Effects of MWNT nanofillers on structures and properties of PVA electrospunnanofibres

Abstract

In this study, we have electrospun poly(vinyl alcohol)(PVA) nanofibres and PVA compositenanofibres containing multi-wall carbon nanotubes (MWNTs) (4.5 wt%), and examined theeffect of the carbon nanotubes and the PVA morphology change induced by post-spinningtreatments on the tensile properties, surface hydrophilicity and thermal stability of thenanofibres. Through differential scanning calorimetry (DSC) and wide-angle x-raydiffraction (WAXD) characterizations, we have observed that the presence of the carbonnanotubes nucleated crystallization of PVA in the MWNTs/PVA composite nanofibres,and hence considerably improved the fibre tensile strength. Also, the presence of carbonnanotubes in PVA reduced the fibre diameter and the surface hydrophilicity of thenanofibre mat. The MWNTs/PVA composite nanofibres and the neat PVA nanofibresresponded differently to post-spinning treatments, such as soaking in methanoland crosslinking with glutaric dialdehyde, with the purpose of increasing PVAcrystallinity and establishing a crosslinked PVA network, respectively. The presenceof carbon nanotubes reduced the PVA crystallization rate during the methanoltreatment, but prevented the decrease of crystallinity induced by the crosslinkingreaction. In comparison with the crosslinking reaction, the methanol treatmentresulted in better improvement in the fibre tensile strength and less reduction in thetensile strain. In addition, the presence of carbon nanotubes reduced the onsetdecomposition temperature of the composite nanofibres, but stabilized the thermaldegradation for the post-spinning treated nanofibres. The MWNTs/PVA compositenanofibres treated by both methanol and crosslinking reaction gave the largestimprovement in the fibre tensile strength, water contact angle and thermal stability.