Bodo FIEDLER 博士 特別講演会

Since the discovery of carbon nanotubes (CNTs) in 1991 by Iijima [1] research activities focussed mainly on the evaluation of nanotube properties themselves. The unique mechanical properties of CNTs, their high strength and stiffness and the enormous aspect ratio exhibit a high potential for several applications. Composites with nanotubes as reinforcing elements should show improved mechanical properties [2-5], and an electrical and thermal conductivity together with a low density [6].The investigation of a functionalisation of the nanotube surface on the dispersion behaviour and the interfacial adhesion will be a key issue in the realisation of nanotube reinforced polymers. A mechanical reinforcement of polymers by CNTs can only be realised by finding appropriate methods to achieve a homogeneous dispersion of the nanotubes in the polymer and to strengthen the interfacial adhesion between the CNT and the matrix. Frankland et al. [7] confirmed the influence of a functionalisation on the interfacial adhesion by simulations which predict that a functionalisation of less then one percent would improve the interaction between nanotubes and the polymer without decreasing their strength significantly.

Within this presentation the results of the investigation of nanocomposites based on epoxy resin and catalytically grown nanotubes, either functionalised or not will be presented. The DMTA showed strong influence of the nanotube content and functionalisation on the loss modulus and glass-transition temperature Tg (Fig. 1). This effect gives evidences for the relevance of a surface modification of carbon nanotubes to achieve good nanotube-polymer interactions. The introduced nanotubes can interact with the epoxy due to their enormous surface area. This interfacial interaction reduces the mobility of the epoxy matrix around the nanotubes and leads to the observed increase in thermal stability. The results could be substantiated by SEM and TEM observations (Fig. 2)[8].

Besides the influence of the CNTs on an improvement of strength and stiffness of the nanocomposite also a toughening effect could observed.

By an RTM process a glass fibre reinforced carbon nanotube modified epoxy matrix composite was produced. By adding 0.1% CNT the fracture toughness of the neat resin was increased by 20% [9] and the interlaminar shear strength (ILSS )of the GFRP increased by 15% [10].