Characterisation of electrospun PS/PU polymer blend fibre mat for oil sorption

Abstract

Electrospun polystyrene (PS) fibre mat has been shown to have great potential as an oil sorbent due to its high sorption capacity and oil-water selectivity. Poor mechanical properties, due to the lack of inter-fibre bonding, has been a limiting factor in its use in such applications. In this study, mats of polymer-blends of polystyrene (PS) and thermoplastic polyurethane (PU) fibres, in different polymer weight ratios, were produced and investigated for possible oil sorption application.A comprehensive physico-chemical, thermal, mechanical and sorption characterisation of the different polymer-blends was undertaken, to examine the effect of blend ratio on the fibre mat. Characterisation was by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC), thermo-gravimetric and differential analysis (TG-DTA), mechanical tensile testing, and by sorption analysis.The microstructural properties of the fibres appeared significantly dependent upon the relative blend ratio. DSC revealed that good interaction/miscibility existed between the two polymers. Tensile strength characterisation showed that a pure PS fibre mat had a poor tensile strength, but the value increased over one order of magnitude with the addition of PU in the polymer matrix, attributed to the formation of inter-fibre bonds. Conversely, the sorption capacity (SC) decreased with increasing PU addition. Modulating the blend ratio could therefore provide a balance between the desired sorption capacity and the mechanical behaviour of resultant mats.Sorption capacity is a complex interaction between fibre and mat characteristics but the polymer blend technique reported here offers a simple, effective and inexpensive method of addressing the poor mechanical properties of electrospun PS fibre by adding PU and via enhancing micro/nano scale interactions between the two polymers in the blend.