Increasing burning rate of solid propellants by electric field effects

Claim 1

A method for increasing the burning rate of solid propellants as well as correcting for the anisotropy of burning rate in propellants which contain metal fuel and a metal burning rate promoter selected from metal staples and metal flakes, said method comprising: (i) providing a solid propellant composition comprised of a blended oxidizer of ammonium perchlorate of about 180 mμ particle size and ultrafine ammonium perchlorate of about 1 mμ particle size, aluminum powder metal fuel, aluminum metal burning rate promoter selected from aluminum staple and aluminum flake, a burning rate catalyst of n-hexylcarborane, and a hydroxylterminated polybutadiene binder which includes the additives of a bonding agent which is the reaction product of equimolar quantities of 12-hydroxylstearic acid and tris(2-methylaziridinyl)phosphine oxide, trimethylolpropane crosslinking agent, triphenylbismuthine quick cure catalyst, and isophorone diisocyanate curing and crosslinking agent; (ii) placing said solid propellant composition in electrical contact with electrodes which are connected to a direct current power source; (iii) applying a direct-current voltage from about 40 to about 120 volts to said solid propellant composition; (iv) allowing said voltage to pass through said solid propellant composition for a predetermined time period from about two days to about eight days; and, (v) disconnecting said direct current power source and electrodes from said solid propellant composition, said solid propellant composition characterized by having an increased burning rate as well as a corrected anisotropy of burning rate when compared with a control solid propellant composition having a like composition but to which no direct current voltage was applied.

Claim 2

A method for increasing the burning rate of solid propellants as well as correcting for the anisotropy of burning rate in propellants which contain metal fuel and a metal burning rate promoter selected from metal staples and metal flakes, said method comprising: (i) providing a solid propellant composition comprised of a blended oxidizer of ammonium perchlorate of about 180 mμ particle size and ultrafine ammonium perchlorate of about 1 mμ particle size, aluminum powder metal fuel, aluminum metal burning rate promoter selected from aluminum staple and aluminum flake, a burning rate catalyst of n-hexylcarborane, and a hydroxylterminated polybutadiene binder which includes the additives of a bonding agent which is the reaction product of equimolar quantities of 12-hydroxylstearic acid and tris(2-methylaziridinyl)phosphine oxide, trimethylolpropane crosslinking agent, triphenylbismuthine quick cure catalyst, and isophorone diisocyanate curing and crosslinking agent; (ii) placing said solid propellant composition in electrical contact with electrodes which are connected to a direct current power source; (iii) applying a direct-current voltage from about 40 to about 120 volts to said solid propellant composition; (iv) allowing said voltage to pass through said solid propellant composition for a predetermined time period from about two days to about eight days; and, (v) disconnecting said direct current power source and electrodes from said solid propellant composition, said solid propellant composition characterized by having an increased burning rate as well as a corrected anisotropy of burning rate when compared with a control solid propellant composition having a like composition but to which no direct current voltage was applied.