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Javier S. Acevedo Cortez Thelma Serrano Lucy T. González Oxana V. Kharissova 《Journal of Dispersion Science and Technology》2019,40(6):884-891
Natural sorbent materials have practical advantages for the oil spill cleanup, whose advantages are their low-cost, feasibility for real-life applications and environmental adaptability. In this work, absorption capacity was determined for lyophilized aloe, nopal and agar and their composites with silica, Fe3O4/polysterene and multi-wall carbon nanotubes (MWCNTs). Freeze-drying was performed in order to preserve the structure and increase the internal volume of sorbents. The structures of lyophilized sorbents and composites were analyzed by scanning electron microscopy (SEM). SEM images for lyophilized sorbents show a tridimensional arrangement formed by plant-derived materials, which allows the oil absorption. The composites keep their tridimensional structure after freeze-drying and composite formation and exhibit coupling between both materials. Absorption capacity of aloe, nopal and agar are 9?g/g, 3?g/g, and 26?g/g, respectively without any pretreatment. Composites with Fe3O4/polysterene own capacities of 5.8?g/g, 2.8?g/g, and 14?g/g, respectively. Finally, for MWCNT composites, capacities are 7.8?g/g, 2.9?g/g and 23?g/g. A significant difference of adsorption capacity between lyophilized sorbents and composites is attributed to lyophilized materials absorbing oil, water and other compounds. Meanwhile, for composites the absorption is a more selective process, since the hydrophobization does not allow the absorption of water. 相似文献
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To improve the mechanical properties of polyaspartate polyurea (PAEP), functionalized nano-silica reinforced polyurea composites were prepared. The original nano-silica (O-SiO2) was treated with 3-aminopropyltriethoxysilane (APTES), and the amino group at the end of APTES was used as the initiation site to realize the coating modification of poly(γ-benzyl l -glutamate) (PBLG) onto O-SiO2. The dispersion, wettability, and interfacial properties of functionalized nano-silica (PBLG-SiO2) in PAEP were analyzed. The tensile and tear properties of PBLG-SiO2/PAEP composites were tested, and the reinforcement mechanism was revealed. The results showed the dispersibility of PBLG-SiO2 in PAEP had been improved markedly. The contact angle of PBLG-SiO2 with PAEP was 29.31°, which was significantly lower than that of O-SiO2 (76.48°). The adhesion work between PBLG-SiO2 and PAEP was 97.16 mJ/m2, an increase of 51.7% compared with O-SiO2. When the content of PBLG-SiO2 was 2 phr, the tensile strength, Young's modulus, and tear strength of PAEP composites reached the maximum of 17.43 MPa, 157.12 MPa, and 127.38 N/mm, an increase of 33.6%, 77.9%, and 71.3%, respectively, compared with pure PAEP. The analysis of cross-section showed that the strengthening mechanism of PBLG-SiO2 on PAEP was mainly manifested by non-planar cracks, deflection and bifurcation of cracks, and plastic deformation of PAEP matrix caused by peeling of PBLG-SiO2 from matrix. 相似文献
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Daoxing Sun Xinjian Li Yiheng Zhang Yuwen Li 《Journal of Macromolecular Science: Physics》2013,52(9):1810-1821
The performance of styrene butadiene rubber (SBR) composites filled with nano-silica has been improved by surface modification of the nano-silica using silane coupling agents. The dispersion of nano-silica in SBR rubber and the bonding force of nano-silica with SBR were significantly improved, and the physical and mechanical properties of the vulcanized rubber were greatly improved. The results showed Si69 (bis-(γ- triethoxysilylpropyl)-tetrasulfide) was the best modifier among the six silane coupling agents used in the experiments, and its optimum amount was 12% (wt) of nano-silica. 相似文献
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超声辅助沉淀法制备疏水性纳米SiO2 总被引:1,自引:0,他引:1
采用超声沉淀法制备出SiO2纳米粉体,利用硅烷偶联剂γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)对其进行了表面改性,并利用红外光谱(FT-IR)、热重(TG)、接触角、透射电镜(TEM)等方法对SiO2的结构和性能进行了表征,并研究了KH-570用量和改性时间对SiO2活化指数的影响。结果表明:与普通搅拌相比,超声更利于纳米SiO2的制备和改性。超声条件下,KH-570成功接枝到SiO2纳米粒子的表面。且改性后的SiO2疏水性提高,在无水乙醇中的分散状态得到明显改善。当改性剂用量为6 mL,改性时间为1 h时,SiO2纳米粒子的活化指数达到100%。 相似文献
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Poly(lactic acid) (PLA)/PEG/nano-silica composite degradable films have been prepared by solvent casting method. IR measurements showed that vibration of C–O–C group was confined by silica network. SEM results showed that nano-silica particles were dispersed uniformly in the PLA/PEG matrix. TGA results indicated that the thermal decomposition temperature rose with the increase of nano-silica content. The tensile strength of composite film increased by the addition of nano-silica particles into PLA/PEG matrix. The degradation rate of PLA/PEG/nano-silica composites increased with the acidic medium of degradation. On the other hand, the slower degradation was obtained in the neutral buffer solution. PLA/PEG/nano-silica composites were found to exhibit almost similar degradation behavior as that of PLA/PEG films. 相似文献
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The nano-hybrid pour-point depressant (PPD) was prepared with organically modified nano-silica covering in EVA. The effects of modified nano-silica/EVA on the flow behavior and wax crystallization of model oils with different wax contents were evaluated. Compared with pure EVA and nano-silica/EVA, modified nano-silica/EVA exhibited a better effect, when doped with 500?ppm, the pour point of the model oil containing 20?wt% wax was reduced from 33°C to 0°C. However, it is noteworthy that pour point cannot accurately reflect the effect of YSiO2/EVA as cold flow improver for a high wax content. The crystal morphology and crystallization behavior of the model oils at low temperature were also observed using polarizing optical microscopy (POM). The results indicated that modified nano-silica/EVA can reduce the size of the wax crystals and disperse the wax crystals by heterogeneous nucleation. 相似文献
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MORPHOLOGY EVOLUTION OF POLY(St-co-BuA)/SILICA NANOCOMPOSITE PARTICLES SYNTHESIZED BY EMULSION POLYMERIZATION 总被引:1,自引:0,他引:1
Poly(St-co-BuA)/silica nanocomposite latexes were synthesized via conventional emulsion polymerization in the presence of 3-(trimethoxysilyl)propyl methacrylate modified colloidal nano-silica. The effects of surface property, particle size and content of colloidal nano-silica as well as the concentrations of monomer and surfactant on the morphology of nanocomposite latex particles were investigated by transmission electron microscope (TEM) and scanning electron microscope (SEM) in detail. Various interesting morphologies such as grape-like, Chinese gooseberry-like, pomegranate-like and normal core-shell structures were observed. Droplet nucleation mechanism competing with micelle nucleation mechanism was proposed to explain the morphological evolution of the nanocomposite particles. 相似文献