Browsing by Author "Chiu, Wei-Ming"

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A study of carbon nanotubes/biodegradable plastic polylactic acid composites
(2008-06-05)
Chiu, Wei-Ming
;
Chang, You-An
;
Kuo, Hsan-Yuan
;
Lin, Meng-Hung
;
Wen, Hua-Chiang
Fabrication process was successfully used to embed carbon nanotubes (CNTs) in a polylactic acid (PLA) matrix, forming a composite nanostructure. For the composites, nanoindentation is often used to characterize their mechanical properties (e.g., hardness and Young's moduli). In this experiment, the varied concentrations of CNTs in PLA were analyzed in their mechanical performance. The distribution and conformation of CNTs in the PLA were studied by X-ray diffraction. Then, electrical characterization was performed by four-probe method. Thermal properties were checked by TGA and DSC. Furthermore, the CNTs/PLA nanocomposites were observed by SEM. According to the experimental result, purified CNTs showed better dispersing and properties in the CNTs PLA nanocomposites. (C) 2008 Wiley Periodicals, Inc.
The influences of H-2 plasma pretreatment on the growth of vertically aligned carbon nanotubes by microwave plasma chemical vapor deposition
(2008-06-01)
Jian, Sheng-Rui
;
Chen, Yuan-Tsung
;
Wang, Chih-Feng
;
Wen, Hua-Chiang
;
Chiu, Wei-Ming
The effects of H-2 flow rate during plasma pretreatment on synthesizing the multiwalled carbon nanotubes (MWCNTs) by using the microwave plasma chemical vapor deposition are investigated in this study. A H-2 and CH4 gas mixture with a 9:1 ratio was used as a precursor for the synthesis of MWCNT on Ni-coated TaN/Si(100) substrates. The structure and composition of Ni catalyst nanoparticles were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The present findings showed that denser Ni catalyst nanoparticles and more vertically aligned MWCNTs could be effectively achieved at higher flow rates. From Raman results, we found that the intensity ratio of G and D bands (I-D/I-G) decreases with an increasing flow rate. In addition, TEM results suggest that H-2 plasma pretreatment can effectively reduce the amorphous carbon and carbonaceous particles. As a result, the pretreatment plays a crucial role in modifying the obtained MWCNTs structures.