Effects of Preparation Parameters on Morphology of Cellulose Nanowhiskers

2014 ◽  
Vol 1044-1045 ◽  
pp. 35-38 ◽  
Author(s):  
P. Phanwiroj ◽  
Supachok Tanpichai ◽  
Pranut Potiyaraj
Keyword(s):  
Smart Materials ◽  
Natural Fiber ◽  
Cellulose Nanowhiskers ◽  
Preparation Conditions ◽  
Cellulose Nanowhisker ◽  
Transmission Electron ◽  
Paper Filter ◽  
Commercial Source ◽  
Source Paper ◽  
Titration Technique

This research will thus try to broaden the properties of bioplastics to be used as smart materials. Cellulose nanowhiskers will be initially prepared from different cellulose source and its morphology will be investigated. Water-activated shape memories nanocomposites will be consequently prepared from the obtained cellulose nanowhiskers and three polymers those are PBS and PBAT. The mechanical, physical and morphological will be investigated. The influences of cellulose nanowhiskers and their morphology on water-activated shape memory behavior will be studied.Recently, natural fiber have extensively used as reinforcement materials in polymeric nanocomposite due to environment concerns. Cellulose nanowhisker (CNWs) have also attracted much attention as environmentally friendly nanofillers for polymer composites. Cellulose nanowhiskers were extracted from commercial source, paper filter and alpha cellulose, using acid hydrolysis by sulfuric acid with various hydrolysis times (20,45,70,95,120 minutes), temperature (35,45,60°C). The hydrolyzed cellulose was neutralized with two different techniques, dialysis and titration. The samples were then sonicated and dried with a freeze dryer. The effects of preparation conditions on the morphological of cellulose nanowhisker were investigated. Cellulose nanowhisker powders were characterized scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results showed that it was possible to obtain ultrathin cellulose nanowhiskers with diameters as low as 9 nm. A possible correlation between preparation conditions and particle size was not observed but titration technique time process was reduced.

scholarly journals Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

2016 ◽  
Vol 7 ◽  
pp. 1492-1500 ◽  
Author(s):  
Ionel Stavarache ◽  
Valentin Adrian Maraloiu ◽  
Petronela Prepelita ◽  
Gheorghe Iordache
Keyword(s):  
Optical Properties ◽  
Response Time ◽  
Spectral Width ◽  
Fast Response ◽  
Superior Performance ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Preparation Conditions ◽  
Photoelectric Properties ◽  
Transmission Electron

Obtaining high-quality materials, based on nanocrystals, at low temperatures is one of the current challenges for opening new paths in improving and developing functional devices in nanoscale electronics and optoelectronics. Here we report a detailed investigation of the optimization of parameters for the in situ synthesis of thin films with high Ge content (50 %) into SiO2. Crystalline Ge nanoparticles were directly formed during co-deposition of SiO2 and Ge on substrates at 300, 400 and 500 °C. Using this approach, effects related to Ge–Ge spacing are emphasized through a significant improvement of the spatial distribution of the Ge nanoparticles and by avoiding multi-step fabrication processes or Ge loss. The influence of the preparation conditions on structural, electrical and optical properties of the fabricated nanostructures was studied by X-ray diffraction, transmission electron microscopy, electrical measurements in dark or under illumination and response time investigations. Finally, we demonstrate the feasibility of the procedure by the means of an Al/n-Si/Ge:SiO2/ITO photodetector test structure. The structures, investigated at room temperature, show superior performance, high photoresponse gain, high responsivity (about 7 AW−1), fast response time (0.5 µs at 4 kHz) and great optoelectronic conversion efficiency of 900% in a wide operation bandwidth, from 450 to 1300 nm. The obtained photoresponse gain and the spectral width are attributed mainly to the high Ge content packed into a SiO2 matrix showing the direct connection between synthesis and optical properties of the tested nanostructures. Our deposition approach put in evidence the great potential of Ge nanoparticles embedded in a SiO2 matrix for hybrid integration, as they may be employed in structures and devices individually or with other materials, hence the possibility of fabricating various heterojunctions on Si, glass or flexible substrates for future development of Si-based integrated optoelectronics.

Evaluation of the Mechanical Properties of Glass/Epoxy Composite by Embedding Shape Memory Alloy and Nanoclay

2021 ◽  
Vol 1019 ◽  
pp. 3-11
Author(s):  
Niranjan Pattar ◽  
S.F. Patil ◽  
Pratik Patil ◽  
Iranna Anikivi ◽  
Shridhar Hiremath
Keyword(s):  
Electron Microscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Smart Materials ◽  
Epoxy Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Clay Concentration ◽  
Impact Characteristics

Embedding smart materials in the composite to enhance mechanical strength have become a research hotspot owing to their unique properties. The present research also focus on novel way to fabricate composite by embedding Shape Memory Alloy (SMA) wire and montmorillonite (MMT) nanoclay by varying clay concentration (0-7 wt.%). The extent of dispersion of nanoclay in epoxy resin was studied using Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD). Fabricated samples were examined for tensile, flexural and impact characteristics. Scanning Electron Microscopy (SEM) was used to study the adhesion, delamination and damage occurred within the composite due to tensile loading. Results shows that the tensile strength, flexural strength and impact energy of SMA/MMT/glass/epoxy composite was improved by 23%, 21% and 57% respectively, when it was compared with composite with glass/epoxy composite.

