POLYMER INTERNATIONAL
·
2017
·Vol. 66
·期 6
·876-881
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IF 2.07
Zuoqiang Wu,Jianhua Han,Nan Li,Zhihuan Weng,Jinyan Wang,Xigao Jian
High curing temperature (including post-curing temperature) and long curing time of phthalonitrile resins make them thermally stable but difficult to process. In this paper, novel mixed curing agents (CuCl/4,4′-diaminodiphenylsulfone (DDS) and ZnCl 2 /DDS) were firstly designed for solving these problems. Bisphenol-based phthalonitrile monomer (BP-Ph; melting point: 228–235 °C) was synthesized and used as the curing precursor. Differential scanning calorimetry results indicated that BP-Ph cured with CuCl/DDS and ZnCl 2 /DDS exhibited curing temperatures close to the melting point of BP-Ph with curing ending temperatures of 225.4 and 287.1 °C, respectively. Rheologic investigations demonstrated obvious curing reactions of BP-Ph occurred with the mixed curing agents at 220 °C. Thermogravimetric analysis showed that BP-Ph cured by CuCl/DDS or ZnCl 2 /DDS maintained 95% mass at 573 or 546 °C, respectively, at a post-curing temperature of 350 °C for 2 h. Reasonable long-term thermo-oxidative stability was also demonstrated. When the post-curing temperature decreased to 290 °C, char yield at 800 °C of BP-Ph cured by CuCl/DDS was 77.0%, suggesting the curing procedure can be milder when using mixed curing agents. © 2017 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2016
·Vol. 66
·期 1
·92-97
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IF 2.414
Junzhi Li,Jianhua Liu,Liqun Xu,Jiucun Chen
Nowadays, carbon dots (CDs) have aroused widespread interest due to their chemical stability, biocompatibility as well as low toxicity. Herein, polymerizable CD monomers were synthesized through amidation between hydrophobic CDs and methacryloyl chloride, which has emerged as a facile method for preparing various fluorescent CD monomers. The fluorescent polymerizable CDs were copolymerized with N- isopropylacrylamide (NIPAM) to form thermoresponsive fluorescent nanoparticles. The poly(NIPAM) (PNIPAM) grafted hydrophobic CDs (CDs- g -PNIPAM) have excellent dispersivity in water, rendering hydrophobic CDs with fluorescence properties in aqueous media. Moreover, CDs- g -PNIPAM nanocomposites show a remarkable thermoresponsive behavior, and the fluorescence intensity decreases progressively with increase in temperature. Cytotoxicity tests show that CDs- g -PNIPAM nanocomposites have great biocompatibility. When the CDs- g -PNIPAM nanocomposites were cultured with HaCaT cells at a concentration of 2000 µg mL −1 , cell viability was maintained over 85%. Benefiting from the copolymerization of NIPAM, the excitation-independent fluorescence of CDs- g -PNIPAM nanocomposites can be used for cellular labeling and show long-term biostability in a cellular environment. © 2016 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2017
·Vol. 66
·期 12
·1827-1833
·
IF 2.07
Jian Zhao,Yanlei Liu,Jianglong Cheng,Shengming Wu,Zhaobo Wang,Haiqing Hu,Chunhua Zhou
Solvent-exfoliated graphene (SEG)-reinforced polystyrene (PS) composites were prepared using a straightforward solution-casting method. SEG sheets, obtained by sonication-assisted solvent direct exfoliation from natural graphite, were well dispersed in the PS matrix as evidenced from scanning electron microscopy and transmission electron microscopy observations. Addition of 0.5 wt% SEG resulted in a 6% increase in tensile strength and a 77% improvement in Young's modulus over pure PS due to the effective load transfer between SEG and PS matrix. The Young's moduli of the PS/SEG composites were obtained from both tensile experiments and calculations using the well-established Halpin–Tsai model. Results from dynamic mechanical analysis indicated that the storage modulus of the PS/SEG composites was significantly improved relative to neat PS. The glass transition temperatures of the composites were found to increase substantially upon addition of SEG, consistent with differential scanning calorimetry analysis. © 2017 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2016
·Vol. 66
·期 5
·659-664
·
IF 2.414
Jia Chen,Bin Chen,Jingyu Li,Xin Tong,Haichao Zhao,Liping Wang
