Time- and temperature-resolved in-situ NMR studies on simultaneous quaternization/cross-linking of poly(vinylbenzyl chloride) polymer with hexamine
Quaternization reaction of poly(vinylbenzyl chloride) with hexamine was monitored using NMR at different time intervals and temperatures in this study. The amine to polymer ratios of 0.2:1, 0.33:1, and 1:1 were employed, and the progress of the reaction was monitored instantly after the addition of reactants. NMR was recorded at the intervals of every 10 min until for about an hour. Temperature was also varied from 30 to 60 °C, and progress of the reaction was monitored by NMR. The quaternization reaction was complete immediately after the addition of the reactants at 60 °C, whereas at low temperatures, the reaction proceeded at much lower rates. Even at low temperatures, the reaction proceeded at a faster rate when the amine content was higher. The quaternization reaction rate with different hexamine (HMA)-to-poly(vinylbenzyl chloride) (PVBC) ratios follows the order 1:1 > 0.33:1 > 0.2:1.
KeywordsPoly(vinylbenzyl chloride) Hexamine Quaternization In-situ NMR Anion exchange membrane
The corresponding author gratefully acknowledges CSIR-CECRI for providing financial assistance through the in-house project (project code: OLP 0075).
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