scholarly journals Thermomechanical study of polyethylene porous membrane by coating silicon dioxide nanoparticles

2017 ◽  
Vol 24 (5) ◽  
pp. 661-667
Author(s):  
Xueliang Xiao ◽  
Hao Chen ◽  
Kun Qian
Keyword(s):  
Silicon Dioxide ◽  
Composite Membranes ◽  
Maximum Load ◽  
Porous Membrane ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Thermal Shrinkage ◽  
High Porosity ◽  
Silicon Dioxide Nanoparticles ◽  
X Ray

AbstractPolyethylene (PE) membrane has been extensively used in microtransport areas due to its high porosity, chemical stability, and easy processability. However, pure PE membrane shows poor thermomechanical properties. In this paper, silicon dioxide (SiO2) was used to composite PE membrane in nanogel format. The morphology of the combination and surface layer was demonstrated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SiO2 gel on membrane was analyzed by Fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The effect of the SiO2 gel on the thermomechanical properties of PE membrane was investigated in terms of thermal shrinkage, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The results showed that the SiO2 gel effectively reduced the thermal shrinkage of PE membrane by 47.25% without increased crystallinity, and the coating layer slowed down the decomposed speed of PE membrane at melting point. Comparison tests showed that SiO2 gel enlarged the storage modulus and Young’s modulus of PE membrane. Tensile test revealed that the maximum load on pure PE and PE composite membranes at the yield point were both decreased with the increased temperature.

Surface modification of melt electrospun polypropylene fibrous film by silicon dioxide gel for high thermomechanical properties

2021 ◽  
pp. 004051752110106
Author(s):  
Jumei Zhao ◽  
Hongtao Zhou ◽  
Huizhen Ke ◽  
Xueliang Xiao ◽  
Qingqing Wang ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Thermomechanical Properties ◽  
Thermal Shrinkage ◽  
Gravimetric Analysis ◽  
Measured Temperature ◽  
Heating Chamber ◽  
Force Microscopy ◽  
Gel Network

In this work, a polypropylene (PP) porous film was made-up by melt electrospinning. The fibrous film was coated by a superthin layer of silicon dioxide (SiO2) gel. The surface morphology of the SiO2 gel was decoded by scanning electron microscopy and atomic force microscopy. The SiO2 gel interface with film, as well as its crystallinity, were characterized by Fourier transform infrared spectroscopy, energy dispersive spectroscopy, and X-ray diffraction. The PP composite film's thermomechanical properties were studied through thermal shrinkage, thermal gravimetric analysis, dynamic mechanical analysis, and an Instron tensile machine with a heating chamber. The results showed that the coated SiO2 gel network could effectively reduce the PP film's thermal shrinkage by 48.5% without change of crystallinity. The coated SiO2 gel is capable of enlarging the decomposition temperature range and the storage modulus of the PP film. Meanwhile, it was discovered that, along with the increase of measured temperature, the loads on both pure PP film and PP/SiO2 gel film decreased under a constant strain, or the tensile strain of both of them was enhanced under the same load. The solid gel network endows the PP electrospun film with relatively higher thermal safety.

scholarly journals Enhanced X-ray Attenuating Efficiency of Silicon Dioxide Nanoparticles with Cesium Lead Bromide and 2,5-Diphenyloxazole Co-Embedded Therein

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1531
Author(s):  
Geunpyo Choe ◽  
Hyemin Kwon ◽  
Ilhwan Ryu ◽  
Sanggyu Yim
Keyword(s):  
Silicon Dioxide ◽  
Early Stage ◽  
Imaging Techniques ◽  
Fluorescence Emission ◽  
Hounsfield Unit ◽  
Sio2 Nanoparticles ◽  
Silicon Dioxide Nanoparticles ◽  
X Ray ◽  
Lead Bromide

An X-ray-attenuation-based in vivo imaging can be a promising candidate for real-time detection of cancer in an early stage due to its significantly longer penetration depth compared to currently investigated fluorescence-emission-based imaging techniques. It has recently been demonstrated that this novel concept of imaging is feasible using cesium lead bromide (CPB) quantum dots (QDs) stably embedded in silicon dioxide (SiO2) nanoparticles (NPs). However, further improvements are necessary to realize its practical use, especially in terms of X-ray attenuation efficiency. In this study, we have found that the X-ray attenuation capability of CPB/SiO2 NPs was significantly enhanced by embedding an organic X-ray scintillator, 2,5-diphenyloxazole (PPO), together with CPB QDs in the NPs. The embedment not only solved the water dispersibility and stability problem of PPO, but also significantly increased the Hounsfield unit of the NPs, which was proportional to the degree of X-ray attenuation, by 2.7 times.

scholarly journals Polysulfone Membranes Embedded with Halloysites Nanotubes: Preparation and Properties

