Study On The Structure And Modification Of Electrospun Starch Nanofibers

As a kind of renewable natural resource,starch has many advantages such as rich source,low price and huge output.Besides,it has good biocompatibility and biodegradability.It meets the requirement of environmental protection and sustainable development strategy.Because of its unique polyhydroxy molecular structure,forming a large number of intramolecular hydrogen bonds and intermolecular hydrogen bonds,which greatly limits the ability of starch reprocessing.Electrospinning,as an emerging nanofiber preparation technology,could maintain the advantages of good biocompatibility of starch itself,large specific surface area,small pore size and biodegradability.In this paper,DMSO/H2O solvent system was used to prepare starch fiber by electrospinning technology.The effects of hydrogen bond on starch dissolution and starch fiber formation were studied.Then,the starch/PVA blended fiber was prepared by the same method and modified with glutaraldehyde to achieve double modification.Then the starch/PVA/aspirin drug-loaded membrane was prepared to study its drug release properties.The results show that the addition of a small amount of water can accelerate the dissolution of starch,and the spinnability of the spinning solution becomes worse with the excessive increase of the water content.The Hylon VII high amylose content corn starch showed a typical B-type crystal structure.After electrospinning,the hydrogen bonds between the starch molecules were weakened,and most of the crystal structure was destroyed.The electrospun nanofiber membrane was V-type crystal.DMSO as a strong hydrogen bond acceptor,can destroy the hydrogen bonds in starch.Compared with the nature starch,the DSC peak temperature and enthalpy change of the electrospun starch membrane was decreased.But the peak temperature and enthalpy change increase with the increase of water content.The electrospun starch fiber membrane with pure DMSO as solvent had lower strength and higher elongation at break.The addition of water increased its strength,but the elongation at break was decreased.With the increase of PVA content,the fiber diameter became smaller and the bead phenomenon appeared,but the whole fiber morphology was not affected.The results of infrared spectroscopy showed that there was a certain hydrogen bonding between starch and PVA,and the strength of hydrogen bond increased first and then decreased with the increase of PVA content.The tensile strength of blended fibers also follows the same trend.There was no new endothermic peak in DSC of blended fibers.With the increase of PVA content,the endotherarmic peak of PVA became more and more sharp.It indicating that the starch and PVA were simple physical blending,without chemical reaction.As the cross-linking time increases,the fibers gradually bond to each other.The acetal reaction between glutaraldehyde and starch/PVA makes the electro-spinning membrane water stability has greatly improved.The drug-release property test showed that the starch-loaded fiber membrane could control the drug release,and the starch fiber could be used as a controlled-release carrier.The drug-containing fibers with different drug contents all had a fast release time in the drug release process,and had a good sustained-release phenomenon at the low drug concentration.