Dendrimer Demulsibility Demulsification Mechanism

Dendrimer is a kind of new-type function macromolecular compound that it is set out by multi-functional base kernels, Growing repeatedly outwards. Its characteristics have three-dimensional structure and can be designed the size, shape and functional group at the molecule level. Dendrimer has been receiving the chemists's extensive concern all the time since it was synthesized in middle period of the eighties of the 20th century. Compared with traditional linear high polymer, dendrimer has the form of symmetrical ball, the inside has empty, structure can be controlled accurately, the molecular weight is distributed one, the outer is distributed a large amount of functional groups at the same time. So, dendrimer has a lot of unique physics and chemical natures different from linear high polymer which make it have extensive uses in a great deal of fields, such as biological medicine, catalysis, photoelectricity material, molecular recognition, and molecular self-assembly.This paper synthesized polyamidoamine dendrimers of different generations by divergent method with ethylenediamine core. Adopting infrared spectrums, terminal analysis and nuclear magnetism resonances means to characterize their structure, the results indicate that the products is in conformity with their theory structure. The surface activity of aqueous solution of PAMAM has been studied by drop-volume method. The results show: the surface activation of aqueous solution of PAMAM of half generation is related to its hydrophile and lipophilic groups. Its hydrophilic groups is the inside carbonyl and amine base, and its lipophilic groups is the inside hydrocarbon chain and outer methyl. PAMAM of integral generation basically has not the surface activity. Its reason is that its outer groups is acylamino groups having very strong hydrophilicity so as not to reduce the surface tension of water. PAMAM different from traditional surfactant, have not critical micelle concentration, and exist in the form of "unimolecule micelle" in water.The demulsification performance of PAMAM of different generation and concentration on o/w simulative emulsion was studied in this text. The result shows: PAMAM of integral generation whose terminal groups are amino groups has approved demulsification performance, PAMAM of half generation whose terminal groups are ester groups has not demulsification effect, and the demulsificaton performance is not related to the surface activity of PAMAM. The demulsification performance of PAMAM of integral generation on o/w simulated emulsion is related to its generation and terminal group. The demulsification performance improves with increase of its generation and consentration.The demulsification mechanism of PAMAM was preliminarily studied by single-drop method. The results show on clean-up time of liquid membrane, half time, and cracking rate constant of oil drop with increase of generation and concentration of PAMAM: clean-up time of liquid membrane and half time become small, cracking rate constant increase, and their law conforms to demulsification regulation of PAMAM on simulative emulsion. The demulsification mechanism of PAMAM belongs to displacing mechanism. Acylamino groups of PAMAM of integral having strong polarity can take place chemical adsorption with the materials of strong polarity in the exterior of oil drop and be participated in into the membrane, which will result in adsorbed crude surfactant and other active materials to be partially displaced and reduce the intensity of interfacial film between oil and water.The paper designed and preliminarily synthesized dendrimic macromolecular compound in terms of dendrimer characteristics and the demulsification mechanism of the emulsion of crude oil. LOG has some demulsificatin effect on o/w simulative emulsion. Its demulsification is related to anide groups and benzene rings of dendrimer.