullout and fiber debonding from the matrix. As a result, a significant reinforcement effect on geopolymeric composites was achieved through a fiber-bridging mechanism. This study provided an effective methodology to improve the interracial bonding force for PI fiber and also proves a highly efficient application of CNTs-decorated PI fiber for the mechanical enhancement of geopolymeric composites.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2017
·Vol. 135
·期 10
·45728
·
IF 1.86
Cuijia Duan,Xingming Jie,Haitao Zhu,Dandan Liu,Weiming Peng,Yiming Cao
With MOFs of Cu 3 (BTC) 2 and ZIF-8 as the dispersed phases and four polyimides with CO 2 permeabilities ranging from 1.36 to 564 barrer as the continuous phase, the influence of metal organic frameworks on the gas-separation properties of mixed-matrix membranes (MMMs) was investigated. The results show that the gas permeabilities of all of the prepared MMMs greatly increased and even largely exceeded the predicted value of the Bruggeman model; for example, with the same Cu 3 (BTC) 2 loading of 21.3 vol %, the O 2 permeability increase rate of our prepared Cu 3 (BTC) 2 /Matrimide 5218-20 MMMs was 2.26 times, whereas that predicted by the Bruggeman model was only 1.05 times. In addition, when the gas permeability of the polymeric phase was far lower than the dispersed phase of ZIF-8 or Cu 3 (BTC) 2 compared with ZIF-8, which had a particle size ( R ) around 150 nm, Cu 3 (BTC) 2 of 5–15 µm showed a little better enhancing effect on the gas-permeation performance of the MMMs. In addition to the properties of the dispersed and continuous phases, we speculated that the ratio between R of the dispersed phase to the membrane thickness ( L ) played an important role for MMMs; the larger R / L was, the greater the gas permeability of the MMMs was. This speculation was initially evidenced by the ZIF-8/ODPA/TMPDA-20 MMMs with different L s. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45728.
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Surfaces and Interfaces
·
2024
·
IF 5.7
Hanjiang Li,Zhewen Zhang,Xiaofeng Zhang,Wen Luo,Xueshen Peng,Xinrui Zheng,Jin Huang,Wei Feng
Highly thermal conductive polyimide (PI) composites have shown great potential in electronic equipment and thermal management. However, a high content of heat-conducting fillers is frequently needed, leading to the increased costs and decreased mechanical performance that greatly limit the applications. Herein, we design a carbon woven-mesh nano-template by covalent linkage as filler and obtain in-situ polymerized PI composite films at a low loading content of 1wt%-7wt%. Surprisingly, the specific PI composite films showed significantly improved thermal conductivity with a largest increase of 730% and good mechanical performance for future utilization. The enormous improvement of thermal conductivity is attributed to the efficiently interconnected heat-conducting framework via “covalent bridge”. Moreover, the excellent thermal management capability and cycling stability of the fabricated films was proved by thermal warning display device in Li-ion battery heat managemen tapplication.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Bingyu Zhao,Haojie Li,Zian Chen,Jiawei Lin,Yaodong Liu
The potential of carbon molecular sieve membranes (CMSM) for gas separation is widely recognized, and the key precursor for these membranes is polyimide (PI). This study focuses on enhancing the gas separation properties of CMSMs by introducing a unique structural element, Tröger’s bases, into polyimides, resulting in the creation of five distinct polyimides containing Tröger’s bases (PI-TBs). The incorporation of Tröger’s bases has a profound impact on the arrangement of polymer chains within the PIs, leading to a substantial improvement in gas permeability without compromising selectivity. Following carbonization at 600 °C, the resultant CMSMs exhibit significantly enhanced gas permeability while preserving, and in some cases, improving gas selectivity. Among the various types of diamines considered, the 6FDA variant of PI-TB stands out, boasting outstanding gas permeability with a H 2 permeability of 4991.0 Barrer and a H 2 /CH 4 selectivity of 30.7; this level of performance surpasses the 2015 Robeson’s upper bound. Furthermore, thermal analysis coupled with mass spectrometry (TG-MS) reveals that the pyrolysis of Tröger’s bases commences prior to that of polyimide . This sequential degradation process facilitates the formation of pyridine N and promotes the π-stacking of PI chains; both of which are instrumental in maintaining excellent gas selectivity. These findings provide valuable insights into the roles of Tröger’s bases in enhancing the gas separation performance of PIs and CMSMs, offering a promising avenue for further advancements.
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TALANTA
·
2024
·
IF 5.6
Xiaoxia Zhang,Jinchang Liu,Han Zhang,Qinming Zhang,Jiwei Shen,Yinmao Wei,Chaozhan Wang
Efficient enrichment is crucial for the highly sensitive monitoring of phenylurea herbicides (PUHs) in various environmental waters. In this work, a stable core-shell spherically magnetic polyimide covalent organic framework (COF) was synthesized via a simple template-mediated precipitation polymerization method under mild conditions using tri(4-aminophenyl)amine (TAPA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) as the building units (denoted as Fe 3 O 4 @TAPA-BPDA). The Fe 3 O 4 @TAPA-BPDA exhibits remarkable adsorption performance for PUHs with an optimized adsorption time of only 10 min. The adsorption of PUHs by Fe 3 O 4 @TAPA-BPDA followed the pseudo-second-order kinetic model and the Langmuir model. Furthermore, hydrogen bonding , halogen bonding, hydrophobic interaction, electro donor-acceptor interaction and π-π interactions are identified as the dominant mechanisms contributing to excellent adsorption performance. It was demonstrated that halogen bonds play an important role in the adsorption of substances containing chlorine atoms . The Fe 3 O 4 @TAPA-BPDA is easy to operate and highly regenerable. A simple magnetic solid-phase extraction (MSPE) method based on the Fe 3 O 4 @TAPA-BPDA was then developed for the rapid extraction of five PUHs in real samples, coupled with high-performance liquid chromatography (HPLC) determination. The analytical method developed has a linear range of 0.5–50 ng/mL, and the limit of detection (LOD) ranges from 0.06 to 0.10 ng/mL. The method exhibits good accuracy with recoveries ranged from 74.5 % to 111.4 %. The analytical method was successfully applied to the highly sensitive detection of PUHs in environmental water samples, which highlighting the potential application of the Fe 3 O 4 @TAPA-BPDA in the sample pretreatment.
