高等学校化学学报

高等学校化学学报

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低浓度HPAM/AlCit交联体系的27Al NMR研究

林梅钦, 董朝霞, 李明远, 吴肇亮   

  1. 中国石油大学提高采收率研究中心, 北京 102249
  • 收稿日期:2007-04-04 修回日期:1900-01-01 出版日期:2007-08-10 发布日期:2007-08-10
  • 通讯作者: 林梅钦

27Al NMR Studies on HPAM/AlCit Crosslinking System with Low Concentration Polymer

LIN Mei-Qin*, DONG Zhao-Xia, LI Ming-Yuan, WU Zhao-Liang   

  1. Enhanced Oil Recovery Research Center, China University of Petroleum, Beijing 102249, China
  • Received:2007-04-04 Revised:1900-01-01 Online:2007-08-10 Published:2007-08-10
  • Contact: LIN Mei-Qin

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摘要： 用27Al NMR谱研究了高分子量低浓度的部分水解聚丙烯酰胺(HPAM)与柠檬酸铝(AlCit)体系交联反应过程中Al的化学位移和Al的自旋-晶格弛豫时间的变化. 结果表明, HPAM与AlCit反应后, 与HPAM分子链上的羧基发生配位交联的Al的化学位移向低场移动, 而不参与交联反应的AlCit分子结构中Al的化学位移基本不变. HPAM/AlCit交联体系中存在三种形态的Al, 分别对应三种不同的自旋-晶格弛豫时间. 当HPAM的质量浓度≤200 mg/L时, HPAM与AlCit反应过程中交联态Al的自旋-晶格弛豫时间τ13随反应进行变小, HPAM与AlCit主要发生分子内交联反应. 当HPAM的质量浓度≥250 mg/L时, HPAM与AlCit反应过程中交联态Al的自旋-晶格弛豫时间τ13随反应进行变大, HPAM与AlCit主要发生分子间交联反应.

关键词: 部分水解聚丙烯酰胺, 柠檬酸铝, 自旋-晶格弛豫时间, 交联体系, 化学位移

Abstract: The change of the chemical shift and the spin-lattice relaxation time of Al in the reaction process of partially hydrolyzed polyacrylamide(HPAM) with a low concentration and high molecular weight and aluminum citrate(AlCit) system are investigated via 27Al NMR measurement. The experimental results show that after crosslinking the chemical shift of Al which crosslinked with the carboxyl of HPAM increased, but the chemical shift of Al which didn't react with HPAM almost kept the same. There are three phases of aluminum in the HPAM/AlCit crosslinking system.These three phases of aluminum correspond to three different spin-lattice relaxation time of Al. When the concentration of HPAM is less than or equal to 200 mg/L, the spin-lattice relaxation time(τ13) of Al was decreased with the increase of reaction time after crosslinking, the linked polymer solution was formed mostly by intra-molecular crosslinking reaction between HPAM and AlCit when the concentration of HPAM was more than or equal to 250 mg/L, the spin-lattice relaxation time(τ13) of Al was increased with the increase of reaction time after crosslinking, the linked polymer solution was formed mostly by inter-molecular crosslinking reaction between HPAM and AlCit.

Key words: Partially hydrolyzed polyacrylamide, Aluminum citrate, Spin-lattice relaxation time, Crosslinking system, Chemical shift

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