Surface modification of astralenes for obtaining optical composites based on photocurable acrylates

The development of communication systems based on the principle of quantum key distribution (QKD) requires the creation of new materials capable of limiting the power of laser radiation in optical systems. A promising solution may be a material based on acrylates and astralenes. However, the creation of an optical composite requires modification of the particle surface for uniform distribution of particles in the matrix. The two-stage modification technique developed by the authors allows reducing the amount of disordered carbon in the astralenes, as well as making them compatible with photocurable acrylic monomers. As a result, a transparent optical composite is obtained by photopolymerization. The success of the modification process is confirmed by the results of Raman and FTIR spectroscopy, TG analysis. The TEM method showed that the toroidal structure of the particles is preserved after the modification process. The study compared composites with 0.01, 0.05, 0.10%wt. astralenes and the acrylic copolymer. It is found that the introduction of particles into the reaction mass reduces the polymerization rate by more than 40%. At the same time, the conversion degree in samples with and without astralenes is comparable. The introduction of astralenes in the selected concentrations does not significantly affect the optical band gap of the material. The transparency of the obtained composites in the visible region and near IR range is ~ 90%, which allows them to be called optical.