Ultrasonic characterization of transversely isotropic epoxy/multiwalled carbon nanotube reinforced polyvinyl alcohol nanofiber mats nanocomposites

Transversely isotropic materials’ mechanical properties are often determined using destructive testing methods. However, the data obtained from these tests are not sufficient for determining all mechanical properties of transversely isotropic materials. Thus, the aim of this study is to determine some elastic and mechanical properties of transversely isotropic nanocomposite materials, which are difficult to determine by destructive methods, using ultrasonic method. The polyvinyl alcohol (PVA) nanofiber mats reinforced with multi-walled carbon nanotubes (MWCNTs) at 1%, 3% and 5% ratios were produced using the electrospinning method. The resulting nanofiber mats were combined with epoxy resin (ER) with 5, 10 and 15 layers to form transversely isotropic ER/PVA-MWCNT nanocomposites. The effects of different MWCNT ratios and number of layers on the elastic constants and mechanical properties of materials were investigated using the ultrasonic pulse-echo overlap method. In addition, the morphologies of pure ER, PVA-MWCNT nanofiber mats and ER/PVA-MWCNT nanocomposites were evaluated by TEM and SEM analyses. According to the results obtained, in terms of some ultrasonic wave velocities (V L11 , V L33 , V L45°, V S12 ), elastic constants (c 11 and c 66 ), and mechanical properties (E 1 , E 3 , and μ 11 ), ER/PVA-MWCNT nanocomposites showed superior performance compared to pure ER. The most durable nanocomposite sample was determined as sample 3CPE-10, which contains 3% MWCNT and consists of 10 layers.