Browsing by Author "Hwang, WG"

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Mechanical, thermal, and barrier properties of NBR/organosilicate nanocomposites
(2004-11-01)
Hwang, WG
;
Wei, KH
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材料科學與工程學系
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Department of Materials Science and Engineering
Nanocomposites of intercalated and exfoliated organosilicates in acrylonitrile butadiene rubber (NBR) were prepared by a solution-blending method. The dispersion and intergallery spacings of organosilicates in these nanocomposites were examined by transmission electron microscopy and X-ray diffraction. Dramatic enhancements in the mechanical and thermal properties of NBR are found by incorporating less than ten parts of organosilicate. In particular, the addition of ten parts of organosilicate provided a more than sixfold increase in tensile strength, a twofold increase in M500, and 168% and 39% enhancements in tear strength and elongation at break compared with pure NBR. The degradation temperature for NBR with ten-parts' loading of organosilicate was 25 degreesC higher than that of pure NBR. In addition, the relative vapor permeability of the NBR nanocomposites for water and methanol were 85% and 42% lower, respectively, than that of pure NBR. (C) 2004 Society of Plastics Engineers.
Preparation and mechanical properties of nitrile butadiene rubber/silicate nanocomposites
(2004-07-22)
Hwang, WG
;
Wei, KH
;
Wu, CM
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Elastomer nanocomposites consisting of nitrile butadiene rubber (NBR) latex and layered silicates are prepared by a modified latex shear blending process aided with ball milling. The mode of dispersion of layered silicates in NBR is partially exfoliated and intercalated when the concentration of layered silicates is below 7.5 wt%, as evidenced by transmission electron microscopy and X-ray diffraction results. The tensile and tear mechanical properties are much higher than that of neat NBR. Specifically, the tensile and tear mechanical properties of the NBR/layered silicates increase by 200 and 60%, respectively. The decomposition temperature of the nanocomposites increases slightly. (C) 2004 Elsevier Ltd. All rights reserved.
Synergistic effect of compatibilizer in organo-modified layered silicate reinforced butadiene rubber nanocomposites
(2006-01-01)
Hwang, WG
;
Wei, KH
;
Wu, CM
;
材料科學與工程學系
;
Department of Materials Science and Engineering
We have prepared nanocomposites of intercalated and exfoliated organosilicates in butadiene rubber (BR) by using a two-stage melt blending process. We used X-ray diffraction and transmission electron microscopy to examine, respectively, the intergallery spacing of the organosilicates and their dispersion in the BR. Marked enhancements in the mechanical and thermal properties of BR occurred when it incorporated < 10 parts of organosilicates and the loading ratio of the organosilicate to dicarboxylic acid-terminated butadiene oligomer was approximately three. In particular, the addition of 10 parts of organosilicate and 3 parts of compatibilizer in the BR led to a more than four-fold increase in the tensile strength, a 150% increase in modulus at 100% elongation (M 100), and 232 and 410% enhancements in the tear strength and elongation at break, respectively, relative to those of neat BR. The degradation temperature for the BR nanocomposite containing only a 10-part loading of organosilicate was 51 degrees C higher than that of neat BR; these increases reduced, however, to 9-13 degrees C upon the addition of the CTB compatibilizer. In addition, the relative water vapor permeabilities of the BR nanocomposites containing 10 parts of organosilicate- both in the presence and absence of the compatibilizer- reduced to 20% of that of the neat BR.