Preparation And Application Of Nonwoven Electrospun Membranes Based On SIS Copolymers

Owing to the weak interfiber connection,most nonwoven electrospun membranes have relatively poor mechanical properties,which limits their practical applications.Thus,various methods are developed to cross-link nonwoven electrospun membranes,such as solution blending,heat treatment,solvent vapor treatment,and so on.But,these methods often encounter some problems such as difficult selection of co-solvents and large changes of fibers structures.In this study,a self cross-linking method was developed to fabricate cross-linked nonwoven electrospun membranes based on styrene-isoprene-styrene(SIS)thermoplastic elastomers.To effectively regulate the cross-linked structures,detail study was carried out on various factors of influencing cross-linked structures.Furthermore,SIS-based cross-linked nonwoven electrospun membranes were applied in improving the various properties of polystyrene nonwoven electrospun membranes and SIS-based pressure-sensitive adhesive substrates.The main study of this paper as follows:(1)Fabrication of cross-linked SIS nonwoven electrospun membranes.The cross-linked structures of SIS nonwoven electrospun membranes are adjusted through solution concentration,spinning voltage and receiving distance.The results show that when the fibers reach the receiving device,the more residual solvent in the fiber,the greater resilience of the fiber,and the more intense movement of the segments in the fiber,the more obvious cross-linked structures in the membranes.Most cross-linked structures appear in the SIS nonwoven electrospun membranes as they are electrospun with a solution concentration of 13%,a spinning voltage of 20 kV,and a receiving distance of 20 cm.(2)Fabrication of cross-linked PS/SIS nonwoven electrospun membranes.Their cross-linking structures are regulated by changing the nozzle ratio of PS to SIS(4/0,3/1,2/2,1/3 and 0/4).Detail investigations are carried out their surface morphology,mechanical properties,porosity factor and water contact angle.The results show that cross-linking structures appear in PS/SIS nonwoven electrospun membranes due to the introduction of SIS.The higher proportion of SIS,the more obvious cross-linked structures appear in the membrane.This method can greatly improves the tensile strength of the fiber membrane with high porosity and hydrophobicity.It provides a novel method of improving mechanical properties of nonwoven electrospun membranes,and enriches the application of SIS based cross-linked nonwoven electrospun membranes.(3)Fabrication of SIS/C5 nonwoven electrospun pressure-sensitive adhesive membranes.Their cross-linking structures and properties are regulated by the weight percentage of C5 resin.Since the fluidity of SIS/C5 is greatly enhanced by the addition of C5 resin as they reach the receiving device,their cross-linking structures increase but the porosity decreases with the increment of C5 resin.The nonwoven electrospun pressure-sensitive adhesive membranes have better water vapor permeation rate and adhesion performances as the C5 content is 50 wt%.As their thickness increases,their water vapor permeation rate has slight change but their adhesion performances is significantly enhanced.This method successfully resolves the disadvantages of traditional SIS/C5 pressure-sensitive adhesive for transdermal drug delivery,such as poor permeability and poor adhesion.It provides a new method of preparing pressure-sensitive adhesive matrix for transdermal drug delivery,and also opens a novel path for the application of cross-linked SIS-based nonwoven electrospun membranes.