Achievement of high surface charge in poly(vinylidene fluoride) fiber yarns through dipole orientation during fabrication

Abstract

Electrospun fiber materials are of scientific interest for use in multiple application areas. Charged fiber structures show enhanced properties as desired for some of these applications. One factor influencing the charge on the fiber structure that has not been explored is fiber alignment. Electrospun fiber structures, such as membranes, typically consist of randomly oriented fibers. Structural properties of the membranes such as mechanical strength are known to be affected by the random orientation of the fibers. It is suspected that fiber orientation may also affect the charge capacity of charged fiber structures. A few approaches to form electrospun yarns have been reported. Some of these approaches can also cause fibers to preferentially align along the yarn axis instead of assembling into a random structure. In this work, a rotating metal cone was used to collect Poly(vinylidene fluoride) electrospun fibers from which stretched yarns were drawn and twisted into yarns. The alignment of the fibers in the yarns was controllable to a degree that allowed exploration of the effect of alignment on charge. Long continuous oriented or random yarns of relatively uniform thickness were produced at a rate of about 10 m/h. The yarns were polarized by methods of heating, stretching, and poling. The results show that the fiber yarn formation process endows more charges to the fibers compared to the normal fiber membrane electrospinning and post polarization. This provides a facile route for the preparation of enhanced chargefunctionalized fiber structures for a wide range of applications.

Acid-Cured Norbornylized Seed Oil Epoxides for Sustainable, Recyclable, and Reprocessable Thermosets and Composite Application

“…7−11 Vegetable oils are a predominant set of natural resources majorly used in alkyds for baking finishes and metal coatings 12−14 or as comonomers in various reported research works 14−18 for varied applications like plasticizers, elastomers, and thermosets. 12,19,20 However, the application of vegetable oils in thermosets is limited by their lower glass transition temperature and sluggish reactivity. 21 However, higher-reactive norbornene ring-incorporated functionalized vegetable oils and their epoxides offer massive promise to surmount the intrinsic constraints.…”

“…One of the key strategies in the development of a sustainable economy of renewable materials is the sustainable use of natural resources . Integration of biodegradability, lower cost, minor toxicity, and green chemistry provides a competitive advantage to bio-based materials compared to petrochemicals. − Naturally resourced polymer products are of the highest demand, − with strong research efforts on understanding their degradation mechanisms, recycling, and environmental impact. − Vegetable oils are a predominant set of natural resources majorly used in alkyds for baking finishes and metal coatings − or as comonomers in various reported research works − for varied applications like plasticizers, elastomers, and thermosets. ,, However, the application of vegetable oils in thermosets is limited by their lower glass transition temperature and sluggish reactivity . However, higher-reactive norbornene ring-incorporated functionalized vegetable oils and their epoxides offer massive promise to surmount the intrinsic constraints. ,− Epoxidized seed oils are currently being used for additives, plasticizers, stabilizers, and specialty coating applications, with many more perspectives being researched for novel applications. − …”