NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 28
·12068-12078
·
IF 3.288
Hongtao Liu,Huafeng Tian,Yuanyuan Yao,Aiming Xiang,Haisong Qi,Qiangxian Wu,A. Varada Rajulu
Graphene oxide (GO) plays an important role in improving the mechanical properties and flame resistance of materials. In this work, polyimide (PI) composite foams were in situ generated by introducing modified GO based on a novel method. GO was modified by the interaction of its surfactant groups with dopamine (Do) using noncovalent bonds, to facilitate its dispersion in the PI matrix. The π–π conjugation was confirmed between GO and Do. Chemical interactions occurred between GO and PI through the reaction between the active groups on GO and –NCO of isocyanates. The resulting PI composite foams were characterized for their morphological, structural, mechanical, thermal and flame retardant properties. The cell structure of PI composite foams was uniform. Meanwhile, the compressive strength of composite foams significantly increased from 130 kPa to 163 kPa, resulting in a distinct enhancement in mechanical properties. The thermal stability of the composite foams was highly enhanced by GO as evidenced by the decreased mass loss during the maximum decomposition stage and increased residue at 800 °C. Furthermore, the values of limited oxygen index (LOI) of PI foams increased from 42.0% to 44.5%, while the PI composite foams exhibited self-extinguishing property. Therefore the modified GO dramatically improved the mechanical, thermal and flame resistance properties of PI foams.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Shuge Peng,Yamin Chen,Xiaopan Jin,Weiwei Lu,Minglei Gou,Xuefeng Wei,Jingpei Xie
To take advantage of Ag NPs‒enhanced membrane properties, how to slow the release of silver ions from membrane surface is the key. In this study, to enhance silver stability, half encapsulated Ag NPs by a loosely polyimide (PI) were covalently grafted onto ceramic membrane (CM) via in-situ reduction during thermal imidization. Various techniques were used to characterize the micro‒structure, pore size distribution , surface tension, and Zeta potential of the polyimide‒silver nanoparticle‒ceramic composite membrane (PI–Ag/CM). The antibacterial activity was assessed with fluorescent imaging method. The stability of silver was evaluated by static immersion and dynamic filtration tests. The anti‒biofouling performance was evaluated using bovine serum albumin (BSA) and E. coli as the model foulants, respectively. The results showed that the Ag NPs with the size of 50–80 nm were uniformly embedded on the surface of the grafted PI, which endowed the PI‒Ag/CM with improved silver stability, antibacterial activity, and anti‒biofouling performance simultaneously. This study demonstrated a new pathway for the modification of CM‒based and other inorganic membranes with lasting anti‒biofouling performance in water treatment.
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2020
·
IF 7.635
Yanyan Wang,Xian Zhang,Xin Ding,Ping Zhang,Mengting Shu,Qian Zhang,Yi Gong,Kang Zheng,Xingyou Tian
Owing to the unique layered structure, abundant functional groups and appropriate band gap, carbon nitride nanosheets (CNNS) has captured extensively attention in photocatalytic pollutants degradation and hydrogen evolution , while few study has been focused on improving the thermal conductivity . Considering its graphene-like network that is confined to 2D atomic thickness, CNNS would also show desirable thermal conductivity due to the highly aligned atoms decreasing phonon scattering. Here, CNNS is first used to improve the thermal conductivity of polyimide (PI) film. Based on the orientation of PI molecules during imidization and strong interaction with PI, CNNS realize in-plane self-orientation during solvent evaporation to form continuous thermal pathway in PI film. The thermal conductivity of PI/CNNS nanocomposite films reach 2.04 Wm −1 K −1 with relatively low CNNS loading (20 wt%) which is about eleven times of the corresponding pure PI (0.18 Wm −1 K −1 ). Furthermore, the potential application of the PI/CNNS nanocomposite films for effective heat dissipation is explored by experiments and simulation. Meanwhile, the PI/CNNS nanocomposite films keep superior electrical insulation property and thermal stability. This work expands the application of CNNS and provides a facile, efficient approach to the design of high thermal conductive materials .
