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Li B.,Shandong University | Sheng X.,Shandong University | Xing W.-G.,Shandong University | Dong G.-L.,Shandong University | And 5 more authors.
Chinese Journal of Chemical Physics | Year: 2010

The absorbing process in isolating and coating process of α-olefin drag reducing polymer was studied by molecular dynamic simulation method, on basis of coating theory of α-olefin drag reducing polymer particles with polyurethane as coating material. The distributions of sodium laurate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate on the surface of α-olefin drag reducing polymer particles were almost the same, but the bending degrees of them were obviously different. The bending degree of SLA molecules was greater than those of the other two surfactant molecules. Simulation results of absorbing and accumulating structure showed that, though hydrophobic properties of surfactant molecules were almost the same, water density around long chain sulfonate sodium was bigger than that around alkyl sulfate sodium. This property goes against useful absorbing and accumulating on the surface of α-olefin drag reducing polymer particles; simulation results of interactions of different surfactant and multiple hydroxyl compounds on surface of particles showed that, interactions of different surfactant and one kind of multiple hydroxyl compound were similar to those of one kind of surfactant and different multiple hydroxyl compounds. These two contrast types of interactions also exhibited the differences of absorbing distribution and closing degrees to surface of particles. The sequence of closing degrees was derived from simulation; control step of addition polymerization interaction in coating process was absorbing mass transfer process, so the more closed to surface of particle the multiple hydroxyl compounds were, the easier interactions with isocyanate were. Simulation results represented the compatibility relationship between surfactant and multiple hydroxyl compounds. The isolating and coating processes of α-olefin drag reducing polymer were further understood on molecule and atom level through above simulation research, and based on the simulation, a referenced theoretical basis was provided for practical optimal selection and experimental preparation of α-olefin drag reducing polymer particles suspension isolation agent. © 2010 Chinese Physical Society. Source


Li B.,Shandong University | Xing W.,Shandong University | Dong G.,Shandong University | Chen X.,Linyi Institute of Product Quality Supervision and Inspection | And 3 more authors.
Petroleum Science | Year: 2011

Microcapsules containing oil drag-reducing polymer particles were prepared by melting-scattering and condensing of polyethylene wax, in-situ polymerization of urea and formaldehyde, and interfacial polymerization of styrene respectively. The related processes were studied by a molecular dynamics simulation method, and molecular design of microcapsule isolation agent was carried out on the basis of the simulation. The technologies for preparing microencapsulated oil drag-reducing polymer particles were compared and the circulation drag reducing efficiency of the microencapsulated polymer particles was evaluated based on the characterization results and their dissolution properties. Molecular design of a microcapsule isolation agent suggests that α-olefin polymer particles can be stably dispersed in water by using long-chain alkyl sodium salt surfactant which can prevent the agglomeration of α-olefin polymer particles. The results of simulation of the adsorption process shows that the amount of alkyl sodium salt surfactant can directly affect the stability of microencapsulated α-olefin polymer particles. and there must be a minimum critical amount of it. After characterization of the morphology by Scanning Electron Microscopy (SEM) and comparison of the static pressure stability, especially the conditions of reaction and technological control of microcapsules with different shell materials, microencapsulation of α-olefin polymer particles with poly-(urea-formaldehyde) as shell material was selected as the optimum scheme, because it can react under mild conditions and its technological process can be controlled in a large range. The relationship of drag reducing rate and dissolving time of microcapsules showed that the formation of microcapsules did not affect the maximum drag reducing rate, and the drag reducing rate of each sample can reach about 35% along with the dissolving time, i. e. microencapsulation did not affect the drag reducing property of α-olefin polymer. © 2011 China University of Petroleum (Beijing) and Springer-Verlag Berlin Heidelberg. Source


Dong G.-L.,Shandong University | Yu P.,Shandong University | Li B.,Shandong University | Zhou N.-N.,China Institute of Metrology | And 3 more authors.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2010

