Poly (glycidyl nitrate) is a more energetic materials than poly (NMMO) and preferred in many propellant formulations. Although the poly (glycidyl nitrate) prepolymer has a satisfactory shelf life, the ageing characteristics of isocyanate-cured materials is not satisfactory.
Investigations indicated that the instability of the urethane link is probably due to an intramolecular rearrangement.
This paper describes a modification of the prepolymer ends, thus changing the molecular environment of the urethane linkages.
After the initial polymerization of glycidyl nitrate, appropriate second monomer, ethylene oxide was added to the chain ends.
End-capped Poly (glycidyl nitrate) with ethylene oxide has been crosslinked with isocyanate to give cured rubbers of acceptable long term stability compared to the original poly(glycidy nitrate).