Swelling behaviors of vermiculite/poly (acrylic acid) superabsorbent composite induced by glow discharge electrolysis plasma
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摘要: 在水溶液中，以丙烯酸（AA）和蛭石（VMT）为原料，N，N’-亚甲基双丙烯酰胺（MBA）为交联剂，用辉光放电电解等离子体（GDEP）技术引发一步制备蛭石/聚丙烯酸高吸水性复合材料。采用FTIR、XRD对蛭石/聚丙烯酸的结构进行了表征，探讨了GDEP引发聚合和溶胀动力学行为的机制，研究了pH值和盐浓度对蛭石/聚丙烯酸平衡溶胀率的影响。结果表明，蛭石/聚丙烯酸高吸水性复合材料在蒸馏水中2 h达溶胀平衡，溶胀过程遵循拟二级动力学模型；该复合材料具有pH敏感性、盐敏感性和可逆溶胀-消溶胀开关行为，其在单价阳离子溶液中的平衡溶胀率比二价阳离子溶液中的更高。
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关键词:
- 蛭石 /
- 聚丙烯酸 /
- 高吸水性复合材料 /
- 辉光放电电解等离子体(GDEP) /
- 溶胀行为
Abstract: A vermiculite/poly(acrylic acid) (VMT/PAA) superabsorbent composite is prepared in aqueous solution by a simple one-step using glow-discharge electrolysis plasma (GDEP) induced graft copolymerization of acrylic acid (AA) and vermiculite(VMT), in which N,N'-methylenebisacrylamide (MBA) is used as a crosslinker. The structure of the resulting product is characterized by FTIR and XRD. A mechanism for synthesis of vermiculite/poly(acrylic acid) superabsorbent composite is proposed and the swelling kinetics in distilled water is systematically investigated. The influences of various pH values and salts solutions on the equilibrium swelling ratio are preliminarily studied. The results show that the swelling kinetics follows the pseudo-second-order swelling kinetics model. The vermiculite/poly(acrylic acid) superabsorbent composite is responsive to pH and salts, and it has excellent on-off switching behavior as reversible swelling and deswelling. In addition, the equilibrium swelling ratio of univalent cation salt solution is higher than that of bivalent cation salt solution. -
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