基于γ-环糊精包合作用的大分子自组装网络及其流变性能调控

Rheological Property Modulation of Polymer Networks Based on γ-Cyclodextrin Inclusion Association

将γ-环糊精(γ-CD)和3种不同长度烷基(Cn,n为12,16,18)分别按照一定的接枝率接枝于聚丙烯酸链上,利用环糊精与疏水烷基链之间的包合作用,成功制备了大分子自组装网络,并利用流变学手段对影响高分子网络结构的因素进行了系统研究。结果表明:γ-CD与Cn之间的包合作用主要以1∶2的量化模式进行,即1个γ环糊精空腔可以同时穿入2条烷基链。当聚合物的质量分数较低时(w≤1.7%),聚合物之间以包合作用交联为主;随着聚合物质量分数的增加并超过临界浓度,疏水缔合作用产生且迅速增大,并最终超过包合作用。单体γ-CD及表面活性剂十二烷基硫酸钠(SDS)的加入可以调节聚合物的网络结构,从而对自组装体系的黏度起到调控作用。

γ-Cyclodextrin（γ-CD） and three alkyl groups（C12,C16,C18） with different lengths were grafted onto poly（acrylic acid）（PAA）.Polymer networks were prepared by mixing γ-CD and Cn（n=12,16,18） modified PAA based on the inclusion associations between alkyl and γ-CD grafts.Rheological method was employed to study the properties of polymer networks.The γ-CD/alkyl inclusion compounds were formed at a stoichiometric ratio of 1∶2,i.e.two alkyl groups entered into one γ-CD cavity.At low polymer concentration（w≤1.7%）,the inclusion associations between γ-CD and alkyl grafts were dominated while the hydrophobic associations among the hydrophobic alkyl groups became stronger upon increasing polymer concentration.Viscosity of polymer solutions could be modulated by addition of γ-CD and surfactant SDS and thus regulating the structure of polymer networks.