JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 43
·49320
·
IF 2.52
Zhenggang Luo,Huijian Ye,Jiawei Hu,Te Hu,Boyuan Zhang,Xuanhe Zhang,Lixin Xu
A strategy for preparing ethylene-vinyl acetate (EVA)/graphene nanocomposites from liquid-phase exfoliated graphene has been explored with the use of a pyrene-functionalized hyperbranched polyethylene (HBPE) ternary copolymer, HBPE@Py@PMA, as stabilizer for graphite exfoliation. The HBPE@Py@PMA was synthesized by combining the Pd-diimine-catalyzed chain walking ternary ethylene copolymerization and atomic transfer radical polymerization techniques and has been confirmed to possess a HBPE core simultaneously bearing pyrene terminal groups and polymethacrylate side chains. As stabilizer, it is found to effectively promote graphite exfoliation in CHCl 3 to render high-quality few-layer graphene with an efficiency as high as 43%. Meanwhile, it can be steadily adsorbed on the exfoliated graphene surface to concurrently render functionalized graphene well dispersible in EVA matrix with strong interfacial interactions. This allows us to obtain EVA/graphene nanocomposites from resulting graphene dispersion through simple solution mixing process. By adding only 0.5 wt% of graphene, the dielectric constant of resulting composite increases by 55% compared to pure EVA, with a dielectric loss only 0.012. The role mechanism of the HBPE@Py@PMA for promoting graphite exfoliation in CHCl 3 and the formation of EVA/graphene nanocomposites from the resulting graphene has been proposed.
研究领域:
高分子化学
·
纳米复合材料
·
材料科学
·
胶体与界面化学
·
功能高分子
✓ 已验证
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2018
·
IF 2.955
Yuhua Dong,Siyi Li,Qiong Zhou
The self–healing capability of epoxy coatings modified with coaxial core–shell nanofibers loaded with the corrosion inhibitor 2–mercaptobenzothiazole (MBT) was investigated using electrochemical techniques. The polyvinyl alcohol/polyvinylidene fluoride core–shell nanofibers were prepared by coaxial electrospinning. Electrochemical impedance results showed that the MBT–loaded coaxial nanofibers improved the barrier properties and decreased the corrosion activity of the coatings. Results of the Scanning Kelvin Probe technique revealed that the MBT–loaded coaxial nanofibers healed corrosion over artificial defects exposed to NaCl electrolytes. These results indicate that adding MBT–loaded coaxial nanofibers to epoxy coatings is a promising strategy toward the development of self–healing epoxy coatings.
研究领域:
材料科学
·
高分子化学
·
腐蚀与防护
·
表面工程
·
功能材料
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Xiong Wang,Zhenyou Li,Xiaoyu Han,Zhengang Han,Yongxiao Bai
Porous organic Polymers (POPs) can not only exhibit high specific surface area and pore volume, but also tunable pore size distribution. Herein, copolymers of 2-hydroxyethylmethylacrylate (HEMA) and divinylbenzene (DVB) with specific pore structure were synthesized via a dispersion polymerization strategy, and then immobilized metallocene catalysts with well-defined pore structure were obtained on the produced POP supports. The nitrogen sorption and Gel permeation chromatography (GPC) results demonstrate that the pore structure of the immobilized metallocene catalyst is highly dependent on the pore structure of the POPs , and the pore structure of metallocene catalysts or the POPs has a significant influence on the molecular chain growth of the produced polyethylene. By tuning the distribution of the active species scattered in the micro- and the narrow meso-pore range (roughly ≤4 nm), the chain growth of the polyolefin can be tailored effectively during the polymerization process, although differential scanning calorimetry (DSC) and temperature rising elution fractionation (TREF) results show that the chemical composition distributions (CCDs) of produced PE from the POPs-supported metallocene catalysts are not determined by polymerization activity or molecule chain length, but mainly by the active site species scattered in the supported catalysts. Scanning electron micrograph (SEM) shows that the produced polyethylene has highly porous fabric which consists of nanofiber and spherical beads of micron dimension.