Hexagonal boron nitride (hBN), a two-dimensional nanofiller with good mechanical properties, high thermal conductivity and excellent lubrication properties, has the potential to substantially reinforce polymers to form nanocomposites with advanced properties. In this study, we successfully prepared hBN nanosheets with a thickness of a few atoms by using amine-capped aniline trimer (AT) as dispersant. Epoxy/hBN nanocomposites were prepared by curing reaction of epoxy E51, Jeffamine D230 and AT-modified hBN nanosheets, where the hBN contents were 0.5, 1, 2 and 4 wt%. An increase in contact angle of the epoxy/hBN nanocomposites was evident in the presence of hBN nanosheets, implying an increase in the hydrophobic nature of the composites. The as-prepared composites exhibited enhanced mechanical and tribological performance compared to pure epoxy resin. This effectiveness in improving the mechanical, friction and wear behavior of the epoxy composites could be attributed to the complementary action of excellent mechanical properties, lubrication and thermal conductivity of hBN nanofillers. © 2016 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2017
·Vol. 66
·期 12
·1891-1896
·
IF 2.07
Yongjie Zhang,Xiaopei Li,Shuwei Wang,Jing Xu,Huayi Li
Organo-modification of montmorillonite (MMT) is crucial for the promotion of a fine dispersion of MMT into an (often hydrophobic) polymer matrix. Ammonium-terminated polymers are more efficient in modifying clay compared to small organic cations such as alkyl ammoniums or side functionalized polymers. Herein, tri-amino end functional polyethylene (PE-3 N) with low molecular weight was first synthesized via an efficient and robust epoxide ring-opening reaction by treating epoxide-terminated PE with diethylenetriamine. The chemical structure of PE-3 N was unambitiously characterized by chromatographic and spectral methods. By reacting with excess HCl, PE-3 N was subsequently converted to tri-ammonium end functional polyethylene (PE-3 N + ), which serves as an intercalation agent of MMT. By adjusting the weight ratio of PE-3 N + to pristine MMT ( R P/M ) applied in the static melt intercalation process, correlations between the extent of exfoliation and R P/M were successfully established. XRD results revealed that complete exfoliation of MMT could be afforded with R P/M as low as 1, which is the lowest value ever reported for ammonium-terminated polymers applied as intercalation agents. SEM micrographs showed that MMT sheets were swollen by PE-3 N + , affirming the successful modification of MMT. The PE modified MMT obtained may find application in preparing high-performance PE/MMT nanocomposites. © 2017 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2016
·Vol. 66
·期 6
·779-786
·
IF 2.414
Fubin Luo,Kun Wu,Hongyan Zhu,Xiaoya Li,Mangeng Lu
Two kinds of foam based on melamine − formaldehyde (MF) condensates (PVA/MF (PVA, polyvinyl alcohol), PVA/APTES/MF (APTES, 3-triethoxysilylpropylamine)) were prepared by chemical modification. Pure MF foam has the serious disadvantage that it is very hard and brittle, breaks easily and crumbles when handled. After modification, PVA/MF and PVA/APTES/MF display excellent resilience. The structures of the foams were characterized by Fourier transform infrared (FTIR), SEM and XRD. XRD data indicate that modifiers hinder the crystallization of MF, which might contribute to the improvement of resilience. Flame retardancy of the foams was characterized by limiting oxygen index testing, and the thermal degradation behavior was studied using TGA. The mode of flame retardant action is suggested by gaseous and solid phase analysis. TGA-FTIR results demonstrate that the sublimation of the melamine of MF and foams based on MF occurs during thermal decomposition, which contributes to the high flame retardancy. © 2016 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2015
·Vol. 64
·期 10
·1415-1424
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IF 2.409
Weijuan Sheng,Teng Liu,Shouxin Liu,Qinqin Wang,Xuan Li,Naer Guang
A novel temperature responsive copolymer, poly[2-(2-methoxyethoxy)ethyl methacrylate- co -oligo(ethylene glycol)methacrylate- co-N -hydroxymethyl acrylamide] [P(MEO 2 MA- co -OEGMA- co -HMAM)], was synthesized by atom transfer radical polymerization. pH responsive poly(methacrylic acid) (PMAA) was synthesized by reversible addition-fragmentation chain transfer polymerization. After the hydroxyl groups on P(MEO 2 MA- co -OEGMA- co -HMAM) were transformed into azide groups and the carboxyl groups on PMAA were transformed into alkyne groups respectively, a novel temperature and pH responsive hydrogel was fabricated by click chemistry between the azide-P(MEO 2 MA- co -OEGMA- co -HMAM) and alkyne-PMAA in the presence of CuSO 4 and sodium ascorbate in aqueous solution. The rheological kinetics of gel formation demonstrated that gelation had commenced within 5 min at 25 °C, since then the storage modulus ( G ′) was higher than the loss modulus ( G ″). SEM images of hydrogel morphology and the swelling ratios of hydrogel at different temperatures and pH proved that the formed hydrogel had temperature and pH sensitivities. Bovine serum albumin was used as a model to evaluate the sustained release of the hydrogel; the results indicated that the hydrogel was a promising candidate for controlling protein drug delivery. © 2015 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2015