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 48
·e53231
·
IF 3.057
Shang Ke Yang,Zhao Xin Zhang,Ai Ping Zhang,Hai Lan Lin,Xun Tao Zhang,Liu Xin Xiao,Jun Bian,Dai Qiang Chen
This work employed polymer active agent polyvinylpyrrolidone (PVP) treated barium titanate (BT) nanoparticles (PVP@BT) as functional nanofillers to fill polyimide (PI) matrix to fabricate PI nanocomposite films. The microstructure, dielectric properties, and heat resistance of PI, PI/BT, and PI/PVP@BT dielectric nanocomposite films were investigated. Fourier transform infrared spectrometer (FTIR) indicated that PVP has been successfully coated on the surface of BT nanoparticles. Due to the enhanced aggregation of monomers on the PVP@BT nanoparticles, higher molecular weight and viscosity of PI/PVP@BT nanocomposite films were achieved. Compared with PI/BT nanocomposite films, the dispersion of PVP@BT nanoparticles in PI/PVP@BT nanocomposite films was better, as verified by field emission scanning electron microscope and high-resolution transmission electron microscopy. Filling a small amount of PVP@BT nanoparticles into the PI matrix improved the dielectric properties of the resultant nanocomposite films. The dielectric constant of the nanocomposite films with 10 wt% filler loading was up to 7.1 at 1000 Hz, which was 2.5 times higher than that of pure PI (2.9). PI nanocomposite film dielectric loss was generally lower than 0.015. Thermogravimetric analysis (TGA) tests verified that both pure PI and PI nanocomposite films showed excellent thermal stability. This work can be expected to provide a new strategy for designing and manufacturing PI dielectric nanocomposite films for energy storage applications.
✓ 已验证
产品关联
DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2022
·Vol. 62
·期 12
·4226-4234
·
IF 2.573
Wang Zhang,Hanzhou Jiang,Yong Nie,Xingzhong Fang,Guofei Chen
A series of polyimide/polytetrafluoroethylene (PI/PTFE) hybrid films were synthesized by blending water-soluble polyamide acid salts with water-based PTFE dispersion and thermal imidization to enhance the dielectric proprieties of PI. The relationship between PTFE filler content and the properties of films has been investigated. The results showed that the dielectric properties of PI were effectively improved by PTFE fillers and all films showed excellent heat resistance. When the addition of PTFE filler was 30 wt%, the PI and PTFE in PI/PTFE-30 hybrid film still showed good compatibility and dispersity. The dielectric constant and dielectric loss factor were decreased to 2.42 and 0.0044 at 10 GHz, respectively. Meanwhile, the film PI/PTFE-30 had the lowest water absorption (0.11%) and maximum water contact angle (95.3°).
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Xu Yang,Ligang Lin,Zitian Liu,Jing Yang,Qi Cheng,Wensong Ma,Meina Xu,Fengling Tang,Qiying Wang,Xinyang Li,Aishan He,Chunhong Wang,Xiaolan Zhang
It is extremely difficult to separate salts and dyes from high-salinity printing and dyeing wastewater. In this study, modified montmorillonite (EPTAC-CD-MMT) was obtained by intercalation of 2,3-epoxypropyltrimethylammonium chloride (EPTAC) modified cyclodextrin (CD). PI/EPTAC-CD-MMT membrane was prepared by blending EPTAC-CD-MMT with polyimide (PI). The addition of EPTAC-CD-MMT could inhibit the motion of PI molecular chains and increase the solvent resistance of the membrane. Additionally, EPTAC-CD-MMT exhibited spontaneous “internal drive” during the phase transition and segregated to the membrane surface. The pore structure of the membrane was adjusted to a well-developed “side pore” structure. Thus, solvent-resistant membranes for dye/salt separation with high flux were finally obtained. The successful modification of MMT was demonstrated by FTIR, XRD, TGA and XPS. EDX and SEM were used to characterize the surface segregation phenomena and well-developed pore structures of the membranes. When EPTAC-CD-MMT was added at 3 wt%, the membranes showed a significant increase in pure water flux (138.0 L·m −2 ·h −1 ·bar −1 ), high dye rejection (>98.5 %), low salt rejection (<10.0 %), and good solvent resistance in six organic solvents. This demonstrated the potential of PI/EPTAC-CD-MMT separation membranes for the treatment of dye wastewater containing sophisticated organic solvents.
