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以丙烯酰胺(AM)和丙烯酸(AA)单体的水溶液为分散相,失水山梨醇单油酸脂(Span80)/聚氧乙烯失水山梨醇脂肪酸脂(Tween80)/异辛烷为分散介质,分别以N,N′-亚甲基双丙烯酰胺(MBA)、过硫酸铵/亚硫酸氢钠((NH4)2S2O8/NaHSO3)为交联剂和氧化还原引发剂,在30℃进行反相微乳液聚合制备了一系列不同单体摩尔百分数的P(AM-co-AA)微凝胶.通过傅立叶红外光谱、浊度法、透射电镜(TEM)和动态光散射(DLS)等测试手段分别对微凝胶特征官能团的存在、pH敏感性、微观形态、粒径大小及粒径分布等进行表征分析.结果表明,共聚物中存在AM和AA结构单元;样品的TEM照片显示在原料中AA的摩尔百分数为60%时,P(AM-co-AA)微凝胶粒子的数均粒径为90 nm左右,呈现非规则球形;DLS结果表明,P(AM-co-AA)微凝胶与PAM微凝胶相比具有较宽的粒径分布,且随原料中AA摩尔百分数增加,粒径分布逐渐变宽;P(AM-co-AA)微凝胶具有良好的pH敏感性,敏感pH值与AA的解离常数有关,通过调节pH值可以迅速控制自身体积的溶胀与收缩.
The aqueous solution of acrylamide (AM) and acrylic acid (AA) monomer was used as disperse phase, and sorbitan monooleate (Span80) / polyoxyethylene sorbitan fatty acid ester (Tween80) , Respectively, with N, N’-methylenebisacrylamide (MBA), ammonium persulfate / sodium bisulfite ((NH4) 2S2O8 / NaHSO3) as crosslinking agent and redox initiator, respectively, A series of P (AM-co-AA) microgels with different monomer mole percentages were prepared by microemulsion polymerization. Fourier transform infrared spectroscopy, turbidimetry, transmission electron microscopy (TEM) and dynamic light scattering (DLS) The existence of the functional groups, pH sensitivity, microscopic morphology, particle size and particle size distribution of the microgel were characterized and analyzed. The results showed that there were AM and AA structural units in the copolymer. The TEM images of the sample showed that AA (AM-co-AA) microgels with an average particle size of about 90 nm, showing an irregular spherical shape. The results of DLS indicated that the microgels of P (AM-co-AA) Compared with PAM microgel, it has a wide particle size distribution. With the increase of AA molar percentage in the raw material, the particle size distribution broadens. P (AM-co-AA) microgel Good pH-sensitive, and the pH-sensitive solution dissociation constant related to AA, can quickly control the volume swelling and contraction itself by adjusting the pH.