Crosslinking and carbonization of electrospun lignosulfonate fiber

Abstract

Submicron-sized fiber of lignosulfonate can be electrospun from aqueous solution, signifying the possibility of green processing for biobased polymer. The resulted fiber, however, is susceptible to the influence of water, which limits its use for wet applications such as water filtration. The objective of this study is to examine the effects of crosslinking on the water resistance of the electrospun fiber. It is also aimed at investigating thermal stability of the crosslinked fiber, paving the way for facilitating its further conversion to activated carbon fiber and related products. Selected crosslinkers are blended at various dosages into the spinning solution. The electrospun fiber mat is thermally treated to allow chemical crosslinking, and in the case of carbon fiber fabrication, to further induce pre-oxidation. The pre-oxidized fiber is then carbonized and physically activated. The effects of crosslinking on fiber properties are evaluated using water soaking and thermogravimetric analysis; its subsequent influence on carbonization is examined based on the morphology (electron microscopy), carbon content (elemental analysis), gravimetric yield, and specific surface area (N2 adsorption) of the carbon fiber mats. Results of these tests will be discussed in relation to water and thermal stability of the modified fiber, together with implications on its application potential.