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2023
·
IF 6.2
Siyu Wei,Xinfang Wang,Xinyu Zhao,Ke Zhao,Linzhe Xu,Yingbo Chen
Background Excessive pesticide residues will seriously endanger human health. The complexity and lag of the current popular analytical methods hinder the timeliness of food safety analysis. Surface-enhanced Raman scattering (SERS) was an ultra-sensitive vibration spectroscopy technology with the advantages of less time cost, non-destructive and semi-quantitative detection, which has attracted much attention in the rapid field detection of pesticide residue. It was clear that we need an efficient and convenient substrate for pesticide residue detection based on SRES technology, which needs to be portable, flexible, transparent and easy to detect irregular object surfaces. Results A novel SERS sensor was designed to detect single and multi-component pesticide residues on irregular fruit and vegetable surfaces by in-situ growth of silver nanoparticles on a flexible and transparent fluorinated polyimide (FPI) substrate. Among them, Ag NPs were synthesized by liquid phase reduction method (AgNO 3 -PVP and NaBH 4 ). The results showed that the detection limit of 1–4 BDT was down to 10 −10 mol L −1 , the enhancement factor (EF) was up to 1.57 × 10 7 , and relative standard deviation (RSD) was 7.49 %. By this method, tricyclazole solution at a concentration of 0.01 mg L −1 was still detectable by the FPI@Ag SERS substrate. The linear quantification was achieved in the range from 100 mg L −1 to 0.01 mg L −1 . Two mixed pesticides, tricyclazole and imazalil, were also successfully distinguished. Significance This represents the formation of a flexible, foldable and transparent substrate for rapid on-site detection. Results can be obtained in <5 min by attaching the substrate to the substance to be tested. And the SERS substrate prepared with high sensitivity, stability, portable and convenient analysis, which provided new ideas for efficient and rapid household food safety detection.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Mingwei Cai,Heng Liu,Jiongcai Chen,Jiahao Wu,Zhenjing Han,Zhiyin Chen,Shiyang Zhang,Yonggang Min
Membrane-based gas separation is attracting more and more attention in hydrogen purification and CO 2 separation. One critical challenging remaining for large-scale production is fabricating a high-performance membrane with both inexpensive and excellent separation performance. In this work, a novel hybrid-carbon molecular sieve (CMS) membranes were reported for hydrogen purification by pyrolysis of commercial polyimide precursor (PMDA-ODA) with incorporation of modified 10X zeolite . The addition of modified 10X zeolite provided additional gas transport channels to the CMS mixed matrix membrane (MMM), and contained a significant fraction of micropores within the 0.6–0.8 nm range, which greatly enhance hydrogen adsorption capacity. Interestingly, despite this, the selectivity for H 2 /N 2 and H 2 /CH 4 also increases with higher zeolite content. This unexpected phenomenon may be attributed to the partial blocking of zeolite pores by CMS strand, which narrows the 10X pore size to a dimension smaller than CH 4 and N 2 , enabling differentiation between H 2 and CH 4 gas pairs. Therefore, the permeability and selectivity of H 2 was significantly enhanced. The CMS/10X-7.5 (with 7.5 wt % 10X zeolite) exhibited an advanced H 2 permeability (1709 Barrer) and high gas selectivity of 551 for H 2 /CH 4 and 105 for H 2 /N 2 , respectively, which is higher than other samples and exceed the 2015 trade-off lines. Furthermore, the CMS/10X-7.5 delivered excellent stability after 20 cycles. Therefore, this hybrid CMS/10X-7.5 obtained by carbonization of zeolite-doped polymer precursors has great potential for larger industrial applications.
✓ 已验证
产品关联
DOI
高影响因子
Materials Horizons
·
2023
·Vol. 10
·期 12
·5835-5846
·
IF 13.3
Yaya Tian,Ming-Sheng Zheng,Yuchao Li,Chuqi Xu,Yiyi Zhang,Wei Liu,Zhi-Min Dang,Jun-Wei Zha
Polymer dielectric materials with excellent temperature stability are urgently needed for the ever-increasing energy storage requirements under harsh high-temperature conditions. In this work, a novel diamine monomer (bis(2-cyano-4-aminophenyl)amine) was successfully synthesized to prepare a series of cyano-containing polyimides (CPI-1–3), which possessed excellent dielectric properties and high thermostability. The maximum dielectric permittivity was up to 5.5 at 102 Hz for CPI-3, being 2.5 times higher than that of commercially used BOPP. In comparison, the CPI-1 exhibited an outstanding breakdown strength of 433 MV m−1 and a high energy density of 2.5 J cm−3 even at 250 °C, which was the highest value reported under the same conditions. The synthesized CPIs through such an intrinsic approach are potential candidate materials for energy storage and even other applications under simultaneously harsh electrical and thermal conditions.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yuluo Chen,Huicong Liu,Jinpeng Luo,Hang Xu,Xinran Hou,Yujie Yang,Chuanqiang Yin,Xiaomin Li,Lei Ma,Puxuan Yan,Lang Zhou
