Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Technologiepark Zwijnaarde 904, B-9052 Ghent, Belgium; Polymer Chemistry & Biomaterials Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, Building S4-bis, B-9000 Ghent, Belgium.
Design & Synthesis of Organic Semiconductors, Institute for Materials Research, Hasselt University, Agoralaan 1-Building D, 3590 Diepenbeek, Belgium.
Carbohydr Polym. 2017 Jul 15;168:173-181. doi: 10.1016/j.carbpol.2017.03.037. Epub 2017 Mar 15.
Smart pH-responsive superabsorbent polymers (SAPs) could be useful for self-healing of cracks in mortar. They will swell minimally during the alkaline conditions of mixing, leading to only small macro-pores but will swell stronger with a lower pH when water enters the cracks. As such, polysaccharides (alginate, chitosan and agarose) were methacrylated and cross-linked with amine-based monomers (dimethylaminoethyl methacrylate and dimethylaminopropyl methacrylamide) to induce a varying pH-sensitivity. These materials showed a strong cross-linking efficiency and induced moisture uptake capacities up to 122% at 95% relative humidity with a negligible hysteresis. Additionally, interesting pH-responsive swelling capacities were obtained, especially for SAPs based on chitosan and agarose with values up to 110gwater/gSAP. Most of these materials showed limited hydrolysis in cement filtrate solutions, making them very promising for use in mortar.
智能 pH 响应型超吸水性聚合物 (SAP) 可用于自修复水泥砂浆中的裂缝。在混合时的碱性条件下，它们的膨胀程度最小，只会导致少量的大孔，但当水进入裂缝时，它们会在较低的 pH 值下更强地膨胀。因此，多糖（海藻酸盐、壳聚糖和琼脂）被甲基丙烯酰化，并与基于胺的单体（甲基丙烯酸二甲氨基乙酯和甲基丙烯酰胺丙基二甲胺）交联，以诱导不同的 pH 敏感性。这些材料表现出很强的交联效率，并在 95%相对湿度下具有高达 122%的水分吸收能力，几乎没有滞后。此外，还获得了有趣的 pH 响应性溶胀能力，特别是基于壳聚糖和琼脂的 SAP，其值高达 110gwater/gSAP。这些材料中的大多数在水泥滤液溶液中水解有限，因此非常有希望用于水泥砂浆中。
