Nanofiber and Nanofiber Powder of Syndiotactic Polystyrene Fabricated by Laser-Heated Drawing of Sea-Island-Type Conjugated-Spun Fiber

By laser beam irradiation of laser-heated drawing, running fiber can be heated rapidly and uniformly. By applying laser-heated drawing to sea-island-type conjugated-spun fibers of syndiotactic polystyrene (sPS) and poly(ethylene terephthalate) (PET), sPS nanofiber and nanofiber powder were fabricated after extraction of the PET component. The PET/sPS conjugated-spun fibers could be laser-drawn stably at the glass transition temperature of each component polymer. By drawing at the glass transition temperature of sPS, the sPS island fibers could be drawn continuously and the sPS component in the drawn fibers indicated a higher crystal orientation than the PET component. The sPS nanofiber bundles had a strength of approximately 300 MPa and sPS nanofibers with an average diameter of 0.43 µm were obtained after extraction of the PET component. By drawing at the glass transition temperature of PET, the fiber could be drawn to a higher draw ratio if the PET fraction was high, but the sPS island fibers were broken into small pieces. As a result, sPS nanofiber powders with a length almost 24 times of their diameter were obtained by extracting the PET component after drawing. The 0.5 µm diameter and 12 µm length were the minimum sizes of the obtained nanofiber powder.