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Zhang B.,Heilongjiang Institute of Petrochemistry | Sun M.,Heilongjiang Institute of Petrochemistry | Li J.,Heilongjiang Institute of Petrochemistry | Wang L.,Heilongjiang Institute of Petrochemistry | Qin C.,Heilongjiang University
Pigment and Resin Technology | Year: 2014

Purpose - In order to obtain functionalized core-shell nanoparticles (CSNPs) as excellent toughening agents for epoxy resins. The paper aims to discuss these issues. Design/methodology/approach - Functionalized CSNPs containing epoxy groups on the surface were synthesized by emulsion polymerization with butyl acrylate as the core and methyl methacrylate copolymerizing with glycidyl methacrylate (GMA) as the shell. CSNPs were used as toughening agents for epoxy resins and their chemical structure was characterized by FT-IR. The morphology of modified epoxy networks (MEPN) was analyzed by SEM and TEM. Both the mechanical properties and thermodynamic properties were studied. Findings - The results show that nearly spherical CSNPs with the particle size of 50-100 nm are obtained. A certain amount of CSNPs are uniformly dispersed in epoxy resins by the grinding method and the MEPN shows the ductile fracture feature. The miscibility between CSNPs and epoxy matrix increases with the increase of GMA concentration which makes more bonds form between them. Epoxy resins toughened with 10 wt% CSNPs containing 10 wt% GMA show the best mechanical properties and the increase in tensile strength and impact strength of the MEPN is 13.5 and 59.7 percent, respectively, over the unmodified epoxy networks. And the improvement in impact strength is not accompanied with loss of thermal resistance. Practical implications - The MEPN can be used as high-performance materials such as adhesives, sealants and matrixes of composites. Originality/value - The functionalized CSNPs are novel and it can greatly increase the toughness of epoxy resins without loss of thermal resistance. © Emerald Group Publishing Limited.


Du J.,Heilongjiang University | Li Q.,Heilongjiang University | Qin C.,Heilongjiang University | Zhang X.,Heilongjiang Institute of Petrochemistry | And 2 more authors.
Pigment and Resin Technology | Year: 2015

Purpose - The purpose of this paper is to develop nitrogen-enriched carbon (NC) with high conductivity and specific capacitance as electrode materials for supercapacitors. Design/methodology/approach - Graphene oxide (GO) was synthesized by the modified Hummers-Offeman method. NC was synthesized by carbonization of melamine formaldehyde resin/graphene oxide (MF/GO) composites. Supercapacitors based on Ni(OH)2/Co(OH)2 composites as the positive electrode and NC as the negative electrode were assembled. The electrochemical performances of NC and supercapacitors are studied. Findings - The results show that obtained NC has high nitrogen content. Compared to NC-GO0 without GO, high conductivity and specific capacitance were obtained for NC with GO due to the introduction of layered GO. The presence of pseudocapacitive interactions between potassium cations and the nitrogen atoms of NC was also proposed. When the weight ratio of GO to MF is 0.013:1, the obtained NC-GO3 has the highest specific capacitance of 154.07 F/g due to GO and its highest content of N-6. When the P of the asymmetric supercapacitor with NC-GO3 as the negative electrode is 1,326.70 W/kg, its Cps and Ep are still 23.84 F/g and 8.48 Wh/Kg, respectively. There is only 4.4 per cent decay in Cps of the supercapacitor over 1,000 cycles. Research limitations/implications - NC is a suitable electrode material for supercapacitors. The supercapacitors can be used in the field of automobiles and can solve the problems of energy shortage and environmental pollutions. Originality/value - NC based on MF/GO composites with high nitrogen content and conductivity was novel and its electrochemical properties were excellent. © Emerald Group Publishing Limited 2015.


Li Q.,Heilongjiang University | Du J.,Heilongjiang University | Zhang X.,Heilongjiang Institute of Petrochemistry | Qin C.,Heilongjiang University | And 2 more authors.
Pigment and Resin Technology | Year: 2015

Purpose The purpose of this paper is to develop porous nitrogen-enriched carbon (NC-U) with high nitrogen concentration and high specific capacitance (Cpe) as the electrode material for supercapacitors. Design/methodology/approach NC-U was obtained by carbonization of polyvinylpyrrolidone/melamine formaldehyde resin (PVP/MF) with different contents of urea. In comparison, NC-K was also prepared by the KOH activation method. A series of asymmetric supercapacitors with NC as a negative electrode was assembled. The composition, microstructure and electrochemical properties of NC and their supercapacitors were studied. Findings The results show that NC-U shows irregular particles with a porous honeycomb structure. High Cpe was obtained for urea-treated NC-U because of the improvement of nitrogen, conductivity and specific surface area (SBET). NC-U50 with 13.15 per cent at nitrogen has the highest Cpe of 148.53 F/g because of the highest concentration of N-6 and N-5. NC-K with higher SBET has lower Cpe than NC-U50 because of its lower nitrogen concentration. When the specific power of the supercapacitor with NC-U50 as a negative electrode is 1,565.56 W/kg, its specific energy is still 4.35 Wh/kg. There is only 5.9 per cent decay in Cpe over 1,000 cycles. Research limitations/implications NC-U is a suitable electrode material for supercapacitors, which can be used in the field of electric vehicles to solve the problems of energy shortage and environmental pollutions. Originality/value Porous NC-U based on PVP/MF/urea composites with high nitrogen concentration and Cpe is novel, and it owns good electrochemical properties. © Emerald Group Publishing Limited.


