Rheological behaviors and structural dynamics of HTPB pasty propellant gelled by PEO-PPO-PEO block copolymer/ultra SiO 2

new promising HTPB pasty propellant was designed and prepared using PEO-PPO-PEO block copolymer and ultra SiO 2 as gelators. Then the gelling mechanism and rheological behaviors of this slurry were respectively studied through molecular simulation and rheological tests, further, an improved constitutive model for the slurry was proposed. Results show that the gels in slurries are formed by the hydrogen bondings between gelators and binder, and micellization of the block copolymer. The characteristics of shear thinning and creep-recovery were found in slurries in the rheological tests, viscosity of the slurry containing more block copolymer is insensitive to shear rate ( γ̇ ), moreover, this slurry has higher deformation in the creep process and greater elastic recovery during unloading. The improved structural dynamic model was built by introducing the structural coefficient ( λ ) related yield stress ( τ y ) and plastic viscosity ( μ p ) into the structural equation, it can describe the relaxation and thixotropic behaviors of slurry well. Graphical Abstract We designed and prepared a new promising HTPB pasty propellant using the PEO-PPO-PEO block copolymer and ultra SiO 2 as gelators. Moreover, the gelling mechanism and rheological behaviors of these pasty slurries were explored through theoretical and experimental techniques. Remarkably, we established a dynamic model considering the variation of micro structures for this fuel.