scholarly journals Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

scholarly journals Incorporation of CdFe2O4SiO2 nanoparticles in SbPO4-ZnO-PbO glasses by melting quenching process

2018 ◽  
Vol 43 (2) ◽  
pp. 32 ◽  
Author(s):  
Juliane Orives ◽  
Wesley R. Viali ◽  
Marina Magnani ◽  
Marcelo Nalin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sio2 Nanoparticles ◽  
Silica Layer ◽  
Scanning Calorimetry ◽  
Optimum Parameters ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Quenching Method ◽  
Average Size

The development of glasses containing nanoparticles dispersed homogeneously with controlled size and optimum parameters for functionality is a challenge. Glasses in the ternary system 60SbPO4-30ZnO-10PbO containing CdFe2O4-SiO2 nanoparticles  were studied. The CdFe2O4 nanoparticles were synthesized by the coprecipitation method and the average size was 3.9 nm and then, they were protected by a silica layer. The nanoparticles were mixed with the glass precursors and transformed into glasses by melt-quenching method. Thermal and structural properties were evaluated by differential scanning calorimetry, Raman spectroscopy, scanning electronic microscopy and transmission electron microscopy. While the optical properties were studied by M-Lines spectroscopy and UV-VIS spectroscopy. The glass samples obtained were completely transparent, with amber color and showed no sign of crystallization according to the techniques used. Scanning and transmission electron microscopy confirm that the methodology used for the incorporation of nanoparticles was efficient. The nanoparticle protection methodology prior to incorporation into glasses may contribute towards the development of glasses containing nanoparticles useful for magneto-optics devices.

Effect of Nanosilicon Dioxide on Structure and Properties of Poly(Vinyl Alcohol)/ Sodium Carboxymethylcellulose Blending Film

2013 ◽  
Vol 779-780 ◽  
pp. 7-11
Author(s):  
Xiao Xue Zhang ◽  
Li Xing Dai
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Structure And Properties ◽  
Sodium Carboxymethylcellulose ◽  
Casting Method ◽  
Transmission Electron ◽  
Solution Casting Method ◽  
Structure Properties

Poly (vinyl alcohol) (PVA)/sodium carboxymethylcellulose (Na-CMC)/nanosilicon dioxide (nanoSiO2) films were prepared by solution casting method. The structure, properties and morphology of the films affected by nanoSiO2 were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical testing. With the increase of nanoSiO2 content from 0 to 2.3 wt%, tensile strength increased from 20.98 to 34.80 MPa, while further increase of nanoSiO2 decreased the tensile strength. FTIR spectroscopy of the films confirmed that Si-O-C bonds and hydrogen bonding were formed among PVA, Na-CMC and nanoSiO2, which was suggested to improve the tensile strength of the films.

Morphology of E-Beam Evaporated Cr Thin Films

1990 ◽  
Vol 187 ◽  
Author(s):  
Y. Cheng ◽  
M. B. Stearns ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Large Angle ◽  
Cross Sectional ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Scattering Spectra ◽  
Average Size

AbstractStudies were made of the structural dependence on the growth rate and substrate temperature of Cr thin films prepared by e-beam evaporation. The d-spacings and the average size of the crystallites were determined from large angle x-ray scattering spectra. Detailed studies of the morphology were made by cross-sectional high resolution transmission electron microscopy.

Study on the modification of hexamethylenediamine-phenol-based polybenzoxazine resins by halloysite nanotubes

2019 ◽  
Vol 31 (9-10) ◽  
pp. 1204-1216 ◽  
Author(s):  
Jing Li ◽  
Zhiqiang Shen ◽  
Li Xu ◽  
Huaijun Song ◽  
Gang Guan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silane Coupling Agent ◽  
Succinic Anhydride ◽  
Halloysite Nanotubes ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Silane Coupling ◽  
Flexural Tests ◽  
Thermal Stability Of

In this study, hexamethylenediamine-phenol-based benzoxazine monomer (Ba-h) was synthesized using 1,6-hexamethylenediamine, phenol, and paraformaldehyde. Halloysite nanotubes (HNTs) were treated with silane coupling agent and succinic anhydride, respectively. Then the pristine and grafted HNTs were used as nano-fillers to modify Ba-h at different mass ratios ranging between 0 and 2.5 wt% via solution processing. Nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared spectroscopy confirmed the molecular structure of the monomer. The curing behaviors of the nanocomposites were examined by differential scanning calorimetry (DSC). The results of DSC, thermogravimetric analysis, and dynamic mechanical analysis displayed the obvious improvement in the thermal stability of the nanocomposites modified by the grafted HNTs. The results of impact and flexural tests revealed the improvement in the mechanical property of the nanocomposites modified by the pristine HNTs. These enhancements are related to the homogeneous dispersion of HNTs based on the scanning electron microscopy and transmission electron microscopy results.

Light-cured dental composites characterization by Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 428-429
Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Service Performance ◽  
Dental Composite ◽  
Dental Composites ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Research Meeting ◽  
Formulation Variables

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.

scholarly journals Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3096-3104
Author(s):  
Valeria Castelletto ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Ian W. Hamley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ph Dependent ◽  
Ray Scattering

A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties.

Preferential dissolution along misoriented boundaries in heterogenite

2000 ◽  
Vol 620 ◽  
Author(s):  
R. Lee Penn ◽  
Alan T. Stone ◽  
David R. Veblen
Keyword(s):  
Electron Microscopy ◽  
Aspect Ratio ◽  
Reductive Dissolution ◽  
Morphology Evolution ◽  
Crystal Chemical ◽  
Transmission Electron ◽  
Micron Size ◽  
Primary Particles ◽  
Size And Morphology ◽  
Preferential Dissolution

ABSTRACTHigh-Resolution Transmission Electron Microscopy (HRTEM) results show a strong crystal-chemical and defect dependence on the mode of dissolution of synthetic heterogenite (CoOOH) particles. As-synthesized heterogenite particles are micron-size plates (aspect ratio ∼ 1/30) constructed of crystallographically oriented ∼ 3-nm primary particles or are single ∼ 21-nm unattached heterogenite platelets (aspect ratio ∼1/7). Reductive dissolution, using hydroquinone, was examined in order to evaluate morphology evolution as a function of reductant concentration. Two end-member modes of dissolution were observed: 1) non-specific dissolution of macroparticles and 2) preferential dissolution along misoriented boundaries. In the case of non-specific dissolution, average macrocrystal size and morphology are not altered as building block crystals are consumed. The result is web-like particles with similar breadth and shape as undissolved particles. Preferential dissolution involves the formation of channels or holes along boundaries of angular misorientation. Such boundaries involve only a few degrees of tilt, but dissolution occurs almost exclusively at such sites. Energy-Filtered TEM thickness maps show that the thickness of surrounding material is not significantly different from that of undissolved particles. Finally, natural heterogenite from Goodsprings, Nevada, shows morphology and microstructure similar to those of this synthetic heterogenite.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

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