疏水缔合聚合物临界缔合浓度研究

A Study on Critical Associating Concentrations of Water Soluble Hydrophobically Associating Polymers for EOR

认为水溶性疏水缔合聚合物在水溶液中的疏水缔合可分为两个阶段 ,聚合物浓度大于第一临界缔合浓度(CAC1)后发生分子内和分子间缔合 ,粘浓曲线斜率增大 ,在第二临界缔合浓度 (CAC2 )下分子内缔合 (引起粘度下降 )达到平衡 ,此后缔合主要发生在分子间 ,粘浓曲线斜率再次增大。由粘浓曲线测定了 3种商品聚合物的CAC1和CAC2 ,考察了多种因素的影响。CAC1和CAC2 随 pH值的增大 (4 .8～ 8.2 )近似地呈线性降低 ,随矿化度增大(1.0～ 10 0 g/L)趋于升高 ,随温度升高 (2 0～ 5 0℃ )略有升高 ,随剪切速率增大 (32～ 10 3s-1)保持不变。在聚合物S3(M =1.2 8× 10 7,HD =2 9.3% )溶液中加入 6 .0 g/L重烷苯磺酸钠 (该加量处于与溶液增粘峰对应的浓度范围 ) ,使CAC1和CAC2 由 970和 2 14 0mg/L降至 5 6 7和 110 0mg/L。讨论了矿化度、外加阴离子表面活性剂等对疏水缔合的影响。图 2表 2参 11。

It is considered that the hydrophobical association of hydrophobically associating polymers in aqueous solutions proceeds in two stages: the intra- and intermolecular association take place and result in increase in slope of viscosity-concentration curves when the polymer concentration is higher than the 1st critical associating concentration, CAC_1; the intramolecular association causing solution viscosity reduction reaches its equilibrium at the 2nd critical associating concentration, CAC_2, and beyound this concentration the intermolecular association occurs mainly and the slope of viscosity-concentration curves become steeper again. The values of CAC_1 and CAC_2 are determined from viscosity-concentration curves for 3 commercial polymers and the effects of a lot of factors are investigated. CAC_1 and CAC_2 values decrease nearly linearly with increasing pH value in range 4.8-8.2, increase with increasing salinity in range 1.0-100 g/L, slightly increase with increasing temperature in range 20-50℃ and keep unchanged with increasing shear rate in rang 32-103 s^(-1). For solution of polymer S3 (M=1.28×10~7 and HD=29.3%), introducing a heavy alkyl benzene sulfonate of dosage 6.0 g/L (in concentration range of viscosifying peak of the polymer solution) results in decrease in CAC_1 and CAC_2 values from 970 and 2140 mg/L to 567 and 1100 mg/L, respectively. The effects of salinity, anionic surfactant and other factors on hydrophobical association are discussed.