研究领域:
高分子化学
·
催化化学
·
材料科学
·
纳米材料
·
聚合物科学
·
石油化工
✓ 已验证
DOI
高影响因子
POLYMER
·
2021
·
IF 4.43
Lu Shi,Wei Liu,Yanhu Xue,Mei Hong,Xiangling Ji
Temperature Rising Elution Fractionation (TREF) is effective for separating polyolefin resins according to crystallizability. A relatively low isothermal crystallization temperature is necessary to fractionate poly(1-butene) (PB-1) resin because of its slow crystallization kinetics . This study aims to investigate the influence of isothermal crystallization temperature of TREF on the fractionation and chain microstructure of eluted fractions for one poly(1-butene-co-ethylene) with 5.8 mol% ethylene. The resin is fractionated using P-TREF under four different isothermal crystallization temperatures, i.e. 0 °C, −5 °C, −10 °C, and −30 °C, and then the fractions are characterized by high-temperature gel permeation chromatography (HT-GPC), 13 C nuclear magnetic resonance spectroscopy ( 13 C NMR), and differential scanning calorimetry (DSC) to acquire their chain microstructure information. The isothermal crystallization temperature significantly affects the nucleation and growth of the crystals, which consequently results in differences in the relative content of eluted fractions. With the decrease of isothermal crystallization temperature from 0 °C to −30 °C, the copolymer is fractionated more effectively since fractions are more evenly distributed among elution temperatures rather than concentrated at lower elution temperatures. Furthermore, the isothermal crystallization temperature influences the chain microstructure of fractions obtained at the same elution temperature, which are different in ethylene content, isotacticity, and average sequence length. The distribution of ethylene content and isotacticity becomes broader with the decrease in isothermal crystallization temperature. Lower isothermal crystallization temperature is conducive to effective separation of the fractions with weak crystallizability. These results are of great significance for the selection of fractionation conditions and chain microstructure analysis of poly(1-butene-co-ethylene) resins.
研究领域:
高分子化学
·
材料科学
·
聚合物表征
·
热分析
·
核磁共振波谱学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Haoyu Gu,Tong Lv,Qiankun Zhang,Dequan Chi,Yang Zhang,Zhongjun Cheng,Zhimin Xie,Yongjun Xu,Dongjie Zhang,Yuyan Liu
Smart reconfigurable metamaterials can better adapt to changing electromagnetic environments and broaden the range of applications. However, constructing electromagnetic reconfigurable metamaterials, especially those with large areas or applied to complex surfaces via a universal approach, is still a challenge. Here, we introduce a smart reconfigurable metamaterial consisting of a thermadapt shape memory polymer ethylene vinyl acetate copolymer (EVA) matrix and a flowable liquid–metal resonant unit. Based on the excellent self-healing properties of EVA, large-area metamaterials can be constructed by thermal assembly of metamaterial units. In addition, the original shape of the metamaterial can be reprogrammed to apply to complex three-dimensional surfaces with the reprocessing properties of EVA. Moreover, by utilizing the shape memory performance of the EVA, the temporary resonant frequency of the metamaterial can be set by programming and the resonant frequency tuning of the metamaterial can be controlled under external temperature stimulation, achieving noncontact tuning. In the future, this concept can be broadly applied in fields such as complex structure stealth layers and multifunction filters.
研究领域:
材料科学
·
电磁学
·
高分子化学
·
智能材料
·
功能材料
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 32
·期 11
·1564-1574
·
IF 1.42
Li Ming,Zhang Li-fen,Tao Mei-xia,Cheng Zhen-ping,Zhu Xiu-lin
In this work, a fluorescent monomer 2-(9-carbazolyl) ethyl vinyl ether (CEVE) was synthesized in our lab, and its photo-induced living cationic copolymerization behavior with isobutyl vinyl ether (IBVE) was investigated in detail using diphenyliodonium chloride (DPICl)/2,2-dimethoxy-2-phenylacetophenone (DMPA) and zinc bromide (ZnBr 2 ) initiating system in dichloromethane solution at 5 °C, −5 °C, and −15 °C, respectively. The living nature of this copolymerization system was confirmed by adding fresh comonomer method after the copolymerization almost finished. In addition, the obtained fluorescent copolymer poly(IBVE- co -CEVE) has a low glass transition temperature ( T
g ), below −10 °C.
