THERMOPLASTIC COMPOSITE SOLID PROPELLANT AND PREPARATION METHOD THEREFOR

Abstract

Disclosed in the present invention is a thermoplastic composite solid propellant, which comprises, by mass: 5-16% of a thermoplastic elastomer having a bonding function; 5-25% of a plasticizer; 5-18% of a metal fuel; 50-70% of an oxidizing agent; and 0.4-5% of a functional auxiliary agent. In the thermoplastic composite solid propellant, a thermoplastic elastomer grafted or copolymerized with a bonding functional group is used as an adhesive, and an adhesive matrix and a solid filler have relatively strong interaction, such that an interfacial effect is enhanced, and the phenomenon of dehumidification in the tensile failure process can be slowed down. Further disclosed is a method for preparing the thermoplastic composite solid propellant. The method overcomes defects in the prior art, safely and efficiently prepares the thermoplastic composite solid propellant in an acoustic resonance mixing manner, and meets the requirements of a solid engine for rapid charging.

Claims

1. A thermoplastic composite solid propellant, characterized by comprising, in percentages by mass: 5% to 16% of a thermoplastic elastomer with bonding function; 5% to 25% of a plasticizer; 5% to 18% of a metal fuel; 50% to 70% of an oxidizing agent; and 0.4% to 5% of a functional auxiliary agent.

2. The thermoplastic composite solid propellant according to claim 1, characterized by that a bonding functional group or block in the bonding functional thermoplastic elastomer comprises one or more of maleic anhydride, styrene, glycidyl methacrylate, butyl acrylate, hydroxyethyl acrylate, acrylic acid and methacrylic acid.

3. The thermoplastic composite solid propellant according to claim 2, characterized by that the bonding functional group or block in the bonding functional thermoplastic elastomer has a mass percentage of 0.1 wt % to 5 wt %.

4. The thermoplastic composite solid propellant according to claim 1, characterized by that the plasticizer comprises one or more of naphthenic oil, dioctyl sebacate, liquid paraffin and dioctyl phthalate.

5. The thermoplastic composite solid propellant according to claim 1, characterized by that the oxidizing agent comprises one or more of ammonium perchlorate, ammonium nitrate, phase-stable ammonium nitrate, hexogen, octogen and 5,5-bistetrazole-1,1-dioxodihydroxylammonium salt.

6. The thermoplastic composite solid propellant according to claim 1, characterized by that the functional auxiliary agent comprises a stabilizing agent and a combustion catalyst, wherein the stabilizing agent comprises one or more of N,N-dimethylaniline, N-methylaniline and diphenylamine; and the combustion catalyst comprises one or more of n-octylferrocene, ferric oxide and copper chromite.

7. A method for preparing a thermoplastic composite solid propellant, characterized by comprising the steps of: S1: heating and melting a bonding functional thermoplastic elastomer and a plasticizer, adding a functional auxiliary agent, and mixing them uniformly; S2: adding a metal fuel and mixing them uniformly by means of acoustic resonance; and S3: add an oxidizing agent in batches and mixing them uniformly by means of acoustic resonance, to give the thermoplastic composite solid propellant.

8. The method for preparing the thermoplastic composite solid propellant according to claim 7, characterized by further comprising: pouring the prepared thermoplastic composite solid propellant into a mold, which is naturally cooled and cured for shaping.

9. The method for preparing the thermoplastic composite solid propellant according to claim 7, characterized by that the step S1 has a melting temperature of 85? C. to 95? C.

10. The method for preparing the thermoplastic composite solid propellant according to claim 7, characterized by that the step S2 has a mixing temperature of 85? C. to 95? C., an acoustic resonance strength of 30 g to 70 g, and a resonance time of 5 min to 10 min.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0032] FIG. 1 is a process flow chart of a method for preparing a thermoplastic composite solid propellant of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter the present invention is further described by specific embodiments. It should be noted that several variations and improvements can be made by persons of ordinary skills in the art without departing from the principles of the present invention, which should be considered to fall within the protection scope of the present invention.

[0034] The contents which are not described in detail in the specification of the present invention belong to well-known techniques of those skilled in the art.

[0035] The present invention discloses a thermoplastic composite solid propellant, which comprises in percentages by mass: 5% to 16% of a bonding functional thermoplastic elastomer; 5% to 25% of a plasticizer; 5% to 18% of a metal fuel; 50% to 70% of an oxidizing agent; and 0.4% to 5% of a functional auxiliary agent; wherein a sum of the mass percentages of various materials in the thermoplastic composite solid propellant is 100%.

