POLYMER
·
2018
·
IF 3.483
Guodong Zhou,Weitao Wang,Mao Peng
Molecular composites using rigid-rod macromolecules as the reinforcement have attracted tremendous research interest. However, dispersion of rigid-rod macromolecules at molecular level in the matrix remains a great challenge. Herein, we report new epoxy (EP)-based molecular composites with sulfonated aromatic polyamides , poly( p -sulfophenylene terephthalamide) (sPPTA) and poly(benzidine-2,2′-disulfonic acid terephthamide) (PBDT), as the reinforcement, which disperse uniformly in epoxy. Covalent bonds formed by the reaction between the sulfonic acid groups of the polyamides and epoxy prevent reaction-induced phase separation during high temperature curing. The novel molecular composites exhibit extraordinarily high strength and toughness, with maximum tensile strength of sPPTA/EP and PBDT/EP (100.2 ± 4.8 MPa and 121.9 ± 12.5 MPa, respectively) increased by ∼81% and ∼120%, respectively. To the best of our knowledge, the improvement of mechanical properties surpasses those of molecular composites, nanofiller reinforced thermosets and liquid crystalline thermosets ever reported.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Cheng Liu,Xinyue Zhang,Yunfei Zheng,Zijie Ren,Weng Fu,Siyuan Yang
Fluorite is easily affected by the slime coating of fine barite during the froth flotation separation. In this work, the water glass (WG) was utilized as a dispersant to improve the flotation separation performance between fluorite and barite slimes. The single minerals flotation results revealed that barite slimes could be selectively depressed by gelatinized starch (GS), while WG had little effect on the floatability of barite and fluorite using sodium oleate (NaOl) as a collector. The flotation results of artificially mixed minerals showed that the separation efficiency of fluorite from barite was significantly reduced when barite existed as slimes. However, the presence of WG could eliminate the negative effect of barite slimes on the flotation fluorite by using the reagents scheme of GS/NaOl. Zeta potential results indicated that the fluorite surface charge turned from positive to negative with the addition of WG, then the barite slimes coating was detached from the fluorite surface because of the electrostatic repulsion, allowing the cleaning fluorite surface to once again interact with NaOl. The DLVO calculation was also conducted to reveal the agglomerate and disperse of different particles in the flotation system of fluorite-barite slimes.
研究领域:
矿物加工工程
·
浮选化学
·
胶体与界面科学
·
资源综合利用
·
无机非金属材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 46
·期 16
·24799-24804
·
IF 3.83
Pengfei Pan,Xu Wang,Yaqi Ji,Wumei Dong,Lei Zhang,Ling Wang,Ming Zhang
A simple, efficient and low-cost method to synthesize zirconia nanopowders dispersed with graphene by wet ball milling was reported in this paper. The raw material for ball milling is cheap graphite powder rather than expensive graphene. Graphite powders were exfoliated into graphene nanosheets (GNSs) in the process of ball milling, as a result of strong shear forces and moderate impact forces between graphite powders, milling balls, and ZrO 2 nanoparticles . The mixed powders were milled for 3, 10, 20, 30, 40, and 50 h, respectively. Moreover, the morphology, composition and structure of the mixed powders milled were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy , Fourier transform infrared spectroscopy , and field emission transmission electron microscopy . Results showed that the graphite powders were exfoliated effectively, and the GNSs were dispersed uniformly in the zirconia simultaneously. The presence of zirconia nanoparticles significantly improved the efficiency of ball milling exfoliation.
