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Luo J.-Z.,State Key Laboratory of Organic Inorganic Composites | Chu G.-W.,State Key Laboratory of Organic Inorganic Composites | Luo Y.,State Key Laboratory of Organic Inorganic Composites | Arowo M.,State Key Laboratory of Organic Inorganic Composites | And 2 more authors.
AIChE Journal | Year: 2017

In this work, a novel helical tube reactor (HTR) was constructed, including a pre-mixer for adjusting the premixing behavior of reactants and a helical tube as a further mixing unit. The pre-mixer was modified to optimize the premixing behavior by using two methods, named as tangential-feeding and insertion of a helical baffle. The premixing behaviors were investigated via computational fluid dynamics (CFD) simulation. Simulation results indicated that both methods can change the fluid flow, enhance the turbulence kinetic energy, and improve the premixing performance in the pre-mixers. Based on the results of CFD simulation, it could be predicted that the micromixing efficiency of the HTR can be regulated by these methods accordingly. Then the predicated results were confirmed experimentally by a parallel competing reaction. Furthermore, the relationship between the premixing performance increasing and the corresponding micromixing efficiency increasing of the HTR was quantitatively analyzed. © 2017 American Institute of Chemical Engineers.


He X.,Beijing University of Chemical Technology | Wu D.,State Key Laboratory of Organic Inorganic Composites | Zhuang J.,Beijing University of Chemical Technology | Zheng X.,Beijing University of Chemical Technology | Zhou Y.,Beijing University of Chemical Technology
Key Engineering Materials | Year: 2012

In this paper, the relations between scattering intensity and the radius of scattering particles, the refractive and the wavelength have been studied based on the MATLAB software, and the relations between the concentration of the particles, the radius and the refractive and the optical properties of diffuser have also been simulated by the Light Tools software based on the Monte-Carlo Method. The results show that with the increasing of radius and the wavelength, the distribution of scattering light energy gets concentrated. With the increasing of the particles, the transmittance decreases, and the uniformity increases first and decreases later. With the increasing of radius, the transmittance decreases. With the increasing of the index of refractive, the transmittance increases first and decreases later. © (2012) Trans Tech Publications, Switzerland.


Gao X.,Beijing University of Chemical Technology | Wu D.,State Key Laboratory of Organic Inorganic Composites | Zheng X.,Beijing University of Chemical Technology | Liu Y.,Beijing University of Chemical Technology
Advanced Materials Research | Year: 2013

In this paper, the filling coefficient is defined by the ratio between effective by light area and the total area of the light diffuser when a beam of light strikes it, namely micro lens array structure of configuration density. In order to analyze the relation between the filling coefficient of the microstructure and the optical properties of the diffuser, the filling coefficient is expressed as center-to-center spacing of the microstructure. As the the center-to-center spacing increases, the filling coefficient becomes smaller.and the relation between the filling coefficient of the diffuser microstructure and the optical properties of diffuser have also been simulated by the Light Tools software based on the Monte-Carlo Method. Then the test sample which has the same aspect ratio and filling coefficient with the simulation sample has been obtained by using micro injection casting, Comparing the haze and transmittance of the experimental diffuser with the simulation result, the relation between the filling coefficient of the diffuser microstructure and the optical properties of diffuser have been gotten. © (2013) Trans Tech Publications, Switzerland.


Chen Y.,State Key Laboratory of Chemical Resource Engineering | Liu L.,State Key Laboratory of Chemical Resource Engineering | Liu L.,Key Laboratory of Carbon Fiber and Functional Polymers | Yang Q.,State Key Laboratory of Organic Inorganic Composites | And 5 more authors.
Langmuir | Year: 2013

In this work, nonequilibrium molecular dynamics simulations were performed to investigate the dispersion and spatial distribution of spherical nanoparticles (NPs) in polymer matrix under oscillatory shear flow. We systematically analyzed the influences of four important factors that consist of NP-polymer interfacial strength, volume fraction of NPs, shear conditions, and polymer chain length. The simulation results showed that the oscillatory shear can greatly improve the dispersion of NPs, especially for the polymer nanocomposites (PNCs) with high NP-polymer interfacial strength. Under specific shear conditions, the NPs can exhibit three different spatial distribution states with increasing the NP-polymer interfacial strength. Interestingly, at high interfacial strength, we observed that the NPs can be distributed on several layers in the polymer matrix, forming the PNCs with sandwich-like structures. Such well-ordered nanocomposites can exhibit a higher tensile strength than those with the NPs dispersed randomly. It may be expected that the information derived in present study provides a useful foundation for guiding the design and preparation of high-performance PNCs. © 2013 American Chemical Society.


