Wet Functionalization of Carbon Nanotubes and Its Applications in Rubber Composites

Vulcanized rubber products have found various application fields for more than 100 years. Generally, reinforcing fillers such as carbon black (CB) and silica are used to compound with the rubber for the desired properties. Due to prominent mechanical, thermal, and electrical properties, carbon nanotubes (CNTs) have received tremendous interest as the reinforcing filler to fabricate functional polymer composites. Compared with CB and silica, the exceptionally high aspect ratio and surface area of CNTs gives CNT-reinforced rubber composites extraordinary properties with very low loading concentrations. However, due to strong internal van der Waals interactions, the functionalization, usually physical and/or chemical, of the CNTs is often conducted before incorporating them into the rubber matrix. This chapter comprehensively describes functionalization of CNTs. Particular emphasis is placed on the physical and chemical approaches. Afterwards, a discussion on the mechanical, thermal, and electrical properties of functionalized CNTs/rubber composites is included.