Modified conjugated diene based polymer, manufacturing method thereof, binder composition for solid propellant comprising the same, modified conjugated diene based binder for solid propellant, and manufacturing method thereof

A modified conjugated diene based polymer comprising:

• a conjugated diene based monomer-derived repeating unit;
• and
• a chain extender-derived part which is linked to both terminals of the conjugated diene based monomer-derived repeating unit, respectively, includes one or more urethane groups in a molecular chain, and has different functional groups at both terminals, wherein one of the functional groups is an alkyne group,
• wherein a terminal of the chain extender-derived part which is not linked to both terminals of the conjugated diene based monomer-derived repeating unit is an alkyne group,
• wherein the chain extender-derived part is formed from a chain extender having an alkyne group at one terminal and an isocyanate group at the other terminal, and
• bonded to the isocyanate group of the chain extender by reacting with hydroxyl groups at both terminals of the conjugated diene based monomer-derived repeating unit.