한국추진공학회 2010년도 추계학술대회 논문집 pp.199~204 2010 KSPE Fall Conference - 199 - * VEDA Design & Production Enterprise ** University of Belgrade, Faculty of Mechanical Eng. *** LIG Nex1, PGM R&D Lab Corresponding Author, E-mail: bjlee.snu@gmail.com Composite Rocket Propellants Based on Thermoplastic Elastomer Binders Vladica Bozic* ․ Boris Jankovski* ․ Marko Milos** ․ Bok Jik Lee*** ABSTRACT The objective of this paper is to present new binder systems that can be applied in composite rocket propellants, to improve properties of these propellants not only for better performance, but also to reduce waste and pollution. These novel systems are based on the thermoplastic elastomer (TPE) binders, which consists of copolymers with the addition of a plasticizer, and additives. The effect of the novel TPE binder systems on the burning rate and mechanical properties of AP based propellants was studied. The results show that propellants based on the novel TPE binders have a better energy performance than today’s workhorse hydroxyl terminated polybutadine/ammonium perchlorate propellant, exhibit a similar range of burning rate, possess appropriate mechanical properties, and exhibit good processing and aging characteristics at low cost. Key Words: Thermoplastic Binders, Composite Rocket Propellants 1. Introduction Modern solid propellants emerged in the early 1940’s with the invention of composite propellants, which are basically heterogeneous mixtures of binder and oxidizer. First among the modern composite propellant was GALCIT 53, based on potassium perchlorate as oxidant, dispersed in a thermoplastic binder (liquid organic resin, asphalt). Limitations in operating temperature range, poor mechanical properties and low solids content precluded possible applications of this propellant, as well as of the later developed composite thermoplastic propellants based on polyvinyl chloride (Arcite propellants) and also polyisobutylene. These properties narrowed their application to sounding rockets, small motors and gas generators. The appearance of liquid prepolymers made possible the introduction of chemically cured (cross-linked or thermoset) binders in composite propellants (Fig. 1), which have better properties. These composite propellants find wider application as power sources covering the range from small rocket systems to large launch vehicles in space programs. At present, workhorse propellants [1, 2] are composite propellants based on hydroxyl terminated polybutadine (HTPB) and ammonium perchlorate (AP).