Deterioration of Polyamideamine?Epichlorohydrin (PAE) in Aqueous Solutions During Storage: Structural Changes of PAE

Structural changes of polyamideamine-epichlorohydrin (PAE) in solution during storage at 4 °C and pH 4.2-4.5 for up to 8.9 years were studied by ^sup 1^H- and ^sup 13^C-NMR analyses, colloidal titration and others. NMR signals due to 3-hydroxy-azetidinium groups of PAE decreased during storage, and...

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Bibliographic Details
Published in:Journal of polymers and the environment 2005-01, Vol.13 (1), p.1-6
Main Authors: Obokata, Takao, Isogai, Akira
Format: Article
Language:English
Subjects:
Amides
Aqueous solutions
Colloids
Decomposition
Degree of polymerization
Deterioration
Hydrolysis
NMR
Polymers
Q1
Ring opening
Titration
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Summary:Structural changes of polyamideamine-epichlorohydrin (PAE) in solution during storage at 4 °C and pH 4.2-4.5 for up to 8.9 years were studied by ^sup 1^H- and ^sup 13^C-NMR analyses, colloidal titration and others. NMR signals due to 3-hydroxy-azetidinium groups of PAE decreased during storage, and correspondingly 2, 3-dihydroxypropyl groups were formed by the ring opening. The content of 3-hydroxy-azetidinium groups in PAE determined by ^sup 1^H-NMR were similar to that determined by the colloidal titration, although the former was higher than the latter. About 50% of the 3-hydroxy-azetidinium groups present in the fresh PAE were lost during storage for 8.9 years. Furthermore, ^sup 13^C-NMR analysis revealed that significant depolymerization of polyamideamine chains occurred by hydrolysis of the amide linkages during storage. Rough evaluation of number average degree of polymerization (DPn) of the amideamine repeating unit showed that the DPn decreased from 12 to 2 during storage for 8.9 years.[PUBLICATION ABSTRACT]
ISSN:1566-2543
1572-8900
1572-8919
DOI:10.1007/s10924-004-1210-y