Thermal degradation of PAN fibers modified with hydrazine hydrate and strontium ions

In this work, we added strontium ions to hydrolyzed PAN fibers to improve their thermal resistance. For comparison, we characterized hydrolyzed non-modified (PAN-H) and strontium-modified PAN fibers (PAN-H-Sr) using techniques such as XRD, FTIR, TG, DSC, and SEM. Our XRD diffractograms demonstrated that PAN-H-Sr was more crystalline, while the FTIR spectra confirmed that both fibers underwent hydrolysis by breaking nitrile group bonds, and the refractory cation was incorporated into the fiber through the O–Sr–O bond. SEM micrographs showed that the width of the PAN-H-Sr fiber decreased, and a stiffer structure was obtained. The TG and DSC analysis indicated that PAN-H-Sr presented higher thermal stability since the presence of strontium delayed the degradation reactions of PAN, and, at the end of the heat treatment, exposed a more significant residual mass equivalent to 48.55%.