不同共混方式下非对称嵌段共聚物PS-b-PMMA对PCHMA/PMMA体系增容效果的研究:界面与胶束的竞争

Effect of Asymmetric Block Copolymer PS-b-PMMA on the Compatibility of PCHMA/PMMA Blends by Different Blending Methods:Interface vs Micelles

采用熔融共混方式,利用非对称两嵌段共聚物聚苯乙烯-b-聚甲基丙烯酸甲酯(PS-b-PMMA)对聚甲基丙烯酸环己酯(PCHMA)/聚甲基丙烯酸甲酯(PMMA)共混体系进行增容。重点研究了嵌段比、共混方式以及分散相PMMA分子量对共混体系中非对称嵌段共聚物分布的影响,即嵌段共聚物稳定相界面与所形成胶束数量、位置之间的竞争关系。结果表明,在低分子量PMMA情况下共混方式对非对称嵌段共聚物的分布影响显著,改变共混方式可以有效减少分散相中的胶束数量,使嵌段共聚物主要分布在二元不相容增容体系两相界面。另一方面,增大PMMA分子量会改变非对称嵌段共聚物在两相界面的界面曲率,导致其在分散相中的溶解性增大,在界面上的稳定性减小,从而迁移至分散相内部并最终形成胶束。

Using melt blending,the asymmetric diblock copolymer polystyrene-b-poly（methyl methacrylate）（PS-b-PMMA）was added to compatibilize poly（cyclohexyl methacrylate）（PCHMA）and poly（methyl methacrylate）（PMMA）blends.Effects of the block ratio,blending method,and molecular weight of the dispersed phase PMMA was discussed to study the distribution of asymmetric block copolymer,namely the competition of interface and micelles.The results show that the blend method has significant influence on the distribution of the asymmetric block copolymer in the case of a low molecular weight PMMA.The change of the blending method can effectively reduce the number of the micelles in the dispersed phase,and the asymmetric block copolymer is mainly distributed on the interface of the compatibilized blends.On the other hand,the increase of the PMMA molecular weight can change the interfacial curvature of the asymmetric block copolymer between two phases,resulting in an increase of the solubility in the dispersed phase and the unstablility of block copolymer on the interface,which leads to the migration of BCPs into the dispersed phase and finally the micelles were formed.