Modification of Polyacrylonitrile Fibers with Fibroin Nanoparticles. Production and Attachment of Fibroin Nanoparticles to Pan Fiber

Abstract

An aqueous solution of fibroin nanoparticles, obtained as a result of thermal hydrolysis of the waste products from silk fibers, was used to modify polyacrylonitrile fibers. According to light scattering data, the fibroin nanoparticles in aqueous solution had hydrodynamic radii of 75-95 nm. It was established by chromato-mass spectroscopy that the nanoparticles contain oligomeric fragments of a polypeptide chain and the products from their condensation with the formation of cyclic diketopiperazines. In the IR spectra of the fibers after treatment with fibroin nanoparticles there are bands associated with the absorption of N–H groups. The intermolecular interaction between the carbonyls of PAN in the fiber and the active groups of the fibroin oligomers can be judged from the shift of the C=O bands of itaconic acid into the low-frequency region and from the increase in the absorption of the ester groups. Strong attachment of the fibroin nanoparticles to the PAN fiber is favored by chemical reaction between the carboxyls of the itaconic acid in the structure of the fiber and the amino groups of the fibroin fragments. The increase of the relative nitrogen content after modification of the PAN fibers with fibroin nanoparticles is confirmed by the results of elemental analysis.