scholarly journals Influence of Evaporation Drying on the Porous Properties of Carbon/Carbon Composite Xerogels

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2631
Author(s):  
Kriangsak Kraiwattanawong ◽  
Noriaki Sano ◽  
Hajime Tamon

Carbon/carbon (C/C) composite xerogels dried by evaporation were prepared in this study to observe the change of their porous properties and their morphology by nitrogen sorption apparatus and a scanning electron microscope. Resorcinol and formaldehyde (RF) sols as a matrix phase and cotton fibers (CF) as a dispersed phase were mixed and gelated to be CF/RF composite hydrogels. The composite hydrogels were exchanged by t-butanol (TBA), dried by evaporation at 50 °C, and carbonized at 1000 °C to become the C/C composite xerogels. The results show that the CF addition does not decrease the mesoporous properties of the C/C composite xerogels. Moreover, the CF addition can alleviate the pore shrinkage, and it can maintain the mesopore structure. The mesopore size and the micropore size of C/C composites are insignificantly changed because the CF addition and the solvent exchange using TBA may suppress the pore shrinkage despite the gas-liquid interface existing during the evaporation drying.

2020 ◽  
Vol 16 (2) ◽  
pp. 12
Author(s):  
Solihudin Solihudin ◽  
Haryono Haryono ◽  
Atiek Rostika Noviyanti ◽  
Muhammad Rizky Ridwansyah

<p>Komposit forsterit-karbon merupakan salah satu material modifikasi dari forsterit yang berpotensi memiliki sifat isolator panas baik. Karbon dalam komposit dapat mengisi cacat titik pada kristal forsterit. Arang sekam padi (residu gasifikasi) mengandung SiO2 amorf dan karbon yang tinggi. Penelitian ini bertujuan menentukan pengaruh suhu kalsinasi dalam medium gas inert (dengan pengaliran gas argon) terhadap karakteristik komposit forsterit-karbon dari arang sekam padi dan magnesium karbonat. Metode penelitian meliputi preparasi arang sekam padi hasil gasifikasi, dan sintesis forsterit-karbon. Proses sintesis komposit forsterit karbon dilakukan dengan cara mencampurkan arang sekam padi dengan kalium karbonat pada rasio mol magmesium terhadap silikon sebesar 2 : 1 kemudian dikalsinasi dengan suhu divariasikan (700, 800, 900, dan 1000 oC). Selanjutnya sampel hasil sintesis dikarakterisasi dengan Fourier-transform infrared (FTIR), X-ray diffraction (XRD), dan scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Hasil karakterisasi dengan FTIR dan XRD diperoleh kesimpulan bahwa forsterit mulai terbentuk pada suhu kalisiasi 800 oC dan sempurna pada suhu 1000 oC, karenanya komposit yang terbentuk pada 1000 oC dimungkinkan sebagai forsterit-karbon, di mana unsur-unsur yang terkandung ditunjukkan oleh SEM-EDS.</p><p> </p><p><strong>The Effect of Calcination Temperature on the Characteristics of Forsterite-Carbon Composites Synthesized in Argon Gas Medium</strong>. Forsterite-carbon composite is one of the material modifications of forsterite, which potentially has a good heat insulation property. Carbon in composites can fill point defects in forsterite crystals. Rice husk charcoal, as gasification residues, contains high amorphous SiO2 and carbon. This study aims to determine the effect of temperature on the calcination of a mixture of rice husk charcoal and magnesium carbonate under an inert gas (argon gas) on the characteristics of the forsterite-carbon composite produced. The experimental research performed includes the preparation of gasified rice husk charcoal and the synthesis of the carbon-forsterite composite. The synthesis process of the carbon-forsterite composites was carried out by mixing rice husk charcoal with potassium carbonate at a mole ratio of magnesium to silicon of 2 : 1. The mixture was then calcined with varying temperatures (700, 800, 900, and 1000 °C). Furthermore, the synthesized sample was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The FTIR and XRD analysis show that the forsterites began to form at a calcination temperature of 800 °C and perfectly formed at a temperature of 1000 °C; therefore, the composite formed at 1000 °C is possible as forsterite-carbon, in which the contained elements were indicated by SEM-EDS.</p>


2014 ◽  
Vol 625 ◽  
pp. 106-109 ◽  
Author(s):  
Maimoon Sattar ◽  
Fareeda Hayeeye ◽  
Watchanida Chinpa ◽  
Orawan Sirichote

Polysulfone/Activated Carbon (PSF/AC) composites in bead form were prepared for Rhodamine B sorption. The scanning electron microscope (SEM) shows that pure PSF bead is smooth surface while PSF/AC bead presents the pore distribution. FT-IR spectra indicate the existence of AC on the PSF/AC bead surface. Under adsorption test of Rhodamine B, it was found that an increase in the AC content in PSF solution results in an increase in the percentages of dye adsorption from 1.38 % to 71.56% for pure PSF bead and PSF/AC added with 4 wt% of AC, respectively.


