Furnace for in-situ characterization of the preoxidation of polyacrylonitrile (PAN) fibers by wide angle X-ray scattering (WAXS)

Polyacrylonitrile (PAN) based carbon fibers possess high performance and wide applications. Preoxidation, as one of the crucial steps in the preparation of carbon fibers, refers to the process in which the polyacrylonitrile fibers are oxidized to form the embryo of carbon lamellar structure below 300 °C in air. Synchrotron radiation wide angle X-ray scattering (WAXS) is an ideal method for the in-situ study of the preoxidation of fibers. However, an appropriate heating furnace is required to obtain anisotropic two-dimensional scattering/diffraction images. This paper reports the development of a small, simple furnace (300 °C) with flared mouth/outlet (90°) and a fiber sample bracket. The preoxidation of polyacrylonitrile fibers in the furnace was monitored in situ by synchrotron radiation wide angle X-ray scattering and the serviceability of the furnace was verified.