Carbon nanotubes filled polyurethane nano-composites: a filler morphology and surfactant study

Carbon nanotubes (CNT) filled nanocomposites have gained much attention due to their excellent electrical and mechanical properties. The excitement related to such materials seems to be ever increasing as they have already proved their significance in many applications including sports, automotive, aeronautical and electronics industry. However, commercialization has been rather slow due to challenges imposed on developing a new technology. Nevertheless, CNTs are predicted to commercialize to a significant extent in next decade, which can be attributed to crossing barriers such as standardizing bulk production and effective processing methods for nanocomposites. Latex technology has emerged as one of these methods and have shown potential by providing a relatively simple pathway to produce finely dispersed nanocomposites. The main aim of this thesis is to examine the effect of CNT morphology on mechanical and electrical properties of CNT filled nanocomposites. It also addresses the surfactant aspect of latex technology and proposes an approach to make it more eco-friendly by eliminating the use of environmentally toxic surfactants. Latex technology was used to prepare polyurethane nanocomposites. CNTs were dispersed in aqueous surfactant solution with the aid of ultrasonic energy to produce CNT dispersions; which were further mixed with polymer latex and casted into nanocomposite films. The results of this study suggests that aspect ratio of CNTs is more accurate parameter for characterizing the mechanical properties. On the other hand, electrical properties are more dependent on length of CNTs. The results of surfactant study, for the first time, suggest that Dabco DC 193 is an efficient surfactant for dispersing nanotubes in water. DC193 has indicated to have potential as an eco-friendly alternative to Triton X-100; a popular surfactant which is toxic to the environment. Results drawn in this work provides lucid understanding to behaviour of CNTs in polymeric matrix, which are likely to contribute towards commercialization of latex technology.