Fabrication And Characterization Of Colored Nanofiber Membranes Via Bubble Electrospinning

The domestic and foreign researches on nanofibers have been quite mature,including raw materials,preparation methods and the applications of products.In recent years,the researchers have begun focusing on the study of the coloring technology of nanofiber membranes.It has opened a new research direction for the study of nanofibers.At present,the researches of nanofiber coloring technology mainly focus on foreign countries,and the dyes of coloring are mostly synthetic dyes.China is abundant in natural dyes resources,and the natural dyes are no pollution to the environment.Therefore,this paper selects the natural dyes as colorants.In addition,the processing conditions and technologies of dope dyeing method and bubble electrospinning method for the colored nanofiber membranes produced are introduced in detail.This paper selects the polyacrylonitrile polymer with stable chemical properties as the bubble electrospinning raw material,using natural dyes of emodin and purpurin as colorants,using potassium aluminum sulfate,copper sulfate,ferrous sulfate and zinc sulfate as mordants,and colored nanofiber membranes are fabricated via dope dyeing and bubble electrospinning.In addition,the morphological structure,color features,chemical bonds,crystallinity,thermal properties,mechanical properties and the light fastness of nanofiber membranes are analysed by scanning electron microscopy,spectrophotometer,infrared spectroscopy,X-ray diffraction,thermal analysis,universal material testing machine and light fastness tester.The experimental results of yellow nanofiber membranes produced showed: When the emodin concentration increases,the color of yellow nanofiber membranes becomes deeper.The 10% concentration of emodin is not conducive to bubble electrospinning,because the increasing of emodin concentration will have precipitation in the spinning solution.The appropriate concentration of emodin is 4%-5%.The infrared spectrum showed the characteristic peaks of polyacrylonitrile and emodin,but no new characteristic peak appeared.Addition of zinc sulfate increases the color yield,breaking strength and light fastness of nanofiber membrane,besides,the fiber diameter almost no change.The experimental results of red nanofiber membranes produced showed: When the purpurin concentration increases,the color of red nanofiber membranes becomes deeper.The bubble electrospinning can still proceed smoothly with the 10% concentration of purpurin.The appropriate concentration of purpurin is 4%-10%.Addition of potassium aluminum sulfate and zinc sulfate can change the color and luster of nanofiber membrane,besides,the fiber diameter,breaking strength and light fastness of nanofiber membrane almost no change.The experimental results of mixed colors nanofiber membranes produced showed: When the mass ratio of emodin and purpurin is 1:1,the color and the fiber diameter of nanofiber membrane are between two kinds of monochromatic nanofiber membranes.Also,the light fastness of nanofiber membrane is Grade 4-5.Addition of ferrous sulfate can make nanofiber membrane gain green tone,besides,the fiber diameter,breaking strength and light fastness of nanofiber membrane almost no change.In sum,this paper successfully prepared six kinds of colored nanofiber membranes:(1)emodin 5%,zinc sulfate 2%;(2)purpurin 10%,no mordant;(3)purpurin 5%,aluminum potassium sulfate 2%;(4)purpurin 5%,zinc sulfate 2%;(5)emodin / purpurin 5%(1:1),no mordant;(6)emodin / purpurin 5%(1:1),ferrous sulfate 2%.