Study On Properities And Application Of GAP Binder Systems Modified By HTPE

Insensitive propellant is an important direction and active demand of weapon equipment development. In general, insensitive property and high energy are contradictory. It’s important content that how to improve the energy level and the insensitive property at the same time in solid propellant research field. As the typical representative of energetic binders, Glycidyl azide polymer(GAP) has become a research focus in high energy insensitive solid propellant for most countries. However, the difficulties to improve mechanical property have become one of main factors to hinder the wide application of GAP based solid propellant. Therefore, this article designed a GAP binder system modified by HTPE through introducing hydroxyl terminated blocked co-polyether(HTPE) into GAP binder system, and optimized the properties. On this basis, GAP/HTPE/N100 binder system was applied into high energy insensitive solid propellant to gain the formulation of a high energy insensitive propellant with solid content of 80%, theoretical specific impulse of 270 s and density of 1.8g·cm-3. The mechanical property and processing property was optimized and the buring property and safety performance of GAP propellant was characterized. The main content and results are as follows:(1) The GAP binder system modified by HTPE was designed. The effect of R value, mGAP/mHTPE and the content of T12 catalyst on curing property of GAP/HTPE/N100 binder system was researched through dynamic DSC. The research results discovery that, as the increasement of R value at the range of 1.1~1.9, the apparent activation energy Ea of the binder system increased at first and then decreased; as the decrease of mGAP/mHTPE at 9/1~7/3, Ea remained essentially constant at first and then decreased; as the increasement of the content of T12 catalyst at 0.1%~0.7%, Ea decreased gradually. The research also shows that the variation of these factors has little effect on the curing reaction mechanism of GAP/HTPE system.(2) The effect of R value, mGAP/mHTPE and the ratio of plasticizer to binder on the mechacinal properties of cuired film of GAP/HTPE binder system. The research discovers that, the optimal mechanical properties of the formulation with R value of 1.4, mGAP/mHTPE of 7/3 and no plasticizer are ζm=1.55 MPa and εb=151.33%. This article characterized the crosslinking network structure parameters, and the change of these parameters is consistent with that of the mechacinal properties.(3) The processing properties of GAP propellant slurry were optimized. The effect of the content of catalyst on the pot life of propellant slurry and the effect of particle gradation of AP and the bonding agent on the viscosity and leveling property was researched. The research discoveried that, the pot life of the propellant slurry with 0.15%T12(concentration of 0.5%) + 0.45%TPB(concentration of 0.5%) is about 6.5h. When the content of AP-I and AP-III was 30% and 12% respectively, the processing properties were optimal. The research also found that, the bonding agent MAPO can improve the processing properties of slurry, while T313 can significantly increase viscosity and yield value and make the processing poor.(4) The mechanical properties of GAP propellant were optimized. The effect of particle gradation of AP and the bonding agent, R value and the content of N100 and NC on the mechanical properties of GAP propellant was researched. Finally, the formulation of the propellant with the optimal mechanical properties, the parameters of which are as follows: R value of 1.5, the ratio of plasticizer to binder of 1.4, NN100 of 0.6, the content of NC of 0.5%, mGAP/mHTPE of 8/2, AP-I of 20% and AP-III of 22%. The optimal machenical property is that the tensile strength is 0.52 MPa and the elongation is 13.22%.(5) The burning property and safety performance of GAP propellant was characterized. The buring property test shows that PbCO3 can decrease the buring rate pressure exponent. The safety performance test shows that, under the condition that the swing angle of the pendulum was 66 degree, the explosion probability was 52% in friction sensitivity test and When the drop hammer weighted 2kg, and the drop height was 25 cm impact sensitivity test, the explosion probability is 52%. Beside, GAP propellant passed the slow cook-off tests and fast cook-off tests.