Impact of filler on the soft phase molecular dynamics of PP/EPDM/SiO2 thermoplastic elastomeric nano-composites

We investigated the impact of silica nanoparticles on the complex shear moduli and molecular dynamics of elastomeric nano-composites formed from ethylene propylene diene monomer (EPDM) and polypropylene (PP). The blended system was composed of immiscible amorphous/semi-crystalline polymers. The complex shear moduli of the EPDM/PP/SiO₂ nano-composites and their corresponding neat filler blends were measured at different shear rates in the temperature window ? 95–50 °C. The impacts of filler on the stress–strain and thermal behaviors were also investigated. The nano-composites exhibited higher shear moduli than the corresponding neat polymer blends. This trend was linked to the hindered glass-relaxation dynamics of the EPDM polymer in the nano-composites.     

聚乙烯/蒙脱土纳米复合材料结构与力学性能的研究

制备了MMT/MgCl2/TiCl4插层型催化剂,并进行乙烯聚合。考察了MMT片层间距、复合材料形态及蒙脱土在其中的分布状态。考察了材料的冲击强度、拉伸强度等力学性能及蒙脱土的最佳含量。     

插层法制备聚合物/粘土纳米复合材料的原理

介绍了聚合物／粘土纳米复合材料的插层方法、制备原理和工艺过程,探讨了纳米复合材料微观结构的影响因素,概述了聚合物／粘土纳米复合材料的形成机理。     

Investigation of the magnetic properties of nanometric SrSmCoNi ferrite/PST matrix

Y-type hexa-ferrite Sr_1.8Sm_0.2Co₂Ni_1.50Fe_10.50O₂₂ was synthesized via micro-emulsion route. Ferrite/PST composites were obtained by mixing the different ferrite ratio in the pure PST matrix. The microstructure was examined by scanning electron microscopy (SEM) and exhibited heterogonous distribution of grains. A keen observation of these SEM images revealed that the grain morphology changes noticeably with increasing ferrite filler contents. The electrical modulus, Cole–Cole plots and quality factor of ferrite polymer composites have been investigated in the frequency range (1 MHz to 3 GHz). The field dependent magnetic properties of the prepared samples were investigated at room temperature by using vibrating sample magnetometer (VSM). The shape of hysteresis loops and linearity of M_s, M_r, H_c values vs. ferrite contents unfold that the ferrite nanoparticles are evenly dispersed within the composite. The occurrence of resonance at high frequency suggests that the present investigated composite samples are best candidate for multilayer chip inductors.     

用于基因转运和治疗的多功能纳米复合物的制备及应用

基因治疗是将DNA转染进入目的细胞,修复遗传错误或者产生治疗因子。目前基因治疗研究的热点是利用纳米颗粒作为载体,将特异性基因转染到细胞内,从而达到基因治疗的目的。纳米颗粒作为载体可使基因的转染效率提高、增强其稳定性、靶向型。就纳米复合物的组成及在基因治疗方面的应用、面临的问题与挑战进行了综述。     

Sensing of damage and healing in three-dimensional braided composites with vascular channels

With the rise of composite materials as replacements for traditional monolithic materials comes an increase in demand for multifunctionality. Prior studies have demonstrated the ability of an embedded, electrically percolating carbon nanotube network to respond electrically to the onset and progression of damage in composite structures. We build upon this work by incorporating healing functionality into braided composites through the use of a hollow channel resin delivery system. This study demonstrates the ability of a carbon nanotube network to sense crack filling during resin injection, thus providing the scientific basis required for sensing healing in advanced composites. With practical application in mind, a two-part healant system is employed in this study. Two methods for qualitatively assessing healing are employed and compared; these include elastic modulus/strain energy recovery and FTIR spectroscopy.     

Synthesis and characterization of nanocrystalline NiO-GDC via sodium alginate-mediated ionic sol-gel method

In this study, nanocrystalline nickel oxide gadolinium-doped ceria (NiO-GDC) powder was synthesized in-situ using Na-Alginate as the template via ionic sol-gel technique. The effects of calcination time and temperature on the particle size and the physiochemical properties of nanocrystalline NiO-GDC are presented in this paper. Using this method, gel beads were formed by contacting sodium alginate solution as the gelling template and metal (gadolinium/cerium/Ni) nitrates as the precursor. The obtained nanocrystallites were characterized using Field Emission Scanning Electron Microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, thermo gravimetric analysis, nitrogen adsorption/desorption analysis, and Fourier transform infrared spectroscopy. It was observed that the increasing calcination temperature had affected both the particle size and the surface area of the NiO-GDC, whereas the increasing calcination time had only impacted the size of the particles. The smallest mesoporous nanocrystalline NiO-GDC powder (12.1225 ± 0.005 m²/g surface area), composed of cubic GDC (5.18 nm crystallite size) and cubic NiO (7.99 nm crystallite size) were synthesized at a calcination temperature of 500 °C for 2 h. This study hopes to inspire more researches on the ionic-gelation method for synthesizing other metal nanostructures as well as other reaction parameters.     

New effective process to fabricate fast switching and high contrast electrochromic device based on viologen and Prussian blue/antimony tin oxide nano-composites with dark colored state

We developed a new electrochromic device by using compact Prussian blue (PB)/antimony tin oxide (ATO) nano-composites as anodic electrode and viologen anchoring on titanium dioxide (TiO₂) nano-particles as cathodic electrode. The anodic electrode was based on a transparent nanostructured ATO nano-particle film and was electro-deposited by Prussian blue to form compact Prussian blue/ATO nano-composites by means of galvanostatic electrodeposition process. Nanocrystalline TiO₂ thin films on conducting glass were modified with a mono-layer of viologen with two anchoring groups, which were much strongly adsorbed onto the surface of TiO₂ nano-particles. A polymer gel electrolyte sandwiched between the anodic and cathodic layers is used as the ionic transport layer. The 2.5 cm × 2.5 cm electrochromic device shows high contrast (64.8%, at 600 nm) very low transmittance at colored stage (0.1%, at 600 nm), fast switching time (600 and 720 ms for coloration and bleaching, respectively), high coloration efficiency of 912 cm² C⁻¹ at 600 nm and good stability. The enhanced performance of the electrochromic device can be attributed to the ATO nano-particles as inter-conductive materials.     

热固性塑料/蒙脱土纳米复合材料最新研究进展

概述了用插层法制备热固性塑料与蒙脱土纳米复合材料在国内外研究的一些最新进展,并对其复合过程中的影响因素进行了详细的介绍,对其发展应用前景进行了展望。     

纳米技术增韧改性聚氯乙烯的研究进展

综述了近年来纳米技术在聚氯乙烯增韧改性中的应用研究状况。