Effect of Phthalate Plasticizers Existance in Ethyl Cellulose Insulators and Ethyl CelluloseSilica Nanocomposite on the Nitroglycerin Migration from a Double Base Propellant

In this research, the effect of phthalate plasticizers in ethyl cellulose and ethyl cellulosesilica composite was investigated on the nitroglycerin migration from a double base propellant. In this manner, first different insulator and nanocomposite samples containing 10, 15 and 20 phr of diethyl phthalate, dibutyl phthalate and bis 2-ethylhexyl phthalate were prepared and then the double base propellant was examined under migration test by sandwich method. Changes in sample weight (as migration criteria) for significant times were determined and then nitroglycerine amounts were measured by liquid chromatography (HPLC) technique. The results showed that with increasing of the amount of plasticizer from 10 to 20 phr, in sample containing diethyl phthalate, the insulator weight was increased from 14.14 to 15.98 percent and nitroglycerin amount was added from 12.67 to 14.74 percent. Also in the sample containing dibutyl phthalate, the weight gain was increased from 19.61 to 25.86 and nitroglycerin amount was added from 14.56 to 19.86 percent. In follows, use of bis 2-ethylhexyl phthalate with 10phr concentration in the insulator showed the increased weight and nitroglycerin amount of 31.89 and 25.23 percent respectively. Furthermore with increasing of diethyl phthalate concentration from 10 to 20 phr in ethyl cellulosesilica nanocomposite (involving 0.5 phr silica with an average particle size of 12 nanometer), the weight gain and nitroglycerin is nearly constant, but at ethyl cellulose dibutyl phthalatesilica composite the insulator weight was increased from 21.48 to 26.95 percent and nitroglycerin amount was added from 16.27 to 21.30 percent.