POLY 509 |
| Highly branched polymers of styrene and N-isopropylacrylamide (NIPAM) were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization with a polymerizable chain transfer agent (CTA). An acryloyl trithiocarbonate was prepared by copper-catalyzed 1,3-dipolar cycloaddition, an example of “click chemistry,” with an azido-functionalized trithiocarbonate and propargyl acrylate. Due to their increased contribution in the hyperbranched structures, the end groups of the poly(NIPAM) polymers provided a convenient means to selectively tune lower critical solution temperature (LCST) in aqueous media. As compared to the conventional value of 32 °C expected for linear poly(NIPAM), reduced LCSTs were observed for branched polymers with hydrophobic end groups, while hydrophilic chain termini caused the LCST to significantly increase. |
|
Synthetic and Biological Macromolecules for Emerging Nanotechnologies
8:30 AM-12:20 PM, Wednesday, August 22, 2007 Westin Boston Waterfront -- Grand Ballroom A, Oral
Division of Polymer Chemistry |