Study On The Interactions Between Water-soluble Associative Polymer And Montmorillonite Particles

Polymer/MMT nanocomposites prepared by intercalating macromolecules into the galleries of MMT to improve their properties have increasingly become a new and hot research point for polymer composite materials. However, many researches about them are mainly focused on thermal, optical and mechanical properties of melting polymer. Few studies have been done about such kind of nanocomposites prepared to improve their water solution rheological properties. So far no water-soluble associative polymer/MMT nanocomposites were reported. In this thesis, the interactions between water-soluble associative polymer and MMT were studied in order to provide some necessary principles for the preparation of this kind of nanocomposites, which would possibly get much better solution rheological properties with the intercalation of associative polymer into the galleries of MMT and could be used as new materials for petroleum engineering.Firstly, the series of water-soluble associative polymers(AP) as well as the contrast polymer partly hydrolyzed polyacrylamide(HPAM) were synthesized and their molecular parameters were determined and the structural characterization for AP was done through IR. Then, the montmorillonite were purified and cation exchanged with sodium chloride to change it into Na-montmorillonite(NaMMT). After centrifuging the purified NaMMT suspension, not only three kinds of particles with different particle scale were obtained but also were determined by laser mastersizer. Furthermore, AP and NaMMT composite dispersion system(AP-MMT) were also obtained by compounding the solution of AP and NaMMT suspension.In the AP-MMT dispersion system, AP and MMT were compounded with each other to form AP-MMT composite. A greater associative behavior and a lower critical associative concentration were found in the presence of certain amount of MMT than that of pure AP solution without MMT. The viscosity of AP-MMT dispersion system increased when the particle scale of NaMMT got smaller, which indicated the interactions between AP and NaMMT was mainly caused by the hydrogen bond, static electronicity and physical crosslink to AP after the MMT were exfoliated into small pieces. SEM confirmed the AP-MMT composite were compounded in the range of micron scale, and XRD showed that the gallery distance of NaMMT was widened. The viscosity of dispersion system that was compounded by AP with higher amount of hydrophobic groups and the same particle scale MMT was higher compared with that of lower hydrophobic groups ones. From this we could conclude that hydrophobic groupsinteracted with the MMT particles mainly by way of static electronicity and therefore AP-MMT composite were formed and the associations were intensified in the system as well. The viscosity-temperature relation showed that the interaction intensified when temperature increased. But the addition of salt could firstly increase the viscosity of the dispersion system then decrease it, and Shengli salt influenced much evidently than bivalent salt which stronger than univalent salt. In the experiment, a more excellent shear thinning of AP-MMT dispersion system was found and the smaller scale the MMT particle was, the bigger K and smaller n would be detected. It could be explained that the composite structure compounded in the dispersion system was reversible.The adsorption for AP on MMT was studied in this thesis to further the interactions between AP and MMT particles. It has been found that the isotherms were different to HPAM. For AP, there was no evident plateau value but increased to maximum then decreased sharply. It may be due to the adsorption and hydrophobic association. When temperature increased, the adsorption amount decreased and then had a tendency to increase, which re-confirmed temperature intensified the interactions of AP and satic electronicity to the MMT particles that we have observed in the former part. The addition of salt firstly increased the adsorption amount then kept steady and the increase of pH and MMT concentration would weaken the adsorption of AP on MMT...