Reactive & Functional Polymers, Vol.68, No.12, 1682-1695, 2008
Convenient approaches for the synthesis and characterization of well-defined linear-dendritic diblock copolymers having a definite number of peripheral primary amino groups: Exact control of numbers introduced and dendritic distribution to enhance co-operative effect
Efficient and convenient approaches have been developed to prepare a wide array of well-defined linear-dendritic diblock copolymers having a definite number of peripheral primary amino groups by utilizing linear polystyrenes end-functionalized with a definite number of dendritic benzyl bromide and/or benzyl alcohol functionalities as precursory polymers. Various approaches including modified Gabriel synthesis, Michael addition and alkylation reactions have been developed for their synthesis. The resulting primary amine-end-functionalized copolymers always exhibited SEC profiles showing asymmetric long-tailed distributions and their true molar masses were obtained after the acetylation of their peripheral dendritic amino groups with acetyl chloride. All the resulting copolymers possessed well-defined linear-dendritic diblock architectures, with controlled molecular weights. In these polymer series, the molecular weight of linear polystyrene chains remained almost unchanged (M(n) similar to 19.3 kg/mol), while the dendritic blocks increased in both size and molecular weight as the number of peripheral dendritic end-functional groups was increased. The resulting copolymers were fully characterized by elemental, FT-IR, TLC-FID, GPC, (1)H and (13)C NMR analyses. (C) 2008 Elsevier Ltd. All rights reserved.
Keywords:Linear-dendritic block copolymers;Hyperbranched polymers;Dendritic amines;Reactive polymers;End-functionalization