Abstract
D EVELOPMENT of a wide variety of rockets has required development of propellants having a wide range of performance corresponding to the purposes for which they are used. Especially, a high burning rate propellant is neededwhen developing a high performance rocket motor. The use of burning rate modifiers, metal fuels, and high energetic materials is a typical method to obtain a high burning rate propellant. Recently, nanosized metal fuels [1–4] and high energetic materials [5,6] have been developed, and researchers have been investigating the burning characteristics of solid propellants using them [1–13]. Glycidyl azide polymer is a typical energetic binder characterized by the N3 chemical bond [5,6,9–11]. The burning characteristics of the glycidyl azide polymer-based propellant are superior to those of common propellants, such as the hydroxyl-terminated polybutadiene (HTPB)based propellant. However, it is presently difficult tomake a practical solid propellant using high energetic binders and nanosized metal fuels because these materials are expensive and cannot be massproduced. It is necessary to find an inexpensive material to obtain a high performance propellant. Another approach is the application of new nonenergetic materials as the propellant fuel-binder. For example, hydrogenated hydroxylterminated polyisoprene [14], polymethylmethacrylate [15], polyethylene [16,17], polyvinyl chloride [18,19], polycaprolactone [20], etc., are now being evaluated. The burning performances of propellants using these polymers are not inferior to those of the HTPB-based propellant. Polytetrahydrofuran (PTHF) is used as an ingredient for rubber products and is produced in several different molecular weights. This polymer is mass-produced commercially and inexpensive. The chemical properties of PTHF are shown in Table 1. The repeating unit of PTHF consists of a single bond and has one oxygen atom, four carbon atoms, and eight hydrogen atoms. PTHF has a hydroxide group on one side of the molecular chain of PTHF and a hydrogen atom on the other side. The molecular structure of PTHF is similar to that of HTPB. PTHF is not an energetic binder. However, it could be expected that the burning performance of a solid propellant could be improved by using PTHF as a binder, comparedwithHTPB, because the amount of oxygen atom per mole of PTHF is greater than that of HTPB. In this study, the burning rate characteristics of the PTHF-based composite propellant were investigated and compared with the characteristics of the HTPB-based composite propellant. According to the results, it was found that the performance of the PTHF-based composite propellant is superior to that of the HTPB-based propellant.