Browsing by Author "Wang, Yen-Zen"

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A New Technology of Scrape-Applied Method for the Manufacturing of MEA of Fuel-Cell System
(2008)
Wu, Shinn-Dar
;
Lee, Chi-Hung
;
Chou, Chang-Pin
;
Wang, Yen-Zen
;
機械工程學系
The technical transfer from electrode of lithium battery to MEA of fuel cells (including PEMFC and DMFC) were discussed in this study. There are three common methods for the manufacturing of lithium battery electrode; such as roller-applied method, scrape-applied method and spurt-applied method. The first two methods are the most commonly used method. This study was focused on the development of new scrape-applied equipment for lithium battery electrode. This new method was tested by measure the weight and thickness of dry electrode. The stability and reproducibility on electrode fabrication were also conducted by systematical data analysis. The results can offer an important basis to the future research on academic and commercial field.
Effect of Bridging Groups on Sulfonated Poly(imide-Siloxane) for Application in Proton Exchange Membrane
(2010-04-01)
Lee, Chi-Hung
;
Chen, Jia-Ru
;
Shiu, Hung-Wei
;
Ho, Ko-Shan
;
Wu, Shinn-Dar
A series of six-membered sulfonated poly(imide-siloxane)s (SPIs) was synthesized using 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), aminopropyl-terminated polydimethylsiloxane (PDMS) 2,2-benzidinedisulfonic acid (BDSA), as the sulfonation target diamine groups, and various nonsulfonated diamine monomers behaving as bridging groups. The structure-property relationship of SPI-SXx membranes is discussed in detail according to the chemical structure of the various nonsulfonated diamines of the SPI-SXx membranes from the viewpoints of proton conductivity, ion exchange capacity (IEC), and membrane properties (water uptake and membrane swelling) at equal PDMS content SPI-SXx. The PDMS was introduced to enhance the proton conductivity and water uptake attributed from the high flexibility of the siloxane segments. The conductivity and water uptake of angled SPI-SXm and oxydianiline-based SPI-SX membranes (SPI-SXO) are greater than those prepared from diaminodiphenylmethane-based SPI-SX membranes (SPI-SXD) at a given IEC. These differences resulted from the increased number of entanglements of the SPI-SXx membrane. The SPI-SXD showed almost isotropically dimensional changes with the increase in water uptake, and the volume were slightly smaller than those estimated from the additivity rule. Free volume in the SPI-SXx increased with the increase in bulky irregular packing in nonsulfonated segments, which augmented the water uptake and, in turn, the conductivity of the polymer. With the increase in temperature, conductivity increased more rapidly in SPI-SXx than in Nafion 117. Microscopic analyses revealed that these smaller (<10 nm) and well-dispersed hydrophilic domains contribute to better proton conducting properties. The new sulfonated poly(imide-siloxane) s have proved to be a possible candidate as the polymer electrolyte membrane for polymer electrolyte fuel cells (PEFCs) and direct methanol fuel cells (DMFCs). [DOI: 10.1115/1.3200906]
Formation and degradation mechanism of a novel nanofibrous polyaniline
(2009-06-01)
Ho, Ko-Shan
;
Han, Yu-Kai
;
Tuan, Yu-Tsung
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Huang, Ying-Jie
;
Wang, Yen-Zen
A nanotubular, nanofibrous polyaniline (PANINT) was prepared from an emulsion polymerization in the presence of n-dodecylbenzene sulfonic (DBSA) and hydrochloric acids. The building of the tubular structure based on the tubular micelles from the accumulation (pile up) of micelles at high surfactant concentration, leading to early stage of centipede-like and eventual tubular morphologies. The PANINT molecule owning a highly conjugated backbone demonstrated a free carrier-tail in the near-IR region due to its helical conformation. After dedoping, the once empty PANINT with only some complexed DBSA inside shrank into solid rods, after the removal of the complexed DBSA. As a result, the solid rods were filled with helical emeradine base (nano-EB) molecules associated with inter-molecular H-bonding. The solid rods of nano-EB went on crosslinking and carbonization after 200-300 degrees C by opening the quinoid rings and the inter-molecular H-bondings were destroyed with nano-EB molecules crosslinking into ladder-like structure. When temperature was over 300 degrees C and below 800 degrees C, carbonization enhanced by de-ammoniaization, causing a significant weight loss. However, the cleavage of aromatic rings into aliphatic pieces occurred after 800 degrees C, which chopped the ladder-like, strips of carbonized nano-EB sheets into small pieces of nano-particles. The conductivity of the pyrolyzed nano-EB was found to be around 10(-5) s/cm, 10,000 times higher than the neat nano-EB of 10(-9) s/cm due to the carbonization. (C) 2009 Elsevier B.V. All rights reserved.