2017 ◽  
Vol 17 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Dawei Gao ◽  
Lili Wang ◽  
Chunxia Wang ◽  
Yuping Chang ◽  
Pibo Ma

Abstract Polyacrylonitrile (PAN)/Co(OAc)2/carbon nanotubes (CNTs) composite nanofibers were fabricated via electrospinning with N,N-dimethylformamide (DMF) as solvent, and by carbonization and activation of the above precursor nanofibers, porous carbon composite nanofibers were successfully obtained. Scanning electron microscope, X-ray diffraction, ASAP 2020, and Solartron 1470 were used to characterize the surface morphology, the phase composition, specific surface area, and electrochemical property of the nanofibers, respectively. The result showed that some of the fibers were broken after sintering, and the surface area and pore volume of the porous C/Cu/CNTs were 771 m2/g and 0.347 cm3/g, respectively. The specific capacitance of the composite nanofibers reached up to 210 F/g at the current density of 1.0 A/g. Its energy density and power density were 3.1 Wh/Kg and 2,337 W/Kg, respectively, at the current of 0.5 and 5 mA.


Author(s):  
J Li ◽  
Y F Zhang

Polyamide 6 (PA6)-filled polytetrafluoroethylene (PTFE) at different compositions has been successfully prepared in a corotating twin screw extruder where PTFE acts as the polymer matrix and PA6 as the dispersed phase. The morphology and impact properties of these blends were investigated using a scanning electron microscope. The presence of PA6 particles dispersed in the PTFE continuous phase exhibited a coarse morphology. Increasing PA6 contents in the blend improved the impact properties at weak deformation. It was found that the interfacial adhesion played an important role in the creation of an interphase that was formed by the interaction between the PTFE and PA6. This induced an improvement in impact properties. In addition, the optimum impact properties were obtained when the content of PA6 is 30 vol%.


2011 ◽  
Vol 335-336 ◽  
pp. 116-119
Author(s):  
Jue Tan ◽  
Yu Dong Zheng ◽  
Ru Tian ◽  
Shi Bo Zhang ◽  
Hong Yan Chen

Bacterial cellulose (BC)/Poly vinyl alcohol (PVA) multilayer composite hydrogels were prepared by freezing and thawing. The mechanical properties of the composite were investigated in this paper with different mass percent of PVA, number of BC layers. Scanning electron microscope (SEM) was used to characterize the fracture characterizations of the composite and the interface structure between BC membrane and PVA hydrogel. It was found that composite hydrogels with 15wt% PVA and 2 layers BC membranes exhibit excellent mechanical properties and wonderful bonding effect of the interface.


2020 ◽  
Vol 16 (2) ◽  
pp. 163
Author(s):  
Solihudin Solihudin ◽  
Haryono Haryono ◽  
Atiek Rostika Noviyanti ◽  
Muhammad Rizky Ridwansyah

