Вестник Витебского
государственного
технологического
университета

Abstract

To assess the influence of highly dispersed particles on the thermochemical behavior of the thermosetting structure of polyacrylonitrile fibers they modify, a research was carried out using synchronous thermal analysis to determine changes in the nature of heat flow and mass loss in fiber samples with varying particle contents of CuO, Zn, ZnO, MgO, Fe₃O₄, and Ni from 0 to 5.0 % (wt.), with sizes ranging from 20 to 110 nm and specific surface areas ranging from 5 to 40 m²/g.

Significant differences were found in the influence of the nature and content of nanoscale particles on the thermochemical processes in the thermosetting structure of nanomodified polyacrylonitrile fibrous materials. Nanoscale CuO and MgO particles exert the most active, yet antibate, influence on the thermochemical behavior of polyacrylonitrile fibers, while ZnO and Ni particles exert the least noticeable influence. A pattern has been noted whereby the introduction of nanoscale modifiers in amounts of up to 0.5 % (by weight) into polyacrylonitrile fibers typically leads to a greater specific change in the onset, maximum, and end temperatures and magnitudes of thermal effects, as well as mass loss during thermochemical transformation during polycyclization and thermal-oxidative degradation of the fiber's polymer structure, than a subsequent increase in the content of these nanoparticles in the fiber.

Data have been obtained indicating the potential for the effective use of nanoscale modifiers for targeted modification of the thermosetting properties and fire resistance of polyacrylonitrile fibrous materials, both in the development of precursors for carbon fibrous materials containing active inclusions and in materials with reduced flammability or increased heat resistance.

Thermochemical behavior of polyacrylonitrile fibers modified with highly dispersed materials