针对传统的纳米复合材料分散相分散均匀性评价方法的不足,提出了一种以分形理论为数学模型基础,以纳米复合材料的透射电镜(TEM,Transmission Electron Micro-scope)图像为评价对象的分散相分散均匀性的定量评价方法.运用离散对象构成的...针对传统的纳米复合材料分散相分散均匀性评价方法的不足,提出了一种以分形理论为数学模型基础,以纳米复合材料的透射电镜(TEM,Transmission Electron Micro-scope)图像为评价对象的分散相分散均匀性的定量评价方法.运用离散对象构成的自然分形体的分形维数建立了分散相分散均匀性的数学模型.将纳米复合材料TEM图像进行图像处理,以纳米复合材料TEM图像的中心为圆心以不同的半径做圆,提取不同的圆内的粒子数与回转半径,并在双对数坐标中直线拟合.该直线的斜率的倒数即为分散均匀性参数,并以此作为评价分散相分散均匀性的指标.将该方法实际应用于聚合物基纳米填充复合材料分散相分散均匀性的描述,验证了该评价方法的可行性.展开更多
The coarsening process of the droplets in two\|phase polymer blend system was studied under 2\|dimensional conditions using a phase contrast microscope and computer image analyzer.It was found that the substrate (glas...The coarsening process of the droplets in two\|phase polymer blend system was studied under 2\|dimensional conditions using a phase contrast microscope and computer image analyzer.It was found that the substrate (glass) has significant effect on the phase separation and droplets coarsening process.The interfacial interaction(wetting effects)will accelerate the droplets coarsening process when one phase has stronger affinity to the substrate than another phase,and the growth of the droplets radius with time follows r\+3～t\+a a >1.On the other hand,when there is almost the same interaction between the dispersed phase and the matrix with the substrate,i.e.the two phases have the same wettability to the substrate (such as the system of PP/PE),no effect of the substrate on the coarsening process of the droplets was observed,i.e.the growth law is r\+3～t according to Ostwald ripening theory.It is expected that there is a critical value for the interfacial tension between the components of blends under 2\|D condition.The growth law of the dispersed phase changes\|over above or below the critical point.展开更多
Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins. In this study, a multi\|hollow epoxy resin sphere was obtained by incomplete phase invers...Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins. In this study, a multi\|hollow epoxy resin sphere was obtained by incomplete phase inversion emulsification. The dynamic morphological evolution of water droplets dispersed in bisphenol. A epoxy resin/emulsifier (a multi\|block copolymer) during phase inversion process was investigated with scanning electron microscopy. It is shown that small discrete water droplets are dispersed in the epoxy resin continuous phase at low water content. In this case, the dynamic coalescence among the small water droplets is ignored. With increasing water content, the dynamic coalescence becomes remarkable and larger water drops are formed by the coalescence among the small water droplets. The larger water drops are randomly distributed within the continuous phase. Meanwhile, some necklace like structures with varied length co\|exist with the small water droplets and larger water drops. Incomplete phase inversion is achieved through the coalescence among the larger water drops, and some small water droplets are entrapped therein. In this case, a kind of multi\|hollow sphere is obtained. While, in some local regions, all the nearest small water droplets coalesce simultaneously to be continuous phase to achieve complete phase inversion, and small discrete waterborne particles are obtained. The dynamic coalescence among the small water droplets dispersed in epoxy resin continuous phase could be analyzed in terms of the improved Smoluchowski equation.展开更多
文摘针对传统的纳米复合材料分散相分散均匀性评价方法的不足,提出了一种以分形理论为数学模型基础,以纳米复合材料的透射电镜(TEM,Transmission Electron Micro-scope)图像为评价对象的分散相分散均匀性的定量评价方法.运用离散对象构成的自然分形体的分形维数建立了分散相分散均匀性的数学模型.将纳米复合材料TEM图像进行图像处理,以纳米复合材料TEM图像的中心为圆心以不同的半径做圆,提取不同的圆内的粒子数与回转半径,并在双对数坐标中直线拟合.该直线的斜率的倒数即为分散均匀性参数,并以此作为评价分散相分散均匀性的指标.将该方法实际应用于聚合物基纳米填充复合材料分散相分散均匀性的描述,验证了该评价方法的可行性.
文摘The coarsening process of the droplets in two\|phase polymer blend system was studied under 2\|dimensional conditions using a phase contrast microscope and computer image analyzer.It was found that the substrate (glass) has significant effect on the phase separation and droplets coarsening process.The interfacial interaction(wetting effects)will accelerate the droplets coarsening process when one phase has stronger affinity to the substrate than another phase,and the growth of the droplets radius with time follows r\+3～t\+a a >1.On the other hand,when there is almost the same interaction between the dispersed phase and the matrix with the substrate,i.e.the two phases have the same wettability to the substrate (such as the system of PP/PE),no effect of the substrate on the coarsening process of the droplets was observed,i.e.the growth law is r\+3～t according to Ostwald ripening theory.It is expected that there is a critical value for the interfacial tension between the components of blends under 2\|D condition.The growth law of the dispersed phase changes\|over above or below the critical point.
文摘Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins. In this study, a multi\|hollow epoxy resin sphere was obtained by incomplete phase inversion emulsification. The dynamic morphological evolution of water droplets dispersed in bisphenol. A epoxy resin/emulsifier (a multi\|block copolymer) during phase inversion process was investigated with scanning electron microscopy. It is shown that small discrete water droplets are dispersed in the epoxy resin continuous phase at low water content. In this case, the dynamic coalescence among the small water droplets is ignored. With increasing water content, the dynamic coalescence becomes remarkable and larger water drops are formed by the coalescence among the small water droplets. The larger water drops are randomly distributed within the continuous phase. Meanwhile, some necklace like structures with varied length co\|exist with the small water droplets and larger water drops. Incomplete phase inversion is achieved through the coalescence among the larger water drops, and some small water droplets are entrapped therein. In this case, a kind of multi\|hollow sphere is obtained. While, in some local regions, all the nearest small water droplets coalesce simultaneously to be continuous phase to achieve complete phase inversion, and small discrete waterborne particles are obtained. The dynamic coalescence among the small water droplets dispersed in epoxy resin continuous phase could be analyzed in terms of the improved Smoluchowski equation.
