A new fourth-generation poly(propylene imine) dendrimer(G4-M) containing 32 triolefinic 15-membered macrocycles on the surfaces has been synthesized. The bimetallic Ru Rh dendrimer-stabilized nanoparticles(DSNs) were ...A new fourth-generation poly(propylene imine) dendrimer(G4-M) containing 32 triolefinic 15-membered macrocycles on the surfaces has been synthesized. The bimetallic Ru Rh dendrimer-stabilized nanoparticles(DSNs) were first prepared within G4-M by a co-complexation route. The new G4-M dendrimer has been characterized by 1H nuclear magnetic resonance, infrared radiation, and elemental analysis.The dendrimer-stabilized bimetallic ions and reduction courses were analyzed by UV-vis spectroscopy. Highresolution transmission electron microscopy and energy dispersive spectrometer were used to characterize the bimetallic nanoparticle size, size distribution, and particle morphology. The Ru Rh bimetallic DSNs showed high catalytic activity for the hydrogenation of nitrile-butadiene rubber.展开更多
The degradation of hydrogenated nitrile-butadiene rubber（HNBR） soaped in aqueous solutions of HzS and HC1 was investigated, The samples unexposed and exposed to different solutions were characterized by 13C nuclear ...The degradation of hydrogenated nitrile-butadiene rubber（HNBR） soaped in aqueous solutions of HzS and HC1 was investigated, The samples unexposed and exposed to different solutions were characterized by 13C nuclear magnetic resonance（~3C NMR）, X-ray photoelectron and infrared spectroscopies. In contrast to those of unexposed samples and samples soaped in HCI solution, the mechanical properties of samples exposed to H2S solution signifi- cantly deteriorated, in which the new groups of C（=O）--NH2, C--S--C and C=S emerged. The mechanism of C=S and C--S--C formation was speculated, except for that of the formation of group C（=O）--NH2, which was widely discussed in acidic condition such as HC1 solution. The formation of C--S--C was due to radical reaction in- itiated by mercapto radical and that of C=S was due to nucleophilic reaction initiated by mercapto cations. This finding is helpful to understanding the seal failure of HNBR in working cnvironment containing H2S.展开更多
During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separatel...During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure,one at a time,while the remainder of the wellbore is not affected.However,reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature(HPHT)conditions of reservoirs(such as 70 MPa and 170 ℃).In this study,the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments.The optimization process starts from the packer rubber with a conventional structure,and then,the weakest spots are identified by ABAQUS and improved by slightly varying its structure.This process is iterative,and the final optimized structure of a single rubber barrel with expanding back-up rings is achieved.For the structure of three rubber barrels with metallic protective covers,both HNBR and AFLAS fail under HPHT conditions.For the final optimized structure,the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting.The results show that the optimized structure of a single rubber barrel with expanding back-up rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.展开更多
基金supported financially by the National Natural Science Foundation of China (Project No.51273071)
文摘A new fourth-generation poly(propylene imine) dendrimer(G4-M) containing 32 triolefinic 15-membered macrocycles on the surfaces has been synthesized. The bimetallic Ru Rh dendrimer-stabilized nanoparticles(DSNs) were first prepared within G4-M by a co-complexation route. The new G4-M dendrimer has been characterized by 1H nuclear magnetic resonance, infrared radiation, and elemental analysis.The dendrimer-stabilized bimetallic ions and reduction courses were analyzed by UV-vis spectroscopy. Highresolution transmission electron microscopy and energy dispersive spectrometer were used to characterize the bimetallic nanoparticle size, size distribution, and particle morphology. The Ru Rh bimetallic DSNs showed high catalytic activity for the hydrogenation of nitrile-butadiene rubber.
基金Supporter by the National Natural Science Foundation of China（No.51003121） and the Cultivation Fund of the Key Scien- tific and Technical Innovation Project, Ministry of Education of China（No. 707010）.
文摘The degradation of hydrogenated nitrile-butadiene rubber（HNBR） soaped in aqueous solutions of HzS and HC1 was investigated, The samples unexposed and exposed to different solutions were characterized by 13C nuclear magnetic resonance（~3C NMR）, X-ray photoelectron and infrared spectroscopies. In contrast to those of unexposed samples and samples soaped in HCI solution, the mechanical properties of samples exposed to H2S solution signifi- cantly deteriorated, in which the new groups of C（=O）--NH2, C--S--C and C=S emerged. The mechanism of C=S and C--S--C formation was speculated, except for that of the formation of group C（=O）--NH2, which was widely discussed in acidic condition such as HC1 solution. The formation of C--S--C was due to radical reaction in- itiated by mercapto radical and that of C=S was due to nucleophilic reaction initiated by mercapto cations. This finding is helpful to understanding the seal failure of HNBR in working cnvironment containing H2S.
基金financial support from the Fundamental Research Funds for the Central Universities under Grant nos. 17CX05020 and 17CX06002the Research Funds for Introducing Talent (PhD) of China University of Petroleum under Grant no. YJ20170026+1 种基金the National Science and Technology Major Project under Grant no. 2016ZX05042004the Joint Funds of the National Natural Science Foundation of China under Grant no. U1762104
文摘During hydraulic fracturing operations of low-permeability reservoirs,packers are the key component to ensure the success of multistage fracturing.Packers enable sections of the wellbore to be sealed off and separately fractured by hydraulic pressure,one at a time,while the remainder of the wellbore is not affected.However,reliable sealing properties of the packer rubber are required to meet the high-pressure and high-temperature(HPHT)conditions of reservoirs(such as 70 MPa and 170 ℃).In this study,the structures of the packer rubber with two different materials are optimized numerically by ABAQUS and validated by experiments.The optimization process starts from the packer rubber with a conventional structure,and then,the weakest spots are identified by ABAQUS and improved by slightly varying its structure.This process is iterative,and the final optimized structure of a single rubber barrel with expanding back-up rings is achieved.For the structure of three rubber barrels with metallic protective covers,both HNBR and AFLAS fail under HPHT conditions.For the final optimized structure,the packer rubber made of AFLAS can work better under HPHT than that made of HNBR which ruptures after setting.The results show that the optimized structure of a single rubber barrel with expanding back-up rings and the material AFLAS are a good combination for the packer rubber playing an excellent sealing performance in multistage fracturing in horizontal wells.
