Covalent derivatization of boron nitride nanotubes with peroxides and their application in polycarbonate composites

Abstract

The novel derivatization of boron nitride nanotubes (BNNTs) with two organic peroxides (lauroyl peroxide and dicumyl peroxide) is presented. The functionalized-BNNTs (f-BNNTs) were characterized by FTIR, ¹H NMR, TGA, and SEM. These thermally labile peroxides can decompose to generate an alkoxyl radical, or an alkyl radical (with the loss of CO₂), which then acts as a Lewis base to attack the electron-deficient boron sites of BNNTs. This results in the covalent formation of R-O-BNNT or R-BNNT bonds. Thin films (15 to 35 μm thickness) of 0.5 to 1.0 wt% lauryl-BNNT/polycarbonate and 1 wt% BNNT-OH/polycarboante composites were fabricated, and their transparency was demonstrated. Semi-transparent, hot-pressed disks (200 μm thickness) of 1.0 wt% cumyloxy-BNNT/polycarbonate and 1.0 wt% lauryl-BNNT/polycarbonate composites were also fabricated and mechanically tested. The Young's modulus and the maximum tensile stress were increased by 12% and 8%, respectively, compared to the corresponding properties of BNNT-free polycarbonate samples.