It was also confirmed by taking HTPB prepolymer
only in 50% HNO3 and heated under reflux for 3 h which resulted
in a light yellow colour of precipitate and no clear solution was
obtained, further confirms that it is polyurethane that breaks into
smaller molecules and remains soluble in water as liquid fertilizer
not HTPB, hence, degradation of HTPB does not arise.