聚苯乙烯-聚丁二烯嵌段共聚物在选择性溶剂2-丁酮中的自组装行为及其辐射交联固化效应

Self-assembly of polystyrene-block-polybutadiene diblock copolymers in selective solvents and its crosslinking behavior uponγ-ray irradiation

借助Delsa™Nano亚微米粒度粒子动态光散射分析仪、原子力显微镜(AFM)、扫描电子显微镜(SEM)和热重分析仪(TGA)研究了聚苯乙烯-聚丁二烯(PS-b-PB)嵌段共聚物在选择性溶剂2-丁酮中的自组装行为,以及所形成胶束在γ射线辐照后的交联固化效应。由于2-丁酮是PS链段的良好溶剂,PB链段的不良溶剂,因此,在适当条件下,PS-b-PB在选择性溶剂中会形成单分散的“核-壳”结构的纳米胶束。而本文的实验结果也表明,通过控制PS-b-PB在溶剂中的质量分数可以在较大范围内调整胶束尺寸。同时,本文进一步通过γ射线辐照的方法,对2-丁酮/PS-b-PB嵌段聚合物体系的胶束溶液进行无氧辐照,结果发现辐照后的胶束无论在微观形貌还是热力学稳定性方面,均有一定的提升,导致这种现象的原因是由于γ射线辐照诱导胶束中的PB链段发生交联反应而固化,固化后的胶束不再受超声震荡、溶剂稀释和挥发等因素的影响。本项研究为制备高分子纳米胶束提供了新的思路和方法。

In our approach,using Delsa™Nano submicron particle size dynamic light scattering analyzer,atomic force microscope,scanning electron microscope,and thermo-gravimetric analyzer,we investigated the self-assembly behavior of block copolymer polystyrene polybutadiene(PS-b-PB)in selective solvent,2-butanone,as well as the effect of irradiation crosslinking that resulted in the immobilization of micelles.Since the selective solvent,2-butanone,is the soluble solvent of PS segment and insoluble solvent of polybutadiene(Pb)segment,under suitable conditions,PS-b-PB could form monodisperse"core-shell"nano-micelles microstructure.The experimental results showed that under suitable conditions,PS-b-PB could form monodisperse nano-micelles with different core-shell components in selective solvent,and the size of micelles could be adjusted by controlling the mass fraction of PS-b-PB in the solvent.The micelle solution of 2-butanone/PS-b-PB block polymer system was further irradiated byγ-ray irradiation without oxygen,and the results showed that the micelles had a certain improvement in the micromorphology and thermodynamic stability.The reason is that the crosslinking reaction of PB chain in the micelles induced byγ-ray irradiation is immobilized,and the cured micelles are no longer affected by ultrasonic vibration,solvent dilution,and volatilization.This study provided a new approach and method for the preparation of polymer nano-micelles.