[0036] The bonding functional thermoplastic elastomer (Bonding Functional TPE) of the present invention is obtained by grafting or copolymerizing a bonding functional group or block onto a thermoplastic elastomer, wherein the bonding functional group or block comprises one or more of maleic anhydride (MAH), styrene (St), glycidyl methacrylate (GMA), butyl acrylate (BA), hydroxyethyl acrylate (HEA), acrylic acid (AA) and methyl methacrylate (MMA), and the bonding functional group or block in the bonding functional thermoplastic elastomer has a mass percentage of 0.1 wt % to 5 wt %.

[0037] The bonding functional thermoplastic elastomer is, e.g., a maleic anhydride-grafted ethylene-vinyl acetate copolymer; and the bonding functional thermoplastic elastomer has a relative molecular mass of 21,000 to 40,000, a softening point temperature as adhesive of 85? C. to 95? C., a maximum tensile strength at 20? C. of 0.7 MPa to 4.9 MPa, and a maximum elongation at break of 485% to 1330%.

[0038] The plasticizer comprises one or more of naphthenic oil (KN), dioctyl sebacate (DOS), liquid paraffin and dioctyl phthalate; and a mass ratio of the plasticizer to the bonding functional thermoplastic elastomer is (0.6-1.55):1.

[0039] The metal fuel comprises, but is not limited to, aluminum powder (Al).

[0040] The oxidizing agent comprises one or more of ammonium perchlorate (AP), ammonium nitrate (AN), phase-stable ammonium nitrate (PSAN), hexogen (RDX), octogen (HMX) and 5,5-bistetrazole-1,1-dioxodihydroxylammonium salt (TKX-50).

[0041] The functional auxiliary agent comprises, but is not limited to, a stabilizing agent and a combustion catalyst, wherein the stabilizing agent comprises one or more of N,N-dimethylaniline (NN), N-methylaniline (NMA) and diphenylamine (NPA); and the combustion catalyst comprises one or more of n-octylferrocene, ferric oxide and copper chromite.

[0042] As shown in FIG. 1, the thermoplastic composite solid propellant is prepared by the steps of: [0043] S1: heating the bonding functional thermoplastic elastomer and the plasticizer in a high-shear dispersing emulsifier (but not limited hereto) to 85? C. to 95? C. for melting, adding a functional auxiliary agent, and then mixing them uniformly; [0044] S2: transferring the uniformly mixed materials to an acoustic resonance mixer, adding a metal fuel, and mixing them uniformly by means of acoustic resonance for 5 min to 10 min at a mixing temperature of 85? C. to 95? C. and a resonance strength of 30 g to 70 g; and [0045] S3: adding a certain amount oxidizing agent in batches to the above materials, and mixing them uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant.

[0046] Further, in an embodiment, the method further comprises pouring the thermoplastic composite solid propellant into a mold, which is naturally cooled, cured for shaping, and then stored. During charging, a square billet (shaped by curing of the thermoplastic composite solid propellant) is melted and poured into an engine shell for shaping, or loading the square billet into the engine shell and then melt and shaped, wherein a heating temperature during charging is 95? C. to 100? C.

[0047] The prepared thermoplastic composite solid propellant is characterized as follows: [0048] 1) Mechanical properties: the maximum tensile strength, ?.sub.b, and the elongation at break, ?.sub.m, of the mechanical properties are measured under the testing conditions of 20? C. and 100 mm/min with reference to GJB 770B-2005; [0049] 2) Density: the density is measured under the test conditions of 20? C., g/cm.sup.3 with reference to QJ 917A-97; and [0050] 3) Theoretical specific impulse.

Example 1

[0051] Materials were weighed according to the formula in Table 1. The bonding functional thermoplastic elastomer (Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 90? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 90? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 50 g for a resonance time of 5 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00001 TABLE 1 Formula and Properties of The Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt Bonding Functional TPE 8.55 KN 6 DOS 2 Al 18 AP 59 AN / PSAN / RDX 6 NPA 0.1 n-octylferrocene 0.35 Maximum Tensile Elongation Sample Test Test Strength at Break Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 1.62 25.5 Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.71 Theoretical 20? C., 6.86 MPa, s 261.977 Specific Impulse

Example 2

[0052] Various materials were weighed according to the formula in Table 2. The bonding functional thermoplastic elastomer (Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 85? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 85? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 30 g for a resonance time of 10 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00002 TABLE 2 Formula and Properties of The Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt Bonding Functional TPE 7.6 KN 7.2 DOS 1.7 Al 17 AP 59 AN 7 PSAN / 5,5-bistetrazole-1,1- / dioxodihydroxylammonium salt RDX / NN 0.1 n-octylferrocene 0.4 Sample Test Test Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 1.57 23.8 Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.696 Theoretical 20? C., 6.86 MPa, s 259.975 Specific Impulse

