Abstract
Temperature-sensitive poly(N-isopropylacrylamide) [poly(NIPAAm)] was crosslinked with a small amount of N,N′-cystamine-bis-acrylamide which contains a disulfide linkage between two vinyl groups. The hydrogel network could be dissolved into water soluble polymer chains by the reduction of a disulfide bond to two thiol groups. The cleavage of crosslink points led to the experimental determination of the polymer molecular weight (Mn) and the amount of free thiol concentration in the polymer backbone. This permitted the calculation of an average molecular weight between crosslinks (Mc) which has been theoretically predicted by a Flory-Rehner equation based on either swelling or tensile experiments. The experimentally measured Mc values agree well with those obtained from the swelling experiment. When the reduced poly(NIPAAm) was re-oxidized in a dilute aqueous solution, time dependent evolution of inter- and intra-molecularly disulfide linked poly(NIPAAm) species could be observed.
Original language | English |
---|---|
Pages (from-to) | 976-980 |
Number of pages | 5 |
Journal | Polymer Journal |
Volume | 30 |
Issue number | 12 |
DOIs | |
State | Published - 1998 |
Externally published | Yes |
Keywords
- Disulfide
- Hydrogel
- Lower Critical Solution Temperature
- Poly(N-isopropylacrylamide)
- Reversible Gels