<p>Komposit forsterit-karbon merupakan salah satu material modifikasi dari forsterit yang berpotensi memiliki sifat isolator panas baik. Karbon dalam komposit dapat mengisi cacat titik pada kristal forsterit. Arang sekam padi (residu gasifikasi) mengandung SiO2 amorf dan karbon yang tinggi. Penelitian ini bertujuan menentukan pengaruh suhu kalsinasi dalam medium gas inert (dengan pengaliran gas argon) terhadap karakteristik komposit forsterit-karbon dari arang sekam padi dan magnesium karbonat. Metode penelitian meliputi preparasi arang sekam padi hasil gasifikasi, dan sintesis forsterit-karbon. Proses sintesis komposit forsterit karbon dilakukan dengan cara mencampurkan arang sekam padi dengan kalium karbonat pada rasio mol magmesium terhadap silikon sebesar 2 : 1 kemudian dikalsinasi dengan suhu divariasikan (700, 800, 900, dan 1000 oC). Selanjutnya sampel hasil sintesis dikarakterisasi dengan Fourier-transform infrared (FTIR), X-ray diffraction (XRD), dan scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Hasil karakterisasi dengan FTIR dan XRD diperoleh kesimpulan bahwa forsterit mulai terbentuk pada suhu kalisiasi 800 oC dan sempurna pada suhu 1000 oC, karenanya komposit yang terbentuk pada 1000 oC dimungkinkan sebagai forsterit-karbon, di mana unsur-unsur yang terkandung ditunjukkan oleh SEM-EDS.</p><p> </p><p><strong>The Effect of Calcination Temperature on the Characteristics of Forsterite-Carbon Composites Synthesized in Argon Gas Medium</strong>. Forsterite-carbon composite is one of the material modifications of forsterite, which potentially has a good heat insulation property. Carbon in composites can fill point defects in forsterite crystals. Rice husk charcoal, as gasification residues, contains high amorphous SiO2 and carbon. This study aims to determine the effect of temperature on the calcination of a mixture of rice husk charcoal and magnesium carbonate under an inert gas (argon gas) on the characteristics of the forsterite-carbon composite produced. The experimental research performed includes the preparation of gasified rice husk charcoal and the synthesis of the carbon-forsterite composite. The synthesis process of the carbon-forsterite composites was carried out by mixing rice husk charcoal with potassium carbonate at a mole ratio of magnesium to silicon of 2 : 1. The mixture was then calcined with varying temperatures (700, 800, 900, and 1000 °C). Furthermore, the synthesized sample was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The FTIR and XRD analysis show that the forsterites began to form at a calcination temperature of 800 °C and perfectly formed at a temperature of 1000 °C; therefore, the composite formed at 1000 °C is possible as forsterite-carbon, in which the contained elements were indicated by SEM-EDS.</p>


2011 ◽  
Vol 217-218 ◽  
pp. 1601-1605
Author(s):  
Dong Jiang ◽  
Xiao Ran Zhang ◽  
Yan Mei Ma ◽  
Cheng You Ma

polycarbonate (PC), polyethersulfone (PES) and a multi-block random copolymer of PES and PC were blended. It was found that the interfacial adhesion was enhanced, the size of the dispersed phase was reduced and PES and PC formed an interlocking structure with the copolymer, which suggest the addition of the compatibizer may improved the miscibility between PES and PC, and result in the improvement of the mechanical properties of the blends. The compatibility behavior of PES with PC was examined using differential scanning calorimeter (DSC), scanning electron microscope (SEM) and SAXS.


2011 ◽  
Vol 221 ◽  
pp. 640-643 ◽  
Author(s):  
Heng Zhu ◽  
Xiao Yan Lin ◽  
Xiu Rong Zhuo ◽  
Xue Gang Luo ◽  
Chi Zhang

The spherical lignin/polylactide (PLA) adsorbent was prepared by solvent evaporation. The dispersed phase contents, the PLA concentration and ratio of PLA to lignin on the diameter and mechanical strength of the PLA/lignin composite adsorbent spheres were investigated and the morphology structure and mechanical strength of the adsorbent were characterized by scanning electron microscope (SEM) and dynamic mechanical analyzer (DMA). The results showed that the adsorbent has porous structure, and the mechanical strength increased significantly as the ratio of PLA to lignin as 4:1.


2018 ◽  
Vol 928 ◽  
pp. 62-67 ◽  
Author(s):  
Kriangsak Kraiwattanawong

Carbon/carbon composite xerogels are prepared by a vacuum drying technique whereas a carbon cryogel is synthesized by a freeze drying technique to compare the effect of these drying methods at the selective synthesis condition. Resorcinol and formaldehyde are used to prepare a matrix phase and cotton fibers are acted as a disperse phase of the carbon/carbon composite xerogels. Here resorcinol and formaldehyde is utilized to synthesize the carbon cryogel only. The carbon/carbon composite xerogels and the carbon cryogel were analyzed by a nitrogen adsorption apparatus and a field emission scanning electron microscope. The results support that the vacuum drying can decrease the pore shrinkage despite of the gas-liquid interface. The porous properties of the carbon xerogel is quite equivalent to the porous properties of the carbon cryogel. When the porous properties of carbon xerogels are considered, their porous properties can be preserved at the high porosity until 0.15 g/g of the cotton fibers/resorcinol ratio. At 0.25 g/g of this ratio, the porous properties start decreasingly.


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