Dispersion Methods of Carbon Nanotubes for the Development of Polymeric Nanocomposites: Characterization and Application

Composites use is increased worldwide quickly because they present significant advantages over traditional materials, as metals. It is able to get improved and tailored properties to each application by means the formulation. Initially, composites were used in advanced technologically sectors as aeronautical, although the technological advance and manufacturing cost reduction have promoted their use in different industrial sectors as building, renewable energies, automotive, sports, nautic, etc. In all cases there are needs to reduce weight, to improve the resistance in aggressive environments and to keep high performances during the life-span in more demanding applications. In this chapter is shown the development of thermoset multiscale composites with improved properties, making special emphasis in the dispersion method of the nanoreinforcements. Thermoset multiscale composites consist of glass fibers as reinforcement and multiwall carbon nanotubes (MWCNTs) as nanoreinforcement. MWCNTs have a huge potential as nanoreinforcements polymeric matrices because they present unique and excellent mechanical, thermal and electrical properties with a competitive cost. Moreover, currently in the market there is enough availability of these nanomaterials for using in industrial scale. As polymeric matrix has been used polyester resin. These new low cost polymer composite/nanocomposite materials improved with nanoreinforcements opens new market opportunities in large-volume applications as structural composites: civil engineering works, transport sector, etc. The main challenge is to transfer the MWCNTs excellent properties to the polymeric matrix. It requires dispersing the nanoreinforcements as individual particles in the polymeric matrix, to avoid agglomerates. For this reason, it has studied and implemented an advanced dispersion techniques of high shear forces called Three Roll Mills. Following, it has been performed a novel and detailed quality and quantity characterisation of the dispersion rate combining different techniques: viscosity measurements and confocal Raman spectroscopy. Later the samples was characterised from mechanical point of view. It has been obtained a high MWCNTs/CNFs dispersion rate within the matrix by using 3-roll-milling process. It has permitted to work with nanoreinforcements low content: from 0.1 wt % to 1 wt %, obtaining good results with 0.1 wt %. Moreover, it is a process easy to industrial scale up. MWCNT’s distribution map based on intensity RAMAN spectra (at G band) has been obtained. All samples present a high dispersion rate of the nanoreinforcements. Furthermore, correlation between viscosity increasing and nanoreinforcements content and dispersion rate has been observed. From mechanical point of view, the samples present better behavior than original sample (without nanoreinforcements). Depending of nanoreinforcements content and parameters during the dispersion process, the mechanical improvements can be (in the tensile test) up to 13 % in tensile strength and 15 % in Young module, and (in flexural test) up to 26 % and 84 %. Finally is shown an example of structural application of these materials: panel sandwich.