Abstract: For the deficiency of submicron h-BN powder easy to reunite and poor interfacial compatibility with polymeric materials, the dispersion process of ultrafine h-BN powders in the anhydrous ethanol was studied.Firstly, the pH-Zeta potential of the h-BN ultrafine powders in anhydrous ethanol had been measured.Based on the results, the anionic dispersants (SA/OA/SDBS), nonionic dispersants (PVP/KH570/ Span85) and polymeric dispersant (PEG4000) were selected.The dispersion properties of different dispersing agents on the h-BN ultrafine powders were measured after being dispersed by ultrasound.According to the results of the last step, three kinds of dispersant had been chosen to form different composite dispersion systems and their dispersion properties had been tested.The results show that compound dispersion system has a better dispersive property compared with single dispersant, (PEG4000/SA) compound dispersant dispersive property increased by 18%;(KH570/SA) compound dispersant dispersive property increased by 11%.The best dispersion process of the h-BN ultrafine powders in anhydrous ethanol are: the quality fraction of SA(4wt%) and PEG4000 (1wt%) or SA(1wt%) and KH570(4wt%), at a pH of 9 and the ultrasonic (560 W) time for 90 min in anhydrous ethanol.

Key words: submicron h-BN powder;anhydrous ethanol;pH-Zeta potential;compound dispersion;dispersion mechanism