Well-defined AB and BA diblock copolymers were obtained by a one-pot two-step sequential block copolymerization by reverse iodine transfer polymerization (RITP), A being a poly(styrene) block and B a poly (butyl acrylate) block. High monomer conversions during the formation of the first block avoided the purification steps before growing the second block. In a third sequential step, the diblock copolymers were further extended to synthesize ABA and BAB triblock copolymers. Furthermore, the synthesis of ABA and BAB copolymers in only two steps by RITP was investigated starting with the formation of the central block using 2,5-di(2-ethylhexanoylperoxy)-2,5-dimethylhexane as a difunctional initiator and then resuming the polymerization to grow the external blocks in a second step. The obtained copolymers were analyzed by size exclusion chromatography, transmission electron microscopy, and differential scanning calorimetry.

Nanocomposites of poly(methyl methacrylate-b-butyl acrylate)/multiwalled carbon nanotubes were prepared from different copolymers synthesized by RITP technique using iodine functionalized poly(methyl methacrylate) as macrochain transfer agent to obtain block copolymers with butyl acrylate as comonomer in a sequential copolymerization. Poly(butyl acrylate) contents of 7, 20, and 30 wt% were attained in each copolymer. These copolymers were used to prepare nanostructured films by casting process, using chloroform as solvent, and carboxyl functionalized MWCNT at 0.4, 0.6, 0.8, 1.0, and 1.2 wt%. During the film preparation, the absolute drying rate (N) was calculated with respect to the poly(butyl acrylate) and MWCNT composition. For copolymers containing 7 and 20 wt% of poly(butyl acrylate) the N values slightly decrease with the MWCNT concentration, while for the suspension prepared with the copolymer at 30 wt% of poly(butyl acrylate) the N values decrease drastically down to 50% approximately. The MWCNT content at the percolation threshold point was found to be 0.8 wt%, for all nanostructured films. The dispersion of MWCNT within the polymer matrix decreased with increasing the poly(butyl acrylate) composition, but it did not affect the electrical properties, which is assumed to be due to induction of the bridging effect and the MWCNT preference to locate into the poly(methyl methacrylate) phase.