【作者】 鲁智勇；

【导师】 张熙；

【作者基本信息】 四川大学 ， 高分子材料， 2005， 硕士

【摘要】 本文选用具有高反应活性的丙烯酰胺(AM)为共聚单体,采用自由基水溶液聚合方法制备出了N-异丙基丙烯酰胺(NIPA)温敏共聚物P(AM-NIPA),首次在P(AM-NIPA)结构中引入丙烯酸钠(NaAA)单体结构单元,合成了离子型共聚物P(AM-NIPA-NaAA)。采用红外光谱、核磁共振~1H谱对共聚物结构和组成进行了表征;研究了聚合反应的温度、引发剂浓度、N-异丙基丙烯酰胺单体含量对共聚反应产物溶液性能的影响,测定了共聚反应的转化率随时间的变化规律;考察了共聚物P(AM-NIPA)和P(AM-NIPA-NaAA)溶液温敏性的影响因素,采用荧光光谱分析法、乌氏粘度计稀释法以及差示扫描量热法对共聚物溶液温敏机理进行了研究;考察了共聚物P(AM-NIPA)和P(AM-NIPA-NaAA)溶液性能,分别研究了共聚物浓度、共聚单体组成、温度以及剪切速率对共聚物溶液表观粘度的影响。 研究结果表明,聚合反应条件对产物性能影响较大,随着反应温度升高,所得聚合物溶液的表观粘度下降;随着引发剂浓度的增加,溶液表观粘度下降;当NIPA在共聚组分中的含量增大时,相应溶液的表观粘度降低。不同共聚单体的配比以及单体含量对共聚物溶液低临界溶解温度(LCST)均有显著影响。随着亲水性单体丙烯酰胺结构单元在共聚物P(AM-NIPA)中含量的增加,共聚物P(AM-NIPA)溶液的低临界溶解温度也相应的增加;当在共聚物P(AM-NIPA)中加入第三单体NaAA后,其低临界溶解温度明显地得到提高。 不同种类的盐以及盐的含量对共聚物水溶液的热敏性有显著的影响。随着更多还原

【Abstract】 The nonionic thermosensitive water-soluble copolymers P (AM-NIPA) of acrylamide (AM) and N-isopropylacrylamide (NIPA) were synthesized by free radical aqueous solution copolymerization, and the ionic copolymer P (AM-NIPA-NaAA) was prepared by incorporating the third monomer sodium crylic acid (NaAA) to the molecule structure of P (AM-NIPA). The copolymer structures were characterized by IR Spectrum and ~1H-NMR Spectrum. The effects of the reaction conditions such as reaction temperature initiator concentration and NIPA monomer concentration on the performance of the copolymer solution were studied; The conversion of copolymerization with the reaction time was measured; the effect factors on thermosensitivity of the copolymer solution were studied; the thermosensitive mechanism of copolymer solution was studied by the fluorescence Spectrum, intrinsic viscosity and DSC; The effects of copolymer concentration, temperature and shear rate on the apparent viscosity of copolymer solution were studied.The result shows that the conditions of copolymer reaction have notable effect on the performance of the product. The apparent viscosity of the copolymer solution declines with the initiator concentration increasing or polymerization reaction temperature rising. When the NIPA monomer amount in the copolymer increases, the apparent viscosity of the copolymer solution decreases.The proportion of monomer and monomer amount in the copolymer has notableeffect on the low critical solution temperature of the copolymer solution. When the hydrophile monomer AM amount increases in the copolymer, the low critical solution temperature of the copolymer solution increases; when the third monomer sodium crylic acid is added to the copolymer of P (AM-NIPA), the low critical solution temperature of the copolymer solution is increased obviously.The chemical structure and concentration of salts have also notable effect on the low critical solution temperature of the copolymer solution. With NaCl CaCl2 and Na2SO4 concentration increasing, the low critical solution temperature of the copolymer solution declines in linearity, which shows that salt has restraining effect on the low critical solution temperature of the copolymer solution. At the same time, Different of salts have different effect intension on the low critical solution temperature of the copolymer solution. When a little Na2SO4 is added to the copolymer solution, the copolymer separates out from solution at normal temperature. When the NaCl and CaCl2 in aqueous solution equaling to Na2SO4 in ion intensity or mol concentration is added to the copolymer aqueous solution, the effect of NaCl and CaCl2 on the low critical solution temperature is less notable than the Na2SO4, and the effect of NaCl on the low critical solution temperature is more notable than the CaCl2, Which indicates that the low critical solution temperature of the copolymer solution is related to the kind of anion or cation of salt.The fluorescence Spectra of P (AM-NIPA) solution indicates that the polarity of media around the pyrene probe keeps unchanged below the low critical solution temperature of copolymer solution, when the temperature of copolymer solution reaches to the low critical solution temperature, the polarity of media around the pyrene probe decreases sharply, which causes the congregating of the hydrophobe structure of the copolymer.The changing rule of intrinsic viscosity of copolymer solution with temperature shows that the intrinsic viscosity of the copolymer in solution declines accordingly with temperature rising, but in the neighborhood of the low critical solution temperature of the copolymer solution, the intrinsic viscosity declines sharply, which indicates that the parameter of mutual effect between molecule of copolymer andwater molecule change abruptly at the low critical solution temperature of the copolymer solution, which results in the change of molecule chain from clew to globe.Copolymer structure has different effects on the apparent viscosity of copolymer solution. Especially, when the third monomer sodium crylic acid is added to the copolymer, the apparent viscosity of copolymer P (AM-NIPA-NaAA) solution is higher than that of the copolymer P (AM-NIPA) at different concentration of copolymer solution. The apparent viscosity of copolymer solution decreases in linearity with the temperature rising, but when the temperature rises to the low critical solution temperature, the apparent viscosity of copolymer solution increases in different degree, which indicates that the copolymer solution exhibits thermothickening effect at special condition. When temperature is above the low critical solution temperature of copolymer solution, the apparent viscosity of copolymer solution decreases sharply. The copolymer solution acts as typical pseudoplastic and thixotropic fluid.更多还原