Ablation and fire-retardant properties of hydroxyl-terminated polybutadiene-based polyurethane-g-polyhedral oligomeric silsesquioxane composites

Abstract

This study examined the ablation and flammability of hydroxyl-terminated polybutadiene-based polyurethane composites grafted by polyhedral oligomeric silsesquioxane (HTPB-based PU- g-POSS) that were prepared by a one-step PU reaction using the HTPB prepolymer, two types of reactive POSS diol, and isophorone diisocyanate. The ablation property was measured using an oxyacetylene torch, and the ablation rate and relative ablation resistivity were evaluated. The results show that POSS molecules incorporated chemically into the HTPB-based PU matrix make a positive contribution to the ablative resistance. POSS molecules in the HTPB-based PU composites exhibited distinct microphase separation, aggregating into a spherical shape on the nanometer scale. This morphology of the POSS domain in the HTPB-based PU matrix leads to the formation of densely accumulated spherical silica (SiO2) droplets on the top of the ablated surface of materials under thermally oxidative conditions during ablation, resulting in improved ablation resistance compared with pristine HTPB-based PU. This unique SiO2-forming ability of POSS molecules can also enhance the flame-retardant behavior of the composites, as illustrated by the limited oxygen index and cone calorimeter measurements.

Hybrid nanocomposites of elastomeric polyurethane containing halloysite nanotubes and POSS nanoparticles: tensile, hardness, damping and abrasion performance

“…In numerous studies, POSS was used effectively as a chain extender for the replacement of partial diol monomer at polymerization stage of polyurethane (Lewicki et al, 2014;Liu & Zheng, 2005;Lopes et al, 2012;Mahapatra et al, 2012;Markovic et al, 2013;Zhang et al, 2006;Zhang et al, 2011;Zhao et al, 2019). Moreover, POSS promotes flame retardancy (Bourbigot et al, 2009;Kavuncuoglu et al, 2019;Kim et al, 2014;Michalowski & Pielichowski, 2018), self-healing (ehera et al, 2018;Diao et al, 2015), scratch protection (Ghermezcheshme et al, 2015;Lai et al, 2009), thermal shielding (Carmo et al, 2014;Janowski & Pielichowski, 2008;Kannana et al, 2006;Liu et al, 2015;Pagacz et al, 2018;Spoljaric & Shanks, 2012;Szolyga et al, 2018;Zaharescu et al, 2018), hydrogel formation (Mather et al, 2006;Wu et al, 2010), drug releasing stent coating (Guo et al, 2009;Huitron-Rattinger et al, 2013) and thin film applications (Blattmann & Mulhaupt, 2016;Madbouly & Otaigbe, 2009;Oaten & Choudhury, 2005) as it was incorporated with polyurethane networks.…”

Ablative Properties of Polyurethanes Reinforced with Organoclay

“…The incorporation of carbon nanotubes and carbon nanofibers on polymeric matrix showed improvements on thermal properties of materials . Han et al analyzed the effect of polyhedral oligomeric silsesquioxane (POSS) molecules into the PU matrix on ablation resistance under the oxyacetylene torch test.…”

Influence of different crosslinking mixtures on the mechanical properties of composite solid rocket propellants based on HTPB

“…1 –3 From the physical and chemical point of view, PU has several applications in the military and civilian fields. 4,5 PU is compatible with the traditional oxidizers and other materials under standard conditions of storage. As it basically has hydrogen and carbon, it decomposes throughout combustion to increase the rocket motor specific impulse by producing high amounts of stable compounds, such as carbon monoxide, carbon dioxide, and water vapors.…”