Nanoscience and Molecular Nanotechnology

Biography

Biography: Hyunseung Lee

Abstract

MWNT-grafting-polyisoprene (PI) nanocomposites were prepared by an activators regenerated by electron transfer for atom transfer radical polymerization (ARGET-ATRP) process using isoprene end MWNT-Br. MWNT-Br intermediates were prepared by carrying out the MWNT surface treatment processes in several steps and used as an initiator of ARGET-ATRP process. The preparation process flow of MWNT-grafting-PI nanocomposites conducted in this study is presented in Figure 1. MWNT-Br intermediates with different Br element content were prepared by controlling the amount of α-bromoisobutyryl bromide (BiB) which is used as a reactant in order to convert MWNT-OH intermediates into the MWNT-Br. The Br content of MWNT-Br was quantitatively analyzed by the application of peak analysis (total Br element content (%) and C-Br element content (%)) using X-ray photoelectron spectroscopy (XPS) spectrum. Four kinds of MWNT-Br samples with different Br element contents were subjected to the ARGET-ATRP process under the same reaction conditions to produce four types of nanocomposites having different PI contents in MWNT-grafting-PI nanocomposites. The four MWNT-grafting-PI were analyzed for viscosity changes by oscillational viscometer and PI content changes by TGA and reaction yield. To compare with the above results, the changes in the atom (%) values of the C-Br groups on the MWNT surface were analyzed by the application of XPS quantitative analysis. Figure 2 shows the change of viscosity (figure 2-(a)) depending on BiB/MWNT-OH values for the four MWNT-grafting-PI nanocomposites and the change of C-Br atom% (figure 2-(b)) depending on BiB/MWNT-OH values for the four MWNT-Br intermediates. In this study, we successfully prepared the MWNT-grafting-PI nanocomposites with PI content of 70% or more and developed how to maximize the PI content of MWNT-grafting-PI nanocomposites.