scholarly journals Preparation and Characterization of Polyurethane Nanocomposites Using Vietnamese Montmorillonite Modified by Polyol Surfactants

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
C. N. Ha Thuc ◽  
H. T. Cao ◽  
D. M. Nguyen ◽  
M. A. Tran ◽  
Laurent Duclaux ◽  
...  

This study focuses on the preparation of thermoplastic polyurethane (TPU) nanocomposite using Vietnamese montmorillonite (MMT) as the reinforced phase. The MMT was previously modified by intercalating polyethylene oxide (PEO) and polyvinyl alcohol (PVA) molecules between the clay layers. X-ray diffraction (XRD) results of organoclays revealed that galleries of MMT were increased to 18.2 Å and 27 Å after their intercalation with PEO and PVA, respectively. Thermoplastic polyurethane (TPU) nanocomposites composed of 1, 3, 5, and 7%wt organoclays were synthesized. The result of XRD and transmission electron microscopic (TEM) analyses implied that the PEO modified MMT was well dispersed, at 3%wt, in polyurethane matrix. Fourier Transform Infrared Spectroscopic (FTIR) has confirmed this result by showing the hydrogenous interaction between the urethane linkage and OH group on the surface of silicate layer. Thermogravimetric (TG) showed that the organoclay samples also presented improved thermal stabilities. In addition, the effects of the organoclays on mechanical performance and water absorption of the PU nanocomposite were also investigated.

2018 ◽  
Vol 912 ◽  
pp. 269-273
Author(s):  
José Costa de Macêdo Neto ◽  
João Evangelista Neto ◽  
Ricardo Wilson Cruz ◽  
Eduardo Rafael Barreda ◽  
Nayra Reis do Nascimento ◽  
...  

Polymer nanocomposites using natural clays such as nanofiller have mechanical properties, flame-retardant, the gas barrier improvement compared to polymers without nanoclay. The aim of this work is intercalated molecules between the clay layers and characterize it with a view to its use in polymer nanocomposites. The kaolinite neat and modified used was characterized by fourier transform spectroscopy (FTIR), X-ray diffraction (XDR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetry (TGA). The results showed that kaolinite can be used as a nanofiller in polymer nanocomposites.


2013 ◽  
Vol 647 ◽  
pp. 701-704 ◽  
Author(s):  
Rihayat Teuku ◽  
Amroel Suryani

An organically modified clay and a pristine clay were used to prepare biodegradable thermoplastic polyurethane (PU) paint/clay nanocomposites. In this paper, polyurethane paint /clay nanocomposites base on palm oil polyol were prepared by isocyanate, polyol and organoclay (a clay modified with Cetyl trimethyl ammonium Bromide (CTAB) and Octadecylamines (ODA). The morphologies of samples were revealed by transmission electron microscopy (TEM) and Intercalation of PU into clay galleries and crystalline structure of PU were investigated using X-ray diffraction (XRD). The morphology of the resulting composite showed a combination of intercalated and partially exfoliated clay layers with occasional clay aggregates


2016 ◽  
Vol 1133 ◽  
pp. 501-504 ◽  
Author(s):  
Muhammad Zulfiqar ◽  
Abdul Aziz Omar ◽  
Sujan Chowdhury

In this paper, TiO2 nanotubes (TNTs) were synthesized through simple chemical hydrothermal treatment process when anatase TiO2 nanopowder is chemically treated with 10 M NaOH and >99.5% ethanol at 180°C for 24 hr. According to the transmission electron microscopic (TEM) image analysis TNTs tubes were formed in the length sizes from 400 to 700 nm with inner diameter of 5 nm and outer diameter of 8 nm. The morphological and structural properties of synthesized TNTs was characterized by powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), UV–Vis diffuse reflectance spectra (DRS).


2003 ◽  
Vol 76 (2) ◽  
pp. 406-418 ◽  
Author(s):  
Rathanawan Magaraphan ◽  
Woothichai Thaijaroen ◽  
Ratree Lim-ochakun

Abstract Montmorillonite clay was organically modified by primary and quaternary ammonium salts (having C12-C18). The modified clay was added to a solution of natural rubber in toluene at various contents. Characterization of the structure of the nanocomposites was performed by using x-ray diffraction and transmission electron microscope. The results showed that the silicate layers of the clay were expanded so that the exfoliated nanocomposites were obtained at clay content below 10 phr; above that the nanocomposites became partially exfoliated. Moreover, long primary amine showed more improved mechanical properties than the quaternary one (at the same carbon numbers). The longer organic modifying agents resulted in better expansion of silicate layer distance indicating more intercalation of natural rubber molecules in between clay galleries. The curing properties were also improved. It was found that a small loading of 7 phr is enough to bring good mechanical properties in comparison to those of high structure silica filled and carbon black filled natural rubber vulcanizates.


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.


Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2139
Author(s):  
Wei Shian Tey ◽  
Chao Cai ◽  
Kun Zhou

Multi Jet Fusion (MJF) is a recently developed polymeric powder bed fusion (PBF) additive manufacturing technique that has received considerable attention in the industrial and scientific community due to its ability to fabricate functional and complex polymeric parts efficiently. In this work, a systematic characterization of the physicochemical properties of MJF-certified polyamide 11 (PA11) and thermoplastic polyurethane (TPU) powder was conducted. The mechanical performance and print quality of the specimens printed using both powders were then evaluated. Both PA11 and TPU powders showed irregular morphology with sharp features and had broad particle size distribution, but such features did not impair their printability significantly. According to the DSC scans, the PA11 specimen exhibited two endothermic peaks, while the TPU specimen exhibited a broad endothermic peak (116–150 °C). The PA11 specimens possessed the highest tensile strength in the Z orientation, as opposed to the TPU specimens which possessed the lowest tensile strength along the same orientation. The flexural properties of the PA11 and TPU specimens displayed a similar anisotropy where the flexural strength was highest in the Z orientation and lowest in the X orientation. The porosity values of both the PA11 and the TPU specimens were observed to be the lowest in the Z orientation and highest in the X orientation, which was the opposite of the trend observed for the flexural strength of the specimens. The PA11 specimen possessed a low coefficient of friction (COF) of 0.13 and wear rate of 8.68 × 10−5 mm3/Nm as compared to the TPU specimen, which had a COF of 0.55 and wear rate of 0.012 mm3/Nm. The PA11 specimens generally had lower roughness values on their surfaces (Ra < 25 μm), while the TPU specimens had much rougher surfaces (Ra > 40 μm). This investigation aims to uncover and explain phenomena that are unique to the MJF process of PA11 and TPU while also serving as a benchmark against similar polymeric parts printed using other PBF processes.


1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.


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