Influence of the addition of aluminium nanoparticles on thermo- rheological properties of hydroxyl-terminated polybutadiene-based composite propellant and empirical modelling Rohit Lade 1 • Kailas Wasewar 1 • Rekha Sangtyani 2 • Arvind Kumar 2 • Diwakar Shende 1 • Dilip Peshwe 3 Received: 25 June 2018 / Accepted: 19 February 2019 Ó Akade ´miai Kiado ´, Budapest, Hungary 2019 Abstract Composite propellants are highly filled solid materials suspended in a polymeric binder matrix, which causes difficulties related to the processing operations. A proper understanding of rheological behaviour plays a vital role while processing the propellant. Previous studies confirm that aluminium nanoparticles (ANP) show significant improvement in burning properties. A bimodal distribution of ANP and aluminium powder was used for the present study. The quality of ANP was characterized using particle size analyser, field emission scanning electron microscopy and field emission transmission electron microscopy, and the particles were confirmed to be spherical in shape and * 100 nm in size. The present work focuses on the behaviour of viscosity of hydroxyl-terminated polybutadiene-based composite propellant containing ANP with 84% solid loading. Two different composite propellants containing 2 and 4%ANP, respectively, were prepared, and viscosity behaviour with respect to time and temperature was analysed. Presently, very few studies on rheology containing ANP have been reported. In the current study, a mathematical correlation is generated to analyse the synergistic effect of temperature, curing time and %ANP on apparent viscosity of the composite propellant. The model equation was found to fit the experimental data with an average error of ± 3%. Experimental results from previous studies are fitted in the model, and the goodness-of-fit (average error = ± 10%) is found to be better as compared to the previous model equations. The proposed mathematical model equation can be definitely utilized for designing equipments for processing propellant, quality control and process control applications. & Kailas Wasewar k_wasewar@rediffmail.com; klwasewar@che.vnit.ac.in 1 Advanced Separation and Analytical Laboratory, Department of Chemical Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, India 2 Solid Rocket Propellants Division, High Energy Materials Research Laboratory (HEMRL), Pune, India 3 Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, India 123 Journal of Thermal Analysis and Calorimetry https://doi.org/10.1007/s10973-019-08149-0