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PubMed
高影响因子
RSC Advances
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2018
·Vol. 8
·期 19
·10522-10531
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IF 2.936
Tianwen Zhu,Chao Qian,Weiwen Zheng,Runxin Bei,Siwei Liu,Zhenguo Chi,Xudong Chen,Yi Zhang,Jiarui Xu
In this work, halloysite nanotubes (HNTs) were chosen as the fillers and high performance polyimide (PI) as the matrix to form a series of dielectric composite materials with high dielectric constant, low dielectric loss and excellent heat resistance. Firstly, KH550 was used to modify the surface of HNTs to make sure of a good dispersion of HNTs into the polymer. The results showed that the addition of KH550 modified HNTs (K-HNTs) can improve the dielectric constant of the composite films while maintaining their excellent dielectric loss properties. To further increase the dielectric constant of the HNTs/PI composites, conductive polyaniline (PANI) was used to coat the surface of HNTs to obtain PANI modified HNTs (PANI-HNTs). Compared with the K-HNTs filled systems, the dielectric constant of the PANI-HNTs/PI nanocomposite films is greatly enhanced. The highest dielectric constant of the PANI-HNTs/PI films can achieve 17.3 (100 Hz) with a low dielectric loss of 0.2 (100 Hz). More importantly, the as-prepared composite films have high breakdown strengths (>110.4 kV mm−1) and low coefficients of thermal expansion, as low as 7 ppm per °C, and a maximum discharge energy density of 0.93 J cm−3. Also, such properties are maintained stably up to 300 °C, which is critical for manufacturing heat-resisting film capacitors.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
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IF 7.1
Yuluo Chen,Zhenglin Song,Huicong Liu,Hang Xu,Yuchun Xi,Chuanqiang Yin,Xiaomin Li,Lei Ma,Puxuan Yan,Lang Zhou
Electrospun polyimide (PI) nanofiber membranes have served as promising separators for safe lithium-ion batteries (LIBs) due to their excellent thermal stability. However, electrospun PI nanofiber membranes have excessively large pores and low mechanical strength, which have been shown to be unsuitable for direct utilization as LIB separators. To solve these issues, we proposed a novel electrospun PI nanofiber membrane obtained using a triple cross-linking strategy, including precalendering, microsolvent dissolution, and chemical imidization. The precalendering process, as a prerequisite, densified the poly(amic acid) (PAA) nanofiber membrane and followed by microsolvent dissolution and chemical imidization, which provided synergistic cross-linking effects. This resulted in a mutual anchoring effect of the ultralong molecular chains at the cross-linking interface, forming a robust cross-linking structure and efficient imidization transition. As a result, the mechanical properties of the samples significantly improved, while the tensile strength increased from 9.9 to 95.5 MPa. Furthermore, as the pressing degree of the membranes increased, the electrolyte uptake, ionic conductivity, and capacity decreased; however, the ability to inhibit lithium dendrite growth and uniformly produce solid electrolyte interfaces (SEIs) increased. Compared to the noncross-linked PI membrane, the PI membrane obtained using the triple cross-linking strategy had a stable interface with the lithium metal electrodes and a high-capacity retention rate. This robust PI nanofiber membrane could serve as a promising replacement for traditional polyolefin separators in high-performance LIBs.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Linyan Wang,Wenjie Li,Chen Wang,Yuncong Jiang,Hang Liu,Tianliang Pang,Xiaodong He,Mingwei Li,Fei He
The extremely low thermal conductivity, low density, and high-temperature stability of polyimide (PI) aerogels are promising candidates for thermal insulation applications. In this work, the layered PI/Al 2 O 3 composite aerogels (PACAs) were developed, inspired by the biomimetic idea of a “cocktail” layered structure to enhance the service temperature of PI. By exploiting the density difference between the water-soluble polyimide acid (PAA) solution and Al 2 O 3 slurry, we successfully fabricated PACAs with a macro-scale layered structure through side-direction freezing and thermal imidization processes. The PACAs exhibit significant anisotropic structural characteristics, with pore channels presenting a honeycomb structure in the Z-direction, effectively suppressing heat transfer along this direction. Both PI and Al 2 O 3 aerogels demonstrate anisotropic properties in different directions, with the PI aerogel achieving excellent thermal insulation with a thermal conductivity of 0.0197 W/(m·K) along the Z-direction. By adjusting the relative thickness of the PI and Al 2 O 3 layers, optimal thermal insulation performances were achieved at temperatures of 300 °C, 600 °C, and 900 °C. These results showcase the innovative advantages of the layered structure in enhancing thermal insulation while leveraging the low thermal conductivity of PI and the high-temperature tolerance of Al 2 O 3 .
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