Investigation of Adverse Effect of CNTs’ Functionalization on the Long Term Water Conditioned CNT/ Epoxy Composites

Abstract

In the present era, polymer composites are widely used as various structural parts in marine field. In order to check the suitability of these materials in marine applications it is very much essential to know about the water/moisture absorption behaviour of these composites which is strongly correlated with the extent of degradation of properties of these materials when exposed to water. Considering this, the keystone of this present work is to explore the effect of moisture absorption on the mechanical and thermal properties of –COOH functionalised carbon nanotubes (CNTs) epoxy composites. Samples were immersed into sea and distilled water separately at room temperature up to a period of six months. All the samples seem to be degraded due to the long term effect of moisture that diminishes the interfacial properties of the composites. Further, swelling, plasticization of the matrix phase, confirmed by the field emission scanning electron microscope (FESEM), induce several damages in the composite those end up in reducing the flexural modulus, strength, hardness and the glass transition temperature (Tg) of the composites. Results demonstrated that at 0.75 wt.% of CNTs loading, minimum deduction in properties has been observed while at relatively higher wt.%, i.e., in case of 1 wt.% of CNT concentration comparatively higher degradation is realised. Further, it was observed that compared to sea water exposed samples the distilled water exposed composites showed greater degradation which is due to the greater moisture absorption by the later.