The technology of creating a more solid composite reinforcement was developed at the School of Engineering, Far Eastern Federal University (FEFU SE). The inventors proposed adding carbon nanotubes from the moss to improve the physical and mechanical properties of the building material. The authors of the development: Alexander Becker, Director of the Institute of Far Eastern Philology, and Andrey Umansky, Research Associate, Arctic R&D Center International Research and Education Center, received a patent for the invention.
According to Alexander Becker concrete products with composite reinforcement have high deformability and a width of crack growth as compared to samples with steel reinforcement. The FEFU engineers decided to strengthen the structure of the composite reinforcement with the help of nanotechnology.
The basis of the new reinforcement is a variety of high-strength continuous fibers. They are combined into a reinforcement bar by a polymer matrix, which holds the fibers together and protects them from the corrosive effects of the environment. The inventors added carbon nanotubes in the epoxy resin of the matrix. They act as a reinforcement material at the microlevel and, thanks to their properties, are centers of directed crystallization.
“Carbon nanotubes have high mechanical characteristics and can be used as an effective means of improving the physicomechanical properties of composites. This is explained by the fact that the free chemical bonds of nanotubes provide better adhesion of components and, as a consequence, increase the strength of the material,” explained Alexander Becker.
The new reinforcement with nanotubes is characterized by an increased tensile resistance (by 75-97% compared to the conventional one) and a higher modulus of elasticity under compression / stretching (by 7-15%).
An interesting feature of the technology lies in the method of obtaining nanotubes. They are made from brown sphagnum moss (Sphagnum fuscum), collected in the marshes of the Lower Amur region. This moss is actively used in construction due to its low thermal conductivity and resistance to decomposition. Now it demonstrates new unique properties. Carbon nanotubes with a diameter of 10-20 nanometers are obtained after mechanical, thermal, and chemical processing of natural raw materials. Scientists suggest to use the nanotubes for strengthening reinforcement.