Influence of the Localization of Hexagonal-Boron Nitride Particles in a Co-Continuous Polyamide/Polypropylene Blend on the Thermal Conductivity of the Composite
Résumé
Polymers are thermally insulating materials, which limits their use in some specific fields such as
the electronics industry. One way to improve the thermal conductivity of polymers is the introduction
of aceramic filler, in particular hexagonal boron nitride (h-BN), which has distinct properties such
as being thermally conductor and electrically insulator at the same time. Our main objective is to
improve the thermal conductivity of polymer composites for industrial application all whileusing melt-
processing methods and incorporating the smallest quantity of boron nitride fillers.
In this study, we display a strategy based on the control of the localization of theh-BN fillers in a co-
continuous polyamide (PA6)/polypropylene (PP) blend prepared via melt processing. The aim of this
strategy is the formation of a 3D fillers network at low h-BN concentration due to its layered structure.
Which will increase the thermal conductivity of the composite. In a first step, h-BN particles were
treated using different thermal, mechanical and chemical treatments to introduce hydroxyl groups
in their chemical structure. To modify their surface energy,trimethoxy(octadecyl)silane was used in
a second step to introduce alkyl groups (C18) at the edge of the h-BN sheets. Fourier Transform
Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Pyrolysis combined with Gas
Chromatography Mass Spectrometry (Py GC-MS) were used to prove the covalent functionalization
of h-BN withC18 groups. After melt processing, the location of the treated h-BN fillers in the co-
continuous immiscible polymer blend was investigated by Scanning Electron Microscopy(SEM).The
thermal conductivity of the ternary PA6/PP/h-BN composites were measured by a hot-disk method.
The development of these original pathways will allow the development of new lightweight and easy
to shape materials with high thermal conductivity.