Preparation And Properties Of Thermosensitive Molecularly Imprinted Polymer Hydrogels

In this dissertation, the specific recognition of molecular imprinting with specific selective and temperature sensitivity of temperature sensitive hydrogel have been combined, and temperature-sensitive molecularly imprinted intelligent hydrogel was prepared successfully. By means of temperature, we could control the switch of the imprinted polymers to quickly identify the target molecule. The behavior and mechanism of molecularly imprinted intelligent hydrogel improved the efficiency of detection and identification. This dissertation includes four chapters.In Chapter 1, this section discusses that the basic theory and application of molecular imprinting technique. Bedsides, this chapter also introduced briefly the synthesis methods and the latest developments of the temperature sensitive molecularly imprinted polymer.In Chapter 2, highly selective temperature-sensitive molecularly imprinted polymer particles for salicylic acid were prepared by bulk polymerization at 60℃, with SA as template molecule, AM as functional monomer, EDGMA as cross-linker, NIPA as temperature-sensitive monomer, and AIBN as the initiator. The temperature sensitive molecularly imprinted polymer hydrogels showed the good selectivity of SA, which is similar to that of the molecularly imprinted polymers, whereas non-imprinted hydrogels had no selectivity for SA. The maximum adsorption capacity of these particles reached up to 6.35mg/g, which is 3.66 times than non-imprinted particles. And the LCST of those particles is about 40℃.Moreover, with the shrinkage at high temperature and swell at low temperature, the polymer was found in the experiment that the adsorption and elution efficiency were increased by 33.3% and 50%, respectively, compared to molecularly imprinted polymers. Furthermore, the temperature sensitive hydrogels could absorbed or released the target SA when the temperature was changed. But to those analogues of SA, non-imprinted hydrogel is not selective.In Chapter 3, using precipitation polymerization and thermal initiation, temperature sensitive molecular imprinting polymer microspheres with high selectivity of 4-MI were prepared at 60℃. The experiments showed that the adsorption equilibrium had been achieved after 80min, but the non-temperature sensitive polymer needed 150min. And the elution time was only 40% of the non-imprinted polymer. Scatchard model is used to evaluate binding property of 4-MI, and the Scatchard curved into a good linear relationship, the maximum adsorption capacity (Qmax) is 17.28mg·g-1, which is 2.18 times to non-imprinted polymer.In Chapter 4, O-vanillin as template molecule, MAA as functional monomer, and NIPA as temperature sensitive monomer, we prepared temperature-sensitive molecularly imprinted polymer microspheres with high selectivity of O-vanillin by suspension polymerization, at 60℃. The tests showed temperature sensitive imprinted polymer was higher 3% than the adsorption capacity of the imprinted non-temperature sensitive polymers, the desorption rate higher 16%. It indicated that the temperature sensitive imprinted polymer maintained adsorption capacity of the imprinted non-temperature sensitive polymer and had a good thermo-sensitivity, Scatchard curve of temperature sensitive imprinted polymer have a good linear relationship.