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HyperMacs – Highly Branched Network Precursors or Semi‐Interpenetrating Networks?
Author(s) -
Dodds Jonathan M.,
Hutchings Lian R.
Publication year - 2010
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201050504
Subject(s) - dispersity , polymer , molar mass distribution , polymer chemistry , size exclusion chromatography , polymerization , solubility , solvent , fraction (chemistry) , materials science , chemical engineering , chemistry , organic chemistry , engineering , enzyme
We describe here a strategy for the synthesis of HyperMacs – long‐chain branched analogues of hyperbranched polymers. The building blocks for HyperMacs, AB 2 macromonomers, are synthesized by living anionic polymerization and, as such, are well‐defined in terms of molecular weight (MW) and polydispersity. Size exclusion chromatography (SEC) studies show that the nature of the coupling reaction used to generate the highly branched HyperMacs results in branched polymers with a distribution of MWs and architectures. Solubility studies show that, in certain cases, a significant weight fraction of the resulting HyperMacs forms insoluble, swollen gels when added to a good solvent, and SEC analysis shows that a modest weight fraction of the soluble polymer has a “very high MW”, in excess of 10,000,000 g mol −1 . Although an AB 2 coupling reaction should, in theory, not lead to a “crosslinked” network, such is the efficiency of this reaction that the resulting polymers appear to behave as semi‐interpenetrating networks.