Preparation of SiO2-PEGMA/AA Modified Composites and Study on Performance Improvement of Oil Well Cement
Polyethylene glycol methacrylate(PEGMA)and acrylic acid(AA)were grafted onto SiO2 nanoparti-cles through free radical polymerization to prepare SiO2-PEGMA/AA composite materials.For the prepared SiO2-PEGMA/AA,the structure of composite materials was characterized,and the influence of composite materials on the performance of cement slurry was studied,and the microstructure of cement stone was analyzed.The results indicate that the prepared SiO2-PEGMA/AA composite material was successfully grafted with PEGMA and AA,and the thermal stability of the composite material reached 220 ℃,while the particle size remained at the nanoscale.When the dosage is 1％,SiO2-PEGMA/AA composite materials can significantly improve the flowability of cement slurry,with a yield stress below 0.01 Pa.Compared with the blank cement sample,the compressive strength of cement stone cured at 75 ℃ for 28 days increased by 57.8％.SiO2-PEGMA/AA composite can promote the formation of hydrated calcium silicate gel,fill the pores between cement particles,improve the pore structure of cement,and re-duce the average pore size to 41.8 nm after curing for 3 days.SiO2-PEGMA/AA composite materials can not on-ly effectively improve the fluidity of cement slurry,but also significantly promote cement hydration and densify the structure of cement paste.
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