| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.19 MB | Adobe PDF |
Advisor(s)
Abstract(s)
Temperature and pH stimuli-responsive hydrogel particles were
synthesized using inverse-suspension polymerization in batch stirred reactor.
Different water soluble co-monomers were present in the initial mixture (e.g.
N-isopropylacrylamide and acrylic acid) as well as crosslinkers with different
functionalities. Different operating conditions such as polymerization temperature,
monomers dilution, neutralization and the initial ratios of co-monomers and
monomers/crosslinker were also tried. Hydrogel particles were produced considering
classical free-radical polymerization (FRP) and also RAFT polymerization.
Commercially available RAFT agents 4-cyano-4-phenylcarbonothioylthio-pentanoic
acid (CPA), 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT) and
cyanomethyl dodecyl trithiocarbonate (CDT) were alternatively used. Sampling at
different polymerization times allowed the study of the kinetics of polymerization
through the analysis by SEC of the soluble phase. A tetra-detector array with
simultaneous detection of refractive index, light scattering, intrinsic viscosity and
ultra-violet signals was used in these studies. Usefulness of in-line FTIR-ATR
monitoring to study the building process of such networks was also assessed. The
performance of hydrogel beads was studied through drug delivery tests triggered by
changes in the environmental temperature and pH. This research aims to contribute
for the elucidation of the connection between the synthesis conditions, molecular
architecture and properties/performance of such advanced materials.
Description
Keywords
Crosslinking Hydrogels RAFT Stimuli-responsive polymers
Citation
Gonçalves, Miguel; Pinto, Virgínia; Costa, Rita; Dias, Rolando; Hernándes-Ortiz, Julio; Costa, Mário Rui (2013). Stimuli-responsive hydrogels synthesis using free radical and RAFT polymerization. In Polymer Reaction Engineering – 11th International Workshop e Macromolecular Symposia - Special Issue: Polymer Reaction Engineering. Hamburg. WILEY-VCH. p. 41-54.
Publisher
WILEY-VCH