β-环糊精对两亲聚合物黏度与分子量测定的影响

Effect of β-Cyclodextrin on the Viscosity of Amphiphilic Polymers and the Determination of Molecular Weight

沈静静 刘德新 SARSENBEKULY Bauyrzhan 徐德荣 刘同敬 杨红斌 康万利

SHEN Jingjing LIU Dexin SARSENBEKULY Bauyrzhan XU Derong LIU Tongjing YANG Hongbin KANG Wanli

为探究β-环糊精（β-CD）的包合作用对两亲聚合物（丙烯酰胺、丙烯酸、十六烷基烯丙基氯化铵三元共聚物APC16）黏度及黏均分子量的影响，通过流变仪研究了β-CD 包合APC16溶液的黏度变化规律及影响因素，采用乌氏黏度计测定了 APC16包合体系的特性黏数，进而准确计算出无分子间相互作用下 APC16的黏均分子量。结果表明，在45 ℃、矿化度为3×104 mg/L 的条件下，β-CD与APC16物质的量比为1∶2时，APC16溶液的临界缔合浓度升至5300 mg/L；β-CD 与APC16物质的量比为1∶1完全包合时，APC16溶液的临界缔合行为消失。在完全包合比下，温度在25～90 ℃变化时，包合体系的黏流活化能小于APC16溶液的黏流活化能。随NaCl 浓度的增加，包合体系的黏度下降更加平缓，包合强度增强。据此，可以应用β-CD包合作用消除疏水缔合来测定两亲聚合物的黏均分子量。单一APC16的黏均分子量为 537×104Da、部分水解聚丙烯酰胺（HPAM）的黏均分子量为 1292×104 Da。当β-CD与APC16物质的量比为1∶1、2∶1时，APC16的黏均分子量分别为341×104、358×104 Da。当β-CD与HPAM物质的量比为1∶1和2∶1时，HPAM的黏均分子量分别为1223×104 、1272×104 Da。HPAM的黏均分子量在包合前后的测定结果一致，证实β-CD包合法测定两亲聚合物分子量的有效性，为两亲聚合物疏水作用对黏度贡献和分子量

In order to explore the effect of cladding β-cyclodextrin（β-CD）on the viscosity and viscosity-average molecular weight of amphiphilic polymers，such as acrylamide，acrylic acid，cetyl allylammonium chloride terpolymer（APC16），the viscosity variation law and influencing factors of β-CD cladding APC16 solution were studied by rheometer. The characteristic viscosity of APC16 inclusion system was determined by Urkovinometer，and then the viscosity-average molecular weight of APC16 without intermolecular interaction was accurately calculated. The results showed that under the condition of 45 ℃ and 30 g/L salinity，the critical association concentration of APC16 solution shifted to 5300 mg/L when the molar ratio of β-CD and APC16 was 1∶2. When the molar ratio of β-CD and APC16 was 1∶1（complete inclusion ratio），the critical association behavior of APC16 solution disappeared. Under the complete inclusion ratio，the viscous flow activation energy of the cladding system was smaller than that of APC16 solution when the temperature increased from 25 ℃ to 90 ℃. The viscosity of the cladding system decreased more gently with the increase of NaCl concentration，while the cladding strength increased. Accordingly，the viscosity-average molecular weight of amphiphilic polymers could be determined by the β-CD inclusion method based on host-guest interaction. The viscosity-average molecular weight of APC16 was 537×104 Da，while that of HPAM was 1292×104 Da. When the molar ratio of β-CD and APC16 was 1∶1 and 2∶1，the viscosity-average molecular weight of APC16 was 341×104 Da and 358×104 Da，respectively. When the molar ratio of β-CD and HPAM was 1∶1 and 2∶1，the viscosity-average molecular weight of HPAM was 1223×104Da and 1272× 104 Da，respectively. The viscosity-average molecular weight of HPAM was consistent before and after inclusion. The effectiveness of the legal determination of molecular weight of amphiphilic polymers by the β-CD inclusion method was confirmed. A new method was provided for the contribution of hydrophobic action of amphiphilic polymers to viscosity and molecular weight determination.

10.19346/j.cnki.1000-4092.2024.01.018