Isocyanate-free Carboxyl-terminated Polybutadiene and Epoxidised Hydroxyl-terminated Polybutadiene Cross-linking System as a Binder in Solid Heterogeneous Propellants

Abstract

Propellants have found applications in many industries. They play an important role primarily in the armaments and space industries. Research and development of propellant technology has been ongoing for many years. The present authors have turned their attention to the aspect of compatibility of new components with isocyanates. As a result of the search for a solution to combine existing binders with new components, they propose using hydroxyl-terminated polybutadiene (HTPB) derivatives as the main binder components. In this way, the basic parameters of the HTPB binder, such as glass transition temperature, and compatibility with the solid components of propellants are retained. The use of an isocyanate-free binder system opens up possibilities for the use of new isocyanate-sensitive components. The authors have used two HTPB derivatives to create a new binder system. The combination of carboxyl-terminated polybutadiene (CTPB) and epoxidised HTPB, called EHTPB, allowed the elimination of isocyanates and the retention of good physicochemical properties of the binder. Here they present the method of synthesis of the components, the proportions of polymer and curing agent, and the pot-life. Heterogenic propellants based on CTPB, EHTPB, and ammonium perchlorate (AP) were prepared and the feasibility of such a system was confirmed. A study of the physical and chemical properties of the produced propellants confirmed the possibility of using CTPB and HTPB as a new binder system.