Morphological investigation of carbon nanotube reinforced polyurethane foam to analyse its acoustical and non‐acoustical properties

Abstract Acoustic damping analysis for open‐cell polyurethane/carbon nanotube nanocomposite foam is presented. Carboxylic functionalized CNT is used as an energy decaying filler in the PU matrix. The acoustical behaviour and non‐acoustical properties of polyurethane/carbon nanotube nanocomposite foam are explained through its cell morphological properties. For this aim, cellular morphologies such as strut length, strut thickness, cell size, pore diameter, and reticulation rate of the samples are determined from field emission scanning electron microscopy images by using 'Image J' software. Therefore, the effects of adding the carboxylated CNTs with different loading fractions to the PU matrix on its morphological properties and thus on its sound absorption and non‐acoustical physical parameters such as thermal characteristic length and viscous characteristic length are determined and discussed from field emission scanning electron microscopy images. Thermal characteristic length and viscous characteristic lengths are calculated through Johnson–Champoux–Allard porous model from the morphological properties, which has been directly measured on the field emission scanning electron microscopy images. Large differences were observed in the cellular morphologies of the polyurethane/carbon nanotube nanocomposite foams compared with that of the pure PU foam. Results show that the prediction of the acoustical behaviour of the polyurethane/carbon nanotube nanocomposite foams based on their cellular morphologies is in good agreement with the direct measurement of their acoustical properties.