·Vol. 64
·期 11
·1594-1599
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IF 2.409
Qin Liu,Yonggang Feng,Shaomei Huang,Quanzhou Wu,Jianfeng He
Three-dimensionally ordered macroporous molecularly imprinted polymers (MMIPs) were prepared by a combination of the colloidal crystal template method and the molecular imprinting technique. Traditional bulk molecularly imprinted polymers (BMIPs) were simultaneously synthesized with the same recipe as the MMIPs by using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker and chloroform as porogen. SEM and Brunauer − Emmett − Teller measurements show that MMIPs have a more regular macroporous structure, a narrower macropore distribution and a greater surface area and porosity compared with BMIPs. The isothermal and kinetic data of both polymers can be fitted with the Freundlich model and a pseudo-second-order equation, respectively. Their specificities to the template molecules are also similar. However, the binding capability, adsorption rate coefficient and internal effective diffusion coefficient of the MMIPs are higher than for the BMIPs when the particle size is above 54 µm. © 2015 Society of Chemical Industry
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高影响因子
POLYMER INTERNATIONAL
·
2015
·Vol. 64
·期 12
·1715-1721
·
IF 2.409
Tao Xing,Kai Zhang
Novel carborane polyimides were synthesized and studied. Aromatic meta -carborane diamines of different structures were initially prepared. Polymerization of these new diamines with the commercially available 4,4′-oxydiphthalic dianhydride led to meta -carborane polyimides with various structures and thermal properties. The amorphous polymers obtained are of moderate molecular weight and show good solubility in organic solvents. Thermal analyses of these polyimides reveal that they have moderate to ultrahigh thermal stability depending on their specific structures, with 5% decomposition temperatures ranging from 382 to 786 °C in nitrogen. Different thermal properties of these polyimides are observed when the analyses are performed in dry air, with 5% decomposition temperatures shifting to temperatures ranging from 388 to 1128 °C. Due to the ever-present requirement of higher performance polymers in fields like aerospace and defense, the methods developed here could be an impetus for the development of these industries. © 2015 Society of Chemical Industry
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高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 4.1
Li Ying,Pan Chen,Gan Feng,Lin Zhi-Xun,Yu Jin-Chao,Wei Zhen-Zhen,Zhao Yan
Electrospun nanofibrous separators, despite lacking superior mechanical strength, have gained widespread attention with high porosity and facile processing. Herein, utilizing the fact that thermal imidization temperature of poly(amic acid) (PAA) into polyimide (PI) coincides with the pre-oxidation temperature of polyacrylonitrile (PAN) into carbon fiber, we proposed a new cross-electrospinning strategy to obtain a composite nanofibrous separator (PI/oPAN) randomly interwoven by PI and pre-oxidized PAN (oPAN) nanofibers, via synchronously electrospinning the PAA and PAN onto the same collector and then heat-treating for 2 h at 300 °C. The resultant PI/oPAN separator was able to preserve high porosity (71.7%), electrolyte wettability and thermal stability of PI nanofibrous membrane, and surprisingly exhibited high mechanical strength, being 3 times of PI, which mainly because of the numerous adhesion points generated by the melting of PAN in the pre-oxidation process. Meanwhile, the polar groups of oPAN and 3D fibrous network enhanced the PI/oPAN separator’s ionic conductivity and Li + transference number, rendering the corresponding cell with more stable cycling performance than cells assembled with pure PI, PAN or commercial PP separator. Therefore, this work might provide a new avenue for the ongoing design and further development of LIB separators capable of high safety and high performance.
