交联聚合物线团的形态和尺寸研究

THE STUDY OF THE CONFORMATION AND SIZE OF THE LINKED POLYMER COILS

通过建立低压差下核孔膜过滤稀释液的方法 ,研究了低浓度HPAM与AlCit形成的交联聚合物溶液(LPS)中交联聚合物线团 (LPC)的形态和尺寸 .实验结果表明 ,LPC为球形结构 ,由于交联作用 ,其剪切变形程度有限 .低压差下核孔膜过滤法与动态光散射法 (DLS)和扫描电镜法 (SEM)相结合 ,可较为准确地判断LPC的尺寸范围 ,HPAM相对分子质量为 1 1× 10 7～ 1 4× 10 7、浓度为 0 0 2 % ,NaCl浓度 0 2 % ,交联比 2 0∶1的LPS中LPC的直径小于 1 38μm ,相当多的LPC直径在 4 5 0nm以上 ,平均流体力学直径约为 4 92nm .在一定聚合物浓度范围内 ,相同实验条件下 ,随着聚合物相对分子质量的增大 ,LPC尺寸逐渐增大 .LPS制成干片后 ,LPC的尺寸收缩有限 ,利用SEM法直接观测其形态 ,具有一定的准确性 ,可用此法对其进行研究 .

A method of using microporous filter membrane (nuclepore membrane) to filtrate a dilute solution under low pressure is established to study the size and conformation of linked polymer coils (LPC) in solution made up of the low concentration partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (AlCit, crooslinker). The results show that the LPC is spherical. Because of the crosslinking the metamorphism of the LPC under shear is limited. Integrating the method of filtration with dynamic light scattering (DLS) and scanning electron microscope (SEM) could reveal the size distribution of the LPC. The results show that the diameter of the LPC in solution (the relative molecular weight of HPAM is 1 1×10 7～1 4×10 7, the concentration of HPAM is 0 02%,the concentration of NaCl is 0 2%, the mass ratio of HPAM to Al is 20∶1) is less than 1 38?μm,the diameter of a few LPC is more than 450?nm, and the mean hydrodynamic diameter of the LPC is 492?nm. In this range of concentration of HPAM and with the same experimental condition, the higher the relative molecular weight of HPAM, the larger the size of the LPC. Since the shrinkage of the LPC on glass sheets after drying spontaneously is limited the photographs of SEM of the LPC could describe the real size distribution of the LPC.