Polymer optical fibers for textile applications – Bicomponent melt spinning from cyclic olefin polymer and structural characteristics revealed by wide angle X-ray diffraction

To obtain thin and flexible polymer optical fibers (POFs) for textile applications, bicomponent melt-spun fibers with a cyclo-olefin polymer (COP) in the core and a tetrafluoroethylene–hexafluoropropylene–vinylidene fluoride terpolymer (THV) in the sheath have been co-extruded on the pilot scale. With higher draw ratio, the orientation within the amorphous COP core increases and the preferred interchain distances gradually change in response to the drawing parameters, as could be revealed by wide angle X-ray diffraction (WAXD). The bicomponent arrangement can promote the formation of a regular core surface because irregularities at the interface between the core and the sheath component can even out thanks to thermal shielding by the sheath component. Light propagation loss (9 dB/m at 652 nm for the most transparent fibers) and tensile properties of the fibers turned out to be adequate to enable their use in industrially produced luminous textiles.