Melt-spun poly(trimethylene terephthalate) (PTT) fibers were zone-drawn and the structures and properties of the fibers were investigated in consideration of the spinning and zone-drawing conditions. The draw ratio increased up to 4 with increasing drawing temperature to 180°C, at a maximum drawing stress of 220 MPa. Higher take-up velocity gave lower drawability of the fiber. The PTT fiber taken up at 4000 rpm was hardly drawn, in spite of using maximum drawing stress, because a high degree of orientation had been achieved in the spinning procedure. However, an additional enhancement of birefringence was observed, indicating a further orientation of PTT molecules by zone drawing. The exotherm peak at 60°C disappeared and was shifted to a lower temperature with an increase in the take-up velocity, which means that the orientation and crystallinity of the fiber increased. The d-spacing of (002) plane increased with increasing take-up velocity and draw ratio, whereas those of (010) and (001) planes decreased. In all cases, the crystal size increased with take-up velocity and draw ratio. The cold-drawn PTT fiber revealed a kink band structure, which disappeared as the drawing temperature was raised. The physical properties of zone-drawn PTT fibers were improved as the draw ratio and take-up velocity increased.
Coptis chinensis (CC) is used in conventional Chinese medicine. The main active components of CC are isoquinoline alkaloids, including berberine, coptisine, palmatine, and magnoflorine; all these are known to have several pharmacological properties. Poly(vinyl alcohol) (PVA) is a well-known synthetic biocompatible polymer suitable for a range of pharmaceutical uses; it can be used as a matrix for the incorporation of functional materials and has a wide range of applications in the cosmetics, food, pharmaceutical, and packaging industries. In this study, PVA-based electrospun nanofibers containing CC extract were successfully fabricated. Furthermore, the effects of different CC extract contents on the morphologies, and antimicrobial and antifungal properties of PVA/CC extract nanofibers were investigated. Morphological changes were observed using different molecular weights of PVA. For characterization, field-emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared analysis were performed. The effectiveness of these nanofibers has been demonstrated by evaluating the thermal stability against Staphylococcus aureus, antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis, and the antifungal activity against the fungi Aureobasidium pullulans and Penicillium pinophilum. The PVA/CC extract nanofibers were found to have excellent antibacterial and antifungal activity and thermal stability; hence, their use in medicinal sectors is highly recommended.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.