关键词: 水泥石;自修复;微胶囊;热稳定性;力学性能

Abstract: A new type of self-repairing microcapsules (with epoxy resin as the core and urea formaldehyde resin as the wall) for micro-cracks of oil-well cement matrix.The particle size distribution, surface topography, chemical composition and thermal stability of the microcapsules were analyzed by the Laser particle size analyzer, scanning electron microscopy ( SEM ), infrared spectroscopy ( FT-IR ) and differential thermal gravimetric analyzer ( TG/DTA) respectively.After preparation, microcapsules were added into cement paste, and the compressive strength and strength recovery rate of oil-well cement matrix were tested to evaluate the self-repairing effect of microcapsule.The results show that the average particle size is about 36.08 μm, the surface of microcapsules is rough and its thermal stability is good.In addition, the addition of microcapsules can improve the compressive strength of cement matrix by increasing the strength recovery rate ηof cement matrix (after repairing) to 2-3 times co MPared to that of pure cement matrix.When the content of microcapsule is 1.5wt%, the samples have the most excellent mechanical properties than the others.

Key words: cement matrix;self-repairing;microcapsules;thermal stability;mechanical property