Enhancement of Isotropic Heat Dissipation of Polymer Composites by Using Ternary Filler Systems Consisting of Boron Nitride Nanotubes, h-BN, and Al₂O₃

Abstract

In this research article, a poly(dimethylsiloxane) (PDMS)-based composite was postulated adapting an interactive ternary filler system consisting of Al 2 O 3 , hexagonal boron nitride (h-BN), and boron nitride nanotubes (BNNT) to construct a continuous three-dimensional (3D) structure for thermal attenuation. Al 2 O 3 was imposed as a main filler, while h-BN and BNNT were assimilated to form interconnected heat conduction pathways for effective thermal dissipation. The structured framework articulates a profound improvement in isotropic thermal conductivity considering both axial and radial heat dissipation. The presence of h-BN entails uniform heat distribution in a planar mode, eliminating the occurrence of hotspots, while BNNT constructed a connecting phonon pathway in various directions, which insinuates effective overall thermal transport. The generated ternary filler composites attained an isotropic ratio of 1.35 and a thermal conductivity of 7.50 W/mK, which is a 36-fold (∼3650%) increase compared to neat PDMS resin and almost 3-fold (∼297%) that of the Al 2 O 3 unary filler composite and ∼53% that of its binary counterpart, partaking interfacial thermal gaps of ∼36.15 and ∼62.24% on practical heating performance relative to its counterparts. Moreover, the incorporation of BNNT on a traditional spherical and planar filler offers an advantage not only in thermal conductivity but also in thermal and structural stability. Improvement in thermal stability is stipulated due to a melting point (T m ) shift of ∼11 °C upon the assimilation of BNNT. Mechanical permeance reinforcement was also observed with the presence of BNNT, showcasing a 31.5% increase in tensile strength and a 53% increase in Young's modulus relative to the singular filler composite. This exploration administers a new insight into heat dissipation phenomena in polymeric composites and proposes a simple approach to their design and assembly.

Boron Nitride Nanotube-Aligned Electrospun PVDF Nanofiber-Based Composite Films Applicable to Wearable Piezoelectric Sensors

“…Regarding this matter, considering the cost-efficiency-based performance behaviors, the applications of novel nanomaterials, which can highly enhance the properties, have emerged. In this point, boron nitride nanotubes (BNNTs) take the lead with their thermal conduction and stability, low-toxicity, piezoelectric property, and superior performance even at very small ratios. , …”

“…BNNT, since its discovery, has been offering various nanosolutions through its nontoxic compliance, mechanical strength, thermal conductivity, flame resistance, electrically insulating behavior, piezoelectric properties, neutron shielding capability, oxidation resistance, etc. − Therefore, tremendous attention is on BNNTs in various fields such as the pharmaceuticals, electronics, energy and environment, biomedicals, wear- and corrosive-resistant coatings, physical separation, etc. , Especially, thermal conductivity of BNNTs works highly efficient for dissipating heat through very rapid cooling. − In addition, because of the difference in the electronegativities of the B and N atoms, BNNT is a noncentrosymmetric structure that partially exhibits the ionic characteristic of B–N bonds, making it piezoelectric …”

Preparations and Thermal Properties of PDMS-AlN-Al2O3 Composites through the Incorporation of Poly(Catechol-Amine)-Modified Boron Nitride Nanotubes

“…However, due to strong Van der Wall interactions, BNNT nanofillers are susceptible to aggregation [16]. Thus far, BNNT utilization on TIMs is still in its infancy due to its surface chemical inertness that weakens its interaction with solvents and polymeric media, which results in its poor dispersive behavior, leading to severe BNNT agglomeration in the polymeric composite matrix [17]. The BNNT clustering not only influences the abatement of the thermal pathway formation but also degrades the diffusion boundary layer of the polymer's volatile compounds during combustion.…”