Design of Polysaccharide-based New Materials Exhibiting Magnetic and Electromagnetic Functions.by Use of Ion-associated Chelation and Gelation Characteristics of Carbohydrate Polymers

利用碳水化合物聚合物的离子螯合和凝胶特性，设计了具有磁性和电磁功能的多糖基新材料。下面的结果值得注意。海藻酸盐/聚乙烯醇与氧化铁的磁性复合材料：采用原位合成技术成功制备了含氧化铁的海藻酸盐基凝胶。将海藻酸盐在铁盐水溶液中交联，并将所得凝胶浸入不同的碱性溶液中，得到非交换凝胶。凝胶样品用氧化剂处理，然后在冷冻状态下干燥。SQUID磁强计显示，干燥凝胶在室温下表现出超顺磁性或铁磁性，这取决于碱处理中金属阳离子的种类。通过对上述方法的改进，制备了含有离子氧化物的ipn型海藻酸盐/聚乙烯醇复合材料。除了SQUID测量外，还在凝胶状态下测试了复合材料的动态粘弹性。卡拉胶-氧化铁磁性复合材料：通过原位合成的方式制备了卡拉胶基磁性复合材料。进行了电镜观察和磁强计测量。在298K时，几乎所有的复合材料都表现出超顺磁性，并且磁铁矿和/或磁铁矿颗粒以小于几十纳米的尺度分散在构成卡拉胶基体的纤维状实体的内部和内表面。纤维素衍生物/无机盐离子的介观体系：阐明了含盐离子的（羟丙基）纤维素水溶液和凝胶的介观结构特征。探索了一种电光函数来控制亚纯溶液和网络的反射着色和浊度。

Polysaccharide-based new materials ehibiting magnetic and electromagnetic functions were designed by, utilizing ion-associated chelation and gelation characteristics of carbohydrate polymers. The following results are worth noting.1.Magnetic Composites of Alginate/Poly vinyl alcohol) with Iron Oxide:Alginate-based gels containing iron oxides were prepared successfully by an in situ synthesis technique. Alginate was crosslinked in iron salt aqueous solution, and' the resulting gels were immersed into different alkaline solutions, whereupon i.on-exchanged gels were obtained. The gel samples were treated with an oxidizing agent, then dried in frozen state. SQUID magnetometry revealed that the dried gels showed superparamagnetism or ferromagnetism at room temperature, depending on the sort of metallic cation in the alkali treatment. IPN-type alginate/poly(vinyl alcohol) composites containing ion oxides were also prepared by modifying the above method. 'The, dynamic viscoelastic property of the composites was examined in gelatinous state, in addition to SQUID measurements.2.Magnetic Composites of Carrageenan -Iron Oxide:Carrageenan-based magnetic composites were prepared via in situ synthesis, of iron oxides in a similar way stated above. Electron microscopic observations and magnetometry measurements were conducted. It was found that almost alt the composites exhibited superparamagnetic character at 298K, and that magnetite and/or maghemite particles were dispersed in a scale less than several tens of nanometers in the interior as well as on the inner surface of fibrillar entities constituting the carrageenan matrix.3.Mesoscopic Systems of Cellulose Derivative/Inorganic Salt Ions:Mesoscopic structural characteristics of aqueous (hydroxypropyl)cellulose solutions and gels containing salt ions were made clearer. An electrooptical function was explored to control externally the reflective coloration and turbidity of the mesomorphic solutions and networks.