Polymer nanospheres are commonly used in scientific and industrial fields including petroleum, electronics, and biomedicine. The precise synthesis of polymer nanospheres with a controllable size and regular shape is important for achieving thermal stability and mechanical properties, which will directly affect the oil displacement effect. In this paper, amphoteric CP(AM-AMPS-DMDAAC) nanospheres with a small particle size and regular shape were prepared by using an acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), diallyl dimethylammonium chloride (DMDAAC), and methylene-bis-acrylamide mixed solution as the aqueous phase and Span-80 and Tween-80 as the composite emulsifier, followed by reverse-phase microemulsion polymerization. The results showed that nanospheres had temperature and salt resistance and excellent physical and chemical properties. The thermal decomposition temperature was 236.5 °C, the median size of the particles was close to 50 nm, the swelling factor remained at 6.1 nm/nm after water absorption and expansion in the formation water at 120 °C for 7 days, and the swelling factor was 10.4 nm/nm after 14 days. In addition, nanospheres also exhibit good viscoelasticity and pseudoplasticity. The average plugging rate was 79.5% in the low permeability cores, and after the injection of the CP(AM-AMPS-DMDAAC) nanospheres based on water flooding, the average enhanced recovery rate was 13.46%.

中文翻译：

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耐温耐盐驱油用CP(AM-AMPS-DMDAAC)纳米球的合成与性能

聚合物纳米球通常用于石油、电子和生物医学等科学和工业领域。精确合成尺寸可控、形状规则的聚合物纳米球对于实现热稳定性和力学性能具有重要意义，将直接影响驱油效果。本文以丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、二烯丙基二甲基氯化铵(DMDAAC)为原料制备了粒径小、形状规则的两性CP(AM-AMPS-DMDAAC)纳米球。以亚甲基双丙烯酰胺混合溶液为水相，Span-80和Tween-80为复合乳化剂，进行反相微乳液聚合。结果表明，纳米球具有耐温、耐盐性能以及优异的理化性能。热分解温度为236.5 ℃，颗粒中值粒径接近50 nm，在120 ℃地层水中吸水膨胀7 d后，溶胀因子保持在6.1 nm/nm，溶胀率保持在6.1 nm/nm。 14 天后因子为 10.4 nm/nm。此外，纳米球还表现出良好的粘弹性和假塑性。低渗透岩心平均封堵率为79.5%，基于水驱注入CP(AM-AMPS-DMDAAC)纳米球后，平均提高采收率13.46%。