Feng Y.,State Key Laboratory of Organic Inorganic Composites | Feng Y.,Beijing University of Chemical Technology | Zou H.,State Key Laboratory of Organic Inorganic Composites | Zou H.,Beijing University of Chemical Technology | And 6 more authors.
Journal of Physical Chemistry B | Year: 2012

The dispersive and conductive properties of polymer nanocomposites are investigated simultaneously using the molecular dynamics simulation method. Four factors influencing the dispersion and conductivity are concerned, including polymer-nanoparticle interaction, nanoparticles with grafted chains, cross-linking of polymer chains, and blending of polymer. It is shown that the variation of the conductive probability is not linearly related to the corresponding dispersion for all the four concerned cases. As the interaction strength increases, the dispersion of the nanoparticles appears to first increase and then drop, while the conductive probability increases monotonously. Increase of the grafting density on nanoparticles can bring about the modification of the dispersion, whereas the variation of the conductive probability is M-type. The dispersion effect increases monotonously with the increasing cross-linking density, but the corresponding conductive probability appears to first increase and then drop. The dispersive effect of nanoparticles monotonously decreases as the ratio of added incompatible polymer increases; however, the corresponding conductive probability has the maximum value. © 2012 American Chemical Society.


Xiang Z.,State Key Laboratory of Organic Inorganic Composites | Peng X.,Beijing University of Chemical Technology | Cheng X.,State Key Laboratory of Organic Inorganic Composites | Li X.,Beijing University of Chemical Technology | Cao D.,State Key Laboratory of Organic Inorganic Composites
Journal of Physical Chemistry C | Year: 2011

Effectively separating CO 2 from the natural gas, which is one of alternative "friendly" fuels, is a very important issue. A hybrid material CNT@Cu 3(BTC) 2 has been prepared to separate CO 2 from the CO 2/CH 4 mixture. For comparison of separation efficiency, a series of representative metal-organic frameworks (MOF-177, UMCM-1, ZIF-8, MIL-53 (Al), and Cu 3(BTC) 2) have also been synthesized by the solvothermal method. Adsorption isotherms of CO 2 and CH 4 pure gases are measured by Hiden Isochema Intelligent Gravimetric Analyzer (IGA-003). The dual-site Langmuir-Freundlich (DSLF)-based ideal adsorption solution theory (IAST) is used to predict adsorption of each component in the CO 2/CH 4 mixture. The IAST-predicted results show that the hybrid material CNT@Cu 3(BTC) 2 exhibits the greatest selectivity among the six materials, and its selectivity keeps in the range of 5.5 to 7.0 for equimolar CO 2/CH 4 mixture at 1 < p < 20 bar, which is higher than activated carbons. Moreover, the selectivity of CNT@Cu 3(BTC) 2 for the CO 2/CH 4 mixture keeps almost no change with the composition of CH 4, which is one of the excellent properties as a promising separation material. In short, this hybrid material CNT@Cu 3(BTC) 2 shows great potential in separation and purification of CO 2 from various CO 2/CH 4 mixtures by adsorptive processes in important industrial systems. © 2011 American Chemical Society.


Liu H.,Beijing University of Chemical Technology | Zhang L.,Beijing University of Chemical Technology | Zhang L.,State Key Laboratory of Organic Inorganic Composites | Yang D.,Beijing University of Chemical Technology | And 6 more authors.
Journal of Physics D: Applied Physics | Year: 2012

In this work, a new kind of electro-active polymer composite composed of silicone and polyethylene glycol (PEG) was prepared by solution blending. Two types of PEG with average molecular weights of 600(PEG600) and 1500(PEG1500) were first blended with liquid silicone (DC3481) separately. Then, the dielectric, electrical, mechanical and electromechanical properties of pure silicone and the silicone/PEG composites were investigated. The silicone/PEG600 composite shows an increased dielectric constant and a decreased Young's modulus, resulting in an improved figure of merit (FOM) and an actuation strain of 11.5% at 40Vm 1, which is 64% higher than pure silicone. This indicates that the actuation properties of silicone are largely improved by the addition of PEG600. However, for the silicone/PEG1500 composite, a much higher dielectric constant and an increased modulus due to its semi-crystalline structure are obtained, which lead to a decreased FOM and a smaller actuation strain than that of pure silicone. In addition, a comparison between theoretical strain and the corresponding experiment value was made. And the results indicate that not only the FOM, but the dielectric loss and mechanical loss play an important role in the actuation properties. © 2012 IOP Publishing Ltd.