SYNTHESIS AND OPTICAL PROPERTIES OF WATER SOLUBLE ZnSe NANOCRYSTALS

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3881-3884 ◽  
Author(s):  
N. Murase ◽  
M. Y. Gao ◽  
N. Gaponik ◽  
T. Yazawa ◽  
J. Feldmann
Keyword(s):  
Ph Value ◽  
Water Soluble ◽  
Final Solution ◽  
Blue Fluorescence ◽  
Wet Chemistry ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Mean Size ◽  
Surface Capping ◽  
Znse Nanocrystals

ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under ZV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after ~ 40 hrs. The final mean size of the ZnSe nanocrystals measured by transmission electron microscopy is aboyt 2 nm in diameter. The quantum efficiency of the fluorescence form the final solution is estimated to be ~1%, although the preparation conditions have not yet been completely optimized. These properties are discussed in comparison with those of similarly prepared CdTe and differently prepared ZnSe nanocrystals.

scholarly journals Pt Nanocluster Co-Catalysts for Photocatalytic Water Splitting

2018 ◽  
Vol 4 (4) ◽  
pp. 64 ◽  
Author(s):  
Cameron Shearer ◽  
Jason Alvino ◽  
Munkhbayar Batmunkh ◽  
Gregory Metha
Keyword(s):  
Catalyst Activity ◽  
X Ray Diffraction ◽  
Co Catalyst ◽  
X Ray ◽  
Pt Nanoclusters ◽  
Co Catalysts ◽  
Transmission Electron ◽  
Degussa P25 ◽  
Commercial Source ◽  
Photocatalytic Reactions

Degussa P25 is a benchmark form of TiO2 used worldwide in photocatalysis studies. Currently, no such benchmark exists for co-catalysts, which are essential for many photocatalytic reactions. Here, we present the preparation of Pt nanocluster co-catalysts on TiO2 using an unmodified commercial source and equipment that is commonly available. Transmission electron microscopy reveals that the procedure produces TiO2 decorated with Pt atoms and nanoclusters (1–5 atoms). Optical reflectance and X-ray diffraction measurements show that the procedure does not affect the TiO2 polymorph or ultraviolet-visible (UV-Vis) absorbance. Gas phase photocatalytic splitting of heavy water (D2O) shows that the Pt nanocluster-decorated TiO2 outperforms Pt nanoparticle (produced by photodeposition) decorated TiO2 in D2 production. Pt nanoclusters, produced directly from a commercial source, with high co-catalyst activity, are prime candidates to be used in benchmark photocatalytic reactions.

scholarly journals The nanostructure of barium dititanate prepared by hydrothermal method

2019 ◽  
Vol 09 (02) ◽  
pp. 1950011
Author(s):  
Sarah L. Rasheed ◽  
Emad K. Al-Shakarchi
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Hydrothermal Method ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Dielectric Ceramic ◽  
Lattice Constants ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Lcr Meter

The dielectric ceramic of barium dititanate compound BaTi2O5 had been prepared through the hydrothermal process by applying different parameters, such as pH-value, reaction time, temperature and pressure. The prepared powders were examined by X-ray diffraction (XRD). The predominant phase was a monoclinic phase with lattice constants ([Formula: see text], [Formula: see text], [Formula: see text] Å), ([Formula: see text], [Formula: see text]), and the unit cell volume (527 Å3). The surface morphology was demonstrated by Scanning Electron Microscopy (SEM). It exhibited the grains in spherical and elliptical shapes with high homogeneity. The shapes of nanostructure were analyzed by Transmission Electron Microscopy (TEM). The appearance of nanostructures like the nanoparticles and nano rods were found. The size of nanoparticles was in the range of 9–31[Formula: see text]nm, and size of nanorods was 32–37[Formula: see text]nm. The dielectric measurements were done by using LCR meter at different temperature and frequencies (10, 50 and 100[Formula: see text]kHz). It was clear that the Curie temperature had a high value up to (485∘C). The relative permittivity was partially changed for two prepared samples regarding high pressure and long reaction time, which were the main preparation conditions of hydrothermal method.

scholarly journals Composite Nanogels Based on Zeolite-Poly(ethylene glycol) Diacrylate for Controlled Drug Delivery

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Catalina Paula Spatarelu ◽  
Anita-Laura (Radu) Chiriac ◽  
Bogdan Cursaru ◽  
Tanta-Verona Iordache ◽  
Ana-Mihaela Gavrila ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Ethylene Glycol ◽  
Natural Zeolite ◽  
Drug Loading ◽  
Controlled Drug Delivery ◽  
Poly Ethylene Glycol ◽  
Glycol Diacrylate ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Poly Ethylene

This study presents the design of novel composites nanogels, based on poly(ethylene glycol) diacrylate and natural zeolite particles, that are able to act as materials with controlled drug delivery properties. Natural zeolite–nanogels composite, with varying zeolite contents, were obtained by an inverse mini-emulsion technique and loaded with 5-fluorouracil, a widely used chemotherapeutic drug. Herein, the possibility of adjusting final properties by means of modifying the preparation conditions was investigated. The prepared composite nanogels are characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). In light of this tunable drug-loading capability, swelling behaviour, and cytotoxicity, these composite nanogels could be highly attractive as drug reservoirs.

