Effects of Acid, Alkali and Salt Treatments on the Preparation Rate and Morphological Characteristics of Tussah Silk Short Fibers

Abstract

【Objective】The study was conducted to screen suitable methods for preparing tussah silk short fibers to provide more options for the development of new biomaterials.【Method】Tussah silk fibroin was dissolved by HCl, NaOH and FeCl3. The effects of solvent concentration, hydrolysis time and hydrolysis temperature on the preparation rate of tussah silk short fibers were investigated. The morphological and structural characteristics of tussah silk short fibers were observed by the inverted microscope.【Result】The preparation rates of tussah short fibers prepared by HCl, NaOH and FeCl3 solvents were 26.5%, 23.56% and 21.8%, respectively. There was little difference in the preparation rate of short fibers with the three methods. The morphological characteristics of three kinds of tussah short fibers were observed. The ones prepared by FeCl3 hydrolysis were short rod-shaped with flat or bevel cut at both ends, with different lengths, which were darker than the others. The ones prepared by NaOH hydrolysis was lighter in color and transparent, in the form of irregular flakes. The ones prepared by HCl hydrolysis had a better morphology with the shape of short slender rods, lighter color, a smoother surface and flat cuts on both sides, and the lengths of the short fibers were mainly ranged from 50 to 125 μm (accounting for 52.68%).【Conclusion】The process conditions for the preparation of tussah silk short fibers by HCl hydrolysis were: HCl concentration 3 mol/L, hydrolysis time 40 min, hydrolysis temperature 90℃. The hydrolysis conditions were mild, and the tussah silk short fibers processed by HCl method were relatively ideal, which could provide a new carrier for the development of biomaterials.

Keywords

• tussah silk fibroin
• short fiber
• acid hydrolysis
• preparation rate
• morphological structure