Preparation Of Core - Shell Latex And Its Application In Oil Well Cement

Latex can effectively increase the fluid loss of cement, gas channeling prevention performance, the enhanced Interfacial bond strength of cement and so on. But latex applied to cement stability, must often add special stabilizers or additional emulsifiers to maintain stability of oil well cement. This paper has prepared a core-shell structure latex with hard outside and soft within, which will be able to maintain stability of the cement and improve the compressive strength of cement paste without stabilizers, while reducing loss of cement slurry, reinforcing cement slurry thickening properties at right angles, improving Interfacial bond strength,reinforcing elastic-plastic property of cement rock. Using scanning electron microscopy to analysis micro-morphology of cement stone.we found cement and latex membranes forming a clear network structure.This paper using seed emulsion polymerization method to preparing core-shell emulsion, two hard polymers of monomers copolymer nuclear polymer (MMA-St), hard monomers and soft monomers copolymer shell polymer(MMA-n-BA), calculating the quantity of all kinds of monomers in different phases. This paper studied Letterpress-shell polymerization technology、temperature、initiator quantity and different types of emulsifiers on properties of emulsion,then get the polymerization technology and formula. Through infrared spectroscopy、thermogravimetric analysis、Zeta potential measurement、transmission electron microscopy and laser particle size characterization to verifying the composition and structure of core-shell emulsion.We prepared two different systems of core-shell emulsion in this article,one is micro-soap emulsion with polymerizable emulsifier and anionic emulsifier interaction. The other is core-shell emulsion with a single anionic emulsifier involved in the core-shell emulsion. Micro-soap emulsion has significantly stronger core-shell emulsion stability, and the cement slurry has good mobility without adding stabilizers.Geting the resulting that polymerizable emulsifier plays an important role on stability of emulsion and cement stability.