Study On Microcapsule Technology Of Bore-wear Reducing Additive

In order to resolve the loading issues that high-energy propellant charge used the liquid silicone oil as a highly effective bore-wear reducing additive, the preparation arts and crafts of microcapsules of silicone oil were researched by an in-situ condensation polymerization reaction with a urea-formaldehyde resin wall. Several encapsulating parameters were investigated including different emulsifiers,different dispersed emulsion time, pH, stirring speed, acidification time and curing temperature on microcapsule appearance quality such as particle size, and size distribution. What is more, the microcapsules of silicone oil were prepared with a urea-formaldehyde resin wall material, and the performanceuse of wear reducing is mensurated by the erosion tube test.The result of experiments show that the reaction system of emulsifier is the key factors to determine the success of micro-encapsulation. It plays a vital role in the morphology of micro-capsules; Stirring speed is the other major factors in the microcapsules; The speed of acidification has a direct impact on the microcapsules of formation in particle size in the course of condensation; In addition, the level of pH has effect on the microcapsules wall in the process of condensation; When pH is between 4.0 and 5.5, the forming wall is osteoporosised and it is easy to be destroyed. When pH value is low, the formation of micro-capsule wall is hard and not easy to destroyed. The final reaction conditions of the preparation of silicon oil Microcapsules with a urea-formaldehyde resin wall were as follows: SMA, 2h acidification approximately, the curing temperature under 70℃for 120min. Under these conditions, the mean particle diameter of 50μm, uniform and spherical solid microcapsules of silicone oil were obtained. The wear reducing of microcapsules of silicon oil is obvious, and it is similar to the pure silicone oil.