摘要
采用双流模型考察了粘弹性效应对二元高分子复杂流体相分离动力学的影响 .发现高分子混合物的两组分粘弹性相同时 ,相分离形态与简单二元流体类似 ,即非临界组成时少数相呈分散相 ,临界组成时呈双连续相 ,散射函数呈单峰 ;但相区域增长指数比简单二元流体混合物的增长指数小得多 .另一方面 ,对于高分子混合物的两组分存在粘弹性反差的情况 ,非临界组成时出现相反转 ,并导致相区域的增长指数变大 ,临界组成时出现一种持久的海绵状结构 ,相区域增长指数反而下降 .同时由于网络结构的出现导致散射函数出现双峰和肩形峰 ,表明有两种特征尺寸 ,此时用全程圆平均的散射函数来求增长指数将失去意义 。
Two fluid model has been used for investigating viscoelastic effects on phase separtion dynamics of polymer mixtures.It is found that the simulation results of symmetric viscoelasticity model resemble the results of fluid model.The minority phase of blends forms the dispersed phase in off critical component,while bicontinuous phase is formed in critical component.At the same time,the scattering function has only one peak in comparison with the two peaks in the case of viscoelasticity contrast.The growth exponent of domains in polymer mixtures with viscoelastic effects is less than in simple fluids mixtures because viscoelastic effects restrain the concentration fluctuation and domains coarsening.On the other hand,in the two fluid model simulations with viscoelasticity contrast,the unusual phase inversion is formed in off critical component,while longtime sponge structure is formed in critical component.It is found that phase inversion results in the acceleration of domains coarsening.When network is formed,the two peaks of scattering function also suggest that two characteristic sizes exit.So obtaining growth exponent by circle average of scattering function becomes unreasonable in this case,which makes it necessary to treat two peaks separately or use the contour length method.
出处
《复旦学报（自然科学版）》
CAS
CSCD
北大核心
2002年第3期301-308,共8页
Journal of Fudan University：Natural Science
基金
"973"国家重点基础研究专项经费资助项目 (G19990 6 4 80 0 )