研究领域:
材料科学
·
纳米技术
·
无机非金属材料
·
复合材料
✓ 已验证
DOI
高影响因子
DESIGNED MONOMERS AND POLYMERS
·
2019
·
IF 1.528
Shuang Li,Yazhen Wang,Liqun Ma,Xueze Zhang,Shaobo Dong,Li Liu,Xilai Zhou,Chenglong Wang,Zhen Shi
The reverse atom transfer radical polymerization (RATRP) of acrylonitrile (AN) was carried out in N, N-dimethylformamide (DMF) with AIBN as initiator, FeCl3•6H2O/triphenylphosphine (PPh3) and FeCl3•6H2O/pentamethyldle-thylenetrlamlne (PMDETA) as catalytic systems, respectively. Effect of reaction time and initiator concentration on polymerization rate, molecular weight and molecular weight distribution were investigated in detail. The Fourier transform infrared spectrometer (FTIR) and 1H nuclear magnetic resonance spectroscopy (1HNMR) were employed to analyze the chain end of the PAN. Gel permeation chromatography (GPC) was applied to measure the molecular weight and polydispersity index (PDI) of PAN. The polymerization demonstrated a typical pseudo first-order kinetics characteristics as evidenced by the number-average molecular weights (Mn) increasing linearly with monomer conversion; the Mn decreasing with the increasing of the initiator concentration. Meanwhile, the low PDI value (<1.2) indicated the controllability of polymerization.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TheScientificWorldJOURNAL
·
2014
·Vol. 2014
·期 1
·162465
·
IF 1.219
Haiying Luo,Yanping Xian,Xindong Guo,Donghui Luo,Yuluan Wu,Yujing Lu,Bao Yang
A new technique was established to identify eight organophosphate esters (OPEs) in this work. It utilised dispersive liquid-liquid microextraction in combination with ultrahigh performance liquid chromatography/tandem mass spectrometry. The type and volume of extraction solvents, dispersion agent, and amount of NaCl were optimized. The target analytes were detected in the range of 1.0–200 µ g/L with correlation coefficients ranging from 0.9982 to 0.9998, and the detection limits of the analytes were ranged from 0.02 to 0.07 µ g/L ( S / N = 3). The feasibility of this method was demonstrated by identifying OPEs in aqueous samples that exhibited spiked recoveries, which ranged between 48.7% and 58.3% for triethyl phosphate (TEP) as well as between 85.9% and 113% for the other OPEs. The precision was ranged from 3.2% to 9.3% ( n = 6), and the interprecision was ranged from 2.6% to 12.3% ( n = 5). Only 2 of the 12 selected samples were tested to be positive for OPEs, and the total concentrations of OPEs in them were 1.1 and 1.6 µ g/L, respectively. This method was confirmed to be simple, fast, and accurate for identifying OPEs in aqueous samples.
研究领域:
环境分析化学
·
污染生态学
·
毒物代谢
·
水质安全
·
持久性有机污染物
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2013
·
IF 2.224
Kejie Yu,Xuebin Zhang,Hongwu Tong,Xiangyan Yan,Shaomin Liu
Fibrous monodisperse core–shell structured Fe 3 O 4 /SiO 2 /KCC-1 nanoparticles were synthesised successfully through a surfactant-templated microemulsion formation process. The structure and morphology of the synthesised nanoparticles were investigated by scanning electron microscopy , transmission electron microscopy , superconducting quantum interference device susceptometer, X-ray diffraction, thermogravimetric analysis and N 2 adsorption/desorption. These nanoparticles showed monodisperse spherical morphology, high magnetism , good thermal stability , large surface area , direct channels, easily accessible large pores and narrow size distribution. A mechanism for the synthesis of these nanoparticles was proposed and explained. Adsorption experiments indicated that the as-prepared materials had good adsorption capacity for dye and could perform a fast transfer of molecules, indicating its promising application in purification of industrial wastewater, drug delivery and so on.
研究领域:
纳米医学
·
材料科学
·
环境工程
·
生物材料
·
药剂学
·
胶体与界面化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 133
·期 30
·
IF 1.866
Guiming Xie,Pengju Pan,Yongzhong Bao
Evolutions of drop/particle size and size distribution in liquid–liquid dispersions and suspension polymerizations of methyl methacrylate (MMA) were monitored by using an online optical reflectance measurement (ORM), and effects of operating parameters such as the agitation rate, concentration of poly(vinyl alcohol) (PVA) dispersant, and initial concentration of poly(methyl methacrylate) (PMMA) in MMA monomer on the Sauter mean diameter ( d 32 ) and size distribution of drop/particle were investigated. According to the variations of d 32 of drops/particles with time, four characteristic particle formation stages can be identified for suspension polymerization process. The factors that lead to increase the rate of drop break up, such as increasing of concentration of PVA and decreasing of viscosity of dispersed phase, would postpone the particle growth stage. The d 32 and size distribution breadth of drops/particles were significant increased when the liquid–liquid dispersions or suspension polymerizations were conducted at low PVA concentrations or MMA/PMMA solutions with high PMMA contents were used as the dispersed phase, in consistent with the scanning electron micrograph observation on final PMMA particles. It is clear that ORM can be effectively applied in online monitoring of size and size distribution of drops/particles in the liquid–liquid dispersions and suspension polymerizations. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43632.
研究领域:
高分子化学
·
化学工程
·
反应工程
·
材料科学
·
过程监测
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·Vol. 46
·期 4
·4720-4729
·
IF 3.45
Guojiao Ding,Rujie He,Keqiang Zhang,Min Xia,Chengwei Feng,Daining Fang
Stereolithography based additive manufacturing provides an effective method to fabricate complex-shaped SiC ceramic components. The dispersion and stability of the ceramic slurry are very important for stereolithography. In this study, the dispersion and stability of SiC ceramic slurries were investigated systematically. The effects of resin monomers , dispersants , particle size, solid loading and ball milling time on the dispersion, rheological behavior and stability of SiC ceramic slurries were studied in detail. Finally, an optimal SiC ceramic slurry for stereolithography based additive manufacturing was obtained, and complex-shaped SiC ceramic architectures were fabricated.
