Compatibility of Glycidyl Azide Polymer with Hydroxyl Terminated Polybutadiene and Plasticizers

Glycidyl azide polymer (GAP) finds application in a number of energetic material formulations due to many positive attributes. GAP is also one of the most thoroughly studied energetic polymers for application as a solid propellant binder. A large volume of literature is available on the synthesis of GAP and its different derivatives. Detailed studies on the thermal, mechanical, and combustion characteristics of GAP and GAP based formulations are reported in the literature. The use of GAP in composite propellant formulations could considerably improve the processability and performance parameters. However, due to the presence of polar azido groups in the polymer backbone, GAP could have compatibility problems with other ingredients such as hydroxyl terminated polybutadiene (HTPB) and plasticizers used in composite solid propellants. GAP and HTPB are not miscible and phase separation occurs when a mix of pure GAP and HTPB is kept undisturbed for a while after dispersion. The authors had shown that the blends of the two polymers with specific concentration levels could be prepared without phase separation. Also in a previous work, the authors had presented the results of thermomechanical and morphological investigation of the blends.