Effect of ZnO Nanoparticles on Hydrophobicity, Biological and Mechanical Properties of Side-by-Side Bicomponent PP Fibers

This research investigates the effect of ZnO nanoparticles (ZnO NPs) in the mechanically-robust and nanofunctional side-by-side fibers from a single semicrystalline polymer system using polypropylene (PP) as a model matrix. Firstly, the 20 wt.% ZnO-PP nanocomposite masterbatch (ZnO-PP MB) is found to be an optimal condition with well-dispersed nanoparticles unveiled by transmission electron microscopy (TEM) and flow properties. Then, the ZnO-PP MB is co-spun with virgin PP into side-by-side fibers with ZnO on only one side. The partially-oriented yarns (POY) with optimal 0.6 wt.% ZnO (3ZnO-PP) are then thermally texturized for self-crimp phenomena. Scanning electron microscopy (SEM) reveals uniformly distributed ZnO NPs on only one side of the fibers. The fibers' crystallinity and tenacity are significantly promoted, which could be ascribed to the nucleating and toughening effects of ZnO nanofillers. The excellent antibacterial activities of 3ZnO-PP POY against both S.aureus and K.pneumonia reach 99.9 % reduction as evaluated by direct contact under AATCC100 standard method. However, the texturized 3ZnO-PP yarns lose their resistance to the gram-negative K. Pneumonia, due possibly to the enhanced hydrophobicity inherent to the resulted crimp structures preventing effective bacteria-surface contact. Nevertheless, the texturized yarns improve the anti-abrasion properties of silk and cotton fabrics at 29% and 31%, respectively, while maintaining their soft touch and feel as evaluated by the Kawabata valuation system.