1H NMR study on microstructure of a novel acrylamide/methacrylic acid template copolymer in aqueous solution
| Autor: | Erjian Wang, You-Ru Du, Miaozhen Li, Shizhen Mao, Yu-xi Zhang, Gongzhen Cheng, Ai-hong Liu, Maili Liu, Feipeng Wu |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
Aqueous solution Polymers and Plastics Hydrogen bond Carboxylic acid biochemical phenomena metabolism and nutrition chemistry.chemical_compound Colloid and Surface Chemistry chemistry Methacrylic acid Amide Polymer chemistry Materials Chemistry Copolymer Side chain Physical and Theoretical Chemistry Two-dimensional nuclear magnetic resonance spectroscopy |
| Zdroj: | Colloid and Polymer Science. 285:381-388 |
| ISSN: | 1435-1536 0303-402X |
| DOI: | 10.1007/s00396-006-1580-x |
| Popis: | A novel acrylamide/methacrylic acid template copolymer was prepared using polyallylammonium chloride (PAAC) as a template. This copolymer contains acrylamide (PAM), phenoxy acrylate (POA), and acylic acid (PAA) blocks. The investigation by high resolution nuclear magnetic resonance (H-1 NMR) shows that intramolecular hydrogen bonds between the PAM and PAA blocks lead to compact molecular arrangement at quite low pH values, and the motion of the phenoxy side chain of the POA blocks is somewhat restricted. With the increase in pH value of the solution, the carboxylic acid of the PAA block gradually dissociates, which weakens hydrogen bonds between the PAM and PAA blocks. The decrease in D (w), self-diffusion coefficient of water, indicates the growth in aggregate size of the template copolymer. The cross peaks between amide protons and backbone protons shown in 2D nuclear overhauser spectroscopy (NOESY) spectra imply the existence of the intermolecular hydrogen bonding interaction between PAM and PAA blocks. After the carboxylic acid of the PAA block is completely dissociated in alkaline solution, the electrostatic repulsion of the carboxylic ion makes the molecular chain of the copolymer exhibit more outstretched. Consequently, the phenoxy groups (the side chain of the POA block) have more space to move. |
| Databáze: | OpenAIRE |
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