研究领域:
材料科学
·
能源技术
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高影响因子
Polymers
·
2024
·Vol. 16
·期 6
·767
·
IF 4.7
Changhai Zhang,Ziyang Liu,Chao Tang,Tiandong Zhang,Yue Zhang,Yongquan Zhang,Qingguo Chi
With the policy tilt and increased investment in research and development in the world, new energy vehicle technology continues to progress and the drive motor power density continues to improve, which puts forward higher requirements for the comprehensive performance of the core insulating material enameled wire enamel for drive motors. Polyimide (PI) has excellent electrical insulation properties, and heat resistance is often used to drive the motor winding insulation. To further improve the corona resistance and insulating properties of PI wire enamel varnish, in this paper, firstly, fluorene groups with a rigid conjugated structure were introduced into the molecular chain of the PI film by molecular structure modulation, and then uniformly dispersed alumina nanoclusters (AOCs) were introduced into the PI matrix by using an in situ growth process to inhibit the migration of high-energy electrons. The quantum size effect of the alumina nanoclusters was exploited to synergistically enhance the suppression and scattering of energetic moving electrons by PI-based composite films. The results show that the breakdown field strength of the PI-based composite film (MPI/1.0 vol% AOC) reaches 672.2 kV/mm, and the corona resistance life reaches 7.9 min, which are, respectively, 1.55 and 2.19 times higher than those of the initial PI film. A PI-based composite film with excellent insulating and corona resistance properties was obtained.
研究领域:
材料科学
·
电气工程
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PubMed
高影响因子
CARBON
·
2025
·
IF 11.6
Shenquan Yang,Baowei Qiu,Mushan Yuan,Zheng Liu,Hang Jia,Binbin Sun,Haichao Meng,Xiaochuang Di,Yang Chen,Weiyi Kong,Huawei Zou
Fiber-reinforced thermosetting polyimide-based composites have broad application prospects in the aerospace field, which makes it particularly important to optimize their preparation process and improve their electromagnetic (EM) wave absorption performance. In this study, quartz fiber/polyimide@carbon nanotubes (QF/PI@CNTs) prepregs with uniform resin distribution and controllable content were prepared through in-situ polymerization combined with a film-coating method. These prepregs were subsequently laminated and molded by vacuum hot-pressing to obtain composites integrating EM absorption and high-load bearing capability. The QF/PI@CNTs composite at a low filler ratio (3 wt% CNTs), by constructing a stable three-dimensional conductive network and inducing multi-scale interfacial polarization effects, demonstrated excellent EM wave absorption. Specifically, the QF/PI@C-3 composite achieved full-frequency absorption across the entire X-band from 25 °C (2.98 mm) to 300 °C (2.01mm), while maintaining an effective absorption bandwidth (EAB) covering 88% of the X-band at 400 °C (1.78mm). The minimum reflection loss (RL min ) improved from -26.42 dB at 25 °C to -70.35 dB at 100 °C, and remained -29.17 dB at 200 °C. Moreover, the composite also has a relatively high thermal decomposition temperature (T d5% =557 °C) and flexural strength (501.8 ± 22.9 MPa). This research provides feasible insights for the design of structural integrated materials with high-temperature EM absorption capability.
研究领域:
材料科学
·
电磁功能复合材料
·
航空航天材料
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聚合物基复合材料
·
微波吸收
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高影响因子
危险品化学品经营许可证（带存储）