Membranes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Nagla Kamal ◽  
Viktor Kochkodan ◽  
Atef Zekri ◽  
Said Ahzi
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Water Flux ◽  
Total Porosity ◽  
Composite Membranes ◽  
Mechanical Analysis ◽  
Inversion Method ◽  
Water Contact ◽  
X Ray ◽  
Phase Inversion Method

In the present study, nanocomposite ultrafiltration membranes were prepared by incorporating nanotubes clay halloysite (HNTs) into polysulfone (PSF) and PSF/polyvinylpyrrolidone (PVP) dope solutions followed by membrane casting using phase inversion method. Characterization of HNTs were conducted using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and thermogravimetric (TGA) analysis. The pore structure, morphology, hydrophilicity and mechanical properties of the composite membranes were characterized by using SEM, water contact angle (WCA) measurements, and dynamic mechanical analysis. It was shown that the incorporation of HNTs enhanced hydrophilicity and mechanical properties of the prepared PSF membranes. Compared to the pristine PSF membrane, results show that the total porosity and pore size of PSF/HNTs composite membranes increased when HNTs loadings were more than 0.5 wt % and 1.0 wt %, respectively. These findings correlate well with changes in water flux of the prepared membranes. It was observed that HNTs were homogenously dispersed within the PSF membrane matrix at HNTs content of 0.1 to 0.5 wt % and the PSF/HNTs membranes prepared by incorporating 0.2 wt % HNTs loading possess the optimal mechanical properties in terms of elastic modulus and yield stress. In the case of the PSF/PVP matrix, the optimal mechanical properties were obtained with 0.3 wt % of HNTs because PVP enhances the HNTs distribution. Results of bovine serum albumin (BSA) filtration tests indicated that PSF/0.2 wt % HNTs membrane exhibited high BSA rejection and notable anti-fouling properties.

Influence of filler hybridization on thermomechanical properties of hemp/silver epoxy composite

2020 ◽  
pp. 096739112097811
Author(s):  
Munjula Siva Kumar ◽  
Santosh Kumar ◽  
Krushna Gouda ◽  
Sumit Bhowmik
Keyword(s):  
Thermal Conductivity ◽  
Silver Nanoparticles ◽  
Epoxy Polymer ◽  
Hybrid Composites ◽  
Conductive Filler ◽  
Weight Fraction ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Material Behavior ◽  
Good Crystallinity

The polymer composite material’s thermomechanical properties with fiber as reinforcement material have been widely studied in the last few decades. However, these fiber-based polymer composites exhibit problems such as fiber orientation, delamination, fiber defect along the length and bonding are the matter of serious concern in order to improve the thermomechanical properties and obtain isotropic material behavior. In the present investigation filler-based composite material is developed using natural hemp and high thermal conductive silver nanoparticles (SNP) and combination of dual fillers in neat epoxy polymer to investigate the synergetic influence. Among various organic natural fillers hemp filler depicts good crystallinity characteristics, so selected as a biocompatible filler along with SNP conductive filler. For enhancing their thermal conductivity and mechanical properties, hybridization of hemp filler along with silver nanoparticles are conducted. The composites samples are prepared with three different combinations such as sole SNP, sole hemp and hybrid (SNP and hemp) are prepared to understand their solo and hybrid combination. From results it is examined that, chemical treated hemp filler has to maximized its relative properties and showed, 40% weight % of silver nanoparticles composites have highest thermal conductivity 1.00 W/mK followed with hemp filler 0.55 W/mK and hybrid 0.76 W/mK composites at 7.5% of weight fraction and 47.5% of weight fraction respectively. The highest tensile strength is obtained for SNP composite 32.03 MPa and highest young’s modulus is obtained for hybrid composites. Dynamic mechanical analysis is conducted to find their respective storage modulus and glass transition temperature and that, the recorded maximum for SNP composites with 3.23 GPa and 90°C respectively. Scanning electron microscopy examinations clearly illustrated that formation of thermal conductivity chain is significant with nano and micro fillers incorporation.

scholarly journals Silicon dioxide nanoparticles induced neurobehavioral impairments by disrupting microbiota–gut–brain axis

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jun Diao ◽  
Yinyin Xia ◽  
Xuejun Jiang ◽  
Jingfu Qiu ◽  
Shuqun Cheng ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Health Risk ◽  
Silicon Dioxide ◽  
Spatial Learning And Memory ◽  
Rrna Gene ◽  
Silicon Dioxide Nanoparticles ◽  
Potential Health ◽  
Specific Chemical ◽  
Memory Impairments ◽  
Tissue Integrity