The Preparation of C60/C70 and the Characterization by Different Techniques

1992 ◽  
Vol 270 ◽  
Author(s):  
P. Häussler ◽  
H. Bestgen ◽  
H.-U. ter Meer
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Single Crystals ◽  
Absorption Spectra ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Method Evidence ◽  
Fcc Structure

ABSTRACTWe report on the preparation of C60/C70 by the arc method. Evidence of monofunctional C60O, and C60-CH2 has been observed by mass spectrometry. Dependent on their preparation conditions, high resolution transmission electron microscopy of crystals consisting of mixtures of C60/C70 show different structure. Needle-like crystals grown from toluene show superlattice formation while single crystals obtained by sublimation have fcc structure. UV-VIS-absorption spectra in toluene are compared to those of films of various thickness and crystallinity.

Effect of Nanostructure CdSe/CdS Dot-in-Rods Coated on Flexible Cellulosic Substrate to Improve Photoluminescence Potential of Conducting Fiber

2020 ◽  
Vol 18 (3) ◽  
pp. 216-221 ◽  
Author(s):  
S. R. Patra ◽  
B. Mallick
Keyword(s):  
Natural Fiber ◽  
Average Diameter ◽  
Processing Technique ◽  
Emission Peak ◽  
Nano Particle ◽  
Mimosa Pudica ◽  
High Temperature Short Time ◽  
Transmission Electron ◽  
Spherical Core ◽  
Short Time

The work presented here, the flash synthesis of high photoluminescence of CdSe/CdS Dot-in-Rods was carried out by "high-temperature short-time" (HTST) processing technique of quantum yield being 77%. Upon characterization by transmission electron microscope (TEM), it is found to be the dimensions of CdSe-CdS QDs to be rods (rod length rod diameter) of 27.8 × 3.4 nm. A layer of high luminescence CdSe/CdS Dot-in-Rods was grown on the surface of the touch sensitive natural Mimosa pudica (MP) natural conducting fiber by chemical dipping method. The composite CdSe/CdS are made up of a CdSe spherical core (Dot) of average diameter about 2.9 nm embedded in a Rod of CdS shell. The well-oriented CdSe/CdS Dot-in-Rods nano-particle was observed to have an emission peak at 545 nm. The works suggest a sensing plate which enhances Photoluminescence potential of conducting natural fiber.

scholarly journals The Preparation of a Highly Stretchable Cellulose Nanowhisker Nanocomposite Hydrogel

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jiufang Duan ◽  
Jianxin Jiang ◽  
Jianzhang Li ◽  
Liujun Liu ◽  
Yiqiang Li ◽  
...  
Keyword(s):  
Room Temperature ◽  
Nanocomposite Hydrogel ◽  
Cellulose Nanowhiskers ◽  
Composite Hydrogels ◽  
Ammonium Peroxydisulfate ◽  
Cellulose Nanowhisker ◽  
Stearyl Methacrylate ◽  
Highly Stretchable ◽  
Cross Links ◽  
Scanning Electron

Molecules that associate to form cross-links by hydrophobic association are designed and synthesised. Hydrogels, based on cellulose nanowhiskers (CNWs), acrylamide (AM), and stearyl methacrylate (C18), were synthesised by micellar copolymerisation, using ammonium peroxydisulfate as an initiator. CNWs composite hydrogels were characterised by Fourier transform infrared spectroscopy (FTIR) and their morphologies were investigated by scanning electron microscope (SEM). The system shows the original extensibility up to about 2500%: the tensile strength and compressive strength have maximum values of 1.338 MPa and 2.835 MPa, respectively. Besides excellent mechanical properties, CNWs composite hydrogels also have the ability to self-heal and remould: this is mainly attributed to the dissociation and reassociation of the associated micelles. In contrast to conventional cellulose hydrogels, these systems, when broken or cut, can be simply repaired by bringing together fractured surfaces to self-heal at room temperature.

Degradation of bromamine acid by nanoscale zero-valent iron (nZVI) supported on sepiolite

2012 ◽  
Vol 66 (12) ◽  
pp. 2539-2545 ◽  
Author(s):  
Xuening Fei ◽  
Lingyun Cao ◽  
Lifeng Zhou ◽  
Yingchun Gu ◽  
Xiaoyang Wang
Keyword(s):  
Ph Value ◽  
Energy Dispersive Spectrometer ◽  
Zero Valent Iron ◽  
Mass Ratio ◽  
Initial Concentration ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph ◽  
Set Up

Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.

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