Effects of multiwall carbon nanotube and perfluoroalkane additives on the sound absorption properties of flexible polyurethane foams

Abstract

The sound absorption properties and airflow resistivity of polyurethane foams (PUFs) with multiwall carbon nanotube (MWCNT), perfluoroalkane (PFA), dimethylsiloxane (HMDS), and MWCNT/PFA hybrid additives were investigated with varying additive content. The results show the close relationship of the sound absorption coefficient and airflow resistivity, and increasing flow resistivity was found to improve the sound absorption coefficient of the PUF. For the PUF with MWCNT (at 0.50 phr)/PFA (at 1.25 phr) hybrid additives, the sound absorption coefficient and airflow resistivity were 0.80 (in the frequency range of 1,600–2,500 Hz) and 439,900 Ns/m4, respectively, which were the highest values among the investigated additive species and additive content. The sound absorption coefficient of the PUF with MWCNT (at 0.50 phr)/PFA (at 1.25 phr) was increased by 82.0% compared to that of the PUF without additives, probably because the PUF has the smallest cell size among the additive species and compositions investigated in this study. The results of the sound absorption coefficient, airflow resistivity, and cell size of the PUF suggest that to decrease the cell size and to increase the tortuous paths of the foams, MWCNT/PFA hybrid additives appeared to be the most effective additives and showed synergistic effects in the formation of PUF, and its small cell size increased the sound absorption properties of PUF. POLYM. COMPOS., 39:E1087–E1098, 2018. © 2017 Society of Plastics Engineers

The synthesis and properties of isocyanate-based polyimide foam composites containing MWCNTs of various contents and diameters

“…Thus, the residual weight of the composite is up 40% even if the MWCNT content is small. 11,[26][27][28][29] Table 4 shows the T d5% and R 800 of the PIF/MWCNT with different diameters. The T d5% and R 800 of the PIF/MWCNT-1 are better than that of PIF/MWCNT-2, which is better than that of PIF/MWCNT-3.…”

“…The mechanical properties are reduced in all cases, which is because the MWCNTs in the polyimide matrix have crosslinking points that limit the movement of the polymer's molecular chains. [28][29][30] The mechanical properties of PIF/MWCNT containing MWCNTs with different diameters were also compared. MWCNTs act as nucleating agents and facilitate bubble growth, thus improving the mechanical behavior of composites.…”

Engineering foam skeletons with multilayered graphene oxide coatings for enhanced energy dissipation

“…Carbon nanotubes (CNTs), for example, have been used as reinforcements inside the cell struts of polymer foams produced by direct foaming. The overall enhancement in damping exhibited by thus type of porous nanocomposite is however quite limited (no more than 30%), because it merely takes advantage of the polymer-CNTs interfacial sliding mechanism [3,12,13]. Although the increase of the CNTs content can introduce more filler-filler sliding, it can also causes a virulent aggregation of the nanoparticles, therefore leading to a deterioration of the mechanical properties [12].…”

Improving the Sound Absorption Properties of Flexible Polyurethane (PU) Foam using Nanofibers and Nanoparticles

“…Polyurethane foam is one of the absorbing materials with many advantages, including light weight, low absorption, and low cost [10]. This foam is known as an absorbent with a relatively good absorption coefficient [11]. Two mechanisms should be considered in the sound absorption by polyurethane foam: the absorption of sound energy through friction between gaseous molecules fluctuating in the space of porous foam cavities and their kinetic energy converting to heat.…”

“…The second mechanism relates to the wall material of the pores; sound absorption in this mechanism occurs through the intrinsic damping of the system. In this mechanism, sound waves propagate inside the material [11]. Accordingly, the absorption coefficient of foam materials depends on their structural properties [12].…”