Mechanical and Morphological Effects of Layered silicates on Nitrile-Butadiene and Butadiene Rubber Nanocomposites
Dr. Kung-Hwa Wei
|關鍵字:||彈性體柰米複材;機械強度;層狀矽酸鹽;Elastomer nanocomposites;Mechanical strength;Layered silicates|
本文第二章，探討利用乳化相摻混程序，並結合高剪力摻合及球磨分散方式可將無機層狀矽酸鹽黏土均勻混入NBR橡膠乳膠中，經由X光繞射檢測及TEM觀察結果顯示，當層狀矽酸鹽黏土含量低於7.5 wt %時，可形成分散良好之部分剝層與插層結構之奈米橡膠複材，其機械性能如拉力與抗撕裂強度均比NBR原材料性能提昇相當多，分別提昇逾200%與60%，此外其熱分解溫度也相對提昇。
In this thesis, a variety of methods are used to prepare the elastomer nanocomposites comprised of inorganic or organo-modified layered silicates and rubber matrices. Excellent mechanical , thermal and barrier properties can be obtained for each nanocomposite by performing proper process design, material selection, physical and/or chemical reactions by the addition of compatibilizers or surfactants, etc. In chapter 2, 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 properties are much higher than that of neat NBR. Specifically, the tensile and tear mechanical properties of the NBR / layered silicates can increase by 200% and 60%, respectively. The decomposition temperature of the nanocomposites increases slightly. Different methods to form the nanocomposites of intercalated and exfoliated organosilicates in acrylonitrile butadiene rubber (NBR) are carried out by a solution blending process in chapter 3. The dispersion and intergallery spacings of organosilicates in these nanocomposites are 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 organosilicates. The fluid impermeability is also improved significantly. Nanocomposites of intercalated and exfoliated organosilicates in butadiene rubber (BR) have also been prepared by using a two-stage melt blending process in chapter 4. X-ray diffraction and transmission electron microscopy are used to examine, respectively, the intergallery spacing of the organosilicates and their dispersion in the BR. Dramatic enhancements in the mechanical and thermal properties of BR occur when it incorporates less than 10 parts of organosilicates and the loading ratio of the organosilicate to dicarboxylic acid-terminated butadiene oligomer is about 3. In addition, the relative water vapor permeability of the BR nanocomposites containing 10 parts of organosilicate—both in the presence and absence of the compatibilizer—reduce largely compared to that of the neat BR. It can be concluded that the successfully prepared NBR(BR)/organosilicate nanocomposites having intercalated and partially exfoliated structures can be obtained by different blending methods in proper process design and material selection. As a result of significantly improved compatibility and the strong molecular chains interactions between layered silicates and rubber matrices, the mechanical, thermal, and many other properties of these nanocomposites containing a low weight percent of layered silicates can be increased substantially.
|Appears in Collections:||Thesis|
Files in This Item: