The Modification Research Of Electrospun Zein Micro/Nanofiber

Electrospinning is a simple and effective method for the preparation of micro/nanofibers,which can be applied to many kinds of polymers.Zein is a kind of natural protein with excellent properties,such as film-forming,biodegradability and biocompatibility.Zein fiber films prepared by electrospun has the characteristics of large specific surface area,large porosity and biodegradability,it has broad application prospects in the field of biomedicine.There are still many problems restricting the zein fibers‘s industrialized production and application fields extending,especially the poor strength and poor hydrophilicity.So it is an important direction to find a way to improve the mechanical properties and hydrophilicity of zein fibers.This paper focuses on the two respects to conduct researches.On the one hand,the binary mixtures of ethanol and water was chosen as the solvent to prepare zein fibers and the composition ratio of solvent is changed to explore its effect on fiber morphology and properties.On the other hand,the effect of different modification methods on the properties of zein fibers was studied.When the ethanol/water(60%~90%(w/w))solution was used as the solvent of zein electrospun solution,the uniform micro/nanofibers can be obtained.And the zein solution in ethanol/water 60%(w/w)yields the zein fibers with coarse,round-like morphology,while the zein fibers with a smooth and ribbon-like morphology could be observed when zein solution in ethanol/water 70%,80% and 90%(w/w).The width of the fibers increased with the increase of the proportion of ethanol mass.The electrospun zein fiber membranes had poor surface wettability and mechanical property.Pressure treatment of electrospun zein fibers had good modification effect.Whether it was round-like or ribbon-like electrospun zein fibers after a certain range pressure processing,the mechanical property was greatly improved.The breaking strength of zein fiber membranes increased with increasing pressure,and fiber membranes are gradually changed from hydrophobic to hydrophilic.Cellulose nanofibril(CNF)was blended with zein solution to prepare the electrospun zein/CNF micro/nanofibers,and CNF was dispersed in the zein matrix as the reinforcing filler.The results indicated that the breaking strength of the fiber membranes increased with the increase of CNF content,the elongation at break decreased.The water contact angle decreases with the increase of CNF content.The mechanical property and hydrophilicity of zein fiber membrane were improved by the addition of CNF.By using electrospun technology,Zein /PVA and Zein /PVA/CNF micro/nanofibers without bead defects could be obtained.The results indicated that there were two kinds of fibers with different morphology in the Zein/PVA fiber membrane,and only one kind of fiber with coarse,round-like morphology could be found in the Zein/PVA/CNF fiber membrane.It can be inferred from the test results of Fourier transform infrared spectroscopy(FTIR)and differential scanning calorimetry(DSC)that CNF played a role in the connection between zein and PVA.The average breaking strength and elongation were substantial growth when PVA or PVA/CNF were added in zein electrospun solution,and the water contact angle was decreased.The PVA/CNF,PVA has better effect on improving the mechanical property and surface wettability of zein micro/nanofiber membrane.