Abstract
According to the effective medium theory, the anisotropic fillers embedded in dielectric matrix is dominated by interfacial resistance and increase in filling fraction leads to enhanced heat transfer paths. This is a thermal diffusivity dominated mechanism. Previous study has revealed that incorporation of carbon nanotubes (CNTs) into polymers promotes effective thermal conductivity and conduction enhancement is believed arising from the formation of networked conduction paths, consistent with theory described above. This thesis uncovers the primary contribution to conduction from interfacial phonons upon CNT-polymer coupling and phonon density of states is therefore modified, thus influencing specific heat of composites and thermal conductivity. This is described in Chapter 2 and Chapter 3. Although cytotoxicity effect of CNTs has been widely studied, the microbial effect of CNT-polymer composites however remains to be established. In this thesis, we study the Staphyococcus aureus of CNT-nylon 6 composites with or without ultraviolet (UV) radiation exposure. It is confirmed that pure nylon 6 exhibits strong antimicrobial capability under UV irradiation, whereas CNT addition stabilizes composites and antimicrobial effect is found to be suppressed. This outcome is presented in Chapter 4.