Polyimide (PI) has been widely used in aerospace, electronic information, novel energy, and other industries due to its excellent high- and low-temperature, radiation, and chemical corrosion resistance . However, the use of electrospun PI separators in lithium-ion batteries (LIBs) is limited due to their poor electrolyte wettability and insufficient mechanical strength . Inorganic materials such as aluminide have typically been used in the coating composition of PI separators. To investigate the effects of different aluminide components, in this work, PI materials were prepared by the complexation–hydrolysis method and used as separators for LIBs. The physicochemical and electrochemical properties of the different nanofiber membranes were studied by adjusting the calcination temperature. The results showed that the sample with the highest tensile strength was 107.6 MPa, which is close to the commercial polyolefin separator. When the calcination temperature increased to 300 °C and then exceeded 400 °C, the aluminide shell initially transformed into thin boehmite and then into γ-Al 2 O 3 phases. The mechanical properties of the nanofiber membranes were enhanced, and the wettability and electrochemical characteristics also improved to some extent. Furthermore, the nanofiber structure was destroyed at 500 °C and could not meet the long-term battery cycles. Therefore, when the calcination temperature was controlled between 300 °C and 400 °C, the aluminide-armored PI nanofiber membranes exhibited better comprehensive performance and were suitable for use as separators in LIBs, which was of great significance for improving the safety and stability of LIBs, especially power batteries.
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2023
·
IF 6.6
Yaodong Zhang,Yuewen Huang,Zhijun Liu,Yihao Yang,Bin Wang,Yujie Peng
The development of coatings with high thermal resistance and strong adhesion is desirable and challenging. Herein, we firstly reported a novel bismaleimide silicone (PMI-HSi) oligomer as well as the matching titanium-containing phthalate curing agent (PAEs). Subsequently, PMI-HSi and PAEs are semi-cured by a de-ethanolization reaction in humid ambient atmosphere. Resultant prepolymer molecular skeletons comprise acylimine bonds yielding strong hydrogen bonds , benzene rings, and titanium atoms, which facilitates the stability of the prepared coatings in high-temperature conditions. Ultimately, the final coating was successfully obtained via thermal initiated radical polymerization . The DTG results indicated that the residual carbon content of PMI-HSi@PAEs50% is as high as 63.9 %. And the T d5% , T d30% and T HRI of PMI-HSi@PAEs50% were separately increased by 142.2 %, 29.2 % and 47.9 % compared with the control group. It is worth noting that PMI-HSi@PAEs50% can remain stable at a high temperature up to 600 °C, and no color changes and cracks appeared on the coating surface . All these results indicate that the as-prepared coatings exhibited excellent high temperature stability. In addition, due to the introduction of PAEs, the adhesion of PMI-HSi@PAEs50% reaches the highest grade of 0 and the hardness reaches 5H. Meanwhile, the reinforcement mechanisms were elucidated in detail. Overall, the as-prepared coating possesses high temperature resistance, strong adhesion, and great hardness, which possesses enormous potential for applications in the field of high-temperature protection.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Xiaoli Ding,Weiji Wang,Xianyun Cheng,Xiaoqian Fan,Hongyong Zhao,Qingping Xin,Yuzhong Zhang
Ether oxygen-rich polymeric membranes emerge as promising membranes in CO 2 separation due to the high affinity between CO 2 molecules and ethylene oxide segments. However, there is a massive challenge in developing asymmetric membranes with high CO 2 permeation performance and CO 2 /light gas separation performance. This work revealed composite membranes with ether oxygen-rich polyimide separation layers were developed by interfacial polymerization between 1,2,4,5-benzenetetracarbonyl tetrachloride and commercial diamines named o,o'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol followed by thermal imidization. The influences of the polymerization time and monomer concentrations on the gas transport and separation properties of the composite membranes were studied based on single-gas permeation. The optimum membrane possessed a superior high ideal CO 2 /N 2 separation factor of 429 accompanied with a moderate permeance of 150 GPU for CO 2 at 25 o C and 0.2 MPa. The performance stability was studied by operating the membrane at various pressures and temperatures. The result showed the composite membrane possessed excellent plasticization resistivity at high pressures. The separation property of composite membranes for CO 2 /N 2 binary mixture was also evaluated. The influences of the operation parameters, including stage-cut and pressure ratio on the product purity and recovery were investigated. The results showed great practical application potential in efficient separation of flue gas .
✓ 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）