Electrospinning with Condensed Tannins: Effects on Co-spinning with Zein

Abstract

Electrospinning can be applied to renewables creating new materials and applications. We have utilized electrospinning in an attempt to create nanofibers from condensed tannins as well as from binary conjugates formed between this tannin with zein protein. While attempts to directly electrospin pine bark tannin extract proved unsuccessful, combining zein with this tannin gave electrospun fiber from acetic acid and dimethyl formamide (DMF) solutions. To achieve nanofibers possessing significant tannin content, high solids content (≥35%) in DMF solution was required. Electrospun nanofibers (200–400 nm dia.) could be created from zein-tannin combinations with up to 80% tannin content and appropriate solution solids content. Nanofibers could be produced from pre-formed tannin-zein conjugates or via their direct combination as a mixture in the spinning solution. Analysis of thermal stability shows the zein-tannin conjugates have similar thermal properties and stability to zein, being stable up to 240°C.

Keywords:

• Electrospinning
• condensed tannins
• zein protein
• protein conjugates

Acknowledgments

The authors are grateful and would like to thank the New Zealand Royal Society for funding and travel assistance, which was provided through the RSNZ International Mobility Fund.