CLOUD POINT OF POLY(N-ISOPROPYLACRYLAMIDE) SYNTHESIZED IN THE PRESENCE OF CYCLODEXTRIN

Polymerization of N-isopropylacrylamide (NIPAAm) was performed in the presence of beta-cyclodextrin (beta-CD) [or hydroxypropyl-beta-cyclode xtrin (HOP-beta-CD)]. The formation of an inclusion complex between PN IPAAm and beta-CD was confirmed by FT-IR, H-1 NMR and 2D-NOESY NMR. It was found that the cloud point (CP) of poly(N-isopropylamide) (PNIPAA m) in the PNIPAAm/beta-CD complex in aqueous solution increased up to about 57 degrees C whereas that in the PNIPAAm/beta-CD blend is about 33 degrees C. The CP of PNIPAAm in the PNIPAAm/beta-CD complex is high er than that in the PNIPAAm/HOP-beta-CD inclusion complex. IR and NMR results suggest that PNIPAAm chains are included in CD cavities.