Polymers
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2020
·Vol. 12
·期 1
·107
·
IF 3.426
Qinqin Zhang,Xiaoqi Lin,Weisheng Chen,Heng Zhang,Dezhi Han
Many achievements have been made on the research of composite polyurethane foams to improve their structure and mechanical properties, and the composite foams have been widely utilized in building insulation and furniture. In this work, rigid polyurethane foams (RPUFs) with the addition of different fillers (nano-SiO2, peanut shell, pine bark) were prepared through the one-step method. The effects of inorganic nano-SiO2and organic biomass on foam properties were evaluated by means of physical and chemical characterization. The characterization results indicate that the compressive strength values of prepared foams could fully meet the specification requirement for the building insulation materials. The inorganic and organic fillers have no effect on the hydrogen bonding states in composite RPUFs. Furthermore, compared to the biomass fillers, the addition of nano-SiO2greatly influenced the final residual content of the fabricated foam. All composite foams exhibit closed-cell structure with smaller cell size in comparison with the parent foam. The prepared composite foams have the potential for utilization in building insulation.Keywords:rigid polyurethane foam;peanut shell;pine bark;nano-SiO2;insulation materials
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JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 137
·期 16
·48595
·
IF 2.188
Mengfan Liang,Yu Wang,Shuhong Sun,Wenlong Yang
In this article, the effects of coupling agent, silica particle size, and particle shape on the mechanical properties of polyimide (PI) were studied by molecular dynamics (MD) simulations, and the effect of SiO 2 surface treated with coupling agent on the mechanical properties of PI was investigated by experiment. At the same doping volume fraction (5%), the simulation results show that the surface interaction energy between the matrix and particle gradually increases with the radius of the embedded nanoparticles. Meanwhile, the interface interaction energy and mechanical properties of the sphere-type were significantly higher than the ones of other shaped nanoparticles. Moreover, the simulations were compared with the experimental results; atomic force microscopy and scanning electron microscopy images can verify that after being treated with coupling agent, interface interaction between nanosilica and PI enhances quite a little. The mechanical experimental results show that the tensile strength and elasticity modulus of pure PI, unbonded (UB) PI/SiO 2 , and bonded PI/SiO 2 films are 34.47 and 1.13, 36.46 and 1.32, and 66.20 MPa and 1.72 GPa, respectively. It is indicated that the coupling agent plays a crucial role in nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48595.
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RSC Advances
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2019
·Vol. 9
·期 53
·30790-30796
·
IF 3.049
Haoyang Zou,Lan Wang,Huaizhi Tao,Yi Liu,Meiqi Chang,Shiyu Yao
Recently, polyacrylamide (PAM) has been widely used in polymer flooding technology to enhance oil recovery and oil production. However, the difficulty in removing hydrolysed PAM (HPAM) from wastewater still seriously blocks the further application of polymer flooding in the oilfields. Herein, we demonstrate the preparation of SiO2@TiO2:Eu3+@TiO2 core double-shell microspheres (STT) through a two-step solvothermal and sol–gel coating strategy. The as-prepared STT exhibits an ideal photocatalytic activity for the photodegradation of HPAM. More importantly, by using STT as the model, the correlation between fluorescence intensity and photocatalytic activity of the photocatalysts is investigated. The results suggest their oppositional relationship. Since many kinds of photocatalysts are utilized in the degradation of organic pollutants, it is believed that our work will not only promote the development of photocatalysis in the field of oil extraction, but also offer a convenient method for evaluating the photocatalytic activity of the photocatalysts.
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RSC Advances
·
2019
·Vol. 9
·期 66
·38772-38782
·
IF 3.049
Danya Huang,Ying Zhang,Jingjing Zhang,Hongli Wang,Minggang Wang,Chen Wu,Daowen Cheng,Yue Chi,Zhankui Zhao
The design and synthesis of an efficient adsorbent for antibiotics-based pollutants is challenging due to the unique physicochemical properties of antibiotics. The development of a mesoporous SiO2–ZnO composite is a novel way to achieve excellent adsorption efficiency for doxycycline hydrochloride (DOX) in aqueous solutions due to the engineered highly open mesoporous structure and the ZnO-modified framework. Unlike the traditional method of obtaining mesoporous composites by post-synthesis techniques, the novel one-step method developed in this study is both effective and environment-friendly. The adsorption mechanism based on the novel synergetic effect between SiO2 and ZnO was demonstrated through several experiments. SiO2 led to the creation of a 3D open framework structure that provides sufficient space and rapid transport channels for adsorption, ensuring rapid adsorption kinetics. A higher number of active sites and enhanced affinity of the contaminants are provided by ZnO, ensuring high adsorption capacity. The mesoporous SiO2–ZnO could be easily regenerated without a significant decrease in its adsorption efficiency. These results indicate that the developed strategy afforded a simple approach for synthesizing the novel mesoporous composites, and that mesoporous SiO2–ZnO is a possible alternative adsorbent for the removal of DOX from wastewater.