研究领域:
材料科学
·
先进制造
·
陶瓷工程
·
高分子材料
·
复合材料
✓ 已验证
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Wenbo Shen,Ling Wang,Gang Chen,Chunxin Li,Lanying Zhang,Zhou Yang,Huai Yang
A liquid crystalline epoxide was synthesized and its curing reactivity was compared with that of the conventional epoxy monomers . By utilizing the difference in curing reactivity between the liquid crystalline epoxide and non-liquid crystalline epoxy monomers, a coexistent system of polymer-dispersed and polymer-stabilized liquid crystal (LC) in the intelligent films can be obtained by two-step thermal curing method. If the later curing process was undertaken under an external electric field , the ordered microstructure of liquid crystalline epoxy polymer (LCEP) network can be implanted into the conventional epoxy resin. The competition of the anchoring effect on the LC molecules from the LCEP network and the conventional epoxy resin matrix was crucial to the electro-optical performance of the films. Moreover, the performance of the films can be adjusted by controlling the content of liquid crystalline epoxide and the external electric field applied during later curing. This approach can provide a facile route to regulate the electric-optical performance of polymer-dispersed liquid crystal films for practical applications.
研究领域:
材料科学
·
高分子化学
·
功能材料
·
光电工程
·
智能材料
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Junwang Zhang,Lili Song,Kunlan Li,Qingda An,Hao Ma,Liyu Yang,Ligang Wei
Water addition was found to enhance the thermal stability of alkylimidazolium–acetate ionic liquids (ILs). Especially in the case of high water content (30–50 wt%), few decomposition products can be observed in the 1 H NMR spectra even after treatment for 24 h at 150 °C. On the basis of this finding, lignin treatment of water and acetate IL mixtures (50–90 wt% IL content) were investigated at 150 °C. The addition of water, as opposed to pure IL treatment, can inhibit the lignin depolymerization into small fragments. Lignin degradation and the structure of regenerated lignin are more affected by cation types of ILs rather than the IL contents and pH values. In the case of 50–70 wt% 1-ethyl-3-methylimidazolium acetate–water system, the specific inter-unit linkages of lignin can be broken down, and regenerated lignin with a narrow polydispersity index (5.0–9.6) can be obtained.
研究领域:
绿色化学
·
生物质转化
·
高分子化学
·
离子液体化学
·
木质素化学
·
可持续材料
·
热化学转化
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2014
·Vol. 33
·期 1
·125-130
·
IF 1.04
Ting Zhou,Hao Yu,Mingqiang Liu,Ying-Wei Yang
Carboxylated pillar[5]arene (CP5) macrocycles were modified onto the surface of reduced graphene oxide (RGO) via covalent bonds to form new pillarene-functionalized RGO nanosheets, i.e. , RGO-CP5. The obtained RGO-CP5 nanosheets capable of molecular recognition exhibited much better water-dispersibility and enhanced fluorescence-quenching property as compared with native RGO. This new sensing platform holds great potentials in the sensing and detection of analytes, such as organic dye molecules and pesticides, in aqueous solutions.
研究领域:
分析化学
·
纳米材料科学
·
传感器技术
·
环境监测
·
分子识别
✓ 已验证
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2016
·Vol. 217
·期 9
·1047-1056
·
IF 2.495
Liang Qiu,Chao-Ran Xu,Feng Zhong,Chun-Yan Hong,Cai-Yuan Pan
Pure cross-linked spherical micelles, nanowires, and vesicles are successfully fabricated from poly(2-hydroxypropyl methacrylate- b - p -(methacryloxyethoxy)benzaldehyde)s (PHPMA– b –PMAEBAs) through reversible addition-fragmentation chain transfer dispersion polymerization of MAEBA in methanol using PHPMA as a macro-CTA and subsequent cross-linking. The cross-linking reaction is conducted by stirring a mixture of 1,4-butanediamine and the resultant nano-objects in methanol at room temperature. For all polymerizations with feed molar ratios of MAEBA/PHPMA ranging from 75/1 to 240/1, the monomer MAEBA conversions are almost complete, and block copolymers with controlled molecular weight are obtained. The transmission electron microscopy, dynamic light scattering, and gel permeation chromatography results reveal that the following three factors significantly influence the morphology of the nano-objects: the feed molar ratio of MAEBA/PHPMA, the copolymer concentration, and the degree of polymerization of PHPMA. The cross-linked nano-objects are very stable in good solvents, the spheres and nanowires slightly decrease in size after cross-linking, whereas the vesicles slightly increase in size. The cross-linked nano-objects are stable in neutral solutions, but they dissociate in weekly acidic solutions. The loading of 1-pyrenemethylamine (PMA) into the vesicles and the unloading of PMA from the vesicles are studied.
研究领域:
高分子化学
·
纳米材料
·
药物递送
·
生物医学工程
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）