Study On Wet Spinning Of Regenerated Silk Fibroin Fiber

Cocoon silk has been noted by biologist, chemist and materials scientist in recent years for its excellent comprehensive mechanical properties which is produced sustainably and ecologically and its biology’s highly evolved production’technology’. Combine insights into the characterization and understanding of evolved structure, property and function in natural silk proteins, people has designed various artificial spinning processes to produce regenerated silk fibroin fibers, hoping their mechanical properties could be comparable with natural ones. Regenerated silk fibroin (RSF) fibers were obtained by extruding of concentrated silk fibroin aqueous solution into ammonium sulphate coagulation bath. A custom-made simplified industrial wet-spinning device with continuous mechanical post-drawn was used in our trial spinning. It is interesting to note that the draw down ratio of6producing the best molecular orientation and tensile properties in the present work after modulation of rolling rate, draw ratio and step distribution. We further investigated the influence to the morphology and mechanical properties of RSF fibers when calcium ions or multi-wall carbon nanotubes were introduced.As to wet-spinning, firstly, to the draw down ratio of6, the mechanical properties of RSF fibers produced by45r/minâ†'135r/minâ†'270r/min stood out of three routes. Secondly, we compared RSF fibers produced in coagulation bath with different concentration and temperature. Found that RSF fibers produced in higher temperature had a relatively better morphology and mechanical properties. While fibers produced in lower concentration had a relatively better morphology but a worse mechanical properties.Once calcium ions were introduced in RSF solution, RSF fibers with good morphology and mechanical properties were produced in both lower and higher temperature. Its break strength was0.36GPa, break elongation was36%.We used simplified blend method to prepare RSF/modified MWCNTs solution with a RSF/CNTs ratio of1000/1. The solution was homogeneous and stable. RSF fibers produced from this solution showed a dense and homogeneous cross section morphology. The mechanical test showed Its break strength was0.39GPa, break elongation was48%. It illustrated that the introduction of modified MWCNTs enhanced the mechanical properties of RSF fibers.