Influences of NCO/OH and triol/diol Ratios on the Mechanical Properties of Nitro-HTPB Based Polyurethane Elastomers

Document Type: Research Article


Department of Chemistry and Chemical Engineering, Faculty of Chemistry, Malek-Ashtar University of Technology (MUT), Tehran, I.R. IRAN


The present study describes the effect of NCO/OH and triol/diol ratios on the mechanical properties of Nitro functionalized Hydroxyl-terminated polybutadiene (Nitro-HTPB) elastomers. The progress of the cure reaction of Nitro-HTPB and toluene diisocyanate (TDI) is evaluated by following up the variations in the IR absorption bands of the NCO stretching and the CO Stretching. Experiments are carried out at NCO/OH ratios (R values) ranging from 0.8 to 1.2 and triol/diol ratios in the range of 0.05-0.7. Also as the R-value increases, the tensile strength increases, and elongation decreases. The rubbery character of elastomers is improved followed by increased rigidity with an increase in triol/diol value of 0.05. In general, desirable mechanical properties were achieved for the polyurethane elastomers of Nitro-HTPB as a novel energetic binder.


Main Subjects

[1] Gopala Krishnan P.S., Ayyaswamy K., Nayak S., Hydroxy Terminated Polybutadiene: Chemical Modifications and Applications, J. Macromol. Sci. Part A, 50(1): 128-138 (2013).

[2] DeLuca L., Galfetti, L., Maggi F., Colombo G., Merotto L., Boiocchi M., Paravan C., Reina A., Tadini P., Fanton L., Characterization of HTPB-Based Solid Fuel Formulations: Performance, Mechanical Properties, and Pollution, Acta Astronaut., 92(2): 150-162 (2013).

[3] Agrawal J.P., Recent Trends in High-Energy Materials, Prog. Energ. Combust. 24(1): 1-30 (1998).

[4] Colclough M.E., Desai H., Millar R.W., Paul N.C., Stewart M.J., Golding P., Energetic Polymers as Binders in Composite Propellants and Explosives, Polym. Advan. Technol. 5(9): 554-560 (1994).

[5] Badgujar D., Talawar M., Asthana S., Mahulikar P., Advances in Science and Technology of Modern Energetic Materials: an Overview, J. Hazard. Mater. 151(2): 289-305 (2008).

[6] Chien J., Kohara T., Lillya C., Sarubbi T., Su B.H., Miller, R., Phase Transfer‐Catalyzed Nitromercuration of Diene Polymers, J. Polym. Sci. 18(8): 2723-2729 (1980).

[7] Abdullah M., Gholamian F., Zarei A., Investigation of Composite Solid Propellants Based on Nitrated Hydroxyl-Terminated Polybutadiene Binder, J. Propul. Power. 30(3): 862-864 (2014).

[8] Colclough M., Paul N., Nitrated Hydroxy-Terminated Polybutadiene: Synthesis and Properties, Am. Chem. Soc. 623: 97-103 (1996).

[9] Wang Q., Wang L., Zhang X., Mi Z., Thermal Stability and Kinetic of Decomposition of Nitrated HTPB, J. Hazard. Mater. 172(2): 1659-1664 (2009).

[10] Sankar R.M., Roy T.K., Jana T., Functionalization of Yerminal Varbon atoms of Hydroxyl Terminated Polybutadiene by Polyazido Nitrogen Rich Molecules, Bull. Mater. Sci. 34(4): 745-754 (2011).

[11] Gross M.L., Hedman T.D., Son S.F., Jackson T.L., Beckstead, M.W., Coupling micro and Meso-Scale Combustion Models of AP/HTPB Propellants, Combust. Flame 160(5): 982-992 (2013).

[12] Nagamachi M.Y., Oliveira J.I.S., Kawamoto A.M., Rita de Cássia L.D., ADN - The New Oxidizer Around the Corner for an Environmentally Friendly Smokeless Propellant, J. Aerosp. Technol. Manag. 1(2): 153-160 (2011).

[13] Shekhar Pant C., Santosh M.S., Banerjee S., Khanna P.K., Single Step Synthesis of Nitro‐Functionalized Hydroxyl‐Terminated Polybutadiene, Propell. Explos. Pyrotech. 38(6): 748-753 (2013).

[14] Abusaidi H., Ghaieni H.R., Pourmortazavi S.M., Motamed-Shariati S.H., Effect of Nitro Content on Thermal Stability and Decomposition Kinetics of Nitro-HTPB, J. Therm. Anal. Calorim. 124(2): 935-941 (2016).

[15] Kumari D., Balakshe R., Banerjee S., Singh H., Energetic Plasticizers for Gun & Rocket Propellants, Rev. J. Chem., 2(3): 240-262 (2012).

[16] Li S., Vatanparast R., Lemmetyinen H., Cross-Linking Kinetics and Swelling Behaviour of Aliphatic Polyurethane, Polymer 41(15): 5571-5576 (2000).

[17] Rao K.P., Sikder A.K., Kulkarni M.A., Bhalerao M.M., Gandhe B.R., Studies on n‐Butyl Nitroxyethylnitramine (n‐BuNENA): Synthesis, Characterization and Propellant Evaluations, Propell. Explos Pyrotech. 29(2): 93-98 (2004).

[18] Standard A., “Annual Book of ASTM Standards”, American Society for Testing and Materials Annual, Philadelphia, PA, USA 4(04.08) (2004).

[21] Lapprand A., Boisson F., Delolme F., Méchin F., Pascault J.-P., Reactivity of Isocyanates with Urethanes: Conditions for Allophanate Formation, Polym. Degrad. Stabil. 90(2): 363-373 (2005).