Polymer-gelled propellant and method for its production

Abstract

A liquid propellant is converted to a gelled propellant by use of a nanogellant material having a three-dimensional polymeric structure that either is formed in the propellant itself, or is formed separately from the propellant and later dispersed in the propellant. In one form of the invention, the nanogellant material is bis-trimethoxysilylethane (BTMSE), which, when mixed with a suitable liquid propellant, such as monomethyl hydrazine (MMH), in the presence of water, polymerizes to form a gelled propellant with desirable properties. In the other form of the invention, the nanogellant is polymerized in a solvent separate from the propellant, and is then recovered from the solvent and redispersed in the propellant.

Description

BACKGROUND OF THE INVENTION [0001] This invention relates generally to rocket propellants and, more particularly, to gelled propellants. It is well known in the field of rocket propulsion that gelled propellants offer significant advantages over solid and liquid propellants. Solid propellants have inherently high energy but offer no mission flexibility because once ignited they must normally be burned to completion. Liquid propellants are less energetic than solids, as measured by specific impulse, but offer high mission flexibility because the flow of liquid fuels can be controlled as desired. Gels combine the advantages of solids and liquids and have additional advantages that are well known to designers of rocket engines for use both in space and within a planet's atmosphere. [0002] Although the advantages of gelled propellants are widely appreciated, gelled propellants available prior to this invention have been produced by mixing essentially inert solids with liquids. A commonl...

AI Technical Summary

Benefits of technology

[0013] In accordance with a second embodiment of the method, the invention comprises the steps of placing a selected monomer in a reaction vessel with a selected solvent; polymerizing the selected monomer in the reaction vessel, to produce a nanogellant polymer in solution with the selected solvent; recovering the nanogellant polymer from the solvent by a process that utilizes solvent processing or drying methods that effectively reduce or eliminate liquid surface tension during solvent removal and recovery of dry nanogellant materials. These methods include: use of surfactants, freeze drying or solvent sublimation, and super-critical or near critical point fluid processing; and dispersing the recovered nanogellant polymer in a selected propellant to form a gelled propellant. In this embodiment of the method, the selected monomer may be bis-trimethoxysilylethane (BTMSE) and the propellant may be monomethyl hydrazine (MMH). However, the propellant may also be selected from other liquids, such as other forms of hydrazine and such as cryogenic liquid fuels, including liquid propane or liquid ethane.

Problems solved by technology

Solid propellants have inherently high energy but offer no mission flexibility because once ignited they must normally be burned to completion.

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