Fu Y.,State Key Laboratory of Organic Inorganic Composites | Fu Y.,Beijing University of Chemical Technology | Liu L.,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials | Liu L.,Beijing University of Chemical Technology | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Using tetraethyl orthosilicate as a main raw material, silica nanofibers (SiNFs) were prepared through the combination of a sol-gel process and an electrospinning technique followed by pyrolysis. Surface modified electrospun SiNFs developed by self-polymerization of polydopamine on the surface (SiNFs-PDA) served as templates for the electroless plating of silver nanoparticles (Ag NPs), using glucose as a reducing agent. The electrical resistivity of silver coated SiNPs-PDA (SiNFs-PDA/Ag) was measured by the four-point probe method and was found to be as low as 0.02 mΩ·cm at room temperature. The morphology of SiNFs-PDA/Ag before and after the blending with silicon rubber indicated a strong interaction between the silver layer and the SiNFs-PDA. The electrical and mechanical properties of the silicon rubber filled with SiNFs-PDA/Ag were studied to demonstrate the conductive performance application of SiNFs-PDA/Ag. © 2014 American Chemical Society.


Liu Y.,Key Laboratory of Preparation and Processing of Novel Polymer Materials | Zhang L.-Q.,Key Laboratory of Preparation and Processing of Novel Polymer Materials | Zhang L.-Q.,Beijing University of Chemical Technology | Wang W.-C.,Beijing University of Chemical Technology | And 5 more authors.
Journal of Applied Polymer Science | Year: 2012

A novel method for the organic modification of a ceramic thermal conductive filler (α-alumina) with cold plasma was developed for the preparation of elastomer thermal interface materials with high thermal conductivities and low moduli. The α-alumina fillers were first coated with low-molecular-weight polydimethylsiloxane (PDMS) by solution dispersion and then treated in argon plasma for different time. The modified α-alumina fillers were characterized with high-resolution transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results revealed that a thin PDMS film with several nanometers thick was tightly coated on the surface of the alumina filler after plasma treatment, and this thin film could not be removed by 48 h of Soxhlet extraction with n-hexane at 120°C. Plasma modification of the alumina could dramatically weaken the strength of the filler-filler networks and, thus, remarkably reduce the modulus of the alumina-filled silicone rubber composites but did not affect the thermal conductivity of the composites. © 2011 Wiley Periodicals, Inc.


Wang W.,State Key Laboratory of Organic Inorganic Composites | Wang W.,Beijing University of Chemical Technology | Cheng W.,State Key Laboratory of Organic Inorganic Composites | Cheng W.,Beijing University of Chemical Technology | And 8 more authors.
Electrochimica Acta | Year: 2012

A biomimetic method for the preparation of highly conductive silver-plated polyethylene terephthalate (PET) fiber was demonstrated. First, the PET fibers were functionalized with a bio-inspired polydopamine (PDA) coating, simply by being dispersed in a dopamine solution under mild stirring at room temperature. Electroless plating of silver was then carried out on the surface of the PET-PDA fiber. An aqueous solution of silver nitrate and glucose was used as silver precursor and reducing reagent, respectively. The overall procedure is fast, simple, efficient, nontoxic, as well as controllable. The PDA layer on the PET surface was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and contact angle measurement. The crystalline structure of the modified PET fiber was studied by X-ray diffraction (XRD). The morphology of the PET-PDA and the PET-Ag fiber was observed by scanning electron microscopy (SEM). SEM results showed that the silver layer coated on PET-PDA was continuous, uniform, and compact. The as-prepared PET-Ag fibers have good electrical conductivity, with surface resistivity as low as 0.4 mΩ cm. The binding force between the silver layer and PET-PDA fiber was strong enough that the silver layer remained compact and continuous after the PET-PDA/Ag fiber was rinsed under ultrasound for 4 h. © 2012 Elsevier Ltd.

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