Influence of Sulfonationity of Epoxy-Based Semi-Interpenetrating Polymer Networks of Sulfonated Polyimides as Proton Exchange Membranes on the Performance of Fuel Cell Application
(2010-04-01)
Wang, Yen-Zen
;
Ho, Ko-Shan
;
Wu, Shinn-Dar
;
Hsieh, Kuo-Huang
;
Lee, Chi-Hung
A novel epoxy-based semi-interpenetrating polymer networks membrane (SPIX-EP40) as the proton exchange membrane was prepared by a flexible epoxy network with sulfonated polyimide. A series of sulfonated polyamic acid (SPAA) were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2-benzidinedisulfonic acid (BDSA) and non-sulfonated diamines, such as 4,4'-diaminodiphenyl sulfone. Solid-state (13)C nuclear magnetic resonance spectra and Fourier transform infrared spectroscopy were used to verify the synchronization of the imidization of SPAA and the crosslinking reactions of epoxy. The sulfonationity of the copolymers was regulated through a variation in the molar ratio of BDSA to diamine. These membranes owned a good thermal stability and exhibited high proton conductivity that was measured as a function of temperature. The resulting SPI0.7-EP40 and SPI0.8-EP40, at 100% relative humidity, displayed proton conductivities higher than those of Nafion (R) 117. The membranes displayed higher conductivities than Nafion (R) membranes because of owning higher activational energies and higher ion exchange capacities. An isotropic swelling phenomenon in water was found for the membrane. From the results of water uptake and the microstructure analyses using transmission electron microscopy (TEM) on different sulfonated levels, it was found that the number of water clusters in SPIX-EP40 membranes increased as the increasing water uptake and the size of water cluster were changed with the sulfonation levels. TEM confirmed the widespread and well-connected hydrophilic domains, demonstrating the presence of the favorable proton-transporting performances of the SPIX-EP40 membrane. [DOI: 10.1115/1.3177383]
Novel epoxy nanocomposite of low D-k introduced fluorine-containing POSS structure
(2007-02-15)
Wang, Yen-Zen
;
Chen, Wen-Yi
;
Yang, Chao-Chen
;
Lin, Chen-Lung
;
Chang, Feng-Chih
A nanoporous additives, polyhedral oilgomeric silisesquioxane containing eight functional hexafluorine groups, octakis(dimethylsiloxyhexafluoropropyl ether)silsesquioxane (OF) has been synthesized and blended with the UV-cured epoxy resin. The OF containing (10%) epoxy has significantly lower dielectric constant (2.65) than the plain epoxy (3.71). The incorporation of fluorine containing additives is well-known to reduce dielectric constant due to lower its polarizability. In addition, the presence of the bulky POSS structure is able to create additional free space or pores and further reduces the dielectric constant of the epoxy matrix. (c) 2007 Wiley Periodicals, Inc.
Novel nanocomposite of epoxy resin by introduced reactive and nanoporous material
(2007-12-01)
Yang, Chao-Chen
;
Chang, Feng-Chih
;
Wang, Yen-Zen
;
Chan, Chia-Ming
;
Lin, Chen-Lung
A reactive and nanoporous particle (OG) was introduced to UV-cured epoxy resin to form great low D-k material for electronic industrial. We expected the porous cage of OG to decrease the dielectric constant of UV-cured epoxy resin and multiple reactive functional groups (oxirane ring) of OG reacted with photoinitiator to increase the curing density of UV-cured epoxy resin. The glass transition temperatures (T-g) of epoxy increases with the increase of the OG content up to 10 phr due to the increase of crosslinking density. Excessive aggregation at highest OG content of 15 phr results in the reduced crosslinking density and T-g. The char yield of the composite increases with increase of OG content because stable Si and SiO2 are formed after thermal decomposition. The presence of OG results in the higher porosity and thus the lower dielectric constant.