Regulating the formation and extent of crazing through the application of argon plasma surface functionalisation

Polymer crazing is a phenomenon observable as fine cracks on the surface of a material. For polymers crazing is often a precursor to mechanical failure with the capacity of a craze to propagate and develop into a larger structural crack. In this study polypropylene (PP) fibres, known to be susceptible to crazing, were subjected to argon (Ar) plasma treatment with the aim of creating a crosslinked surface that displays the ability to withstand the formation of crazes. To evaluate Ar plasma success at achieving this aim: the resulting Ar treated fibres were characterised to evaluate their capacity to avoid the formation of crazes and also identify any changes induced to the chemical and mechanical properties of PP as a consequence of Ar plasma exposure. This analysis was conducted by application of low voltage (LV)-scanning electron microscopy imaging, uniaxial tensile testing, Energy Dispersive X-ray Spectroscopy (EDS) and attenuated total reflectance - fourier-transform infrared spectroscopy (ATR-FTIR). The results of this study highlight the potential of the application of Ar plasma to influence the formation of crazes on PP fibres after exposure to repeated dynamic distention cycles. Ar plasma treated PP also showed a capacity to reduce bulk fibre oxidation when compared to that of non-treated PP when exposed to dynamic distention and subsequently immersed in an oxidative stress environment.