EP-PI及BMI-PES的反应诱导相分离  

Reaction-Induced Phase Separation of the Epoxy/Polyimide and Bismaleimide/Polyethersulfone Blends

作　　者：陈凤华[1] 郭颖[1] 孙同臣[2] 周恒[1] 赵彤[1] 

机构地区：[1]中国科学院化学研究所,北京100190 [2]航天特种材料及工艺技术研究所,北京100074

出　　处：《宇航材料工艺》2016年第3期37-42,共6页Aerospace Materials & Technology

摘　　要：研究了EP/PI和BMI/PES两种TS/TP共混体系的反应诱导相分离过程及形貌结构。采用相差显微镜原位研究了反应诱导相分离的过程,发现分相初期形成了均匀的相结构;随着相分离的发展,一定浓度区域样品中的双连续结构经过演化发展,分相后期样品内部与边缘的形貌不一致。通过对固化后样品断面的SEM观察,发现在TP浓度很低时形成海岛结构,当TP浓度稍高,样品形成了核壳结构,在样品边缘和与基板接触的上下等外侧形成了TS的富集区,只有极少量的TP分散颗粒存在;在样品的中间,TS和TP形成双连续结构,其中TP富集相具有细丝状的网络特征。分析认为,EP和BMI为热固性树脂,初始样品为小分子,在反应开始时表现为流体,为快组分;PI和PES为典型的热塑性聚合物,它们的黏弹性特征随着相分离的发展越来越显著,即Tg以下为玻璃态,Tg以上表现出弹性、黏弹性特征,为慢组分。在反应分相过程中,由于TP富集相缠结网络的松弛慢于相分离的速度,因此TP富集相网络的整体收缩不可避免,在TP与TS动力学极不对称的作用之下,初始均匀的双连续结构最终发展为核壳结构。Two types of thermoset（ TS） / thermoplastic（ TP） blends were studied in this work,including the EP / PI and BMI / PES systems. In-situ reaction-induced phase separation was studied by the phase contrast microscope. In the initially homogeneous sample,uniform phase separate morphology was formed in all the samples. At certain concentrations,the initial bicontinuous structure gradually changed to be ununiform inside and outside the samples. Scanning electron microscope was used to observe the fractured cross sectional surface,after the samples were isothermally cured. At very low TP concentrations,sea-island structure is formed,with the TP-rich particles dispersed in the TS-rich matrix. At relative higher TP concentrations,a macroscopic core-shell structure is formed in the whole sample. The outer area,including edge of the sample and upper and lower part close to the substrates,mostly consisted of TS-rich domains,with only few of TP-rich particles randomly located. In the inner part,bicontinuous structure formed,where the TP-rich phase is thin and extending like a network. The current two systems have some points in common： TS monomer and oligomers are good fluid at the experimental temperatures,as are the fast component; the TP polymers are macromolecules and have high glass transition temperatures,as are slow component with viscoelastic features; with the phase separation proceeding,viscoelasticity of the TP gradually showed,being glassy below Tgand elastic or viscoelastic under Tg. The entangled TP-rich network need much time to relax,which cannot follow the speed of phase separation. Thus,the whole entangled TP-rich network would inevitably shrink to promote the phase separation. With the strong dynamic asymmetry in such systems,the initially formed bicontinuous developed to be the macroscopic core-shell structure in the whole sample.

关 键 词：热固性树脂 热塑性树脂 反应 相分离 形貌 层状结构 海岛结构 

分 类 号：TQ343[化学工程—化纤工业]