Abstract Background Silicon dioxide nanoparticles (SiO2NPs) are widely used as additive in the food industry with controversial health risk. Gut microbiota is a new and hot topic in the field of nanotoxicity. It also contributes a novel and insightful view to understand the potential health risk of food-grade SiO2NPs in children, who are susceptible to the toxic effects of nanoparticles. Methods In current study, the young mice were orally administrated with vehicle or SiO2NPs solution for 28 days. The effects of SiO2NPs on the gut microbiota were detected by 16S ribosomal RNA (rRNA) gene sequencing, and the neurobehavioral functions were evaluated by open field test and Morris water maze. The level of inflammation, tissue integrity of gut and the classical indicators involved in gut–brain, gut–liver and gut–lung axis were all assessed. Results Our results demonstrated that SiO2NPs significantly caused the spatial learning and memory impairments and locomotor inhibition. Although SiO2NPs did not trigger evident intestinal or neuronal inflammation, they remarkably damaged the tissue integrity. The microbial diversity within the gut was unexpectedly enhanced in SiO2NPs-treated mice, mainly manifested by the increased abundances of Firmicutes and Patescibacteria. Intriguingly, we demonstrated for the first time that the neurobehavioral impairments and brain damages induced by SiO2NPs might be distinctively associated with the disruption of gut–brain axis by specific chemical substances originated from gut, such as Vipr1 and Sstr2. Unapparent changes in liver or lung tissues further suggested the absence of gut–liver axis or gut–lung axis regulation upon oral SiO2NPs exposure. Conclusion This study provides a novel idea that the SiO2NPs induced neurotoxic effects may occur through distinctive gut–brain axis, showing no significant impact on either gut–lung axis or gut–liver axis. These findings raise the exciting prospect that maintenance and coordination of gastrointestinal functions may be critical for protection against the neurotoxicity of infant foodborne SiO2NPs.

scholarly journals Electrospun Membranes Based on Polycaprolactone, Nano-Hydroxyapatite and Metronidazole

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 931
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Ondine Lucaciu ◽  
Petru Pascuta ◽  
Mihaela Vlassa ◽  
...  
Keyword(s):  
Fiber Diameter ◽  
Maximum Load ◽  
Guided Bone Regeneration ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Total Reflectance ◽  
X Ray ◽  
Electrospun Membranes

The aim of this research was to develop new electrospun membranes (EMs) based on polycaprolactone (PCL) with or without metronidazole (MET)/nano-hydroxyapatite (nHAP) content. New nHAP with a mean diameter of 34 nm in length was synthesized. X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) were used for structural characterization of precursors and EMs. The highest mechanical properties (the force at maximum load, Young’s modulus and tensile strength) were found for the PCL membranes, and these properties decreased for the other samples in the following order: 95% PCL + 5% nHAP > 80% PCL + 20% MET > 75% PCL + 5% nHAP + 20% MET. The stiffness increased with the addition of 5 wt.% nHAP. The SEM images of EMs showed randomly oriented bead-free fibers that generated a porous structure with interconnected macropores. The fiber diameter showed values between 2 and 16 µm. The fiber diameter increased with the addition of nHAP filler and decreased when MET was added. New EMs with nHAP and MET could be promising materials for guided bone regeneration or tissue engineering.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

scholarly journals Vacuum-Free and Highly Dense Nanoparticle Based Low-Band-Gap CuInSe2 Thin-Films Manufactured by Face-to-Face Annealing with Application of Uniaxial Mechanical Pressure

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 484
Author(s):  
Matthias Schuster ◽  
Dominik Stapf ◽  
Tobias Osterrieder ◽  
Vincent Barthel ◽  
Peter J. Wellmann
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Coarse Grained ◽  
High Porosity ◽  
Low Band Gap ◽  
Seeding Layer ◽  
X Ray ◽  
Face To Face ◽  
Copper Indium ◽  
Vis Spectroscopy

Copper indium gallium sulfo-selenide (CIGS) based solar cells show the highest conversion efficiencies among all thin-film photovoltaic competition. However, the absorber material manufacturing is in most cases dependent on vacuum-technology like sputtering and evaporation, and the use of toxic and environmentally harmful substances like H2Se. In this work, the goal to fabricate dense, coarse grained CuInSe2 (CISe) thin-films with vacuum-free processing based on nanoparticle (NP) precursors was achieved. Bimetallic copper-indium, elemental selenium and binary selenide (Cu2−xSe and In2Se3) NPs were synthesized by wet-chemical methods and dispersed in nontoxic solvents. Layer-stacks from these inks were printed on molybdenum coated float-glass-substrates via doctor-blading. During the temperature treatment, a face-to-face technique and mechanically applied pressure were used to transform the precursor-stacks into dense CuInSe2 films. By combining liquid phase sintering and pressure sintering, and using a seeding layer later on, issues like high porosity, oxidation, or selenium- and indium-depletion were overcome. There was no need for external Se atmosphere or H2Se gas, as all of the Se was directly in the precursor and could not leave the face-to-face sandwich. All thin-films were characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and UV/vis spectroscopy. Dense CISe layers with a thickness of about 2–3 µm and low band gap energies of 0.93–0.97 eV were formed in this work, which show potential to be used as a solar cell absorber.

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