Versatile and efficient functionalisation of multiallylic dendronised polymers: can dense packing be reached? (original) (raw)
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Dendronized polymers with tailored surface groups
Journal of Polymer Science Part A: Polymer Chemistry, 2005
A series of polymers tethered with bis-MPA dendrons was synthesized by a combination of divergent growth and atom transfer radical polymerization (ATRP). Macromonomers of first and second generation were synthesized utilizing the acetonide protected anhydride of bis-MPA as the generic esterfication agent. The macromonomers were polymerized in a controlled fashion by ATRP utilizing Cu(I)/Cu(II) and N-propyl-2-pyridylmethanamine as the halogen/ligand system. The end-groups of these polymers were further tailored to achieve hydroxyl, acetate, and aliphatic hexadecyl functionality. With this approach all polymers will emanate from the same backbone, enabling for an evaluation of both the generation and end-group dependent properties. Furthermore, a dendronized tri-block copolymer was synthesized. All materials were analyzed by 1 H and 13 C NMR, as well as size-exclusion chromatography (SEC). The SEC analysis revealed that the molecular weights of the divergently grown dendronized polymers increased with increasing generation while the polydispersity (PDI) was kept low. V
Synthesis and Characterization of Dendronized Polymers
Macromolecular Symposia, 2007
ABSTRACT This research aims at the synthesis of several dendrons with different functional groups on their surface, and their use as functionalizing agents of synthetic polymers. Two principal products were synthesized and characterized: dendronized MDI oligomers and dendronized PMMI. The results of the characterization studies of dendronized polymers demonstrated the influence of the polarity of dendrons and the dendronization pathway on the properties of the final products. Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.
Surface modification of activated polymeric matrices by dendritic attachments
Journal of Polymer Science Part A: Polymer Chemistry, 2000
Aware of the growing interest in materials that exhibit specific physiochemical properties and potential applications, we focused our work on modifying commercial agarose with polyfunctional dendrons capable of molecular recognition through hydrogen bonding. 2,6-Di(acylamino)pyridine moieties within the internal superstructure of dendritic macromolecules have been reported to be capable of forming H-bonded complexes with imide groups, such as barbituric acid and its derivatives. We report the synthesis of new dendrons possessing multiple 2,6-di(acylamino)pyridinyl sites, each capable of molecular recognition, and the development of new polymeric supports of an activated agarose matrix by surface modification. From comparative studies of the beads modified by different dendrons, we found improved results in those dendritic supports possessing 2,6-di(acylamino)pyridinyl moieties, except when their juxtaposition between the groups promoted inner H bonds.
Macromolecules, 1998
The fourth generation tridendron dendrimer based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) with 48 hydroxyl groups was synthesized in high yields using N,N′-dicyclohexylcarbodiimide (DCC) for the coupling steps. A double-stage convergent approach reduced the number of synthetic and liquid chromatographic steps required in the synthesis and purification of the final dendrimers. The hydroxyl functional dendrimer was subjected to a variety of surface modifications by reaction with different acid chlorides. The acetonide, hydroxy, acetate, n-octanoate, n-palmitoate, and benzoate end-functionalized dendrimers showed large differences in thermal and solution behavior depending on the nature of their end groups. The glass transition temperature varied from -4°C for the acetate-terminated dendrimer to +57°C for the hydroxyl-functionalized dendrimer. Dendrimers terminated with long alkyl chains were highly soluble in hexane and dichloromethane and poorly soluble in water and methanol whereas the hydroxy-terminated dendrimer showed the opposite solution behavior. All surface modified dendrimers were amorphous according to differential scanning calorimetry (DSC) except for the n-palmitoateterminated dendrimer that showed a distinct melting transition at +28°C in its DSC trace due to the crystallization of the long alkyl chains.