| The dissolvability mechanism about nitrocellulose (NC) dissolve in ethanol- aether mix solvent has been studied through two ways (experimentation and computer simulation) in this paper.Firstly, it is assumed that the dissolution time and solution viscosity has linear relation and its slope is defined as dissolution velocity in experimentation part. The 2~#NC and 3~#NC dissolution velocity in the ethanol-aether mix solvent with volume ratio of 2:1, 3:2, 6:5, 1:2 and 2:1, 1:1, 5:6, 1:2 has been studied respectively though determining the solution rotary viscosity in different time gaps of 60h dissolve time under 20℃. The effect of ethanol and aether in dissolving NC has been studied respectively though different solvent addition order. Polarizing microscope has been used to observe the dissolve process about NC in ethanol-aether mix solvent with different volume ratio.The experimental results indicated that the phase of constant dissolution viscosity-time curve has linearity in faith and the slope of viscosity-time curve can be set as dissolvable velocity. When the proportion of ethanol-aether mixed solvent is 1:1 and 3:2, 2~# NC and 3~# NC has its largest solution velocity respectively which was 0.1976 and 0.2361. The mostly action of ethanol in dissolve process was giving birth to hydrogen bond with NC and destroying entanglement of macromolecules. However the action of aether was destroying the associating effect inside of ethanol molecule, that the more ethanol molecules could give birth to hydrogen bond with NC. The results of polarizing microscope observed inosculate to experimental data.The solubility parameters of ethanol-aether mixed solvent having different proportion and the interaction parametersχ1 of different nitrate replace units in NC molecule with ethanol and aether have been calculated in the part of computer simulation.It will be found the dissolvability mechanism about the effect of NC dissolving in ethanol-aether mix solvent from molecule configuration. At the same time the diffusion ratio of the ethanol and aether molecules in NC has been calculated in order to validate the experimental results of dissolution.The computer simulation results indicated that the dissolving ability of ethanol-aether mixed solvent to 2~#NC and 3~#NC respectively was 5:6>1:2>1:1>2:1 and 1:1>3:2>6:5>2:1. As the temperature up the interaction parametersχ1 of replace units in NC with ethanol and aether fall, namely up temperature could be propitious to dissolving. On the contrary it can be accelerate NC dissolving when the temperature achieve one critical value . Ethanol and aether could not dissolve NC alone under normal temperature. As the ethanol quantum increased the diffusion of the ethanol and aether molecules in 2~#NC would be decreased .However it would be increased in 3~#NC. The computer simulation results accord with experimental data by the large.
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