超临界CO_2中疏水改性聚丙烯酸的合成及其溶液性质

在水溶性单体丙烯酸(AA)与疏水性单体丙烯酸十八酯(ODA)中,加入N,N′-亚甲基双丙烯酰胺(MBAM),在超临界CO_2介质中合成了疏水改性聚丙烯酸(HMPAA)。采用扫描电子显微镜、乌氏黏度计和旋转黏度计对HMPAA的性质进行了表征,考察了温度、HMPAA溶液质量浓度、MBAM含量、HMPAA溶液pH对HMPAA溶液表观剪切黏度的影响。实验结果表明,HMPAA为白色粉末,由粒径约2μm的颗粒组成;HMPAA溶液表观剪切黏度随HMPAA溶液pH的增大先增大后降低;HMAA溶液表观剪切黏度随HMPAA溶液质量浓度的增加而增大;当MBAM的质量分数小于0.51%时,HMPAA溶液表观剪切黏度随MBAM含量的增加而增大。当HMPAA溶液质量浓度为0.8 g/dL、温度30℃、m(AA):m(ODA)=9:1、w(MBAM)=0.51%时,HMPAA溶液的表观剪切黏度达到75.0Pa·s。

Synthesis of Hydrophobically Modified Poly(Acrylic Acid)in Supercritical Carbon Dioxide and Its Solution Properties

Hydrophobically modified poly(acrylic acid)(HMPAA)were synthesized in supercritical carbon dioxide by precipitation polymerization of acrylic acid(AA),octadecyl acrylate(ODA)and N,N′- methylene-bis-acrylamide(MBAM)with different mole ratios.Morphology and properties of HMPAA were studied by means of scanning electron microscopy,Ubbelohde capillary viscometer and rotational viscometer.HMPAA was obtained in form of white powder in size of about 2μm.Effects of temperature, HMPAA mass concentration,MBAM content in polymerization feed,pH of HMPAA solution on apparent shear viscosity of HMPAA solution were investigated.Apparent shear viscosity of HMPAA solution increases along with HMPAA mass concentration in solution,and MBAM content in polymerization feed particularly when it was lower than 0.51%.It also increases along with pH of the solution,but dropped after reaching maxium.Apparent shear viscosity of HMPAA solution is 75.0 Pa·s under the conditions of HMPAA concentration solution 0.8 g/dL,30℃,m(AA):m(ODA)9:1 and w(MBAM)0.51%.