Thee-dimensional structural analysis and rheology on phase-separated structure of polymer blends

(L)聚合物共混物相分离结构的观察与结构分析利用激光扫描共聚焦显微镜对聚合物共混物相分离结构的双连续形态进行了直接测量。在三维(3D)中得到了相分离结构。实验得到了相界面曲率及其分布的时间演化曲线，由此发现在相分离过程中发生了两个基本的减小界面面积的过程。(2)细化算法的发展提出了一种确定网络结构连通性的算法。该算法是在已有算法的基础上进行改进的，包括修改边缘平面的细化规则，更好地处理附着在边缘平面上的交点等，以提供可靠的结果。使用无限周期最小曲面(IPM)来检验…的精度和可靠性更多的是算法。3.三维细化算法在聚合物共混物相分离形态中的应用进一步将三维细化算法应用于聚合物共混物双连续相分离结构的几何和拓扑特征提取。研究发现，相分离区域在每个结点上大部分都有3个分支。相间距离在比分相结构的周期稍短的距离处出现最大值。欧拉特征显示了网络的复杂性，表明聚合物共混物的双连续结构在拓扑上等同于具有2到3个手柄的球体。从几何参数和拓扑参数的时间演化中证实了液滴的动态自相似性。(4)分散液滴相变形和形状恢复的观察装置研制了一种施加大的阶跃应变并从两个垂直方向观察变形液滴相形状的装置。研究发现，液滴形状发生变化，界面面积减小。(5)分散液滴的形状回复与应力松弛的关系研究了聚苯乙烯/聚碳酸酯共混熔体的分散相的形变、形状回复及界面应力贡献。仿射变形液滴恢复为球形，松弛时间最大，与应变大小有关。(6)连续结构聚合物共混熔体的粘弹性研究了聚苯乙烯/聚甲基丙烯酸甲酯共混熔体在熔融共混过程中的动态粘弹性和应力松弛行为。储能模数与频率的关系呈幂函数关系，反映了共混物的双连续性质。在大的阶跃应变下，观察到定向角连续结构的拉伸和收缩。较少

The following results were obtained :(l) Observation and structural analysis of phase-separated structure of a polymer blendDirect measurement of phase-separated structure of a polymer blend bicontinuous morphology was done by tuse of laser scanning confocal microscopy (LSCM). The phase-separated structure was obtained in three-dimension (3D). Time-evolution of interfacial curvatures and their distributions were experimentally obtained, from which two basic processes of reducing interfacial area were found to occur in the course of the phase-separation.(2)Development of thinning algorithmAn algorithm to find out the connectivity of network structure was developed. It is based on the existing algorithm but is modified to offer reliable results by applying some improvements that include modification of thinning rules at edge planes, better treatment ofjunctions attaching to the edge planes, etc. Infinite periodic minimal surfaces (IPMS) were used to check the precision and reliability of … More the algorithm. Although a few improvements may be necessary, the algorithm gives reasonable agreement with the mathematical predictions.(3) Application of 3D thinning algorithm to a phase-separated morphology of a polymer blendThe 3D thinning algorithm were further used to obtain geometrical and topological features of the bicontinuous phase-separated structure of a polymer blend. It is found that the phase-separated domain possess, for the most part, 3 branches at each junction. Interjunction distance showed maximum at a distance a little bit shorter than the periodicity of the phase-separated structure. The Euler characteristics, demonstrating complexity of the network, showed that the bicontinuous structure of the polymer blend is topologically equivalent to a sphere with 2 to 3 handles. The dynamical self-similarity has been confirmed from the time-evolution of the geometrical and topological parameters.(4) Observation of deformation and shape recovery of a dispersed droplet phaseAn apparatus was developed to apply large step strains and to observe the shape of a deformed droplet phase from two perpendicular directions. It was found that the droplet shape changes to reduce the interfacial area. Starting from a flat ellipsoid, the shape changes to a rodlike, a dumbbell, an ellipsoid of revolution and finally back to a sphere.(5)Relationship between shape recovery and stress relaxation for a dispersed droplet phaseThe deformation and shape recovery of dispersed phase and the stress contribution from the interface are investigated for a blend melt of polystyrene and polycarbonate. The affinely deformed droplets recover to the spherical shape with the maximum relaxation time depending on the strain magnitude. The process of this recovery corresponds very well with the plateau and terminal relaxation appeared in the relaxation modulus.(6) Viscoelasticity of polymer blend melt with continuous structureThe dynamic viscoelasticity and stress relaxation behavior are investigated for a 50/50 blend melt of polystyrene and poly (methyl methacrylate) with the modulated structure due to melt blending. The frequency dependence of the storage modulus shows a power law, reflecting the bicontinuous nature of the blend. The stretching and contraction of the continuous structure with the constant orientation angle are observed under large step strains. Less