Flexible polyurethane/boron nitride composites with enhanced thermal conductivity

Abstract

Polymer-based composites with high thermal conductivity have great potential application as thermal management materials. This study was devoted to improving the thermal conductivity of the flexible thermoplastic polyurethane (TPU) by employing boron nitride (BN) as heat filler. We prepared flexible and thermally conductive TPU/BN composite via solution mixing and hot pressing. The thermal conductivity of the TPU/BN composite with 50 wt% BN (32.6 vol%) reaches 3.06 W/m·K, approximately 1290% enhancement compared to that of pure TPU (0.22 W/m·K). In addition, the thermal conductivity of our flexible TPU/BN composite with 30 wt% BN is almost not varied (a decrease of only 2.5%) after 100 cycles of mechanical bending, which indicates the high stability of heat conduction of our flexible TPU/BN composite under mechanical bending. The maximum tensile strength of the TPU/BN composite with 5 wt% BN is 48.9 MPa, 14% higher than that of pure TPU (43.2 MPa). Our flexible and highly thermally conductive TPU/BN composites show promise for heat dissipation in various applications in the electronics field.

An overview of boron nitride based polymer nanocomposites

“…Preparation of TPU/BN composites via solution mixing and hot pressing technique was explained by Xia et al [ 145 ] The thermal conductivity of the TPU/BN composite with 50 wt% BN exhibited 1,390% enhancement compared with that of TPU. Ultrasonic exfoliation and evaporated self‐assembly methods were used to prepare boron nitride nanosheets (BNNS)/thermoplastic polyurethane (TPU) composites with small (S) and large (L) sizes connected BNNS as additives.…”

High thermal conductivity thermoplastic polyurethane/boron nitride/liquid metal composites: the role of the liquid bridge at the filler/filler interface

“…50 As shown in Fig. 4, all composites with different BN/LM ratios have similar I 002 /I 100 value (~19), which is similar to that of the pure BN platelets (17). It means that the orientation of BN is not found in TPU/BN/LM composites.…”

“…13,14 The interface is the key issue to control TC of the polymer composites because phonon scattering usually occurs at the filler/filler or filler/polymer interfaces, which further leads to interfacial thermal resistance (ITR). Strategies to decrease the ITR at filler/filler interface include modification, 15 orientation, [16][17] 3D network structure, 18 and hybridization 19 of the heat fillers.…”

Studies on mechanical, thermal and tribological properties of carbon fibre-reinforced boron nitride-filled epoxy composites

“…62 The pristine h-BN shows two obvious characteristic peaks at 1372 and 810 cm À1 , corresponding to in-plane BN stretching (BN absorption) and out-of-plane bending (BN bending), respectively, which were attributed to the stretching of B-N bonds and shearing of B-N-B bonds. 60,63 The FTIR spectra results showed almost similar characteristic stretching bands and peaks for all the composites except the variation of their peak intensities throughout its sample test time. When comparing the FTIR spectrum of unfilled CF/Ep and BN-CF/Ep composites, several additional stretching peaks can be observed in the FTIR spectrum of the BN-CF/Ep composites due to the presence of BN filler.…”