Water uptake of epoxy composites reinforced with carbon nanofillers

Carbon nanotube-reinforced glass fiber epoxy composite laminates exposed to hygrothermal conditioning

“…During the first 18 days or 432 h aging, the GFRP specimens demonstrate an increasing trend (except for one outlier data point), thus suggesting Fickian behavior as evident from the linear slope and also attained the maximum water content level for that time. Similar behavior has also been reported by others researchers for polymer matrix composites [5,27,34,35,37,[39][40][41][42][43]. On exposure of GFRP composites to moist or water environment, the exposed surface instantly absorbs water by capillary action, followed by diffusion through the matrix.…”

“…Quantitatively, there was approximately 15 and 32 % drop in D values for ACNT samples immersed in SW and DW, respectively, as compared to hygrothermally aged GFRP specimens. A similar fall in weight % and D values has recently been reported by Prolongo [34] for ACNT composites. In addition to this, it was also concluded that D values plunge even further on increasing the CNT concentration in the composites.…”

“…The possible explanation of such behavior is that (i) the salt particles and/or trace elements in SW were less readily absorbed into the matrix; (ii) the bulky nature of salt water molecules in SW inhibited the water absorption; and (iii) the scale formation on the surface of specimens restricted the capillary motion of water into the composites and lastly, the salt concentration outside the composite was higher as compared to inside the specimen, thus creating an osmotic pressure that again acted against the water absorption [33][34][35]51]. Similar diffusivity behavior and increased rate of water absorption in distilled/deionized water over seawater have been witnessed by other researchers [35,37,[52][53][54][55].…”

“…Although CNT GFRP (hybrid) composites have attracted substantial attention in various commercial applications/products, but not much research has been carried out to investigate the effect of moisture/ water absorption on the material degradation of CNTs-reinforced composites [27,[33][34][35][36]. Prolongo et al [34] and Zafar et al [35] investigated the effect of water uptake in CNT GFRP composites and reported a significant effect on the diffusivity coefficient, mechanical properties, and the glass transition temperature (T g ).…”

“…Prolongo et al [34] and Zafar et al [35] investigated the effect of water uptake in CNT GFRP composites and reported a significant effect on the diffusivity coefficient, mechanical properties, and the glass transition temperature (T g ). Such behavior is probably due to higher barrier properties of CNTs (high-specific area: 300 m 2 /g) and strong chemical bonding between the amino-functionalized CNTs and the epoxy matrix.…”