Abstract
The effect of nanocarbons of different origin – C60 fullerenes, single-wall carbon nanotubes (SWCNTs), and, as a model, carbonised starch (PSC) – on the structure and properties of a filled and an unfilled polyurethane matrix was investigated. The nanocarbons were introduced into part of a polyurethane prepolymer and treated in an ultrasonic field. The specific surface of the fillers was determined by the method of thermal desorption of nitrogen on a Quantachrome NovaWin instrument (Quantachrome Instruments, USA). Small-angle X-ray scattering (SAXS) data obtained on an Anton Paar (Austria) diffractometer suggest a high surface roughness of the SWCNT particles (fractal dimension D = 2.9) and a low surface roughness of the C60 and PSC (D = 2.0), as well as constancy of the structural organisation of the domains of rigid blocks at distances of the order of 3 nm or less. Large-angle scattering (Bruker D2 Phaser) makes it possible to draw a conclusion concerning the preferential distribution of particles of highly dispersed nanocarbons among elements of the free fluctuation volume of the polyurethane matrix. As a consequence, these particles have no effect on the morphology of elements of the matrix. The lack of dependence of the glass transition temperature, determined by differential scanning calorimetry (DSC 8000, PerkinElmer), on the presence and nature of nanocarbons indicates the constancy of motion of the polymer macromolecules. Data of all these methods indicate that nanocarbon particles are distributed in the interdomain space and preferentially among areas of local stress of the polyurethane polymer matrix. This conclusion is in good agreement with the strength parameters obtained (Tinius Olsen H10KT tensile testing machine, UK): a 20–50% increase in the stress under 100 and 200% elongation and an increase of up to 80% in the tear strength.