Micro-phase Segregation in Segmented Polyurethane for Blast Protection Applications

Abstract

The bomb has long been a favored weapon of terrorists, political dissidents, criminals and others intent on killing people, destroying property or disrupting operations. Since the Khobar Towers bombing in Dhahran Saudi Arabia in June 1996, the world has focused on improving their ability to combat terrorism. Research organizations are studying ways to improve a building’s resistance to bomb blast effects. Nine eleven (destruction of world trade center on 11th Sep 2001 in USA) make it the basic necessity and then many terrorist attacks on the buildings all over the world changes this need to demand. An industry of anti-blast materials is therefore, being established in the developed countries of the world.

Pakistan also faced terrorism after nine eleven and thousands of people have been killed and injured in these attacks. Many buildings are seriously damaged like the GPO and FIA offices (11 March 2008) in Lahore and attacks on Marriott hotel, Islamabad (20th sep 2008), Blasts in Manawa Police Academy (30th March 2009), Rescue 15 Building blast (27th May 2009) and blast in PC hotel Peshawar (10th June 2009) led to increase the need of making anti blast materials for the protection of military as well as civilian buildings.

Protective structures over the years have relied on distance and mass for protection. Defenders have used guards, fences, walls, ditches, hills, moats and other barriers to keep potential threats at safe distances but all such barriers are only impact resistive during bomb explosion they usually failed. Keeping in view the need, the anti-blast material is prepared and tested. Castor oil and Hydroxyl terminated polybutadiene (HTPB) based Polyurethane samples are prepared with isophorone diisocyanate (IPDI) as hard segment while castor oil and HTPB as soft segments. Hexane and Butane diols are used as chain extenders. The microphase segregation as well tensile strength, Modulus and Tg of all samples are studied with UTM and DMTA analysis. Both castor oil and HTPB samples are compared as well. HTPB samples show high tensile strength, lower Tg without sacrificing the elongation values.