ИСТИНА

The primary factor restricting the application of optical fibres in a various areas, such as the oil and gas industry, chemical industry and medicine, is their insufficient resistance to the aggressive attack of the ambient medium and temperature, which is determined primarily by the properties of their protective coating. Coating should protect the surface of optical glass fibres against mechanical damage and direct contact with the ambient medium.  Widely used (acrylate-based) protective polymer coatings allow optical fibres to be employed at temperatures no higher than 85 °C. They are sensitive to the presence of many chemicals in the ambient medium. Currently protective coatings based on polyimides are the most progressive. Polyimides provide termalstability; oil, acid resistance and etc. However, the main imperfections of polyimides are the multistage coating method and significant variation in mechanical strength. In this research, we present our first results on the fabrication of new, high-performance coatings for optical fibres based on polycaproamide/carbon nanotubes nanocomposites. The polycaproamide (PCA) composites were obtained by anionic in situ ε-caprolactam polymerization in the presence of 0.001-0.1 wt. % of previously functionalized by polyimides single-walled carbon nanotubes (SWCNTs). Such nanotubes modification provides their homogeneous distribution inside polymer as well as improves some performance properties of polycaproamide. Two methods for the modification of SWCNTs were proposed: covalent and non-covalent functionalization by polyimides. The modified nanotubes as well as PCA/SWCNTs composites were thoroughly examined by the series of instrumental techniques including thermogravimetric and elemental analysis, XPS, SEM, TMA, mechanical tests, etc. It was shown both methods of nanotubes modification increase the thermal stability; enhance the compression modulus and impact strength of polymer blocks and advance the tensile strength and elongation of polymer films. Obtained composites were used as coatings for optical fibers. These composites as the coatings have high adhesion to the optical fibers, feature sufficient resistance to the aggressive medium and possess a combination of valuable mechanical properties. This work was supported by the Russian Science Foundation (Grant No. 14-13-01273).