Hiện tại, vật liệu cao su nanocomposite – dùng chất độn kích thước nano – thu hút sự quan tâm rộng rãi do tính chất cơ lý tốt. Các chất độn thường được sử dụng trong vật liệu cao su nanocomposite là đất sét, than đen. Phần tài liệu sau đây sẽ giới thiệu chung về chất độn carbon nanotubes.
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Over recent years, carbon nanotubes (CNT) have inspired scientists for a range of potential applications [7–12]. Carbon nanotubes are allotropes of carbon with a unique atomic structure consisting in covalently bonded carbon atoms arranged in long cylinders with typical diameters in the range 1–50 nm and a wide variety of lengths. Individual carbon nanotubes are characterized by a high aspect ratio (300–1000), high flexibility [13] and unique combination of mechanical, electrical and thermal properties [14, 15]. The combination of these properties with a very low mass density [16] makes them potentially useful as ideal reinforcing fibers for high-performance polymer composites.
Carbon nanotubes are usually produced by three techniques: arc discharge, laser ablation and chemical vapor deposition. The quality and yield of carbon nanotubes strongly depend on the synthesis and purification techniques and the specific growth conditions used [11]. There are two basic types of CNT: single-walled carbon nanotubes (SWCNT) and multiwalled carbon nanotubes (MWCNT). The structure of a SWCNT is characterized by wrapping a one-atom thick layer of graphite called graphene (graphene is a monolayer of sp2-bonded carbon atoms) into a seamless cylinder. The carbon atoms in the cylinder have partial sp3 character that increases as the radius of curvature of the cylinder decreases. SWCNT exhibit important electric properties that are not shared by the multiwalled carbon nanotubes.
MWCNT consist of multiple layers of graphite arranged in concentric cylinders with an interlayer distance close to the distance between graphene layers in graphite (circa 0.34 nm). Of particular interest are the double-walled carbon nanotubes (DWNT) because they combine a similar morphology and properties in relation to SWCNT, while improving significantly their resistance to chemicals.
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Trích đăng từ sách Rubber Nanocomposites: Preparation, Properties and Applications, Sabu Thomas và Ranimol Stephen, Wiley, 2010, trang 147 – 148
Nguồn: www.books.google.com.vn
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