EFFECT OF INORGANIC FILLERS ON MECHANICAL PROPERTIES OF POLYURETHANES

 A number of polyurethane foam composites modified with fillers of different nature (hydrophilic modified fullerene soot, hydrophobic fullerene soot, alumina (III) oxide, chromium (III) oxide) were synthesized. The filler was introduced into the prepolymer, which was then mixed with the hardener, in the way that the polymerization and crosslinking took place in its presence. A «Shimadzu» rupture machine, a «Novotcontrol» dielectric spectrometer, a «Bruker» IR Fourier spectrometer were used for the study. The cells were analyzed with the use of «Micromed С-11» microscope. The physical properties of polyurethane foams depend heavily on the size of the bubbles and, as a consequence, on the apparent density. In turn, these parameters are determined by a large number of others: the distribution of bubbles in size, the thickness of the bubble walls, and anisotropy of the polyurethane foam internal structure. Statistical analysis of the microscopy of samples showed that the introduction of nanoparticles leads to increase in the average cell diameter, and, as a result, to thermal conductivity growth. In addition, the mechanical strength of all foams increases with the introduction of all types of nanoparticles, except for the case with chromium (III) oxide. This fact may be associated with the antiplasicizing action of the particles on the polymer matrix. FT-IR spectroscopy was used to analyze the effect mechanisms of the fillers. It showed that the effect of particles on the polyurethane properties is related to the formation of hydrogen bonds between the particles and the matrix that leads to a change in the ratio of rigid and mobile polyurethane domains. The use of dielectric spectroscopy made it possible to establish that the glass transition temperature of the polymer also increases together with the increase in the content of hard domains

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