scholarly journals The Effect of Ultrasonic Treatment on Thermal Stability of the Cured Epoxy/Layered Silicate Nanocomposite

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
N. Y. Yuhana ◽  
S. Ahmad ◽  
A. R. Shamsul Bahri

The effect of ultrasonic treatment on thermal stability of binary systems containing epoxy and organic chemically modified montmorillonite (Cloisite 30B) was studied. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), and wide angle X-ray diffraction (WAXD) analysis were utilized. The mixing of epoxy and Cloisite 30B nanocomposites was performed by mechanical stirring, followed by 1 or 3-hour ultrasonic treatment, and polyetheramine as the curing agent. Both XRD and TEM analyses confirmed that the intercalation of Cloisite 30B was achieved. Thed0spacings for silicate in cured sample prepared at 1- and 3-hour duration of ultrasonic treatment were about 21 and 18 Å, respectively. This shows that shorter duration or ultrasonic treatment may be preferable to achieve higherd0spacing of clay. This may be attributed to the increase in viscosity as homopolymerization process occurred, which restricts silicate dispersion. The 1-hour sonicated samples seem to be more thermally stable during the glass transition, but less stable during thermal decomposition process.

2011 ◽  
Vol 320 ◽  
pp. 3-7
Author(s):  
Jian Hong Gong ◽  
Shu Xia Lin ◽  
Jun Gao

Transmission Electron Microscope (TEM) and Different Scanning Calorimetry (DSC) Methods Were Used to Investigate the Diamonds Grown with Different Boron Content Alloy Catalysts under High-Pressure High-Temperature (HPHT). Experimental Results Demonstrated the Microstructure and Composition of Boride Compounds in Synthetic Diamond, such as (FeNi)23(CB)6 ,(Fe, Ni)3(C,B), (Fe,Ni)B and B4C, Whose Formation Process Was Analyzed. the Thermal Stability of Diamond Depends on Boron Concentration in Catalyst According to DSC Studies. we Analyzed the Reason of Diamond Oxidation.The Work Offers Valuable Information for Improving the Thermal Stability of Synthetic Diamond Crystals by Adjusting Boron Content in the Fe-Ni Based Catalyst.


2011 ◽  
Vol 45 (25) ◽  
pp. 2595-2601 ◽  
Author(s):  
Tsuyoshi Saotome ◽  
Ken Kokubo ◽  
Shogo Shirakawa ◽  
Takumi Oshima ◽  
H. Thomas Hahn

Novel nanocomposite films of polycarbonate (PC) with fullerene derivatives, such as pristine fullerene C60 and polyhydroxylated-fullerenes, C60(OH)12 and C60(OH)36, were prepared. The optical, thermal, and mechanical properties of the composites were measured. Nanocomposite films of poly (vinyl alcohol) (PVA) with C60(OH)36 were prepared as a reference to show how improved dispersion of the nanofiller affects the overall transparency of the composites. Ultraviolet-visible spectroscopy showed that the addition of hydroxylated fullerenes did not affect visible light transmittance of the films significantly in the range of 400–800 nm. Differential scanning calorimetry (DSC) and thermo–gravimetric analysis (TGA) measurements showed the increased thermal stability of PC/C60(OH)12 film as compared to pristine PC film. This phenomenon was explained by the rigid polymer interphase regions formed around C60(OH)12 due to the plausible hydrogen bonding and hydrophobic interaction. On the other hand, the lower thermal stability of PC–C60(OH)36 was assumed to be caused by large agglomeration of the C60(OH)36 particles and the partial hydrolysis of the polycarbonate matrix. Tensile testing of the composites showed reduction in elongation at break and yield tensile strength. These results may be caused by the particle agglomerations which act as the initiation points for cracks.


2013 ◽  
Vol 750-752 ◽  
pp. 2021-2025 ◽  
Author(s):  
Hui Zhang ◽  
Jie Yao Song ◽  
Jian Chao Zhan

We prepared the magnetic cenospheres deposited with magnetite Fe3O4nanoparticles under hydrothermal conditions. The crystalline phase, magnetization properties, morphology, chemical composition and thermal stability of asobtained cenospheres are analyzed by Xray diffraction, vibrating sample magnetometer, scanning electron microscope, Xray energy dispersive spectroscope, transmission electron microscope, thermal gravimetric analysis and differential scanning calorimetry techniques. The results show that the inverse cubic spinel phase of Fe3O4nanoparticles with an average size 50 nm are synthesized, and synchronously deposited on cenosphere surface. As the thickness of Fe3O4coating increases, the saturation magnetization increases to some extent. The growth of Fe3O4nanoparticles can be controlled by adding ethanol to the reaction solution.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2641 ◽  
Author(s):  
Tang ◽  
Wang ◽  
Wang ◽  
Cheng ◽  
Guo

The demand for eco-friendly renewable natural fibers has grown in recent years. In this study, a series of polypropylene-based composites reinforced with single bamboo fibers (SBFs), prepared by non-woven paving and a hot-pressing process, were investigated. The influence of the content of SBF on impact strength, flexural strength, and water resistance was analyzed. The properties of the composites were greatly affected by the SBF content. Impact strength increased as SBF content increased. The modulus of rupture and modulus of elasticity show an optimum value, with SBF contents of 40% and 50%, respectively. The surface morphology of the fractured surfaces of the composites was characterized by scanning electron microscopy. The composites showed poor interfacial compatibility. The water resistance indicates that the composites with higher SBF contents have higher values of water absorption and thickness swelling, due to the hydrophilicity of the bamboo fibers. The thermal properties of the composites were characterized by thermal gravimetric analysis and by differential scanning calorimetry. The thermal stability of the composites was gradually reduced, due to the poor thermal stability of SBFs. In the composites, the maximum decomposition temperature corresponding to SBF shows an increasing trend. However, the maximum decomposition temperature of polypropylene was not influenced by SBF content. The melting point of the polypropylene in the composites was lower relative to pure polypropylene, although it was not affected by increasing SBF content.


