机械活化淀粉基膨润土复合高吸水树脂性能的研究

Study on the Properties of Composite Superabsorbent Based on Mechanically Activated Starch and Bentonite

摘要:

为了提高淀粉基高吸水树脂的吸水率和保水性能，以机械活化60 min的木薯淀粉、丙烯酸和膨润土为原料，合成可降解复合高吸水树脂（CSA），研究膨润土（BT）的用量对CSA吸水率（Aeq）的影响以及CSA的溶胀性能。采用SEM、TGA 和FTIR对样品的形貌、热稳定性和结构进行表征。结果表明，CSA呈多孔层状结构。适量的引入BT（其用量为淀粉质量的30 %）可使CSA的吸水率从1604 g/g提高到1807 g/g，并能提高CSA的热稳定性和保水能力。在700 ℃下，CSA的失重率为79.3 %，低于未添加BT树脂的失重率（83.4 %）；CSA在1912 Pa的承压下保水率为48.3 %，高于未添加BT树脂的保水率（45.5 %）。另外，CSA吸水过程符合一级动力学过程，吸水率受溶液的pH、盐溶液的浓度和种类的影响。 关键词：复合高吸水树脂，机械活化，淀粉，膨润土，溶胀性能

Abstract:

The composite superabsorbent (CSA) with biodegradability was synthesized by using cassava starch mechanically activated for 60 min, acrylic acid and bentonite (BT) to enhance its water absorbency (Aeq) and retention. The effect of bentonite’s dosage on the water absorbency and the swelling properties of CSA were studied. The morphology, thermostability and functional groups of the samples were characterized by SEM, TGA and FTIR, respectively. The results showed that CSA had a microporous and laminate structure, the Aeq of CSA was increased from 1604 g/g to 1807 g/g by introducing an appropriate amount of BT (30 % to the weight of starch), and the thermostability and capacity of water-holding were also strengthened. The weight loss of CSA was 79.3 % when it was heated to 700 ℃, which was lower than that of superabsorbent without BT (83.4 %). The water retention for CSA was 48.3 % in the pressure of 1912 Pa and higher than that of superabsorbent without BT (45.5 %). Meanwhile, the swelling processes of CSA exhibited first-order dynamics, and the Aeq was of pH and salt dependent.