孪尾疏水缔合共聚物P(AM/NaAA/DiC_6AM)盐水溶液在中高温下的粘度

Viscosity Properties of Aqueous Solutions in Brine at Higher Temperature for Twin-Tailed Hydrophobically Associating Tercopolymers P(AM/NaAA/DiC_6AM)

在十二烷基硫酸钠 (SDS)存在下进行胶束聚合 ,采用先加碱共聚后水解的方式 ,改变表面活性剂、疏水单体摩尔比 (SMR) ,疏水单体摩尔分数为 0 .372 % ,由丙烯酰胺 (AM )、N ,N 二己基丙烯酰胺 (DiC6AM )合成了孪尾型疏水缔合三元共聚物P(AM/NaAA/DiC6AM) ,理论水解度 15 %。介绍了合成过程。考察了不同SMR(12 .5 0～ 10 0 .0 )下得到的共聚物水溶液 85℃ ,7.34s-1下的 (表观 )粘度 ,共聚物浓度一般为 2 .0 g/L。共聚物的水溶性随SMR的增大而改善 ,SMR≥ 13.36时溶于标准盐水 (含Ca2 + 、Mg2 + 、HCO-3 ,矿化度 19334mg/L) ;疏水单元平均序列长度NH 和Huggins常数KH 随SMR增大而减小 ,SMR =10 0 .0时KH 趋近HPAM的值。浓度 0 .5～ 5 .5 g/L范围的共聚物标准盐水溶液粘度曲线 ,随SMR增大移向高浓度低粘度方向。随NaCl浓度 (2 0～ 2 0 0g/L)或CaCl2 浓度 (2～ 10 g/L)增大 ,共聚物水溶液粘度先降低 ,后升高 ,出现增粘效应 ,SMR越小 ,增粘效应越强。外加SDS在一定浓度范围对共聚物标准盐水溶液产生增粘效应 ,SMR越小 ,增粘效应越强。共聚物标准溶液粘度在 35～ 80℃范围随温度升高而降低 ,在 0～ 12 2s-1范围随剪切速率增大而降低。对实验结果作了解释。图 6表 2参 10。

Twin-tailed hydrophobically associating tercopolymers P(AM/NaAA/DiC_6AM) of calculated degree of hydrolysis 15% are synthesized from acrylamide, AM, and N,N-dihexylacrylamide, DiC_6AM, in micellar copolymerization with sodium dodecylsulfate, SDS, followed by hydrolysis at conditions of hydrophobe molar fraction 0.372% and varying surfactant to hydrophobe molar ratio, SMR. The process of synthesis is described. The apparent viscosities of aqueous solutions of concentration 2.0 g/L in most cases for the tercopolymers (TCPs) obtained at SMR in range 12.50-100.0 are determined at 85℃ and shear rate 7.34 s^(-1). The (solub) (ility) in water of the TCPs increases with increasing SMR and the TCPs of SMR≥13.36 dissolve in a standard brine of TSD=19 334 mg/L and containing Ca^(2+), Mg^(2+), HCO^-_3 and others; the average sequence length of hydrophobes, N_H, and the Huggins constant, K_H, decrease with increasing SMR and K_H becomes close to K_H for HPAM at SMR=100.0. The viscosity-concentration curves for TCPs solutions in brine shift in direction of increasing concentration (0.5-5.5 g/L) and decreasing SMR value. With increasing NaCl concentration in range 20-200 g/L or CaCl_2 concentration in range 2-10 g/L, the viscosity of aqueous TCPs solutions decreases at first and then increases, with salt induced viscosification being observed and the smaller the SMR value the stronger the viscosifying effect is. The SDS additionally indroduced induces viscosification of TCPs solutions in brine in some SDS concentration range and the smaller the SMR value the stronger the viscosifying effect is. The viscosity of TCPs solutions in brine decreases with increasing temperature in range 35-85℃ and with increasing shear rate in range 0-122 s^(-1). The experimental results are explained.