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Luo, H., Ren, S., Ma, Y., Fang, G., and Jiang, G. (2015). "Preparation and properties of kraft lignin-N-isopropyl acrylamide hydrogel," BioRes. 10(2), 3507-3519.

Abstract

Kraft lignin was used to prepare kraft lignin-N-isopropyl acrylamide hydrogel (KNIAH). The results indicated that using a 1:2 mass ratio of KL-to-N-isopropyl acrylamide (NIPAM), 48 h reaction time, and 1.5 mL of crosslinking agent yielded KNIAH with the maximum swelling degree (209.3%). The crosslinking reaction was verified by C-N shifting at 1272 cm-1 and increased C=O bonding at 1720 cm-1. KNIAH with a smooth and uniform surface was created. DSC demonstrated that free water combined with KNIAH at 200 °C, after which KNIAH began exothermic decomposition. TGA shows that KNIAH with good performance of heat resistance and degradation. Absorption was maximized at 20 °C; low temperature and neutral solution was conducive to water absorption. Decolorization increased with decreasing concentration and pH value.
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