Silanization of boron nitride nanosheets (BNNSs) through microfluidization and their use for producing thermally conductive and electrically insulating polymer nanocomposites

• Published in: Journal of solid state chemistry Vol. 249; pp. 98 - 107
• Main Authors: Seyhan, A.Tuğrul, Göncü, Yapıncak, Durukan, Oya, Akay, Atakan, Ay, Nuran
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2017
• Subjects: Boron nitride nanosheets (BNNSs); BORON NITRIDES; FOURIER TRANSFORMATION; INFRARED SPECTRA; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Microfluidization; NANOCOMPOSITES; NANOSCIENCE AND NANOTECHNOLOGY; NANOSTRUCTURES; ORGANIC MATTER; PARTICLE SIZE; Polymer nanocomposites; POLYMERIZATION; POLYMERS; Polypropylene; SCANNING ELECTRON MICROSCOPY; Silane coupling agent; SILANES; SURFACES; THERMAL CONDUCTIVITY; THERMAL GRAVIMETRIC ANALYSIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; Microfluidization; Boron nitride nanosheets (BNNSs); Thermal conductivity; Polypropylene; Silane coupling agent; Polymer nanocomposites
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2017.02.020

Chemical exfoliation of boron nitride nanosheets (BNNSs) from large flakes of specially synthesized micro-sized hexagonal boron nitride (h-BN) ceramics was carried out through microfluidization. The surface of BNNSs obtained was then functionalized with vinyl-trimethoxy silane (VTS) coupling agent through microfluidization once again in an effort to make them compatible with organic materials, especially those including polymers. The morphology of BNNSs with and without silane treatment was then systematically characterized by conducting various different analytical techniques, including Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Bright field Transmission Electron Microscopy (BF-TEM), Contact angle analyzer (CAA), Particle size analyzer (PSA) and Fourier Transmission Infrared (FTIR) spectroscopy attached with attenuated total reflectance (ATR) module. As a result, the silane treatment was determined to be properly and successfully carried out and to give rise to the irregularity of large flakes of the BNNSs by folding back their free edges upon themselves, which in turn assists in inducing further exfoliation of the few-layered nanosheets. To gain more insight into the effectiveness of the surface functionalization, thermal conductivity of polypropylene (PP) nanocomposites containing different amounts (1wt% and 5wt%) of BNNSs with and without silane treatment was experimentally investigated. Regardless of the weight content, PP nanocomposites containing silanized BNNSs were found to exhibit high thermal conductivity compared to PP nanocomposites containing BNNSs without silane treatment. It was concluded that microfluidization possesses the robustness to provide a reliable product quality, whether in small or large quantities, in a very time effective manner, when it comes to first exfoliating two-dimensional inorganic materials into few layered sheets, and functionalizing the surface of these sheets afterwards to make it possible to utilize them as promising filler constituent in manufacturing thermally conductive and electrically insulating polymer nanocomposites that could be considered as whole or a part of a heat-releasing device.
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