2006 ◽  
Vol 317-318 ◽  
pp. 669-672 ◽  
Author(s):  
D.H. Kim ◽  
Seong Soo Park ◽  
B.S. Jun ◽  
Jong Kook Lee ◽  
Kyu Hong Hwang ◽  
...  

Polymer/layered silicate nanocomposities were prepared by in situ polymerization with microwave process. The influence of the amount of clay on the structure and thermal properties for the synthesized nanocomposites were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). It was found that the structure of nanocomposites, an intercalated/exfoliated structure, depended on the clay content.


2019 ◽  
Vol 17 (1) ◽  
pp. 1266-1278
Author(s):  
Omaima Alhaddad ◽  
Safaa H. El-Taweel ◽  
Yasser Elbahloul

AbstractThe effects of bacterial poly(hydroxyoctanoate) (PHO) and talc on the nonisothermal cold crystallization behaviours of poly(lactic acid) (PLA) were analysed with differential scanning calorimetry (DSC), and the thermal stability of the samples was observed with thermal gravimetric analysis (TGA). The modified Avrami’s model was used to describe the nonisothermal cold crystallization kinetics of neat PLA and its blends. The activation energies E for nonisothermal cold crystallization were calculated by the isoconversional method of Kissinger-Akahira-Sunose (KAS). The DSC results showed that the PLA/PHO blends were immiscible in the whole studied range, and as the PHO and talc content increased, the crystallization rate of PLA accelerated, and the crystallinity of PLA in the PLA samples increased. The values of the Avrami exponent indicated that the nonisothermal cold crystallization of the neat PLA and its blends exhibited heterogeneous, three-dimensional spherulitic growth. The E values were strongly dependent on PHO and talc. The TGA results showed that the presence of PHO and talc slightly influenced the thermal stability of PLA.


2017 ◽  
Vol 24 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Varun Mittal ◽  
Shishir Sinha

AbstractThe present paper deals with a study of the thermal properties of bagasse fiber (BF)-reinforced epoxy composites. BFs are subjected to untreated and chemical treatments with 1% sodium hydroxide followed by 1% acrylic acid at ambient temperature before the composites are made. The thermal stability of the components was studied by thermogravimetric analysis and differential scanning calorimetry, as well as by differential thermal gravimetric analysis. Thermal analysis results of untreated BF-reinforced epoxy composite were compared with treated BF-reinforced epoxy composite. The chemical treatment of BF induces reasonable changes in the thermal stability of the polymer composites.


e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Yong Xie ◽  
Shi-Hao Zhang ◽  
Hai-Yun Jiang ◽  
Hui Zeng ◽  
Ruo-Mei Wu ◽  
...  

AbstractA new conductive composite composed of nanoscale carbon black (CB) and poly(3,4-ethylenedioxythiophene) (PEDOT) was prepared by a simple in-situ polymerization. The morphology of the composite was characterized by scanning electron microscopy and transmission electron microscopy. The structure and thermal stability were examined by Fourier transform infrared spectroscopy and thermal gravimetric analysis, respectively. The results indicated that the addition of CB improved the agglomerated state of PEDOT. On the one hand, CB effectively hindered the agglomeration of PEDOT during the polymerization. Thus, the obtained CB-PEDOT composite dispersed well in solution, which can facilitate the reprocessing of CB-PEDOT. On the other hand, CB covered most of the surface of PEDOT, which enhanced the electrical conductivity of CB-PEDOT. Furthermore, the interfacial interaction between CB and PEDOT improved the thermal stability of CB-PEDOT. The findings of this research suggest that CB can replace polyelectrolyte poly(styrenesulfonic acid) (PSS) to achieve reprocessable materials for certain applications.


2008 ◽  
Vol 140 ◽  
pp. 97-102 ◽  
Author(s):  
M. Sarah Mohlala ◽  
Suprakas Sinha Ray

This paper describes the preparation, characterization and properties of nanostructured composite materials based on poly(butylene adipate-co-polycaprolactam) (PBA-co-PCL)/multiwalled carbon nanotubes (MWCNTs) and polycaprolactone (PCL)/MWCNTs. The polymer/MWCNTs nanocomposites were prepared by mixing the polymers with various amounts of MWCNTs using both solution and melt blending processes. The dispersion of MWCNTs into the polymer matrix was analyzed by transmission electron microscopy (TEM) and the thermal stability of the nanocomposites was studied by thermal gravimetric analysis (TGA). Differential scanning calorimetry (DSC) was used to study the crystallization and melting behaviour of the polymer matrices containing the MWCNTs.


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