Ultra-high burn rate gun propellants

Abstract

 A family of ultra-high burn rate gun propellant systems based upon a nitrocellulose binder matrix, and containing a variety of azide components to provide formulations having reduced isochoric flame temperatures and ultra-high mass consumption rates.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] This invention relates to propellants and is particularly directed to gun propellant formulations containing azido nitramines in conjunction with carboranes, to provide reduced isochoric flame temperatures and ultra-high mass consumption rates.

2. Description of Related Art

[0002] Various propellant formulations have evolved over the years in response to requirements for improved gun propellant compositions which impart high velocity and penetrability to associate projectiles. For modern applications, mass impetus levels approaching 450,000 ft-lb_f/lb_m or greater are desired. Such ultra-high force propellants have heretofore been dispossessed of the desirable combination of reduced isochoric flame temperatures and ultra-high mass consumption rates.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION

[0003] The aforementioned disadvantages associated with known gun propellants are obviated by the present invention which encompasses a family of ultra-high burn rate gun propellants having acceptable impetus levels and lowered isochoric flame temperatures.

[0004] The advantages of the present invention are realized in propellant formulations utilizing a combination of select azide compounds and additives in a nitrocellulose binder matrix.

[0005] Accordingly, an object of the present invention is to provide improved propellants.

[0006] Another object of the present invention is to provide gun propellants having flame temperatures which are lower than those of current propellants, while yielding comparable or greater mass impetus.

[0007] These and other objects and features of the present invention will be apparent from the following detailed description.

[0008] FIG. 1 graphically compares the burn rates of propellant compositions according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0009] The propellants of the present invention are characterized by the utilization of highly energetic azido compounds and select plasticizers in a nitrocellulose matrix. Preferred energetic compounds which may be used in the gun propellant formulations include the cyclic nitramine 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 1,7-diazido-2,4,6-trinitrazaheptane (DATH) and mixtures thereof. The preferred plasticizers to be utilized are selected from 1,5-diazido-3-nitrazapentane (DANPE) or carbornylmethylpropinate (CMP) and mixtures thereof.

[0010] Propellant compositions having reduced isochoric flame temperatures and high mass impetus, prepared in accordance with the present invention, are set forth in the table below wherein M-9 corresponds to Military Specification No. MIL-P-20306.

TABLE

WEIGHT PERCENT					lm	Tv
NC(12.6%N)	DANPE	CMP	RDX	DATH	(J/G)	(°K)
24	0	6	70	0	1295	3601
24	3	3	35	35	1338	3692
24	3	3	-	70	1355	3651
18	6	6	-	70	1339	3515
24	-	6	-	70	1325	3526
24	6	-	-	70	1382	3790
M-9 (REFERENCE)					1175	3869

[0011] FIG. 1 is a graphic comparision of the burn rates in centimeters per second at 65 megapacals of various propellant formulations according to the instant invention. In FIG. 1, oxidizer 1 comprises 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), oxidizer 2 comprises a blend of fifty percent each RDX and 1,7-diazido-2,4,6-trinitrazaheptane (DATH) and oxidizer 3 comprises DATH. As shown, for example, with respect to the formulations above oxidizer 1, wherein DOP comprises dioctylphthalate and DANPE is 1,5-diazido-3-nitrazapentane, the first formulation comprises 6 wt. percent DOP, 24 wt. percent nitrocellulose (NC) and 70 wt. percent oxidizer which in this formulation is oxidizer 1 or RDX. In each formulation reference is made to the legend in the upper left hand corner of FIG. 1. As shown by FIG. 1, the novel compositions making up the propellant formulations of the present invention are a clear advancement over comparable formulations known in the art.

[0012] Obviously, numerous varifications and modifications may be made without departing from the present invention. Accordingly, it should be clearly understood that the forms of the present invention described above are not intended to limit the scope of the present invention.

Claims

1. A composition of matter comprising a nitrocellulose binder matrix and a compound selected from the group consisting of 1,5-diazido-3-nitrazapentane; carbornylmethylpropinate;
1,3,5-trinitro-1,3,5-triazacyclohexane;
1,7-diazido-2,4,6-trinitrazaheptane, and mixtures thereof.

2. A composition of matter comprising:

(a) about 24 wt% nitrocellulose binder;

(b) about 6 wt% carbornylmethylpropinate; and

(c) about 70 wt% 1,3,5-trinitro-1,3,5-triazacyclohexane.

3. A composition of matter comprising:

(a) about 24 wt% nitrocellulose binder;

(b) about 3 wt% 1,5-diazido-3-nitrazapentane;

(c) about 3 wt% carbornylmethylpropinate;

(d) about 35 wt% 1,3,5-trinitro-1,3,5-triazacyclohexane; and

(e) about 35 wt% 1,7-diazido-2,4,6-trinitrazaheptane

4. A composition of matter comprising:

(a) about 24 wt% nitrocellulose binder;

(b) about 3 wt% 1,5-diazido-3-nitrazapentane;

(c) about 3 wt% carbornylmethylpropinate; and

(d) about 70 wt% 1,7-diazido-2,4,6-trinitrazaheptane.

5. A composition of matter comprising:

(a) about 18 wt% nitrocellulose binder;

(b) about 6 wt% 1,5-diazido-3-nitrazapentane;

(c) about 6 wt% carbornylmethylpropinate; and

(d) about 70 wt% 1,7-diazido-2,4,6-trinitrazaheptane.

6. A composition of matter comprising:

(a) about 24 wt% nitrocellulose binder;

(b) about 6 wt% carbornylmethylpropinate; and

(c) about 70 wt% 1,7-diazido-2,4,6-trinitrazaheptane.

7. A composition of matter comprising:

(a) about 24 wt% nitrocellulose binder;

(b) about 6 wt% 1,5-diazido-3-nitrazapentane; and

(c) about 70 wt% 1,7-diazido-2,4,6-trinitrazaheptane.

8. A gun propellant according to Claim 1.

9. A gun propellant according to Claims 2,3,4,5,6,7, or 8.

Drawing