疏水改性pH响应型智能水凝胶P(HEMA-NaAA-DiAC16)的制备及其溶胀性能

以二烯丙基胺和1-溴代十六烷为原料合成了疏水单体N,N-二烯丙基正十六烷胺(DiAC16)，用FTIR、1H NMR 和元素分析对其进行了表征。 以2-羟基甲基丙烯酸乙酯(HEMA)、丙烯酸(AA)和N,N-二烯丙基正十六烷胺为共聚单体，N,N′-亚甲基双丙烯酰胺(BIS)为交联剂，十二烷基硫酸钠(SDS)为表面活性剂，过硫酸铵-四甲基乙二胺(TMEDA)为引发体系，制得的疏水改性智能水凝胶P(HEMA-NaAA-DiAC16)具有pH敏感特性。 研究了DiAC16、NaAA、BIS用量及pH值和离子强度等因素对水凝胶P(HEMA-NaAA-DiAC16)溶胀性能的影响。 结果表明，凝胶在水中的平衡溶胀率(为78.9～163.91)，随DiAC16、BIS用量的增加和NaAA用量的减少而减少，n值(一般在0.5~1.0之间)随DiAC16、NaAA和BIS用量的增加而增加，为非Fickian扩散。 水凝胶的吸水溶胀是放热过程，ΔHm在-2.09～-3.64 kJ/mol，ΔHm的绝对值随DiAC16用量的减少、NaAA用量和BIS用量的增加而增大，聚合物与水的亲和力逐渐增强。 随离子强度的增强，平衡溶胀率下降。

Synthesis and Swelling Properties of Hydrophobically Modified pH Sensitive Hydrogels P(HEMA-NaAA-DiAC16)

Hydrophobical monomer N,N-diallyl-N-hexadecylamine was synthesized by the reaction between diallyamine and 1-bromohexadecane. The monomer was characterized using FTIR, 1H NMR and element analysis. A series of hydrophobically modified pH sensitive intelligent hydrogels poly(2-hydroxylethyl-methacrylate/sodium acrylate/N,N-diallyl-N-hexadecylamine)P(HEMA-NaAA-DiAC16)] was successfully prepared by radically micellar copolymerization with 2-hydroxylethyl methacrylate(HEMA), sodium acrylate(NaAA), and N,N-diallyl-N-hexadecylamine(DiAC16) as comonomers, sodium dodecyl sulfate(SDS) as the surfactant, N,N′-ethylenebisacrylamide(BIS) as crosslinking agent, ammonium persulfate (NH4)2S2O8]-N,N,N′,N′-tetramethylethylenediamine(TMEDA) as initiating agent. The effects of hydrophobical monomer, NaAA, BIS contents and pH, ionic strength on swelling behaviors of P(HEMA-NaAA-DiAC16) had been studied. The results indicate that the equilibrium swelling ratio SR0 of the hydrogels decreases with increasing the amounts of DiAC16 or BIS, with decreasing of NaAA, which are 78.9～163.91 in distilled water. The n values are 0.5~1.0 and increase with the increase of DiAC16, NaAA or BIS. The diffusions of water into P(HEMA-NaAA-DiAC16) gels are found to be a non-Fickian mode and exothermic process. The ΔHm are -2.09～-3.64 kJ/mol, the modulus of ΔHm and affinity between the polymers and water increase with the increase of NaAA and BIS, and the decrease of DiAC16. The equilibrium swelling ratio decreases with the increase of ionic strength.