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CONSTRUCTION AND BUILDING MATERIALS
·
2019
·
IF 4.046
Kai Luo,Jun Li,Qing Han,Zhongyuan Lu,Xin Deng,Li Hou,Yunhui Niu,Jun Jiang,Xiaoying Xu,Pan Cai
As an ideal cementitious material for the maintenance of historic buildings and the replacement of interior decoration mortars, the widespread application of natural hydraulic lime (NHL) is expected to play an important role in CO 2 capture and utilization. Structures and properties of NHL2 mortars with nano-SiO 2 (NS) under carbonation were researched in this paper. NHL mortars could capture CO 2 during hardening process of air-hardening contents, and the captured CO 2 would be fixed in the matrix to form CaCO 3 . Carbonation percentage and extent of NHL2 mortars increased by the addition of NS whatever in atmospheric or accelerated carbonation condition. Much more compacted carbonation surfaces than that of the uncarbonated region for NHL2 mortars with NS was observed. The addition of NS will reduce the porosity and big pores (approximately 1 μm) while increase the mesopores (approximately 50 nm) of the mortars. Carbonation reaction of NHL2 mortars seemed to be improved by the addition of NS, which would be beneficial to the collection, solidification and further utilization of CO 2 .
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2017
·
IF 4.421
Xuqiang Ji,Wenling Zhang,Wenpeng Jia,Xiaoxia Wang,Yu Tian,Li Deng,Jingquan Liu
The cactus-like double-shell structured SiO 2 @TiO 2 microspheres (CDS SiO 2 @TiO 2 microspheres) with high dielectric properties were successfully fabricated and utilized as high-performance electrorheological (ER) fluids and microwave absorbing materials. The SiO 2 nanospheres with average diameters of 190 nm were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS), and used as the core for the first coating layer of TiO 2 achieved by sol-gel method. The final cactus-like TiO 2 layer was prepared via a hydrothermal method. The morphology of the resultant samples was characterized via transmission electron microscopy (TEM), scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). This novel CDS SiO 2 @TiO 2 microspheres based suspension exhibited improved ER properties compared to conventional bare SiO 2 spheres.
研究领域:
材料科学
·
物理学
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MICROCHIMICA ACTA
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2014
·Vol. 182
·期 3
·547-555
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IF 3.719
Liu Jinshui,Liu Guoning,Zang Lingjie,Liu Wenxiu
Calcein was first covalently grafted onto the surface of magnetic silica nanoparticles to obtain a novel fluorescent nanoprobe for sensitive and selective determination of Cu(II) ion. The nanoparticles were synthesized in a two-step reaction under mild conditions and characterized using small-angle X-ray scattering, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The nanoprobe also displays good selectivity over other metal ions and is highly stable under conditions of high ionic strength. The response to Cu(II) ranges from 80 nM to 1.25 μM. The detection limit (LOD) is 43 nM which is lower than previously reported LODs. The probe can be regenerated by adding the complexing agent EDTA and also can be separated from a sample mixture by applying a magnetic field. We conclude that this method represents a new and convenient approach to the development of magnetic and reusable optical probes.
Calcein was first covalently grafted onto the surface of magnetic silica nanoparticles to obtain a novel fluorescent nanoprobe for sensitive and selective determination of Cu(II) ion. The nanoprobe displays good selectivity over other metal ions and is highly stable under conditions of high ionic strength.
研究领域:
分析化学
·
材料科学
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CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Jie Chen,Xiuqing Zhou,Ye Sheng,Xiaoming Xie,Murad M.A. Abualrejal,Meiqi Chang,Zhan Shi,Haifeng Zou
A series of size controllable Tb 3+ and/or Eu 3+ activated nano-sized silica phosphors have been successfully synthesized through a facile sol-gel method. The structure, morphology, compositions, and luminescence properties of as-prepared samples were well investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and photoluminescence spectroscopy (PL). The results showed that all as-prepared samples were spherical nanoparticles but the sizes reduced gradually with the temperature increased from 25 °C to 65 °C, which was contrary to the BET surfaces as well as the luminescence intensity. Under ultraviolet excitation, the SiO 2 :Ln 3+ (Ln=Eu, Tb) spherical nanoparticles showed characteristic red and green emissions corresponding to f-f transition of Eu 3+ and Tb 3+ , respectively. Moreover, the luminescence emissions of samples can be tuned from green to yellow, orange and red by co-doping the Tb 3+ and Eu 3+ ions in different concentration ratio into the SiO 2 host due to the efficient dipole–dipole energy transfer mechanism from Tb 3+ to Eu 3+ under 377 nm excitation. These results show that as-prepared phosphors may find potential applications in color display fields.
