Simultaneous regulation of morphology, crystallization, thermal stability and adsorbability of electrospun polyamide 6 nanofibers via graphene oxide and chemically reduced graphene oxide

Abstract

Modulating the processability, structure and properties simultaneously remains a challenge for the preparation of high-performance electrospun nanofibers. The influence of incorporating graphene oxide (GO) and chemically reduced graphene oxide (RGO) nanosheets on the rheological behaviors of polyamide 6 (PA 6) solutions was systematically investigated. A small amount (0.5 wt%) of GO could dramatically increase the steady viscosity of PA 6 solution at 0.001 s⁻¹ (η_0.001) by a factor of four, while the same content of RGO resulted in a threefold decrease. Based on the modulation of viscosity of the PA 6 spinning solutions by GO and RGO nanosheets, GO/PA 6 and RGO/PA 6 nanofibers with various structures and properties were successfully prepared via electrospinning. The addition of 1 wt% GO and RGO nanosheets improved PA 6 fibrous uniformity and fineness, and the spinnable concentration (SC) range of PA 6 was effectively broadened. The difference in interfacial interaction between nanosheets and the PA 6 matrix led to different crystallization behaviors of the electrospun PA 6 nanofibers. The formation of γ-form crystals was promoted by GO but inhibited by RGO, which offers a convenient strategy to modulate the mechanical properties of PA 6 nanofibers. In addition, the thermal stability and adsorption capacity of PA 6 nanofibers was enhanced by adding GO or RGO.