研究领域:
高分子化学
·
功能高分子
·
光响应材料
·
聚合反应机理
·
荧光材料
✓ 已验证
DOI
高影响因子
Small
·
2024
·Vol. 21
·期 5
·2408929
·
IF 13
Xue Jiao Zhao,Zhi Hao Zhao,Zhong Lin Wang,Guang Zhu,Jie Wang
Triboelectric nanogenerators (TENGs), among the most simple and efficient means to harvest mechanical energy, have great potential in renewable energy utilization. While the output performance of TENGs is still not high enough, which limits its practical application. Here, a poly(vinylidene fluoride) (PVDF)/fluorinated ethylene propylene nanoparticles (FEP NPs) porous nanofiber (PFPN) membrane with waterproof, breathable, surface superhydrophobic and high tribo-negative properties is proposed for achieving high-performance of TENGs. The PFPN-based solid–solid contact PFPN-TENG achieved an optimal electric output with a net tribo-charge density of 294 µC m −2 , which is 42.2% more than that of polytetrafluoroethylene (PTFE) film. The PFNP membrane can maintain the best performance with almost no attenuation after 142680 working cycles. Based on its excellent triboelectric characteristics, the PFPN membrane shows its excellent performance for self-powered body motion sensing and mechanical energy harvesting. A flexible solid–liquid contact PFPN-TENG can achieve high electrical output with an average volume power density of ≈544.1 W m −3 by harvesting water wave energy. Such excellent performance of the PFPN membrane makes it a potential candidate to promote the power density of TENGs in harvesting blue water wave energy.
研究领域:
纳米能源材料
·
柔性电子学
·
生物医学工程
·
可穿戴设备
·
环境能量收集
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 7
·5961-5970
·
IF 3.442
Luo Shuai,Qiao Xuan,Wang Qiu-Yu,Zhang Yun-Fei,Fu Ping,Lin Zhi-Dong,Du Fei-Peng,Cheng Chun
To develop low-cost and high-performance self-healing antifogging coatings, polyvinyl alcohol/hydrolyzed poly(styrene-co-maleic anhydride) (PVA/H-PSMA) coatings were prepared from a mixed solution of polyvinyl alcohol (PVA) and hydrolyzed poly(styrene-co-maleic anhydride) (H-PSMA) via spin coating and annealing. The microstructure, antifogging behavior, and self-healing ability were investigated. High transparency and low surface roughness were observed when the PVA/H-PSMA film was coated on glass slides. The PVA/H-PSMA coatings showed excellent antifogging performance in a warm, humid environment. The coatings also performed well when transferred from a refrigerator to room temperature. The antifogging coatings showed desirable water resistance due to strong chemical bonding between PVA and H-PSMA, as well as excellent self-healing ability due to hydrogen bonding self-assembly in the PVA/H-PSMA structure. The coatings still exhibited excellent antifogging effects after 20 scratching-repairing cycles, illustrating their potential use in practical applications.
研究领域:
材料科学
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Yanru Yin,Ning Ma,Jing Xue,Guoqiang Wang,Shuibo Liu,Hongliang Li,Peizhi Guo
Four types of palladium (Pd) nanoparticles were prepared from the systems containing PdCl2 or Na2PdCl4 with or without the assistance of poly(vinylpyrrolidone) (PVP). Two types of Pd nanoparticles obtained in the absence of PVP were obviously larger than those synthesized with the assistance of PVP. The former large Pd particles showed typical features in cyclic voltammetry in H2SO4 solution, whereas two types of small Pd nanoparticles did not. However, small nanoparticles treated first in an electrochemical way in 0.5 M KOH solution displayed the adsorption and desorption peaks similar to those of typical Pd-modified electrodes in H2SO4 solution. Large Pd nanoparticles from the PdCl2 synthesis system showed a catalytic specific current of 629 mA/mg in the electrocatalysis of ethanol, whereas large particles from the Na2PdCl4 system showed a current of 262 mA/mg. The maximum catalytic currents of small Pd nanoparticles without surface cleaning treatment were 1382 and 1019 mA/mg for samples from the Na2PdCl4 and PdCl2 systems, respectively, higher than those being treated in KOH solution first, and the electrocatalytic stability of the two untreated samples was better. However, small nanoparticles after the electrochemical treatment can reach the maximum catalytic current faster. The synthesis and structure–property relation of four types of Pd nanoparticles have been discussed and analyzed on the basis of systematically experimental data.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
