缓膨型核壳纳米微球的制备及性能

Preparation and properties of slow-expanding core-shell nanomicrospheres

摘要:

采用反向乳液二次聚合法，制备出阳离子核体微球，通过加入带有阴离子单体的壳体材料和阳离子引发剂，利用阴阳离子的相互作用以及阳离子引发机制合成缓膨型核壳纳米微球（PAE）。采用FTIR、TGA、H-NMR、SEM和TEM等技术手段对其进行了表征，评价了微球的化学稳定性、界面张力和润湿能力。评估了PAE微球的吸水膨胀性能和调驱性能。研究结果显示，核壳微球乳液具有较好的分散性和稳定性，3分钟内快速分散并且24h不分层；0.5 %核壳微球乳液可将界面张力从70.1 mN/m降低至1.12 mN/m。在65 ℃下，普通微球3天内快速膨胀12.33，而核壳型纳米微球可缓膨35天，膨胀倍数可达13.51。通过模拟填砂管实验，PAE的驱油率为72.34%，采收率增幅可达18.45%。核壳型纳米微球有望解决常规聚丙烯酰胺提高采收率在低渗透油藏中难以注入的难题，协同提高纳米微球的调剖和提高采收率。

Abstract:

Abstract: Cationic core-shell microspheres were prepared by reverse emulsion secondary polymerization, and slow-expanding core-shell nanomicrospheres (PAEs) were synthesized by incorporating shell materials with anionic monomers and cationic initiators using anionic interactions as well as a cationic initiation mechanism. The microspheres were characterized using FTIR, TGA, H-NMR, SEM and TEM to evaluate the chemical stability, interfacial tension and wetting ability. The water-absorption and swelling properties and the drive modulation properties of PAE microspheres were evaluated. The results show that the core-shell microsphere emulsion has good dispersibility and stability, rapid dispersion within 3 min and no delamination for 24 h. The 0.5% core-shell microsphere emulsion can reduce the interfacial tension from 70.1 mN/m to 1.12 mN/m. The normal microsphere expands rapidly by 12.33% in 3 days at 65 ℃, whereas the core-shell nano-microsphere can be swollen slowly for 35 days, and the expansion factor can be up to 13.51. The PAE microsphere can also be swelled by the core-shell nano-microsphere at 65 ℃. Through the simulated sand-filled tube experiment, the oil repulsion rate of PAE was 73.11%, and the recovery increase could be up to 11.23%. The core-shell nano-microspheres are expected to solve the problem of conventional polyacrylamide enhanced recovery which is difficult to be injected in low-permeability reservoirs, and synergistically improve the dissection and enhanced recovery of nano-microspheres.