Carbon sp3 hybridization bonds in composites “polymer – CNT”

Abstract

The possibilities to enhance the properties of nanostructured surfaces have been demonstrated on "polymermultiwall carbon nanotubes" composites. Carbon nanotubes are among the most anisotropic materials known and have extremely high values of the Young modulus. Influence of sp 3 hybridization bonds on polymer crystallization and strengthening was investigated in composite films of polyethyleneimine, polyamide and polypropylene with multiwall carbon nanotubes. IR absorption maxima were measured after formation of composite "polyethyleneimine-carbon nanotubes" in the area of the sp 3 hybridization bonds at the frequency of primary amino groups of polyethyleneimine. High IR absorption at frequencies of sp 3 hybridization bonds of polypropylene, polyamide-6 with carbon nanotubes is determined by γ ω (CН) and γ ω (CH 2) vibrations as a result of the formation of CC bonds in the polymer chains, which increases the crystallization of polymers and the strength of the composites. The IR absorption peak dependences on the carbon nanotube content at frequencies of sp 3 hybridization bonds are described by a 1D Gaussian curve for the diffusion equation in the electric field. Thus, the way to improve the strength properties of "polymer-CNTs" composites is the polymer crystallization as a result of the transformation of the CC bonds in the polymer chains supported by the resonances of the primary amino groups, γ ω (CH) and γ ω (CH 2) in the electric field between the nanotubes and polymer matrix. Tensile strength for polyamide-6 composites at 0.25 % CNT increases 1.7 times and tensile deformation-2.3 times.