The effect of fillers on chloropolyester blend CPB 4 and inhibition of double-base propellants

A direct bonding inhibition system based on chloropolyester blend CPB 4 has recently been developed for inhibition of double-base rocket propellants. The effect of alumina trihydrate (Al₂O₃ · 3H₂O) and antimony trioxide (Sb₂O₃) on various properties of CPB 4 has been studied, such as effect on gel time, exotherm peak temperature, tensile strength, per cent elongation, water absorption, nitroglycerine absorption, heat resistance, and flame retardant characteristics. The data on flame retardance and other characteristics indicate that CPB 4 with 30% Al₂O₃ · 3H₂O and CPB 4 with 20% Sb₂O₃ are suitable for inhibition of double-base propellants. The double-base propellant sustainers (containing 2-NDPA) have been inhibited with CPB 4 containing 30% Al₂O₃ · 3H₂O and CPB 4 containing 20% Sb₂O₃ separately (without the application of any barrier coating), and statically fired at ambient, sub-zero (after conditioning at ?40°C for 18 h) and high (after conditioning at +50°C for 18 h) temperatures. The pressure—time profiles were found to be smooth and flat in all cases, indicating that the pressure level was the same throughout the combustion duration, inferring the suitability of these systems for inhibition of double-base propellants without the application of any barrier coating.