Multifunctional polymer composites reinforced by carbon nanotubes–Alumina hybrids with urchin-like structure

Abstract

Polymer composites with enhanced mechanical and functional properties are highly desired to develop lightweight function-integrated structures and devices. In this study, one kind of urchin-like hybrids was synthesized by in-situ growing CNTs on alumina microspheres (μAl 2 O 3), and their reinforcing effects to epoxy were investigated in detail. It was found that as compared to pure epoxy the CNTs-μAl 2 O 3 hybrids/epoxy composites possess highly improved electrical, dielectric, thermal and mechanical properties, achieving an enhancement as high as 5 orders of magnitude in the AC conductivity, 92 % and 56 % in the thermal diffusivity and thermal conductivity, respectively, and 26 % in the Young's modulus, when CNT mass fraction used was 2 %. Detailed analyses and various microstructural characterizations were also conducted in order to understand the multiscale reinforcement effects. The significant enhancements observed are mainly due to the urchin-like structure and improved CNT dispersion in the epoxy matrix.

Numerical modeling and experimental characterization of the AC conductivity and dielectric properties of CNT/polymer nanocomposites

“…Neat epoxy were fabricated by manually mixing 1080S and 1084 components in the aforementioned weight ratio. To fabricate the CNTs/Epoxy nanocomposites, the desired weights of CNT were added to the 1080S resin and dispersed using a three-roll mill (EXAKT), following a pre-optimised procedure [41]. After adding the hardener, the mixtures were poured into a mold and shaped under a hot press for 2 hours at 60 • C under 7 bars, followed by a 15-hour long curing at 60 • C under atmospheric pressure.…”

Processing, thermal and mechanical behaviour of PEI/MWCNT/carbon fiber nanostructured laminate

“…Although the incorporation of CNTs in polymeric matrices as reinforcements is not a new concept, the formation of bundles and agglomerates are still the major bottlenecks of their utilization in polymer composites. Due to van der Waals forces acting on them, high surface area and high aspect ratio, the agglomeration of the nanoparticles generate non-homogeneous composites, which results in deterioration of the final properties of the material, thus limiting its applications [13][14][15]. Therefore, several methods have been developed in order to improve the dispersion of the carbon nanotubes in the polymer matrix, as an example, the chemical functionalization that consists of the addition of functional groups in CNT surface and the physical functionalization that represents the use of surfactants as dispersing agents [16,17].…”

Properties of multifunctional composite materials based on nanomaterials: a review

“…Some of the more recent and advanced approaches involve the development of CNTs on the microspheres of alumina (Al 2 O 3 ) and using them as reinforcement in MFCMs. 41 The composite materials showed a 26% improvement in the Young's modulus. Along with the improvements in the mechanical properties of the composite, signicant improvements in the thermal diffusivity (56%) and electric conductivity (92%) by the addition of nano-coated alumina microspheres have been reported.…”