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In this paper, polyamide (PA, composed of at least 60% renewable materials) was used as a polymer matrix to prepare PA-hexagonal boron nitride (hBN) polymer composites with varying hBN contents. Two different PA samples were used in this study: a low viscosity grade PA (PA-30), as well as a high viscosity grade PA (PA-90). The composite polymers were tested to evaluate their thermal, physical, and mechanical properties. It was concluded that these composites had more favourable properties than other polymers that had been previously tested, and so the composites would be a good choice as an electronic packaging material.
Polyactic acid (PLA)-micro hexagonal boron nitride (hBN)-graphene nanoplatelet (GNP) polymer composites were prepared, and the effects of varying filler contents on the thermal and mechanical properties of the polymer composites were investigated. It was determined that the addition of the GNPs resulted in a decrease in thermal conductivity in comparison to a PLA-hBN composite unless the GNP:hBN ratio was 1:1, where the thermal conductivity was equal to that of the PLA-hBN composite. The GNPs were also found to reduce the mechanical properties of the composites; however, their addition resulted in an increase in electrical conductivity.
A paraffin-based composite phase change material (PCM) was prepared by the addition of hexagonal boron nitride (h-BN) nanosheets to melted paraffin wax followed by vigorous stirring. The nanosheets were added in quantities ranging from 1 to 10 wt. %. A reference sample of pure paraffin was also prepared. It was determined that the addition of h-BN nanosheets resulted in an increase in thermal conductivity and that the melting and solidification rates were also accelerated as a result of this addition. The composite PCMs described in this article were prepared without surfactants. This resulted in precipitation of h-BN nanosheets as the PCM was consecutively heated and cooled. Further studies needed to be performed to determine the effects of h-BN shape, size, and thickness on the properties of interest.
The authors examine the melting and crystallization behavior of a polyethylene/boron nitride composite to understand an unexpected exothermic peak when the BN content was greater than 10 wt. %. Based on these observations, an optimal annealing temperature of the composite was investigated to enhance its thermal conductivity. The appearance of the peak was determined to depend on the different nucleated capability of the different BN aggregates in local area. An annealing time of 20 min and a temperature of 130 oC were found to increase the thermal conductivity of the composite by 16% when compared to the non-annealed composite.