Qiu S.,Heilongjiang University | Qiu S.,HIGH-TECH | Zhang X.,Heilongjiang Institute of Petrochemistry | Li Y.,Heilongjiang University | And 7 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

In order to obtain LiFePO4 (LFP) with the fine particle size and high electronic conductivity, the secondary carbon-coated LFP-C composite was synthesized by a facile two-step method with polyethylene glycol (PEG) as a grain growth inhibitor and sucrose as a main carbon source. For comparison, commercial LFP and LFP prepared without PEG and sucrose were also studied. Li-ion capacitors (LICs) using environmentally friendly, safe and low-cost LiNO3 aqueous electrolyte were assembled with LFP samples as the positive electrode. Results show that the secondary carbon-coated LiFePO4-C composite with nanometer-sized particles was synthesized at 550 °C successfully and the carbon content was about 23.4 wt%. The lamellar carbon coating, with much graphitic nature, wraps and connects LFP particles, ensuring the good electronic connection between LFP particles. The results of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance show that the electrochemical performances of secondary carbon-coated LFP dramatically increase due to the decrease of particle size through adding PEG and the increased electronic conductivity by the introduction of carbon coating. It exhibits the Cpe of 845.2 F g−1 at the scanning rate of 5 mV s−1. The LIC delivers a Cps of 59.3 F g−1 and Ep of 8.2 Wh kg−1 at the current density of 2 mA cm−2. The LIC exhibits an excellent cycling performance and it maintains 98 % of its initial Cps after 500 cycles. The secondary carbon-coated LiFePO4-C composite is the suitable positive electrode material for LICs with neutral aqueous electrolytes. © 2016 Springer Science+Business Media New York


Li Y.,HIGH-TECH | Li Y.,Heilongjiang University | Fu D.,HIGH-TECH | Fu D.,Heilongjiang University | And 5 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

LiFePO4/expanded graphite (LFP/EG) composites were prepared by in situ sol–gel synthesis method. Li-ion capacitors (LICs) using LiNO3 aqueous electrolyte were assembled with LFP/EG composites as the positive electrode and active carbon as the negative electrode in order to study the possibility of LFP/EG composites as the positive electrode material for LIC application in aqueous neutral electrolyte. The results show quasi spherical LFP particles were homogeneously wrapped by EG film and embedded into EG sheets, which can form an effective 3D conductive network to improve conductivity and electrochemical performances of LFP/EG composites. Compared with LFP (93.41 F g−1), the optimized LFP/EG composite exhibits Cpe of 326.23 F g−1 at the scanning rate of 5 mV s−1. The optimized LIC exhibits the highest Cps of 53.31 F g−1 at the current density of 200 mA g−1. The LFP/EG composite and Li-ion capacitor maintains 84.8 % and 84.6 % of the initial specific capacitance after 100 cycles, respectively. © 2016 Springer Science+Business Media New York


Yao Z.,Harbin Institute of Technology | Jia F.,Harbin Institute of Technology | Tian S.,Harbin Institute of Technology | Li C.,Harbin Institute of Technology | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2010

Ni-doped TiO2 film catalysts were prepared by a plasma electrolytic oxidation (PEO) method and were mainly characterized by means of SEM, EDS, XRD, XPS, and DRS, respectively. The effects of Ni doping on the structure, composition and optical absorption property of the film catalysts were investigated along with their inherent relationships. The results show that the film catalyst is composed of anatase and rutile TiO2 with microporous structure. Doping Ni changes the phase composition and the lattice parameters (interplanar crystal spacing and cell volume) of the films. The optical absorption range of TiO2 film gradually expands and shifts to the red with increasing dosages. Both direct and indirect transition band gaps of the TiO2 films are deduced consequently. Moreover, the photocatalytic activity of the film catalysts for splitting Na 2S+Na2SO3 solution into H2 is enhanced by doping with an appropriate amount of Ni. The as-prepared TiO 2 film catalyst doping with 10 g/L of Ni(Ac)2 presents the highest photocatalytic reducing activity. © 2010 American Chemical Society.


