物理化学学报 >> 2010, Vol. 26 >> Issue (11): 2907-2914.doi: 10.3866/PKU.WHXB20101110

热力学、热化学和溶液化学 上一篇    下一篇

聚丙烯酰胺稀溶液的分子模拟

刘艳艳1, 陈攀科1, 罗健辉2, 周歌1, 江波1   

  1. 1. 四川大学化学学院, 绿色化学与技术教育部重点实验室,成都610064;
    2. 中国石油勘探开发研究院, 北京100083
  • 收稿日期:2010-07-05 修回日期:2010-08-05 发布日期:2010-10-29
  • 通讯作者: 江波, 周歌 E-mail:jiangbo@scu.edu.cn, zhougekk@scu.edu.cn
  • 基金资助:

    国家自然科学基金(20904035)资助项目

Molecular Simulation of Dilute Polyacrylamide Solutions

LIU Yan-Yan1, CHEN Pan-Ke1, LUO Jian-Hui2, ZHOU Ge1,*, JIANG Bo1   

  1. 1. Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China;
    2. Research Institute of Petroleum Exploration and Development of PetroChina, Beijing 100083, P. R. China
  • Received:2010-07-05 Revised:2010-08-05 Published:2010-10-29
  • Contact: JIANG Bo, ZHOU Ge E-mail:jiangbo@scu.edu.cn, zhougekk@scu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20904035).

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摘要：

聚丙烯酰胺(PAM)是一类重要的线性水溶性聚合物, 具有“百业助剂”之称, 因此对其溶液性质的研究意义重大. 在溶液质量浓度约为1 g·mL-1的基础上, 分别构建了含有不同水分子数的溶液模型. 采用分子动力学(MD)方法模拟分析了不同温度下非离子型的聚丙烯酰胺(PAM-H)和阴离子型的聚丙烯酰胺(HPAM)在纯水溶液及含不同质量分数NaCl 的水溶液中的回旋半径(Rg). 结果发现, 不同温度下PAM-H 和HPAM 的抗盐性能的模拟结果与实验数据基本吻合, 水分子数不同的溶液模型所得模拟结果趋势没有明显变化, 为了提高模拟效率, 选取含有2000 个水分子的溶液模型分析HPAM链中氧负离子及氧原子的径向分布函数, 从微观结构模拟说明了HPAM水溶液粘度随NaCl 质量分数增加而减小, 且HPAM 比PAM-H具有较好的增粘效果及较差的抗盐性能的原因.

 

关键词: 分子动力学, 聚丙烯酰胺, 溶液性质, 回旋半径, 径向分布函数

Abstract:

Polyacrylamide (PAM) applied to various fields is an important class of linear water-soluble polymers. Therefore, it is of great significance to study the solution properties of PAM. We constructed solution models containing different amounts of water molecules with a mass concentration of about 1 g·mL-1. Using molecular dynamics (MD) simulations we calculated the radius of gyration (Rg) for non-ionic PAM (PAM-H) and anionic PAM (HPAM) in pure water and in aqueous solutions with different mass fractions of NaCl. We discussed their behaviors at different temperatures. We found that the salt tolerance of the polyacrylamides fromthe simulation agreed with the experimental results at different temperatures. Furthermore, the simulation results for all the solution models containing a different amount of water molecules basically showed a similar trend. Considering computational efficiency, the solution model containing 2000 water molecules was selected for our study. The radial distribution functions (RDF) for the oxygen ions and oxygen atoms of the HPAMchain were investigated in NaCl solution model containing 2000 water molecules. The reduced viscosity of HPAM solutions with increasing NaCl mass fractions and a better thickening ability as well as poor salt tolerance compared to PAM-H were explained considering their microstructures as determined by RDF.

 

Key words: Molecular dynamics, Polyacrylamide, Solution property, Radius of gyration, Radial distribution function