延时溶胀聚丙烯酰胺微球及其溶胀行为

The delayed-swelling PAM microsphere and its swelling kinetics

摘要:

利用丙烯酸二甲氨基乙酯和1,4-二溴丁烷的季铵化反应，合成了一种新型具有β位季铵结构的可水解交联剂(LC)。将LC单独使用，或和N, N-亚甲基双丙烯酰胺（Bis）联合使用，同时与丙烯酰胺（AM）和2-丙烯酰胺-2-甲基丙磺酸( AMPS)经反相细乳液聚合制得具有延时溶胀特性的交联聚丙烯酰胺(PAM)微球，微球粒径为300 ~ 500 nm，分布窄。通过透光率变化表征了微球的溶胀动力学，测试结果表明LC水解速率较非离子丙烯酸酯快。并且其水解速率随pH的降低而变慢，弱酸性条件可抑制LC水解，pH= 8.9时，溶胀时间为2 d，pH=5.0时，溶胀时间延长至40 d。通过调节LC质量分数（2 ~ 5%）和Bis质量分数（0 ~ 0.05 %）、水质pH值（5.0 ~ 8.9）和温度（75 ~ 100 ℃）使微球溶胀时间在2 ~ 40 d范围内可调，以满足在深度调剖或者堵水应用中的要求。

Abstract:

A new hydrolysable crosslinking agent LC with β-quaternary ammonium structure was synthesized by quaternization reaction of dimethylaminoethyl acrylate and 1,4-dibromobutane. By inverse miniemulsion polymerization, a series of cross-linked polyacrylamide (PAM) microspheres with delayed-swelling characteristics were prepared, containing LC alone or LC and N, N-methylene bisacrylamide (Bis). The particle size of the microspheres was 300 nm ~ 500nm, and the distribution was narrow. The delayed-swelling characteristics of crosslinked PAM microspheres can be dissected by light transmittance. The research showed LC showed faster hydrolysis rate than non ionic acrylate. The swelling time (tS) was 2 d as pH=8.9, while tS was increased to 40 d. Its hydrolysis rate was decreased with the decrease of pH, and the weak acid condition can inhibit the hydrolysis of LC. The swelling time can be adjusted by the usages of LC (2 % ~ 5 %)and Bis(0 ~ 0.05 %), the temperature(75 ~ 100 ℃) and pH(5.0 ~ 8.9), and changed from 2 d to 40 d. The new hydrolysable cross-linker LC and the PAM microspheres prepared by LC-Bis compositecross-linkers have application prospects in depth profile control and water plugging.