Yao Z.,Harbin Institute of Technology | Jia F.,Harbin Institute of Technology | Jiang Y.,Harbin Institute of Technology | Jiang Y.,Harbin College | And 3 more authors.
Applied Surface Science | Year: 2010

The aim of this work was to investigate the photocatalytic (PC) reduction of potassium chromate by Zn-doped TiO2/Ti film catalysts. The film catalyst was prepared by plasma electrolytic oxidation method in H2SO4 solution with different dosages of ZnSO4. The composition and structure of the film catalysts was studied by XRD, SEM and EPMA. The removal rate of potassium chromate was investigated under the conditions of the different dosages of ZnSO4 and the initial concentration of chromate potassium, and the reductive product during the PC reduction process was analyzed. The results showed that the film catalyst was composed of anatase TiO2 and rutile TiO2 with the porous structure. When the dosage of ZnSO4 was 0.2 g/L, the film catalyst presented the highest catalytic activity, which related to the amount and the crystal grain size of anatase TiO2 in the film. The PC reduction of potassium chromate by the film catalyst obeyed the pseudo-first-order kinetic equation. The UV-vis spectrum and XPS analyses proved that chromate Cr(VI) was reduced to Cr(III), which existed in the form of insoluble Cr(OH)3. © 2009 Elsevier B.V. All rights reserved.


Sun M.,Harbin Engineering University | Sun M.,Heilongjiang Institute of Petrochemistry | Zhang B.,Harbin Engineering University | Zhang B.,Heilongjiang Institute of Petrochemistry | And 4 more authors.
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2011

Six sorts of novel condensation type linear polyimides based on 3, 3′, 4, 4′-oxydiphthalic anhydride (OPDA) and different diamines were synthesized in N, N-dimethyl acetamide via transition polymerization. Effects of structure of diamines on heat resistance and adhesion properties were investigated. Their chemical structures were characterized by IR. DSC curves indicated that PI had high glass transition temperature which decreased along with the increasing of flexibility of chain structures. High thermal resistant property was analyzed by TG which shows the decomposed temperature is exceeded 450°C and 1, 4-benzenediamine (PPD)/OPDA-PI has the highest 5% and 10% mass loss temperature decreased as n increased. Adhesion properties of the PI were investigated too. It is found that 4, 4′-diaminodiphenyl ether (4, 4′-ODA)/OPDA-PI has good shear strength, and can be used as high heat resistant adhesive.


Zhang X.,Harbin Engineering University | Zhang X.,Heilongjiang Institute of Petrochemistry | Zhang B.,Harbin Engineering University | Zhang B.,Heilongjiang Institute of Petrochemistry | And 5 more authors.
Applied Mechanics and Materials | Year: 2012

The epoxy resins were toughened with reactive core-shell nanoparticles(CSNPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA) copolymerizing with glycidyl methacrylate (GMA) as the shell. The chemical structure of the CSNPs was characterized by FT-IR. The morphology of toughened epoxy networks were analyzed by SEM and TEM, and their adhesion properties were also detected. The results show that mixing methods and CSNP concentration have great influence on the morphology and adhesion properties of the toughened epoxy networks. CSNPs are uniformly dispersed in the epoxy resins by the grinding method. The modified epoxy networks obtained from the modified epoxy networks prepared by the grinding method(MEPN2) with 10 wt% CSNPs show the best adhesion properties, and the increase in maximum peel strength, 25oC sheer strength and 150oC sheer strength of the modified epoxy networks is 401.3%, 46.9% and 27.6% respectively over the unmodified epoxy networks due to the small-scale coagulations of CSNPs. © (2012) Trans Tech Publications, Switzerland.


Zhang X.,Harbin Engineering University | Zhang X.,Heilongjiang Institute of Petrochemistry | Zhang B.,Harbin Engineering University | Zhang B.,Heilongjiang Institute of Petrochemistry | And 4 more authors.
Pigment and Resin Technology | Year: 2012

Purpose - The purpose of this paper is to obtain liquid acrylate oligomers containing carboxyl groups as excellent toughening agents for epoxy resins. Design/methodology/approach - Liquid acrylate oligomers containing carboxyl groups were synthesised by the solution polymerisation of butyl acrylate (BA), acrylic acid (AA) and acrylonitrile (AN) as monomers. The liquid acrylate oligomers were used as the toughening agents for epoxy resins. The chemical structure of the oligomers was characterised by 13C nuclear magnetic resonance (NMR) spectroscope. The morphology of modified epoxy networks was analysed by scanning electron microscope (SEM). The mechanical and thermodynamic properties were measured by universal testing machine and dynamic mechanical analyser (DMA). Findings - The results show that AA and oligomer concentrations have great influence on the morphology, mechanical and thermodynamic properties of the modified epoxy networks. When the 10?wt percent oligomer containing BA and AN and AA in the ratio of 75/20/5 is used to modify the epoxy resin, the increase in impact strength of the modified epoxy network is 291.5 percent over the unmodified epoxy network due to addition of the oligomers without a sacrifice in heat-resistance properties. Fracture surface analysis by SEM indicates the presence of a two-phase microstructure. Practical implications - The modified epoxy networks can be used as high performance materials such as adhesives, sealants and matrices of composites. Originality/value - The liquid acrylate oligomers containing carboxyl and nitrile groups which were synthesised with BA, AA and AN as monomers by the solution polymerisation are novel and can greatly increase the toughness of epoxy resins without loss of thermal resistance. © 2012 Emerald Group Publishing Limited. All rights reserved.

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