Morphology and properties of cellulose/silk fibroin blend fiber prepared with 1-butyl-3-methylimidazolium chloride as solvent

1-Butyl-3-methylimidazolium chloride ([BMIM]Cl) was selected as co-solvent to dissolve cellulose and silk fibroin and the cellulose/silk fibroin blend fibers were fabricated with dry-jet wet spinning technology. The phase morphology of cellulose and silk fibroin in the blend fibers was studied by scanning electron microcopy and laser scanning confocal microscope. It is shown that the cellulose is in the continuous phase and silk fibroin exists as fibril-like'' in cellulose, in which the radial dimension of silk fibroin phase is 0.5-1.0 mu m. The phase size of silk fibroin along the fiber axis increased with the increase of silk fibroin content and draw ratio. From the wide-angle X-ray scattering, it is found that the total crystallinity of the blend fibers decreased with increasing silk fibroin content. The hydrogen bond between cellulose and silk fibroin was observed from Fourier transform infrared spectra. Although the tensile strength and initial modulus of blend fibers decreased with increasing silk fibroin content, the tensile strength of blend fibers contain 35 wt% silk fibroin was up to 191 MPa.