| Abstract: | Abstract The formation and growth of cracks under an effect of ozone were investigated in different types of rubbers, such as NR, PBR, BMSR, SBR and in composite materials based on these rubbers. The study was carried out by the reflection-light optical microscopy method with using the MMP-4 microscope. In the presence of microinhomogeneities in a surface structure the crack formation is shown to start from those defects. In the absence of inhomogeneities the cracks are formed uniformly over the whole surface of a specimen. It is found that even insignificant quantities of low-modulus rubber in the PBR-based composite material may result in changing the shape of a crack during its growth. An attempt is undertaken to describe the shape of formed cracks quantitatively. The calculational and experimental data are presented. The influence of deformation on the number of cracks per surface unit, on their shape, geometrical size, cracking degree is studied for example of natural rubber specimen. |
