Preparation and characterization of silk fibroin /cellulose acetate blend fiber felt

The blend solution prepared by dissolving silk fibroin(SF) and cellulose acetate(CA) in formic acid at different mass concentrations was electrospun into SF /CA blend fibers and then processed into SF /CA felt.The SF /CA fiber felt was studied by SEM and XRD.The results showed that the spinnability of SF was remarkably improved with a small quantity of CA(no more than 10%),and the blend fibers were fine and uniform with the fiber diameters ranging from 50 nm to 300 nm.When CA content was 10%,the SF /CA blends showed excellent spinnability without any beads or droplets.However,the spinnability of SF /CA deteriorated seriously when the content of CA was more than 30%,and the electrospun SF /CA blend nanofibers were discontinuous,sticky,and forming dendritic structure with lots of beads.The XRD analysis showed that adding a small quantity of CA(no more than 10%) could induce the conformation transition of SF molecules transforming from random coil to β-sheet.Nevertheless,the phase separation was observed between SF and CA in blend nanofibers when the content of CA was more than 30%.