Controlled Expansion Of The Sealing Agent Research And Performance Studies

Hygroscopic colophony is a new kind of higher molecular weight plugging material that developed in recent years. After absorbing water, it swells to become a sort of elasticoviscous gel which has intensity and strong moisture-retaining, anti-salt and stability properties. The key of hygroscopic colophony which used to plugging is well controlling and adjusting the velocity of hygroscope, but the velocity general hygroscopic colophony is fast and hard to control. Thus, the original synthesize a kind of hygroscopic colophony which aimed at the shortage of hard to control hygroscopic velocity. It used mirco-capsule coating technology to improve hygroscopic character of hygroscopic colophony, develop a new style controllable & swelling plugging agent. This plugging agent has better stability and intensity.The original takes acrylic acid (AA), acrylamide (AM) as basic materials, chooses aqueous solution aggregation method synthesize hygroscopic colophony. From single element experiment, we got the best reaction conditions of synthesize colophony, which include, reaction temperature is 50℃, monomer concentration is 30%, neutralization acrylic acid is 80%, quantity partitioning of AA and AM is 6:4, initiating agent of Na2SO3 and (NH4)2S2O8 dosage is 2%, cross linker NMBA dosage is 0.2%. in order to improve the intensity of plugging agent, we add supper tiny CaCO3 at the beginning of the experiment, and evaluate the influence of supper tiny CaCO3 to hygroscopic colophony character.Aimed at control hygroscopic velocity of plugging agent, mirco-capsule coating technology is used plugging agent modification. We choose wax as coating material, use melting condensation method to synthesize plugging agent micro-capsule. In order to solve the problem of low coating rate, the original proposed cooling-crushing method and wax emulsification method to coat synthesized hygroscopic colophony. The hygroscopic velocity of prepared controllable and swelling plugging agent decreases significantly under the temperature of wax melting point, hygroscopic rate decreases too, and achieves hygroscopic velocity controllable.The formation sealing capacity of controllable-swelling plugging agent is evaluated by grit-bed and modified DL experiment apparatus. Resulting shows that controllable & swelling plugging agent could accommodate different size of aperture and fracture through elasticity. It will get better plugging effect to combine with rigidity bridge material.