With polyurethane as wall material, the preparation technology and process of microcapsule coating were studied on the surface of poly-α-olefin viscoelastic polymer particles. Molecular dynamics simulation methods were used to discuss the relevant molecular designs, and stable performance polyurethane microcapsules were produced by the method of interfacial polymerization, with toluene 2, 4-diisocyanate (TDI) and glycerol as active monomers. The influence on coating in monomer type, ratio, particle size and amount of wall material were researched, The surface morphology, oil solubility, heat and pressure resistance of poly-α-olefin microcapsules were tested. The influences of drag reduction effect by the indoor simulative loop evaluation system for oil drag reduction agent were evaluated. The results show that the length and number of branched chains had specific requirements in the design of coated wall material molecular. The reasonable process conditions of polyurethane-coated poly-α-olefin microcapsules were as follows: the system was aqueous solution, the molar ratio of isocyanate group (-NCO) and hydroxyl (-OH) was 1:1, the mesh number of poly-α-olefin particle size was 60-80 (250-180μm), the weight of wall material accounted for 0.5% of poly-α-olefin particles, the weight of surfactant accounted for 0.1% of poly-α-olefin particles, the temperature was 25°C under atmospheric pressure. The producing poly-α-olefin microcapsule had good surface morphology, faster release speed, no effect on the original drag reduction, excellent heat and pressure resistance. Moreover, poly-α-olefin microcapsules which were stored in powder-like solid at room temperature can be made into oil drag reduction agent easily at the time of on-site using by being dispersed into the solvent directly and solved the technical problem of dispersion in industrial applications. Source


Wang C.-H.,Shandong University | Bi Y.-Q.,Shandong Quality Certification Center | Yang M.,Shandong Quality Certification Center | Jiang R.-L.,Shandong Institute of Standardization | And 2 more authors.
Hangkong Cailiao Xuebao/Journal of Aeronautical Materials | Year: 2015

Molecular dynamics simulation (MDS) of the interaction of 1-decne oligomer and the surface of steel at different temperature was conducted. The viscosity, viscosity index and pour point of 1-decne oligomer synthesized at different conditions were examined, and the catalyst was Et3NHCl -AlCl3 ionic liquid. Infrared spectrum (IR) and gas chromatography (GC) were used to characterize the 1-decne oligomer. Results show: the total surface energy change after the interaction of 1-decne trimer and the tetramer with the surface of the steel tends to be constant at a wide range of temperature; at condition of AlCl3/Et3NHCl=3(mole ratio), 5%wt catalyst in 1-decene, reaction temperature 100℃ and reaction time 7h, the viscosities of 1-decne oligomer at 40℃ and 100℃ are 57.49 mm2·s-1 and 9.94 mm2·s-1 respectively, the viscosity index is 60, and the pour point is -63℃; the 1-decne oligomer has very good properties of viscosity-temperature and low temperature fluidity. IR and GC show that the oligomerization is relatively thorough, and the product has a long linear side chain with regular structure; the total content of trimer and tetramer is 84.57%, which is consistent with the former work and the result of MDS. ©, 2015, Chinese Journal of Aeronautics. All right reserved. Source


Zhang C.,Shandong University | Gao C.,Shandong University | Gao F.,Shandong University | Wang J.,Shandong University | And 3 more authors.
Petroleum Science | Year: 2014

A bipolymer maleic anhydride-methyl acrylate (MAMA) was synthesized from maleic anhydride and methyl acrylate based on molecular design. MAMA further reacted with oleylamine or octadecyl alcohol to generate two comb polymers called Oleamide-MAMA (NMAMA) and Octadecanol-MAMA (OMAMA), respectively. The structure of both the polymers was confirmed by their infrared spectral analysis (IR), gel permeation chromatography analysis (GPC) and differential scanning calorimeter (DSC). Moreover, the pour point depressing (PPD) properties of these comb polymers were examined experimentally. Experimental results showed that besides the molecular weight and concentration of the polymers, the length of side chains and the number of functional groups also had great influence on the pour point depressing performance. The π bonds and hydrogen bonds between depressants were the key factors for improving the pour point depressing properties. These results suggest that both OMAMA and NMAMA are potential pour point depressants for industry. © 2014 China University of Petroleum (Beijing) and Springer-Verlag Berlin Heidelberg. Source

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