TRIBOLOGY LETTERS
·
2019
·Vol. 67
·期 1
·1-17
·
IF 2.235
Zhao Yuanliang,Qi Xiaowen,Zhang Wenli,Fan Bingli,Yang Qingxiang
The effects of copper nanoparticles (Cu) located in different regions of polytetrafluoroethylene/polyimide (PTFE/PI) blends on the morphology, thermal, mechanical, and tribological properties of PTFE composites were studied. Region one is PI phases (the corresponding composites is denoted as PPC), region two is PTFE phases and the interface between PTFE and PI (the corresponding composites is denoted as PPC-m). Results indicate that the incorporation of Cu nanoparticles into PI phases improves the dispersibility and homogeneity of PI phases. As a consequence, the crystallinity of PTFE composites is reduced, but compressive strength and modulus of PTFE composites are enhanced by 50.3% and 14.4% respectively. In addition, self-lubricity and wear resistance of PTFE composites are improved by 10.4% and 50.5%. Scanning electron microscopy (SEM) demonstrates that PI phases with Cu nanoparticles hinder the direct contact between PTFE matrix and counterparts. However, Cu nanoparticles located in PTFE matrix and the interface between PTFE and PI deteriorates the dispersibility and homogeneity of PI phases, which lead to the poor mechanical and tribological performance of PTFE composites.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
Na Li,Yaru Peng,Zeng Chen,Wenjuan Xiong,Jiaqi Sun,Yiming Chen,Putao Zhang,Meiyue Liu,Shengjun Li
The electro-deoxidation of MgO does not proceed efficiently due to the electrical insulation properties of MgO and large molar volume of metallic magnesium. In this experiment, an attempt was done to prepare Mg-Zr alloy from their oxides using the method of electro-deoxidation. The electrochemical mechanism of the deoxidation process of MgO, ZrO 2 and MgO-ZrO 2 composite was studied through cyclic voltammetry using metallic cavity electrode (MCE). There was an intermediate phase (Zr 3 O) in the reduction process of ZrO 2 . The electro-deoxidation of MgO occurred for MgO-ZrO 2 composite in CaCl 2 -NaCl molten salt. Moreover, the electro-deoxidation of MgO was promoted by the addition of polyvinyl butyral (PVB). The formation of metal phase Mg was confirmed by XRD, EDS, Raman spectroscopy, and inductively-coupled plasma spectroscopy. The electro-deoxidation products showed significant differences with the concentration of PVB and the ratio between MgO and ZrO 2 . The electro-deoxidation of MgO and ZrO 2 was favorable when the PVB concentration was 5.0% (wt.%). Pure metal phase of Mg-Zr alloys was formed when the molar ratio of MgO and ZrO 2 was 1:2. The atomic fraction of Mg in the electrolytic product was ca. 28.0 mol.%. This work shows that MgO could be directly electro-deoxidized to Mg without the formation of intermediate phase oxide.
研究领域:
材料科学
·
冶金工程
·
无机化学
·
电化学
·
金属合金制备
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 99
·97036-97047
·
IF 3.289
Mei Wang,Jianling Xia,Jianchun Jiang,Shouhai Li,Mei Li
Dipentene-maleic anhydride (DPMA) was prepared by the Diels–Alder addition of dipentene with maleic anhydride. DPMA was converted via ammonolysis with para-aminobenzoic acid (PABA) to form N-(3-amino-benzoic acid)terpene-maleamic acid (ABDPMA), which was then converted to zinc soap (ABDPMA-Zn) or calcium soap (ABDPMA-Ca). Their chemical structures were confirmed by FT-IR and ICP-AES. Thermal stabilizing effects of ABDPMA-Ca/ABDPMA-Zn were compared with ABTMA-Ca/ABTMA-Zn (ABTMA: N-(3-amino-benzoic acid)tung-maleamic acid), C36DA-Ca/C36DA-Zn (C36DA: dimer fatty acid), ZnMA/ZnO (MA: maleic acid), EFC/ZnSt2/ESBO (EFC: calcium salt of epoxidised fatty acid; ESBO: epoxidised soybean oil, and CaSt2/ZnSt2 (St: stearic acid). Thermal stabilities of poly(vinyl chloride) (PVC) compounds were determined using Congo Red test, discoloration test, ultraviolet-visible spectroscopy analysis and thermogravimetric analysis. Dynamic mechanical and tensile properties of the PVC compounds were also studied. Besides better plasticization performance, ABDPMA-Ca/ABDPMA-Zn improved the long thermal stability of PVC compared with ABTMA-Ca/ABTMA-Zn, C36DA-Ca/C36DA-Zn, and CaSt2/ZnSt2.
研究领域:
高分子化学
·
材料科学
·
塑料加工
·
热稳定化
·
功能添加剂
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）