Preparation of nitrocellulose gel based on phase separation in ternary system and study on its dynamic rheological characteristics

The nitrocellulose (NC) gels were prepared from a ternary system NC/acetone/ethanol by solvent evaporation induced phase separation. The response degrees of the gel to external stimuli (such as strain, frequency, temperature) were investigated by linear rheological methods. Dynamic rheological characteristics of NC gels were studied. Results show that the final morphologies of NC gels are influenced by mass ratios of the initial solvent/non-solvent (acetone/ethanol) and NC contents. The effect of changing initial acetone/ethanol ratios on the dynamic rheological characteristics of the NC gels is different from the effect of changing NC contents. With increasing the acetone content, the volume of the NC gel prepared decreases, the NC content in the gel increases, the storage modulus (G') and loss modulus (G″) of NC gels increase as well as the critical strain value (γ_c) decreases with increasing the NC content in the gels, whereas the value of G' and G″ first increase and then decrease with increasing the NC content in the gels when the mass ratio of acetone/ethanol is 2:3. The values of G' and G″ of all NC gels over the entire temperature scanning are basically unchanged, indicating that the interactions among NC chains and between NC/solvent can not be disrupted upon heating to higher temperatures.