Dendrigraft Arborescent -Poly butadienes

The synthetic approach used for dendrigraft-po y(butadicncs) has the potential to provide control over the composition and architecture of the molecules. The branch molecular weight is easily varied with the amount of initiator used in the polymerization reaction. Solvent polarity control in the polymerization allows variation of the proportion of 1,2-units in the side chains, and hence the branching density. 

The solution properties of dendrigraft polybutadienes are, as in the previous cases discussed, consistent with a hard sphere morphology. The intrinsic viscosity of arborescent-poly(butadienes) levels off for the G1 and G2 polymers. Additionally, the ratio of the radius of gyration in solution (Rg) to the hydrodynamic radius (Rb) of the molecules decreases from RJRb = 1.4 to 0.8 from G1 to G2. For linear polymer chains with a coiled conformation in solution, a ratio RJRb = 1.48-1.50 is expected. For rigid spheres, in comparison, a limiting value RJRb = 0.775 is predicted. 

4 DENDRIGRAFT (ARBORESCENT)-POLY(STYRENE)-GRAFT-POLY(ISOPRENE) COPOLYMERS 

Sample Mwbr /103 Mwbr/Mnbr Grafting efficiency LS MJMn f J w Composition/ mol% PIP 

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