Polycaproamide Modified by Single-Walled Carbon Nanotubes as Protective Coating for Optical Fiber

New optical fiber coatings based on polycaproamide modified by carbon nanotubes have been tested. Nanocomposites were fabricated by in situ anionic polymerization of ϵ-caprolactam in the presence of 0.005–0.01 wt.% single-walled carbon nanotubes functionalized with polyimide. It was found that obtained nanocomposites are able to form high-grade, heat and water resistant optical fiber coatings with improved mechanical strength. These as prepared fiber coatings are differed in high bending strength (∼6 GPa). Annealing for 3 and 72 h at temperatures high as 250 and 200°C respectively reduces the bending strength of such coated optical fiber by no more than 5%.