Polypropylene-Clay Nanocomposites Fibers Structure and Performance

Fibers from Polypropylene (PP) and polypropylene nanocomposite (PNC) were produced using a fiber spinning process. Various amounts of different clays were added to the PP matrix. The structure of PP and PNC fibers was evaluated using field emission scanning electron microscopy (FE-SEM) and Xray diffraction. The crystalline axes orientation factors were determined from wide-angle X-ray diffraction pole figures of (I 10) and (040) reflections for PP and of (001) for clay. The d-spacing of the (001) clay crystalline plane, indicative of the clay dispersion, was determined from the intensity - 2 theta plots superimposed on the two dimensional X-ray diagrams. The results obtained for the d-spacing at small angles indicated that the clay in the PNC maintained its intercalated distance at low loadings whereas at higher loadings, some aggregation was observed. Results on orientation of the clay (001) axis (normal to the clay platelets plane) indicated that it was oriented perpendicular to the machine direction, which is expected. Its orientation in the normal and transverse directions was different, suggesting that clay platelets were not randomly distributed in the transverse plane, which was confirmed from SEM observations. The orientation of PP c-axis in the fibers was slightly higher for the nano-composite that the pure resin. Tensile modulus, strength and elongation at break for both PP and PNC fibers increased with increasing draw ratio. Flexural modulus and strength of laminates made by consolidation of the PNC fibers were higher than those of consolidated pure PP fibers as well as those of bulk PP or PNC.