Study Of The Rheology Of Emulsion Explosive Matrix

The rheology is an important property of emulsion explosive matrix. It has an important influence on the preparation, transportation and storage of emulsion explosive matrix. It also can show the relationship between the nature of matrix and its’ microstructure. So, the study of the rheology of emulsion explosive matrix has a certain theoretical value and practical significance. The rheology of emulsion explosive matrix was studied in this paper. The main research contents of this paper are as follows:Firstly, the rheology of emulsion explosive matrix was studied by analyzing the viscosity and visco-elasticity of emulsion explosive matrix. The test results showed that emulsion explosive matrix was a pseudo plastic fluid with visco-elasticity. The curve of viscosity with the increase of shear rate was consistent with Carreau-Yasuda equation. The curve also illustrated that the matrix showed zero shear viscosity in low shear rate region. The matrix had elastic deformation in low strain. But, the viscous deformation happened and the elastic deformation disappeared with the increase of strain. The viscosity of matrix tested with the increase and decrease of shear rate was different. The higher viscosity was observed with the decrease of shear rate because the microstucture was destroyed by the high shear rate, thus there were much ammonium nitrate crystals in matrix. Besides that, the results also showed that emulsion explosive matrix had thixotropy. The structure can recovery when undergoing shear action. But the structure can not recovery when the shear rate of shear stage was 103s-1.Secondly, the effect of the droplet size, the nature of dispersion medium and emulsifier on the rheology of emulsion explosive matrix were studied. The viscosity, shear stress and storage modulus increased with the decrease of droplet size. The viscosity of recovery stage was close to initial viscosity. The viscosity and storage modulus increased firstly and then decreased with the increase of the viscosity of dispersion medium. It increased to the top when the viscosity of dispersion medium was 5.65mm2/s. When the polarity of dispersion medium increased, the viscosity and storage modulus decreased quickly. The storage modulus increased when the interaction between emulsifier and ammonium nitrate was strong. It decreased when the content of emulsifier was decreased. This could be due to the reduction of emulsifying effect caused by few emulsifier reached oil-water boundary. Moreover, the decreased of reverse micelle in oil phase could be the another reason which leads to the decrease of storage modulus. Besides that, the storage modulus increased with the increase of relative molecular mass of emulsifier.Thirdly, the change of storage modulus of emulsion explosive matrix in storage was studied in this paper. The result of the change of storage modulus of emulsion explosive matrix with different particle size of dispersed phase shows that the change of storage modulus during storage is a good way to evaluate the stability of emulsion explosive matrix. The matrix showed better stability when storage modulus increased less. The relationship between the change of microstructure and storage modulus showed that the storage modulus increased with the increase of the content of ammonium nitrate crystals. When the content of ammonium nitrate crystals reaching a certain level, the storage modulus was very high and the linear visco-elasticity region disappeared with the increase of strain. This could be due to the structure break of matrix. The stability of matrix increased with the decrease of droplet size.Finally, the effect of oil and emulsifier on the stability of matrix was studied in this paper by analyzing the change of storage modulus during storage. The stability influenced by the viscosity and polarity of dispersion medium. The stability increased with the increase of the viscosity of dispersion medium. When the polarity of dispersion medium increased, the stability decreased quickly. In the four PIBSA-based emulsifiers of this paper, the matrix formed by PIBSA-TEA showed best stability because the strongest interaction between PIBSA-TEA and ammonium nitrate was seen. The stability decreased with the decrease of the content of emulsifier. The stability of matrix showed a little improvement when the relative molecular mass of emulsifier was improved in short-term storage.