Date

2016

Author

Eşiyok, Hacı

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The present study was aimed at investigating the effects of isocyanate, chain extender and curing catalyst types on the mechanical, structural and thermal properties of Hydroxyl Terminated Polyether (HTPE) based gumstock samples and the effects of oxidizer, energetic plasticizer, and ballistic modifier types on the ballistic and thermal properties of propellant samples. HTPE based polyurethane networks were synthesized by hand mixing and applying vacuum for degassing of resulting mixtures. After curing, they were characterized in terms of mechanical (Uniaxial tensile test, hardness test), structural (Swelling test, X-ray diffraction) and thermal (Differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA), vacuum stability) properties. Propellant samples were prepared by incorporating energetic components like oxidizer, energetic plasticizer, burning rate catalyst to HTPE based elastomers in a 1-pint size vertical mixer. The linear burning rates of the propellant samples were measured by a Crawford bomb with respect to pressure. They were also characterized by DSC, TGA, and vacuum stability tester for thermal properties. Hazard classifications were made by impact and friction sensitivity tests. The smoke classification of propellants was carried out according to the STANAG 6016. A larger scale candidate propellant namely propellant 091 was prepared in an APV BAKER 1 galon mixer. The mechanical, ballistic, thermal and safety properties were determined by procedures as in the case of polyurethane and propellant samples. The ultimate tensile strength, elongation at break and Young’s modulus were obtained as 0.80 MPa, 41.2% and 0.76 MPa, respectively, at 25oC. Glass transition temperature was determined as about -61oC. The propellant showed two stages decomposition pattern with exothermic peaks at about 240 oC and 320oC. The burning rate was calculated as 15 mm/s at 6.89 MPa with a pressure exponent below 0.5 between the 6.9-13.8 MPa pressure range. The shelf life of propellant developed was estimated by means of a microcalorimeter. It was said to be chemically stable for 10 years at 25oC.  

Subject Keywords

Propellants., Polyethers., Hydroxyl group.

URI

http://etd.lib.metu.edu.tr/upload/12620613/index.pdf
https://hdl.handle.net/11511/26152

Collections

Graduate School of Natural and Applied Sciences, Thesis