Investigation into electrospinning water-soluble xylan: developing applications from highly absorbent and hydrophilic surfaces to carbonized fiber

Heteropolysaccharides such as xylans are abundant renewable resources that could potentially replace some fossil-fuel derived chemicals and materials in packaging and personal care products. In this study, water-soluble xylan extracted from wheat straw was electrospun into nanofibers with a high molecular weight carrier polymer, polyethylene oxide (PEO). Bead-free uniform nanofibers with diameters ranging from 167 to 634 nm were produced with content of PEO as low as 4% of dry weight. The rheology of xylan/PEO aqueous solutions were studied and the effects of xylan-to-PEO ratio on the properties of fibers were correlated. Strong intermolecular interactions between xylan and PEO was found by Fourier transform infrared spectroscopy and differential scanning calorimetry as noted by shifts in vibrational absorbance bands and an increase in the T_g of PEO. In addition, an attempt was made to produce carbon material from xylan-based electrospun fiber mats. The effect of heat treatment in air and inert atmosphere on the hydrophilicity and mechanical properties of electrospun fibers was discussed in terms of making xylan into functional materials. The samples were transformed from being able to be rapidly redissolved in water into water-insoluble, yet hydrophilic materials, and finally to hydrophobic materials when comparing the as-spun fiber to air oxidized fiber and samples after carbonization, respectively.