Correlation between manufacturing processes and anisotropic magnetic and electromagnetic properties of carbon nanotube/polystyrene composites

Abstract

We present an original, easy to implement, reliable method of non-destructive testing of the orientation of carbon nanotubes by magnetic moment measurements performed in three perpendicular directions of magnetic field. Multi-wall carbon nanotubes/polystyrene composites were prepared by stretching and forge-rolling methods with the same nanotube loading. Unusually strong diamagnetic anisotropy in the composites prepared by the stretching method was observed and attributed to an additional diamagnetic response from the polystyrene aromatic rings wrapping the nanotubes. Strong anisotropy of diamagnetic susceptibility of the composites with highly aligned nanotubes correlates with anisotropic electromagnetic response and with improved microwave absorption properties. Both magnetic anisotropy and microwave absorbance is considerably lower in the composites prepared by the forge-rolled method. The magnetic results correlate well with polarized Raman spectroscopy. The research findings contribute to a better understanding of nanotubepolymer interface, alignment mechanisms, and ultimately the optimal design and performance of functional nanotube-aromatic polymer nanocomposites.

Ceramic-inorganic polymer composites for protection against electromagnetic radiation mechanical properties designing

“…Thermoreactive polymer composites containing silicon carbide [12], carbon fibers [15], carbon black [16] and carbon nanotubes [17] are also effective. They provide protection as radio shielding materials and coatings due to the absorption mechanisms combination [18]: natural ferromagnetic resonance, resonance of domain boundaries movement, eddy current losses and repolarization, multiple imprints and etc.…”

Broadband millimeter-wave absorbers: a review

“…The utilization of polymeric composites and ceramics for the designing of absorbers has been a very important area of research in this field. Traditionally, these are composed of magnetic loss materials, such as magnetic metals [5,6], ferrites [7,8], dielectric loss materials that are composed of materials containing carbon, either carbon fibers [9], carbon nanotubes (CNTs) [10,11], or silica carbide fibers [12], and conducting polymers [13]. Out of all the above carbonaceous materials, a CNT has been a widely used material due to its extensive properties and high conductivity [10][11][12][13][14][15].…”

“…Traditionally, these are composed of magnetic loss materials, such as magnetic metals [5,6], ferrites [7,8], dielectric loss materials that are composed of materials containing carbon, either carbon fibers [9], carbon nanotubes (CNTs) [10,11], or silica carbide fibers [12], and conducting polymers [13]. Out of all the above carbonaceous materials, a CNT has been a widely used material due to its extensive properties and high conductivity [10][11][12][13][14][15]. CNTs usually have weak microwave absorption property, so it is combined with other lossy materials to achieve the desired absorptivity [16].…”

GO-CNTs hybrids reinforced epoxy composites with porous structure as microwave absorbers

“…Many different types of fillers have been developed. Among them, carbon nanotubes (CNTs) are the ideal materials for microwave absorption and electromagnetic interference (EMI) shielding applications due to their excellent physical and chemical properties [11][12][13][14].…”