研究领域:
材料科学
·
光学
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Journal of Inorganic and Organometallic Polymers and Materials
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2018
·Vol. 28
·期 6
·2701-2713
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IF 1.754
Wu Gang,Guo Shuang,Yin Yue,Sun Gang,Zhong Yongjian,You Bo
This paper presented a facile method to prepare the silica/poly (methyl methacrylate) (SiO 2 /PMMA) nanocomposite hollow microspheres (NHSs) which were firstly applied to fabricate the light diffusion films with high transmittance and high haze simultaneously. The SiO 2 /PMMA NHSs were prepared via in situ diffusion of polymeric core into the voids of inorganic shell under strong electrostatic attraction. The hollow morphologies of the microspheres were studied under the help of transmission electron microscope and scanning electronic microscope. The formation process of these NHSs could be elucidated using a mechanism similar to the Kirkendall effect. These NHSs were firstly used to produce light diffusion films by blending with polyacrylate latex. The new kind of light diffusion films with micro-nano structure were built by casting the SiO 2 /PMMA NHSs/polyacrylate coatings on optical-grade PET films. The transmittance and haze value of the light diffusion films were tested by a haze meter and application on a LED lamp. As a result, the coating films with NHSs had the best light diffusion properties compared to those films with no spheres or nanocomposite solid microspheres, which indicated that the light diffusion films with NHSs were promisingly applied in LED illumination, photoelectric devices and large area LCD.
研究领域:
材料科学
·
光学工程
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Catalysts
·
2015
·Vol. 5
·期 2
·606-633
·
IF 2
Hongmei Qin,Xiaoshuang Qian,Tao Meng,Yi Lin,Zhen Ma
Conventional supported Pt catalysts have often been prepared by loading Pt onto commercial supports, such as SiO2, TiO2, Al2O3, and carbon. These catalysts usually have simple metal-support (i.e., Pt-SiO2) interfaces. To tune the catalytic performance of supported Pt catalysts, it is desirable to modify the metal-support interfaces by incorporating an oxide additive into the catalyst formula. Here we prepared three series of metal oxide-modified Pt catalysts (i.e., Pt/MOx/SiO2, Pt/MOx/TiO2, and Pt/MOx/Al2O3, where M = Al, Fe, Co, Cu, Zn, Ba, La) for CO oxidation. Among them, Pt/CoOx/SiO2, Pt/CoOx/TiO2, and Pt/CoOx/Al2O3showed the highest catalytic activities. Relevant samples were characterized by N2adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), H2temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), CO temperature-programmed desorption (CO-TPD), O2temperature-programmed desorption (O2-TPD), and CO2temperature-programmed desorption (CO2-TPD).Keywords:Pt catalysts;cobalt oxide;CO oxidation
研究领域:
催化化学
·
材料科学
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RSC Advances
·
2015
·Vol. 5
·期 66
·53653-53659
·
IF 3.84
Jing Zhu,Xinzhen Zhao,Chunju He
Hybrid polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes with excellent antifouling properties were prepared by non-solvent-induced phase separation through blending zwitterionic SiO2 nanoparticles. Lysine was used to modify SiO2 nanoparticles to generate a surface zwitterion of the amino acid type. Zwitterionic SiO2 nanoparticles were distributed uniformly in the membrane bulk to avoid massive agglomeration and to significantly improve the hydrophilicity and separation performance of PVDF UF membranes. The amount of BSA adsorbed on a hybrid ZP-5% membrane surface of static fouling test decreased to 10 μg cm−2, and the secondary water flux recovery rate (FRR) increased to more than 95% for the dynamic antifouling test of BSA and HA. The addition of zwitterionic SiO2 nanoparticles enhanced the antifouling ability of the membrane through inhibiting irreversible fouling and prolonging the service life of the PVDF UF membrane.
研究领域:
材料科学
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环境工程
·
膜技术
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JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Benbing Shi,Jie Zhang,Wenjia Wu,Jingtao Wang,Jiajia Huang
Alkaline anion exchange membrane (AAEM) attracts great attention as the key component of the sustainable AAEM fuel cell, while its design and development are still hindered by the structure-conductivity relationship of conducting group. Here three kinds of 200-nm SiO 2 with imidazolium brushes tethered by –NH 2 , –OH, or –CO 2 H are synthesized and incorporated into chitosan matrix to prepare hybrid membranes. The microstructures of the hybrid membrane are investigated in detail. It is found that the hydrophilic brushes help the SiO 2 to achieve uniform dispersion and well compatibility with chitosan matrix, thus resulting in abundant, distinct interfacial transfer pathways within hybrid membrane. Molecular simulation and conductivity measurement jointly reveal the structure-conductivity relationship of conducting group in AAEM: low electrostatic potential of imidazolium or bonding energy favors hydroxide conduction and vice versa. Thus the conduction ability of these three groups follows the order of QVI–NH 2 > QVI–OH > QVI–CO 2 H. The tunable chemical environment, excellent water bonding ability, and continuous transfer sites within these interfacial pathways endows the hybrid membrane with significant hydroxide conductivity enhancement by up to 130%, superior to other inorganic particles. Besides, the hybrid membrane achieves obvious improvement of fuel cell performance relative to chitosan control membrane.
研究领域:
材料科学
·
化学工程
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