模板聚合法合成P(AM/AA)多嵌段共聚物的溶液性质和自缔合作用

研究了模板法合成多嵌段状丙烯酰胺(AM)和丙烯酸(AA)共聚物(简称模板共聚物TP)在水溶液中的溶液性质和缔合作用.结果表明,模板共聚物具有明显的结构效应.不同于无模板参与聚合的无规共聚物(CP),模板共聚物随着溶液pH的降低或加入多价金属离子容易发生相分离.透射电子显微镜(TEM)表明,加入Ca2+离子后,聚合物形成了大的分子间交联体,且随着Ca2+离子浓度的增加,交联程度增加,致使溶液产生相分离.随着溶液pH的升高,模板共聚物溶液粘度变化与丙烯酸均聚物具有相同的规律,都是先增大后减小,粘度有一个最大值,但模板共聚物溶液粘度升高幅度更大.TEM表明在粘度最大处形成了带状分子间缔合体.

SOLUTION PROPERTIES AND SELF-ASSOCIATION OF MULTI-BLOCK COPOLYMER P(AM/AA) PREPARED BY TEMPLATE COPOLYMERIZATION

The association and properties of multi-block copolymers(TP) of acrylamide(AM) and acrylic acid(AA) prepared by template copolymerization in aqueous solution were studied.The results showed that the copolymers of this type exhibited a significant structure effect compared with that of similar random copolymers(CP) obtained by copolymerization in the absence of template.Decrease the pH or add Ca~(2 ) to the copolymer solution may cause phase separation.The TEM images demonstrated that the phase separation by adding Ca~(2 ) was due to the formation of extensive intermolecular cross-linking.With increasing the pH of the copolymer solution the solution viscosity increased first and then decreased similar with that of the homopolyacrylic acid.However the increase range of template copolymer was higher than that of homopolyacrylic acid.TEM images indicated that at the maximal viscosity the template copolymer exhibited coiled aggregates.