新型聚合物溶液的微观结构研究

采用显微、动态光散射和流变测定技术研究了梳形聚合物(CP)、疏水缔合聚合物(HAP)和聚丙烯酰胺(HPAM)溶液的微观结构。HPAM样品和CP样品单个水化分子的水动力学半径主要呈正态分布在10~100nm范围内。聚合物分子在溶液中是无序分布,形成粗细不均的网络骨架。大部分网络骨架不是由单个聚合物分子形成,而是由聚合物分子聚集体形成。在一定条件下才能出现较为有序的网络骨架结构,产生某种符合分形特性的自相似性。网络骨架既对溶液本体有支撑作用,又吸附和包裹大量水分子产生形变阻力。形成的网络结构越完善,增粘能力将越强。溶液中的盐份为非均匀分布,在聚合物分子上带电基团附近富集后形成浓度梯度。多种表面活性剂能造成HAP分子卷缩,聚集程度过大,聚合物分子吸附和包裹水分子的数量急剧减少,使HAP溶液粘度大幅度下降。另外,多孔介质孔喉可造成HAP分子结构的破坏,使增粘能力损失。

Microstructure of novel polymer solution used for oil displacement

The microstructures of comb-shape polymer(CP) solution,hydrophobic associating polymer(HAP) solution and polyacrylamide(HPAM) solution were studied with microscope,dynamic light scattering and rheological analysis technologies.Hydrodynamic radius of single molecule of HPAM and CP samples normally distributed in the order of magnitude range of 10 to 100 nm.Polymer molecules generally distribute randomly in solution to form non-uniform net skeletons,in which there are thick backbones attached with thin branches.Most skeletons were built up with the aggregations of polymer molecules.Some orderly net structures have self similarity with fractal characteristics under a certain condition.This kind of net skeletons either sustain the bulk of the solution or adsorb and wrap water molecules to produce resistance to deformation.More perfect net structures have higher viscosifying ability.Salts could be enriched around electriferous groups of polymer molecules in solution,which formed a salt concentration gradient.Several kinds of surfactants could make HAP molecules curl and aggregate together,which reduced the number of water molecule adsorbed and packaged by HAP molecules and led to rapid drop of HAP solution in viscosity.In addition,when HAP solution flows through porous medium,the pore throats of rock could make the structure of HAP molecule broken,which results in a great loss in viscosifying ability of HAP.