Detection and quantification of branching in polyacrylates by size-exclusion chromatography (SEC) and melt-state C-13 NMR spectroscopy

作者：Castignolles Patrice; Graf Robert; Parkinson Matthew; Wilhelm Manfred; Gaborieau Marianne^*

来源：Polymer, 2009, 50(11): 2373-2383.

DOI：10.1016/j.polymer.2009.03.021

• Branching
• NMR
• Size-exclusion chromatography

Chain branching has been investigated in a homologous series of poly(n-alkyl acrylates) (methyl, ethyl, n-butyl, n-hexyl) obtained by radical polymerization. The total amount of chain branching was quantified using melt-state C-13 nuclear magnetic resonance (NMR) spectroscopy. It gave access to low degrees of branching in both soluble and insoluble polyacrylates, homopolymers; and copolymers. The lowest degree of branching was found for the ethyl member of the series with quantification by conventional solution-state NMR found to take a prohibitively long time. The method proposed here is compared to the ones published previously, and previous literature results are critically reviewed.
The presence of long-chain branching (LCB) was selectively detected using multiple-detection size-exclusion chromatography (SEC), with LCB being found for all soluble homopolymers but the poly(n-butyl acrylate). This finding was confirmed by close examination of the Mark-Houwink parameters for the various polyacrylates studied in this work or those previously published.

• 出版日期2009-5-22