Effect of Polymeric In Situ Stabilizers on Dispersion Homogeneity of Nanofillers and Thermal Conductivity Enhancement of Composites

Abstract

Boron nitride (BN) nanofiller-based polymer composites have been considered promising candidates for efficient heat-dissipating packaging materials because of their superior thermal conductivity, mechanical strength, and chemical resistance. However, strong aggregation of the BN nanofillers in the composite matrix as well as the difficulty in the modification of the chemically inert surface prevents their effective use in polymer composites. Herein, we report an effective method by using in situ stabilizers to achieve homogeneous dispersion of boron nitride (BN) nanofillers in an epoxy-based polymeric matrix and demonstrate their use as efficient heat-dissipating materials. Poly(4-vinylpyridine) (P4VP) is designed and added into the epoxy resin to produce in situ stabilizers during preparation of hexagonal BNs (h-BNs) and BN nanotubes (BNNTs) dispersion. In-depth experimental and theoretical studies indicated that the homogeneous distribution of BN nanofillers in epoxy composites achieved by using the in situ stabilizer enhanced the thermal conductivity of the composite by ∼27% at the same concentration of the BN nanofillers. In addition, the thermal conductivity of the h-BN/epoxy composite (∼3.3 W/mK) was dramatically improved by ∼48% (4.9 W/mK) when the homogeneously dispersed BNNTs (∼1.8 vol %) were added. The concept of the proposed in situ stabilizer can be further utilized to prepare the epoxy composites with the homogeneous distribution of BN nanofillers, which is critical for reproducible and position-independent composite properties.

Artificial Nacre Epoxy Nanomaterials Based on Janus Graphene Oxide for Thermal Management Applications

“…To demonstrate the excellence of E-JPGO nanocomposites in the thermal conductivity enhancement efficiency of polymer composites, we summarize the literature-reported thermal conductivity enhancement of polymer composites (as shown in Figure ): E-BNNS, E-PDA/CuNWs, E-GO, E-CEG, E-Graphene, E-BNNSs/BNMSs, E-hBN/GDE, E-MXene/Ag, PDA-rGO, E-VA/SiC, E-Cu, rGO-PI/BNNS-PI, E-GNP/Al 2 O 3 , PDMS/BNNSs, PMMA/hBN, and PCL/oxi-BNNs . We can find that the TCE at low weight obtained in our work is the highest among these studies.…”

Lyotropic Boron Nitride Nanotube Liquid Crystals: Preparation, Characterization, and Wet-Spinning for Fabrication of Composite Fiber

“…It is noteworthy that the C n values of BNNT dispersions using polymeric stabilizers in this study is relatively higher than the reported ones from highly purified BNNT-based LCs using CSA (8000 ppm, 0.8 wt %). 21 Studies have reported that the phase transition concentration of nanotube-based LCs is highly dependent on the purity, the polydispersity of the aspect ratio, and stiffness of nanotubes. 1,50,51 Accordingly, in the BNNT used here, many impurities such as h-BN and BN-nanocages still coexisted with BNNTs, even after the multistep purification process.…”

Interaction of DNA-Complexed Boron Nitride Nanotubes and Cosolvents Impacts Dispersion and Length Characteristics

“…Stable dispersions of boron nitride nanotubes (BNNTs) enable the effective translation of unique properties of individual nanotubes into macroscopic assemblies using industrially viable, liquid-phase processing techniques. A broad range of applications have been envisioned for BNNTs, such as thermal management of electronics, − water purification and desalination, − protective coatings, , and nanomedicine, , due to the promising mechanical, electrically insulating, thermal, and physicochemical properties of nanotubes. BNNT-enabled applications require versatile processing approaches, where nanotubes are generally integrated with other nanomaterials and polymer solutions in various solvents to achieve property control and enhancement.…”

“…To date, both covalent modification and noncovalent complexation have been explored for BNNT dispersions. Covalent modification causes permanent and unwanted changes in the B−N lattice structure from sp 2 to sp 3 orbital hybridization that often leads to the deterioration of nanotube properties. 11,12 In comparison, noncovalent complexation of BNNTs with surfactants, polymers, small molecules, and biomolecules (often assisted by sonication) has proven to be a simple way of dispersing BNNTs in various solvents, including water.…”