Noncovalent functionalization of multi-walled carbon nanotubes with hydroxyl group-containing pyrene derivatives for their composites with polycarbonate

Pyrene derivative-containing hydroxyl groups such as 1-hydroxypyrene (PO), 1-pyrenemethanol (PMO) and 1-pyrenebutanol (PBO) were examined as new interfacial agents for bisphenol-A polycarbonate (PC)/multi-walled carbon nanotube (MWCNT) composites. The pyrene units adsorbed onto the MWCNT surface by physisorption and the hydroxyl groups in the pyrene derivatives reacted with the carbonate groups in the PC during melt extrusion. The reactivity of the hydroxyl groups in the pyrene derivatives with the carbonate groups in the PC increased as the nucleophilicity of the hydroxyl groups in the pyrene derivatives increased. As a result, the amount of PC grafted onto the MWCNT surface by the reaction between the PC and the pyrene derivative increased in the order of PBO > PMO > PO. The PC/MWCNT composite used PBO as an interfacial agent exhibited the best interfacial adhesion between the MWCNT and PC and the highest level of MWCNT dispersion in the PC matrix among the composites examined. When the MWCNT content in the composite was fixed, the PC/MWCNT composite with the highest interfacial adhesion energy between the PC and the MWCNT exhibited the best tensile strength and modulus.