層狀矽酸鹽補強聚丙烯晴-丁二烯橡膠與聚丁二烯橡膠奈米複合材料之性質研究

Abstract

本論文主旨為探討利用不同組成之有機或無機層狀矽酸鹽黏土強化橡膠材料所形成之奈米橡膠複材的性能改變結果，研究顯示經由適當之製程設計、材料選配與利用可產生化學或物理反應之界面活性劑、共溶劑等寡分子體之導入效果，可獲得極佳之機械性能改良，熱性能與阻斷性能(barrier property)提昇等。 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。 在第三章中，探討以溶液摻合作業方式製備有機改質之層狀矽酸鹽補強NBR橡膠所形成之奈米橡膠複材，經由X光繞射檢測及TEM觀察結果顯示，此一複材之結構為大部分插層與局部剝層之分散相，只需添加少於10份矽酸鹽黏土，即可製備具相當高強度與熱性質之奈米橡膠複材，其抗水滲透等性能也有顯著提昇。 在第四章中，探討經由二階段熔融摻合作業方式製備有機改質之層狀矽酸鹽補強BR橡膠所形成之奈米橡膠複材，經由X光繞射檢測及TEM觀察結果顯示，其結構為大部分插層之分散相，審慎選用有機黏土與共容劑，在含量少於10份之有機矽酸鹽黏土與約3份之共容劑可獲得最佳之機械與物理性能提昇，且抗水滲透等性能也有相對提昇。 本論文的研究結果可得到以下結論，經由適當之製程設計、材料選配，可以有許多不同途徑用以產製具有大部分插層與局部剝層型態學之奈米橡膠複材，這主要是基於經有機改質或特殊表面處理的橡膠高分子與矽酸鹽補強材料之間所產生很強的分子間作用引力，與改善界面相容性之效果所致。

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.