Cf. Jiang et al., Gel formation in atom transfer radical polymerization of 2-(N,N-dimethylamino)ethyl methacrylate and ethylene glycol dimethacrylate, J POL SC PC, 39(21), 2001, pp. 3780-3788
Citations number
18
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
Copolymers of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and ethylene
glycol dimethacrylate (EGDMA) were synthesized via atom transfer radical p
olymerization using ethyl 2-bromoisobutyrate as the initiator, Cu(I)Br as t
he catalyst, and 1,1,4,7,10,10-hexamethyltriethylene tetramine as the ligan
d. At low crosslinker levels, the polymerizations followed the first-order
kinetics. However, when the crosslinker level was above 10 mol %, the ln([M
](0)/[M]) versus time curves showed deceleration at medium conversions beca
use of the higher reactivity of EGDMA than that of DMAEMA. An acceleration
at high conversions was also observed and probably caused by the diffusion
limitations of catalyst/ligand complex in the polymer network. The hydrogel
s were characterized by swelling experiments, and the Sol polymers were cha
racterized by the size exclusion chromatographic technique to determine the
number-average molecular weight and polydispersity. The gel data were anal
yzed and, via a comparison to Flory's gelation theory, found to be more hom
ogeneous than similar hydrogels prepared by conventional free-radical polym
erization methods. (C) 2001 John Wiley & Sons, Inc.