Wall reinforcement mechanical properties

The main reason for the recent popularity of nanotechnology is that the reduction of the dimensions of a material to nanosize leads to new specific properties [82]. It is crucial to understand the intrinsic mechanical properties of CNFs in order to incorporate them into polymer resins to fabricate CNFs-reinforced nanocomposites. Because of the structural complexity of CNFs derived from variations in inner and outer wall thickness, cone angle, orientation of graphite plane, and C-C bonds, determination of their mechanical properties had posted considerable difficulties. To date, direct measurement of tensile properties of CNFs is accessible only with the aid... 

Among the many potential applications of carbon nanotubes (CNTs), their use as reinforcing fillers for fhe fabrication of polymer nanocomposites has received considerable attention [1-4]. Both single-walled and multiwalled carbon nanotubes (SWCNTs and MWCNTs, respectively) are noted for their outstanding thermal, electrical, and mechanical properties. Polypropylene (PP) is a widely used thermoplastic because of its low cost, good processability, and well-balanced physical and mechanical properties. Products of PP take the forms of fibers, films, and molded articles. This chapter highlights the microstructure and properties of PP/CNT nanocomposites. Since most studies dealt with isotactic polypropylene, the term TP" in this chapter refers to isotactic polypropylene unless otherwise stated. 

Similarly, Saeed and Park [65] synthesized PA 6-multiwaIl carbon nanotubes (MWNTs) nanocomposites via the in-situ polymerization technique, using pristine and COOH-functionalized MWNTs. Based on SEM morphology analysis, it was shown that the COOH-functionalized MWNTs were better dispersed in the PA 6 matrix than the pristine ones, owing to the covalent attachment of PA 6 molecular chains to the side walls of MWNTs, which could act as in-situ compatibilizers in the nanocomposites and enhance the dispersion of MWNTs. In terms of physical properties, the crystallization of nanocomposites was increased compared to that of virgin PA 6, due to the nucleation effect of MWNTs, while the thermal stability under nitrogen of the nanocomposites was superior. Turning to the mechanical properties of the nanocomposites, the uniformly dispersed MWNTs improved the tensile properties because of the reinforcement effect. 

Notwithstanding the high mechanical properties of composite materials, a reinforcement intervention taking into account its use has to be carried out on those structural elements not showing special damages, which may prevent the transfer of stresses between the wall ashlars forming it. 

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