Figure 3: Scanning electron microscopy of I-7 (a), Posi-4 (b) and Posi-5 (c) polyester fleeces. SEM shows that fibers of these fleeces are detected in a longitudinal, transversal and oblique course. The fibers exhibit a homogenous composition and a smooth surface without recognizable protrusions or roughness. Posi-4 (b) and Posi-5 (c) polyester fleeces show melted fibers at crossing points and interconnected pores which were not obtained in I-7 (a).