File(s) not publicly available
Synthesis and characterization of branched water-soluble homopolymers and diblock copolymers using group transfer polymerisation
journal contribution
posted on 2023-06-08, 05:24 authored by N C Billingham, Iveta Bannister, D C Sherrington, S P Armes, V BütünGroup transfer polymerization [GTP] was used to synthesize branched statistical copolymers by copolymerizing either 2-(dimethylamino)ethyl methacrylate) [DMA] or 2-(diethylamino)ethyl methacrylate) [DEA] with ethylene glycol dimethacrylate (EGDMA) in THF at 20 °C. Since GTP has reasonable “living” character, it allows good control over both the primary chain length and the molecular weight distribution compared to previous branched vinyl polymers synthesized using conventional radical polymerization. Using GTP allows a remarkably high proportion of EGDMA brancher to be copolymerized without causing macrogelation. This unexpected result is attributed to a significant amount of intramolecular cyclization occurring (in addition to intermolecular branching) in these syntheses. Branched diblock copolymers based on DMA and DEA were prepared by sequential monomer addition, with EGDMA being used to achieve branching in either the DMA block or the DEA block or in both blocks. The order of monomer addition was varied to examine whether branching affected the “living” character of the polymerization. There was some evidence for better blocking efficiencies if the first block was a linear homopolymer, rather than a branched block copolymer. 1H NMR spectroscopy indicated that very high comonomer conversions (>99%) were obtained in all cases. The branched diblock copolymers were characterized in terms of their block compositions and primary chain lengths using 1H NMR, and their molecular weight distributions were assessed by THF GPC using a light scattering detector to obtain absolute Mw values. The evolution of molecular weight with conversion was assessed by periodic sampling of the polymerizing solution. Dynamic light scattering (DLS) and surface tensiometry data obtained for dilute aqueous solutions of the branched block copolymers were compared to those obtained for a linear diblock copolymer. Similar surface tension profiles were obtained regardless of the block architecture, but DLS studies indicated that larger, more polydisperse micelles were obtained if the coronal block was branched.
History
Publication status
- Published
Journal
MacromoleculesISSN
0024-9297Publisher
Journal of the American Chemical SocietyExternal DOI
Issue
12Volume
38Page range
4977-4982Pages
5.0ISBN
0002-7863Department affiliated with
- Chemistry Publications
Notes
This was a collaboration with Sherrington at Strathclyde directed by NCB and Armes. Bütün was a Turkish Government sponsored visitor. This was the first example of a highly-branched non-gelling polymerisation using living chemistry to control primary chain length. Work performed at Sussex with some analytical input at Strathclyde.Full text available
- No
Peer reviewed?
- Yes
Legacy Posted Date
2012-02-06Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC