Investigation Of The Scale-Up Preparation Process Of Hexagonal Boron Nitride Nanosheets

Being a new kind of two-dimensional materials, hexagonal boron nitride nanosheets (BNNSs) have many peculiar properties, including anti-oxidation ability, anti-chemical ability, high temperature stability, permology performance and mechanical nature. Thus it has promising potential applications in polymer composites, adsorption, energy storage, etc. So far, there are still some problems in preparing few-layer BN nanosheets. The exfoliation efficiency is low, mainly in the range of 1%-25%. Thus, the dispersion concentration is low and the dispersant is always expensive and some of them are toxic. The preparation technology is not well developed yet, which makes it impractical to provide enough material for the follow-up work. Hence, how to produce large-scale BNNSs becomes a great challenge.On the basis of the results in literature works, we developed an easy and efficient process using urea to exfoliate h-BN to obtain BNNSs. Then we obtain aqueous dispersion of BNNS and its sheet concentration could be reached as high as 2.7 mg/mL. We use characterization techniques such as XRD?SEM?TEM to study the morphologies and crystal structure of as-obtained BNNSs. Meanwhile, the scale-up process has been explored.The main research content is described as follows:The results demonstrate that the optimum process of the liquid exfoliation is that h-BN/urea (mass ratio=1/20), and the time of ball milling is 10 hours, and the time of sonication is 2 hours, and the dispersion is centrifuged at 3000 rpm for a period of time, the effiency could be reached to 52.7%, the sheet concentration could be reached as high as 2.7 mg/mL. Then, based on the fundamental understanding of the results and equipment selection,. a possible scale-up process has been established, which might provide basis for the subsequent large-scale preparation work.