Effects Of Supercritical CO₂Fluid Treatment On The Structure And Properties Of PBT Fiber

In this paper, the PBT fibers were treated in supercritical CO₂fluid at differenttreatment conditions. The effects of supercritical CO₂fluid treatment on the structure andproperties of PBT fiber are analyzed. The effects of different treatments on the surfacemorphology, aggregation and chemical structures of PBT fiber in supercritical CO₂fluidwere investigated by X-ray powder diffraction （WAXS）, fourier transform infraredspectroscopy （FT-IR）, scanning electron microscope （SEM）, differential thermal analysis（DTA） technology. Some mechanics properties of the PBT fiber were also tested.The results indicated that some low-molecule polymers were removed from the PBTfiber after treating by the supercritical CO₂fluid, and adhered at the surface of PBT fiber.This phenomenon will increase when the temperature and pressure were increased. Butthese low-molecule polymers will be dissolved in the CO₂fluid when the treat-timeincreasing. The crystallization of the PBT fiber will decrease after treating by thesupercritical CO₂fluid. The mechanics properties （fracture strength, fracture elongate ect.）also were decreased at different degree, it has a greatest decrease when the temperature is80℃, the pressure is20MPa and the treating-time is1h. A reduced thermal stability of PBTfiber was also observed after a treatment in supercritical CO₂fluid.