Synthesis of Dendrimer-Like Polystyrene by Atom Transfer Radical Polymerization and Investigation of Their Viscosity Behavior

• Published in: International journal of biological macromolecules Vol. 38; no. 8; pp. 3120 - 3128
• Main Authors: Lepoittevin, Bénédicte, Matmour, Rachid, Francis, Raju, Taton, Daniel, Gnanou, Yves
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 19-04-2005; Elsevier
• Subjects: Applied sciences; Chemical Sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymerization; Polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts; Molecular rigidity; Chemical solution; End group; Branched polymer; Repeated sequence; Atom transfer polymerization; Molecular weight viscosity relationship; Calixarene; Experimental study; Monodispersed polymer; Chemical modification; Preparation; Styrene polymer; Bromine Organic compounds; Dendritic structure; HYPERBRANCHED POLYMERS; MACROMOLECULES; ANIONIC-POLYMERIZATION; TERMINATOR MULTIFUNCTIONAL INITIATOR; CONVENTIONAL MONOMERS; WELL-DEFINED POLYSTYRENE; STAR POLYMERS; COMBINATION; BLOCK-COPOLYMER; ARCHITECTURES
• ISSN: 0024-9297; 0141-8130; 1520-5835
• DOI: 10.1021/ma048106s

The synthesis of dendrimer-like polystyrene (PS) of second and third generations by combination of atom transfer radical polymerization (ATRP) and chain end modifications is reported. Calixarene-based cores were used as initiators for ATRP of styrene yielding star polymers containing precisely 4, 6, or 8 arms. The latter were modified in two steps so as to generate PS stars carrying 8, 12, or 16 terminal bromoisobutyrate groups, respectively. These precursors served as multifunctional macroinitiators for the formation of the second generation of dendrimer-like PS. Reiteration of the aforementioned sequence of reactions allowed to derive dendrimer-like polystyrene of third generation that were constituted of 16, 24, or 32 outer arms, respectively. The chain end modification was monitored by 1H NMR spectroscopy. The dendrimer-like PS were also characterized by size exclusion chromatography equipped with a multiangle laser light scattering detector (SEC/MALLS). The actual polymer architecture and the functionality of the stars were confirmed by analysis of the individual arms obtained upon hydrolysis of the ester links present at the core of the stars and at the branching points. The intrinsic viscosities of these dendrimer-like polystyrenes are similar to those reported for regular dendrimers.