Example 3

[0053] Materials were weighed according to the formula in Table 3. The bonding functional thermoplastic elastomer (Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 85? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 90? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 70 g for a resonance time of 5 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00003 TABLE 3 Formula and Properties of The Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt Bonding Functional TPE 9.94 KN 9.5 Al 17 AP 51 AN / PSAN 8 5,5-bistetrazole-1,1- / dioxodihydroxylammonium salt HMX 4 NMA 0.16 Fe.sub.2O.sub.3 0.4 Sample Test Test Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 1.29 36.6 Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.657 Theoretical 20? C., 6.86 MPa, s 253.397 Specific Impulse

Example 4

[0054] Materials were weighed according to the formula in Table 4. The bonding functional thermoplastic elastomer (Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 95? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 95? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 50 g for a resonance time of 8 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00004 TABLE 4 Formula and Properties of The Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt Bonding Functional TPE 6 DOS 5.5 Al 18 AP 49 AN / PSAN / 5,5-bistetrazole-1,1- / dioxodihydroxylammonium salt RDX 21 NN 0.15 Copper Chromite 0.5 Sample Test Test Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 1.42 16.8 Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.784 Theoretical 20? C., 6.86 MPa, s 266.391 Specific Impulse

Example 5

[0055] Materials were weighed according to the formula in Table 5. The bonding functional thermoplastic elastomer (Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 95? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 95? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 50 g for a resonance time of 5 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00005 TABLE 5 Formula and Properties of Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt Bonding Functional TPE 15.2 KN 6.2 DOS 3 Al 17 AP 48 AN / PSAN 4 HMX 6 NBA 0.15 Fe.sub.2O.sub.3 0.45 Sample Test Test Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 0.86 48.3 Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.597 Theoretical 20? C., 6.86 MPa, s 246.029 Specific Impulse

Example 6

[0056] Materials were weighed according to the formula in Table 6. The bonding functional thermoplastic elastomer (Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 95? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 95? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 50 g for a resonance time of 5 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00006 TABLE 6 Formula and Properties of Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt Bonding Functional TPE 15 KN 20 DOS 5 Al 5 AP 40 AN / PSAN 4 HMX 6 NBA 1 Fe.sub.2O.sub.3 4 Sample Test Test Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 0.59 57.6% Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.382 Theoretical 20? C., 6.86 MPa, s 194.914 Specific Impulse

Comparative Example 1

[0057] Materials were weighed according to the formula in Table 7. The thermoplastic elastomer (i.e., a non-Bonding Functional TPE) and the plasticizer were put into a high-shear dispersing emulsifier and heated to 90? C. for melting. Then, a functional auxiliary agent was added and mixed uniformly. The materials were transferred to an acoustic resonance mixer, heated to 90? C., and Al was added and pre-mixed. The Al was mixed uniformly by means of acoustic resonance with a resonance strength of 50 g for a resonance time of 5 min. Then, a certain amount of oxidizing agent was added in batches, and mixed uniformly by means of acoustic resonance to give the thermoplastic composite solid propellant, which was poured into a mold, naturally cooled, and cured to give a propellant sample.

TABLE-US-00007 TABLE 7 Formula and Properties of Thermoplastic Composite Solid Propellant Composition of Formula Mass Percent/% wt TPE 8.55 KN 6 DOS 2 Al 18 AP 59 AN / PSAN / RDX 6 NPA 0.1 n-octylferrocene 0.35 Sample Test Test Properties Standards Conditions ?.sub.b/MPA ?.sub.m/% Mechanical GJB 770B- 20? C., 0.43 12 Properties 2005 100 mm/min Density QJ 917A-97 20? C., g/cm.sup.3 1.69 Theoretical 20? C., 6.86 MPa, s 259.312 Specific Impulse

[0058] It can be seen from the data in Example 1 and Comparative Example 1, the mechanical properties of the thermoplastic composite solid propellant prepared from the non-bonding functional thermoplastic elastomer (the maximum tensile strength ?.sub.b is 0.43 MPa, and the elongation at break ?.sub.m is 12%) are significantly lower than the mechanical properties of the thermoplastic composite solid propellant prepared from the bonding functional thermoplastic elastomer (?.sub.b is 1.62 MPa, and ?.sub.m is 25.5%). That is, the present invention utilizes the bonding functional group-grafted or copolymerized thermoplastic elastomer as adhesive, so that the adhesive matrix has a strong interaction with the solid filler, which can enhance the interfacial effect and improve the mechanical properties of the propellant, thereby slowing down the occurrence of dehumidification phenomenon.

[0059] The present invention has been detailedly described as above with reference to the specific embodiments and exemplary examples. However, these descriptions should not be construed to limit the present invention. It is appreciated by those skilled in the art that various equivalent substitutions, modifications or improvements can be made to the technical solutions and embodiments of the invention without departing from the spirit and scope of the invention, all of which all fall within the scope of the invention. The scope of protection of the present invention is defined by the appended claims.