摘要
采用透射电子显微镜与小角X光散射分别研究了不同软、硬段分子量及软段极性对聚硅氧烷聚脲多嵌段共聚体系微相结构的影响。结果表明,增加软段分子量及硬段含量有利于聚硅氧烷与聚脲的相分离。将极性氰丙基引入聚硅氧烷后两相混合度明显改善,同时聚脲硬段粒径减小并趋于均一。在聚氰丙基甲基硅氧烷基体中增加聚脲含量及其分子量,则两相界面厚度也随之增大。
The micromorphology of segmented polysiloxane-polyureas based on polydimethylsiloxane or polycyanopropyimethylsiloxane soft segments and semicrystalline methylene diphenylene diiso-cyanate and diethyleneamine hard segments was examined using transition electron microscopy(TEM) and small angle X-ray scattering (SAXS) . Specimens for eletron microscopy studies were prepared by thin film casting. The spherical morphology was observed in all of the samples. The size of the hard domain of polycyanopropylsiloxane polyurea is smaller and more regular than that of polydimethylsiloxane polyurea. The micrcdomain spacings and the size of the poiyurea hard segment measured by TEM were compared to the results calculated from SAXS data. It is also found that there are two steps In the accumulation of the hard domains. At the first step, a few polyurea aggregate by hydrogen bond to form the ''fundamental particles'. In the second step, these 'fundamental particles' gathered up together further to form the hard mierodomains. The slower evaporation rates of the solvents caused the larger polyurea mierodomains.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1993年第5期720-724,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
中国科学院化学所高分子物理实验室资助课题
关键词
聚硅氧烷
聚脲
多嵌段共聚物
TEM
Polysiloxane, Polyurea, Phase separation, Segmented copolymer
