论文部分内容阅读
利用十二烷基硫酸钠/吐温20复配表面活性剂和原位生成的聚甲基丙烯酸甲酯(PMMA)种子乳胶,发展了一种可在全水相中“绿色”合成较高浓度的聚甲基丙烯酸(PMAA)纳米水凝胶的新方法.以PMAA纳米水凝胶为前驱体,采用原位氧化沉淀法制备了磁性PMAA纳米微球.利用动态光散射法、FTIR分析、TEM观察、振动样品磁强计测试(VSM)、热重分析(TG)等对纳米水凝胶和磁性微球进行了表征,并探讨了PMAA纳米水凝胶的形成机理.结果表明,吐温20与MAA和PMAA间的氢键作用,促成了交联PMAA/吐温20复合物层在PMMA种子乳胶表面的选择性生长,导致生成了具有核壳结构的PMAA纳米水凝胶.PMAA纳米水凝胶表现出良好的p H响应性,当介质的p H值由1增加至6时,其流体力学体积扩张了近50倍.磁性PMAA纳米微球具有超顺磁性,其饱和磁化强度高达50 A·m~2/kg.
With sodium dodecyl sulfate / Tween 20 complex surfactant and in situ polymerized PMMA seed latex, a new kind of latex that can be synthesized in the whole “green” (PMAA) nano-hydrogel with high concentration.With PMAA nano-hydrogel as precursor, magnetic PMAA nano-microspheres were prepared by in-situ oxidation precipitation method.FTIR analysis , TEM observation, vibrational sample magnetometer test (VSM) and thermogravimetric analysis (TG) were used to characterize the nano-hydrogel and magnetic microspheres, and the formation mechanism of PMAA nano-hydrogel was discussed. The hydrogen bonding between temperature 20 and MAA and PMAA promoted the selective growth of the crosslinked PMAA / Tween 20 composite layer on the surface of PMMA seed latex, resulting in the formation of PMAA nano-hydrogel with core-shell structure. The hydrogels showed good p H response, and their hydrodynamic volume expanded nearly 50 times when the p H value of the medium was increased from 1 to 6. The magnetic PMAA nanospheres had superparamagnetism and their saturation magnetization reached 50 A · m ~ 2 / kg.