Accession Number : ADD006333

Title :   Solubility of NPGA in a Polyurethane Binder.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE ARMY WASHINGTON DC

Personal Author(s) : Cucksee,Marjorie T ; Allen,Henry C

Report Date : 05 Dec 1978

Pagination or Media Count : 6

Abstract : A method of mixing poly(neopentylglycol)azelate (NPGA) is disclosed which enhances its solubility in polyurethane binders for composite solid propellants. The method comprises withholding the addition of NPGA from the propellant submix and from the total propellant formulation mixing procedure until after the addition of the curing agent has taken place and reaction has taken place for a predetermined period of time with the bonding agent until a 'break' in viscosity occurs. The 'break' in viscosity has taken place when the other binder ingredients have reacted with the curing agent HDI (hexamethylenediisocyanate) so that immiscibility between the binder ingredients is reduced. The late NPGA addition method resulted not only in apparently complete solubilization of the NPGA but also yielded a propellant with dramatically lower end of mix viscosity (reduced by a factor of 10), superior flow characteristics, and better physical properties. Propellants made by the disclosed method of mixing have desirable lower modulus and higher tensile strength. Thus, the propellant mixed in accordance with the late NPGA addition method yields a propellant with a high tensile strength to modulus ratio. The high tensile strength to modulus ratio at low temperature is an indicator of a good propellant. (Author)

Descriptors :   *Patents, *Solid propellants, *Solid rocket propellant binders, *Composite propellants, Solubility, Polyurethane resins, Propylene glycol, Mixing, Formulations(Chemistry), Curing, Viscosity, Tensile strength, High strength

Subject Categories : Organic Chemistry
      Plastics
      Solid Rocket Propellants

Distribution Statement : APPROVED FOR PUBLIC RELEASE