Light Scattering Study of the Formation and Structure of Partially Hydrolyzed Poly(acrylamide)/Calcium(II) Complexes

Autor:	Chi Wu, Shufu Peng
Rok vydání:	1999
Předmět:	Aqueous solution Polymers and Plastics Chemistry Stereochemistry Organic Chemistry Kinetics Ion Inorganic Chemistry Crystallography Hydrolysis chemistry.chemical_compound Ionic strength Acrylamide Materials Chemistry Molar mass distribution Ionomer
Zdroj:	Macromolecules. 32:585-589
ISSN:	1520-5835 0024-9297
Popis:	The Ca2+ concentration and hydrolysis degree [−COO-] dependence of the self-complexation of partially hydrolyzed poly(acrylamide) (HPAM) chains in CaCl2 aqueous solution was systematically investigated by a combination of static and dynamic laser light scattering. We have, for the first time, revealed a transition between the intrachain and interchain complexations. For each given HPAM sample, there exists a critical Ca2+ concentration ([Ca2+]agg) at which the interchain HPAM complexation becomes dominant. [Ca2+]agg is related to [−COO-] by [Ca2+]agg = 7.46 × 10-9 [−COO-]-1.4, indicating that the complexation is not stoichiomeric and many Ca2+ ions are free in water. We also found that even at [Ca2+] > [Ca2+]agg, the complexation at the initial stage was mainly an intrachain process, but gradually evolved into an interchain aggregation. The length of the initial stage increases as [−COO-] and [Ca2+] decrease. Our results showed that in the complexation process, the weight average molecular weight (Mw) of ...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::ea6036e4e12402139edd449633d269e5 https://doi.org/10.1021/ma9809031 Zobrazit plný text záznamu