Mechanism of interaction between hydrolytic lignin and Poly(acrylonitrile)

Abstract

Interaction between polyacrylonitrile (PAN) and hydrolytic lignin (THL) in mixed binary solution dimethyl sulfoxide/water (70:30) allowed us to obtain homogeneous forming solution of the THL/PAN composite. This forming solution was used for preparation of fibers and films which served as precursors for carbon materials. In the present work, we considered and substantiated the proposed mechanism of the formation of the THL/PAN composite based on the structure of the initial polymers. We believe that interaction between reactive groups present in PAN and THL leads to the formation of graft copolymer. Fundamentally, this reaction is possible and may proceed according to the well-known Ritter mechanism It was demonstrated that the process of grafting nitrile groups to THL macromolecules is controlled by duration and temperature of interaction between the initial compounds in solution; this process is completed in 10 h at a temperature of 120 °C. Tentative calculation shows that for each statistically averaged PAN macromolecule there are five THL molecules with activated hydroxyl groups. These forming solutions are suitable for moulding fibers which serve as precursors for carbon fibrous materials.