EFFECT OF HTPB BINDER ON THERMAL, IGNITION AND BURNING CHARACTERISTICS OF TITANIUM - POTASSIUM PERCHLORATE BASED PYROTECHNIC SYSTEM

摘要

A number of studies have been carried out on the effect of binders on various pyrotechnic compositions by different researchers. The increasing use of polymeric binders in pyrotechnic compositions is of recent origin, as newer and more complex polymers are proving to be more attractive than the conventional type of binders like nitrocellulose (NC). This paper presents results on the influence of HTPB (Hydroxyl Terminated Poly Butadiene) binder on the thermal behaviour, burning characteristics, ignition temperature, heat of combustion and sensitivity (impact and friction ) of the titanium - potassium perchlorate (Ti -KClO_4) based system. A number of pyrotechnic compositions were prepared by mixing Ti and KClO_4 on the basis of their mole fractions. Inclusion of HTPB increased the sensitivity of the system considerably. The impact sensitivity measured with a 2 Kg drop weight shows that no explosion occurred upto 170 cm. height for binary mix , whereas with the addition of HTPB impact sensitivity of the system increased to 37 - 53 cm level. Friction sensitivity of the pyrotechnic compositions studied was in the range of 5.4 Kg.(most sensitive) to 36 Kg. (least sensitive) for the binary mix and 4 - 13 Kg. with HTPB. Ignition temperatures of the pyrotechnic compositions was reduced by 80 - 190°C at 40°C min~(-1) heating rate. The heat of combustion values in argon medium increased from 344 cal/g ( binary mix ) to 818 cal/g. ( HTPB ) The heat of combustion for the binary mix was in the range of 675 - 1800 cal/g, which increased in the range of 1293 -1782 cal/g. with the addition of binder.