聚甲基丙烯酸甲酯纳米发泡材料的制备:胶束尺寸对发泡行为的影响

Preparation of Nano-cellular PMMA Foam: Effect of Micelle Size on Foaming Behavior

采用超临界二氧化碳固态发泡法制备聚甲基丙烯酸甲酯(PMMA)纳米发泡材料,通过添加两嵌段共聚物聚苯乙烯-聚甲基丙烯酸甲酯(PMMA/PS-b-PMMA)来调控共混物的胶束尺寸,系统研究胶束尺寸对发泡行为的影响。首先,根据嵌段"自组装"的特性,通过控制嵌段质量比制备出不同胶束尺寸的原始样品。通过透射电镜(TEM)观察可知,胶束尺寸随嵌段质量比增加而变大。其次,利用扫描电镜(SEM)探索了胶束尺寸对其发泡行为的影响。结果表明,胶束尺寸对泡孔形貌有显著影响,胶束尺寸过小反而会导致大小孔形貌出现,只有当胶束尺寸与泡孔尺寸为一个数量级时,才能得到均匀分布的泡孔;此外,研究还发现增大胶束含量有助于得到倍率高且泡孔均匀的纳米孔径发泡材料。

In this work,we systematically investigated the foaming behavior of polymethyl methacrylate nano-cellular foams during the process of supercritical CO 2 assisted solid-state foaming with varied blends micelle sizes which was tailored by adding the dual block copolymer of polystyrene-PMMA.According to the "self-assembly" of block copolymer,specimens with various micelle sizes were prepared by controlling the block ratio,and characterized by TEM.The results revealed that micelle size of the polymer blends increases with increasing block ratio.Furthermore,the cell morphologies of the resultant polymer foams was determined by SEM analysis,and confirmed the significant influence of micelle size on foaming behavior.It should be noted that the small size of micelle leads to poor cell distribution.When micelle size and cell size are at the same order of magnitude,the uniform cell morphology can be obtained.In addition,nano-cellular foams for high expansion and uniform cell distribution can be achieved due to the increase of micelle number.