纳米SiO_2填充PMMA/PS复合物共连续范围的研究  

INFLUENCE OF NANO SILICA ON THE CO-CONTINUITY INTERVAL OF PMMA/PS BLENDS

作　　者：刘文娟[1] 黄亚江[1] 吴冬生[1] 高灵强[1] 杨其[1] 李光宪[1] 

机构地区：[1]四川大学高分子科学与工程学院高分子材料工程国家重点实验室,成都610065

出　　处：《高分子学报》2009年第6期553-559,共7页Acta Polymerica Sinica

基　　金：国家基础研究专项经费(项目号2005CB623800)资助项目

摘　　要：采用流变法、抽提法以及扫描电镜3种表征方法研究了亲水性纳米二氧化硅粒子SiO2填充对聚甲基丙烯酸甲酯(PMMA)/聚苯乙烯(PS)不相容体系共连续范围的影响.对于未填充PMMA/PS体系,3种方法测得的共连续范围基本一致.而对于粒子填充体系,SEM与溶剂抽提法均表明随着粒子含量的增加,体系的共连续范围变宽,这是由于亲水性SiO2粒子选择性填充在极性PMMA相中,导致PMMA相的熔体粘度和弹性均有大幅提高,从而减缓了破坏共连续结构的纤维断裂或回缩等松弛过程.与SEM法和溶剂抽提法相反,流变法测得的共连续范围随粒子含量增加明显变窄,这主要是因为加入SiO2粒子后,PMMA/PS体系的弹性模量和黏度大大提高(加入7vol%的SiO2后分别增加近50倍和5倍),导致填充试样在装样和设定间距之后需要更长的松弛时间才能开始流变测试.试样在测试前长时间处于高温熔体状态时,其共连续结构很容易在界面张力的驱动下发生粗化和破碎,所以得到的共连续反而变窄.SEM和溶剂抽提法比流变法更适合用来判断粒子填充PMMA/PS体系特别是其高填充体系的共连续范围.Rheology, solvent extraction and scanning electron microscopy （SEM） were employed to investigate the influence of hydrophilic nano-SiO2 on the co-continuity interval of immiscible poly（methyl methacrylate） （PMMA）/ polystyrene （PS） blends. For unfilled systems,the co-continuity intervals of PMMA/PS blends measured by the three methods were nearly consistent. However for filled blends, SEM and solvent extraction means showed that increasing the filler content will broaden the co-continuity interval. The preferential distribution of hydrophilic SiO2 particles in more affinitive PMMA phase led to a strong increase both in melt viscosity and elasticity of PMMA and further slowed down all relaxation processes associated with the destruction of the co-continuous structure such as breakup or retraction. However, the co-continuity interval obtained by rheology was found to be narrower than that by SEM and solvent extraction, which was contrary to unfilled system. It was proposed that the enhancement in the melt viscosity and elasticity of PMMA/PS blends due to the incorporation of hydrophilic nano-SiO2 particles could significantly prolong the relaxation time of sample loaded before beginning the rheological tests. When the sample was subjected to high temperature for a long time before test, its co-continuous structure would be easily coarsened and disintegrated under the driving of interfacial tension. Furthermore, the higher filler content the more time consumed, which might seriously destroy the co-continuous structure. It was proposed that SEM and solvent extraction might be more suitable in detecting the co-continuity interval of filled PMMA/PS blends than rheological test. Finally, the advantages, disadvantages and applicable range of three methods were compared and summarized.

关 键 词：不相容共混物 纳米二氧化硅 共连续范围 

分 类 号：TB332[一般工业技术—材料科学与工程]