Preparation and characterization of poly(hydroxyurethane) /halloysite nanocomposites via in-situ polymerization

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Zhaobin Tang ◽  
Peng Liu ◽  
Jinshan Guo ◽  
Zhixing Su

AbstractNaturally occurring halloysite nanotubes (HNTs) with hollow nanotubular structures were used as a new type filler for polyhydroxyurethane. The polyhydroxyurethane/halloysite nanocomposites (PHU/HNTs) were prepared by the in-situ surface-initiated polymerization of a five-membered cyclic carbonate 2,2- bis[p-(1,3-dioxolan-2-one-4-yl-methoxy) phenyl] propane (B5CC) and hexa methylene diamine, from the surfaces of the aminopropyl halloysite nanotubes (APHNTs) for the first time. The percentage of grafting (PG %) and the grafting efficiency (GE %) of 41% and 23% were calculated from the results of the thermogravimetric analysis (TGA) and from the results of elemental analysis (EA) respectively after the free polyhydroxyurethane was washed off. The chemical grafting of the polymer was also confirmed using FTIR; the morphology of the silica nanotubes in the nanocomposite was examined by transmission electron microscope (TEM).

2006 ◽  
Vol 21 (1) ◽  
pp. 112-118 ◽  
Author(s):  
A. Vadivel Murugan ◽  
Mathieu Quintin ◽  
Marie-Helene Delville ◽  
Guy Campet ◽  
Annamraju Kasi Viswanath ◽  
...  

Here we demonstrate the synthesis of a new type of layered poly(3,4-ethylenedioxy- thiophene) (PEDOT)/MoS2 nanocomposite via flocculation of delaminated MoS2 with subsequent in situ oxidative polymerization of 3,4-ethylenedioxythiophene. The resulting nanocomposite was characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, thermal analysis, transmission electron microscopy, and four-probe electrical conductivity measurements with respect to temperature. X-ray diffraction results indicated that the exfoliated MoS2 and PEDOT are restacked to produce a novel nanoscale composite material containing alternate nanoribbons of PEDOT in between MoS2 with a basal distance of ∼1.38 nm. The nanocomposite, which could be used as a cathode material for small power rechargeable lithium batteries, has also been demonstrated by the electrochemical insertion of lithium into the PEDOT/MoS2 nanocomposite, where a significant enhancement in the discharge capacity is observed, compared to that of respective pristine molybdenum disulfide.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2787
Author(s):  
Cheng-Ho Chen ◽  
Ying-Chen Lin ◽  
Fu-Su Yen

Polyaniline doped with dodecylbenzenesulfonic acid/χ-aluminum oxide (PANDB/χ-Al2O3) conducting core-shell nanocomposites was synthesized via an in situ polymerization method in this study. PANDB was synthesized in the presence of dodecylbenzenesulfonic acid (DBSA), which functioned as a dopant and surfactant. The electrical conductivity of the conducting PANDB/χ-Al2O3 core-shell nanocomposite was approximately 1.7 × 10−1 S/cm when the aniline/χ-Al2O3 (AN/χ-Al2O3) weight ratio was 1.5. The transmission electron microscopy (TEM) results indicated that the χ-Al2O3 nanoflakes were thoroughly coated by PANDB to form the core-shell (χ-Al2O3-PANDB) structure. The TEM and field-emission scanning electron microscopy (FE-SEM) images of the conducting PANDB/χ-Al2O3 core-shell nanocomposites also indicated that the thickness of the PANDB layer (shell) could be increased as the weight ratio of AN/χ-Al2O3 was increased. In this study, the optimum weight ratio of AN/χ-Al2O3 was identified as 1.5. The conducting PANDB/χ-Al2O3 core-shell nanocomposite was then blended with water-based polyurethane (WPU) to form a conducting WPU/PANDB/χ-Al2O3 blend film. The resulting blend film has promising antistatic and electrostatic discharge (ESD) properties.


2008 ◽  
Vol 54 ◽  
pp. 325-330 ◽  
Author(s):  
Ana Claudia V. De Araújo ◽  
S. Alves ◽  
W.M. Azevedo

In this work we report the preparation and characterization of a polyaniline/magnetite (PANI)-Fe3O4 nanocomposite, with average diameter around 50 nm and tubular morphology. The tubular nanocomposite was synthesized by an in situ polymerization of aniline using Fe3O4 nanoparticles as an oxidant agent. The Fe3O4 nanoparticles with narrow size distribution were synthesized by co-precipitation technique and the products were characterized by powder X-ray diffractometry (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).


Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2967
Author(s):  
Ignazio Blanco ◽  
Francesco Agatino Bottino ◽  
Gianluca Cicala ◽  
Giulia Ognibene ◽  
Claudio Tosto

Novel polystyrene (PS)/polyhedral oligomeric silsequioxanes (POSSs) nanocomposites were designed and prepared by in situ polymerization, using, for the first time, three-cage POSS molecules. The synthesized compounds were first characterized by Fourier transform infrared spectroscopy (FTIR) and 1H NMR spectroscopy to verify the obtaining of the designed products before their thermal performance was evaluated and compared with those of pristine PS and the corresponding single-cage POSSs nanocomposites. The thermal behaviour was checked by the means of the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was also used to confirm the hypothesis about the dispersion/aggregation of the POSS molecules into the polymer matrix. The parameters chosen to evaluate the thermal stability of the investigated compounds, namely temperature at 5% of mass loss (T5%) and solid residue at 700 °C, showed a significant increase in the stability of the polymers reinforced with the three-cages POSS, in comparison to both PS and single-cage POSS reinforced PSs, which therefore turn out to be promising molecular fillers for nanocomposite production.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 640
Author(s):  
Natalia R. Moyetta ◽  
Fabián O. Ramos ◽  
Jimena Leyria ◽  
Lilián E. Canavoso ◽  
Leonardo L. Fruttero

Hemocytes, the cells present in the hemolymph of insects and other invertebrates, perform several physiological functions, including innate immunity. The current classification of hemocyte types is based mostly on morphological features; however, divergences have emerged among specialists in triatomines, the insect vectors of Chagas’ disease (Hemiptera: Reduviidae). Here, we have combined technical approaches in order to characterize the hemocytes from fifth instar nymphs of the triatomine Dipetalogaster maxima. Moreover, in this work we describe, for the first time, the ultrastructural features of D. maxima hemocytes. Using phase contrast microscopy of fresh preparations, five hemocyte populations were identified and further characterized by immunofluorescence, flow cytometry and transmission electron microscopy. The plasmatocytes and the granulocytes were the most abundant cell types, although prohemocytes, adipohemocytes and oenocytes were also found. This work sheds light on a controversial aspect of triatomine cell biology and physiology setting the basis for future in-depth studies directed to address hemocyte classification using non-microscopy-based markers.


2019 ◽  
Vol 1 (4) ◽  
pp. 1581-1588 ◽  
Author(s):  
S. I. Sadovnikov ◽  
E. Yu. Gerasimov

For the first time, the α-Ag2S (acanthite)–β-Ag2S (argentite) phase transition in a single silver sulfide nanoparticles has been observed in situ using a high-resolution transmission electron microscopy method in real time.


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