Synthesis, molecular characterization and theoretical study of first generation dendritic homopolymers of butadiene and isoprene with different microstructures

We report the Synthesis of first generation dendritic homopolymers consisting of either poly(butadiene) (PB) of 1,4-microstructure or poly(isoprene) enriched in 3,4-microstructure (at least 55% PI3,4). The main aspect was the synthesis of polymers exhibiting high molecular and compositional homogeneity. The preparation of these materials was achieved via anionic polymerization techniques in combination with chlorosilane chemistry. The molecular characterization of the final dendritic materials was made via size exclusion chromatography (SEC), membrane osmometry (MO), dilute solution viscometry and H-1 nuclear magnetic resonance (NMR) spectroscopy, leading to the conclusion that they can be considered as model polymers. The conformational properties of the synthesized dendritic polymers were studied by means of analytical theory and Monte Carlo simulations using coarse graining models with the same number of segments. The radii of gyration and the length of the branches of zeroth and first generations were calculated via lattice, off-lattice algorithms, and renormalization group techniques. The theoretical findings were compared with the respective results of star polymers with the same functionality and equivalent branch lengths. (c) 2006 Elsevier Ltd. All rights reserved.