Radical Propagation Kinetics of N-Vinylpyrrolidone in Organic Solvents Studied by Pulsed-Laser Polymerization-Size-Exclusion Chromatography (PLP-SEC)
Pulsed‐laser polymerization with subsequent analysis of the polymer molar mass distribution by size‐exclusion chromatography, PLP–SEC, is used to measure the propagation rate coefficient, kp, of N‐vinylpyrrolidone (NVP) in a series of organic solvents, varying the NVP concentration from 5 to 100 wt%...
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Published in | Macromolecular chemistry and physics Vol. 215; no. 23; pp. 2327 - 2336 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Weinheim
Blackwell Publishing Ltd
01.12.2014
Wiley Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Pulsed‐laser polymerization with subsequent analysis of the polymer molar mass distribution by size‐exclusion chromatography, PLP–SEC, is used to measure the propagation rate coefficient, kp, of N‐vinylpyrrolidone (NVP) in a series of organic solvents, varying the NVP concentration from 5 to 100 wt% and varying the temperature between –5 and +80 °C. In contrast to the 20‐fold increase observed in aqueous solution upon decreasing the NVP concentration from bulk to dilute conditions, the kp values of NVP in butyl acetate, iso‐propyl acetate, N‐ethylpyrrolidone, and N‐ethylformamide stay within 20% of the bulk value and exhibit no significant dependence on monomer concentration. The kp behavior of NVP in methanol and n‐butanol is intermediate between the one in water and in the other organic solvents, with kp increasing by about a factor of 2 upon lowering the monomer concentration from bulk to 5 wt% NVP. The activation energies for propagation in organic solvents agree within experimental uncertainty with the value reported for bulk NVP. The data demonstrate that hydrogen bonding is responsible for the increase in kp upon dilution, with this effect being much stronger in an aqueous environment than in a solution of alcohol.
The propagation rate coefficient, kp, for N‐vinylpyrrolidone is determined by pulsed‐laser polymerization with subsequent analysis of the polymer molar mass distribution by size‐exclusion chromatography in a series of organic solvents differing in types of intermolecular interactions, and compared with polymerization in water. The hydrogen‐bonding interactions are primarily responsible for the dependence of the kp value on monomer concentration. |
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Bibliography: | Slovak Research and Development Agency - No. APVV-0486-10 ark:/67375/WNG-XD6RNCQZ-L BASF SE Ludwigshafen VEGA Grant Agency - No. 2/0160/12; No. 2/0198/14 ArticleID:MACP201400329 istex:0CD27F8D2B0722B9F03F74F7B06CF9A2A0772C62 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1022-1352 1521-3935 |
DOI: | 10.1002/macp.201400329 |