| Smart hydrogels,as a kind of polymer material that can sense the changes in the external environment and make the corresponding stimuli response,has become a research hotspot,and has shown a broad application prospect in the fields of biomedical,tissue engineering,petrochemical and so on.In this work,according to the unique response performance of smart hydrogels and the characteristics of multi-branched macromolecular structure,the two kinds of smart hydrogels were designed and synthesized innovatively.The temperature sensitivity and pH sensitivity of the hydrogels were systematically studied,and the water plugging performance of the hydrogels was evaluated.The main research contents and results are listed below.1、Star-shaped macromolecules with NH3as the core are used as the core to graft polyethylene glycol glycidyl ether（PEGO-x）with different molecular weight,and then a series of star-shaped smart hydrogel with NH3as a core have been synthesized with different PEG molecular weights.The hydrogel was characterized by fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）and differential scanning calorimetry（DSC）,and the performance of hydrogels was studied by swelling test,anti-stress test and other methods.According to the test results of swelling performance,the hydrogel has a good temperature and pH sensitivity,and its response temperature increases with the increasing molecular weight of PEG.Moreover,the response pH showed the swelling in acid and shrinking in base.The test results of anti-stress performance show that the smart hydrogel with NH3as the core has a certain compressive strength,and its strength varies with the PEG molecular weight and the ratio of raw materials.The maximum load-bearing capacity is 36.2N.2、Star-shaped macromolecules with trimesic acid as the core are used as the core to graft polyethylene glycol glycidyl ether（PEGO-x）with different molecular weight,and then a series of star-shaped smart hydrogel with trimesic acid as a core have been synthesized with different PEG molecular weights.The hydrogel was characterized by fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）and differential scanning calorimetry（DSC）,and the performance of hydrogels was studied by swelling test,anti-stress test and other methods.According to the test results of swelling performance,the hydrogel also has the good temperature and pH sensitivity.The response temperature is roughly the same as that of the star-shaped smart hydrogel with NH3as the core,and its pH responsiveness is expressed as swelling in strong acid and shrinking under weak acid and alkaline conditions.However,the rigid structure of the benzene ring limits the expansion of gel network in water,resulting in a decrease in the equilibrium swelling rate.The test results of compressive performance show that the smart hydrogel with trimellitic acid as the core has a higher compressive strength,and the maximum load-bearing capacity is 90.2 N.3、With the star-shaped smart hydrogel as water shutoff agents,using the NH3and trimellitic acid as the core correspondingly.The effect of temperature,pH,salinity,surfactant,water quality and the shear rate on the gel-forming properties of two hydrogels were studied.The test results show that the two gel water shutoff agents have good temperature resistance,salt resistance,pH resistance,and under high-speed shear,the gel strength does not change significantly,and it has good properties in different water samples.The results of core displacement experiment show that the two gel water shutoff agents have the same plugging effect on cores with different permeability,and have good erosion resistance.The plugging rate of two gels is over 99.99%. |
