Thermally conductive and mechanically strengthened bio-epoxy/boron nitride nanocomposites: The effects of particle size, shape, and combination

Bio-epoxy composites containing boron nitride (BN) particles with different size and shape (0D spherical micro- and nanoparticles, 1D nanotubes (T), and 2D nanosheets (S)) are prepared and revealed appropriate thermal conductivity, thermal stability, and mechanical properties. Systems containing one or two BN nanoparticles showed evenly dispersed structures because of applying high-shear, ultrasonic, or combination of these methods. Microscopic analysis proved that high-shear assisted ultrasonic technique ended up in an homogeneously dispersed BN nanoparticles in the epoxy matrix. The combination of platelet-like and tubular nanoparticles synergistically enhanced both the thermal stability and thermal conductivity of epoxy. Differential scanning calorimetry (DSC) thermographs appeared a sharp peak demonstrating excessive thermal energy released because of network formation of BN conductive fillers. The bi-oepoxy containing equal weight fractions of T and S (1:1 w/w ratio) showed the highest thermal conductivity and tensile strength values of 2.21 W/m.K and 80 MPa, respectively. In conclusion, properties of epoxy nanocomposites are affected by the filler network formation, such that conductive incorporation of 3 wt.% of BN platelet-like and nanotubes increased thermal conductivity up to 1400% and mechanical properties up to 50% with respect to the neat epoxy.

Automated summary

This study prepared bio-epoxy composites containing boron nitride (BN) particles of different sizes and shapes, and found that these composites exhibited appropriate thermal conductivity, thermal stability, and mechanical properties. The combination of high-shear and ultrasonic techniques resulted in even dispersion of BN nanoparticles. The combination of platelet-like and tubular BN nanoparticles synergistically enhanced the thermal stability and thermal conductivity of epoxy. The bio-epoxy containing equal weight fractions of BN nanotubes and nanosheets showed the highest thermal conductivity and tensile strength values.