Investigation of the Effect of NCO/OH on Mechanical Properties of PBXN-109

The aim of this research is improvement of elongation at break of PBXN-109 polymer bonded explosive. Due to the great effect of isocyanate/hydroxyl ratio (r=NCO/OH) on mechanical properties of plastic bonded explosives, in this research, the samples of PBXN-109 with different r-values of 1, 0.95, 0.85, 0.75 and 0.65 were prepared and analyzed by hardness and tensile tests. The results show that sample with r-value of 0.65 does not cure, completely. Besides, with decrement of r-value, the elongation at break of PBXN-109 increases, and tensile strength and stiffness decrease. The results of elongation at break for samples containing r-values of 1, 0.95, 0.85 and 0.75 are 8.46, 10.99, 11.64 and 26.63, respectively. According to this research, PBXN-109 with the r-value of 0.8 indicates satisfactory elongation at break and tensile strength.