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Efficient synthesis of branched poly(acrylic acid) derivatives via postpolymerization modification
Author(s) -
Bou Zerdan Raghida,
Geng Zhishuai,
Narupai Benjaporn,
Diaz Yvonne J.,
Bates Morgan W.,
Laitar David S.,
Souvagya Biswas,
Van Dyk Antony K.,
Hawker Craig J.
Publication year - 2020
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20200287
Subject(s) - chemistry , polymer chemistry , copolymer , amine gas treating , acrylate , trifluoroacetic acid , side chain , acrylic acid , methyl acrylate , chain transfer , steric effects , polymerization , reactivity (psychology) , radical polymerization , organic chemistry , polymer , medicine , alternative medicine , pathology
The utility of pentafluorophenyl esters for the selective introduction of functional units and branch points in well‐defined poly(acrylic acid) (PAA) derivatives is demonstrated using a combination of controlled radical polymerization and postpolymerization modification. Reversible addition‐fragmentation chain transfer enables the synthesis of well‐defined copolymers—poly(pentafluorophenyl acrylate‐co‐ tert ‐butyl acrylate)—with the active ester repeat units serving as attachment points for reaction with primary amines, specifically tris(2‐( t ‐butoxycarbonyl)ethyl)methyl amine (Behera's amine). Deprotection using trifluoroacetic acid removes both the backbone and side chain t ‐butyl esters to give a series of branched PAA derivatives containing novel tricarboxylic acid side chains that are well suited to complexation and multidentate interactions. Surprisingly, the active ester homopolymer is shown to have the highest reactivity with Behera's amine when compared to copolymers with lower incorporation of pentafluorophenyl esters, suggesting an intriguing interplay of neighboring group effects and steric interactions. The ability to tune the efficiency of postpolymerization modification gives a library of PAA derivatives.