AP HTPB PROPELLANTS PDF
Modern chemical synthesis techniques have allowed for improved incorporation of nano‐scale additives into solid propellants. Various. Kumar Ishitha, P. A. Ramakrishna. () Activated charcoal: as burn rate modifier and its mechanism of action in non-metalized composite solid propellants. The combustion of hydroxyl-terminated polybutadiene (HTPB) propellants containing ne ammonium perchlo- rate (AP) was investigated using laser-excited, .
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Several kinds of heat releasing, thermal decomposition by DSC, combustion heat in oxygen environment, and explosion heat in nitrogen environment, are characterized to learn the effect of dispersibility of nano-CuO catalyst on heat releasing hhpb propellants.
In recent years, there has been an explosion of interest in the synthesis, structure, properties, and applications of nanomaterials, mainly because of the fact that materials confined in one or more dimension can exhibit interesting properties, such as catalysis. As a result of the development of nanotechnology, researches on nanocatalysts, including nanometer CuO, are surged up.
Accelerated aging of AP/HTPB propellants and the influence of various environmen :: TNO Repository
However, most researches tend to focus on the catalysis of the diameter or variety of nanomaterials [ 23 ]. Although some of them emphasized the dispersibility improvement technologies of nanomaterials, little attention has been paid to the relationship between dispersibility and catalysis of nanomaterials.
Heat releasing or energy releasing is one of the most important properties of thermal decomposition and combustion of propellants. Catalysts always play a key role in heat releasing procedure of propellant.
As one of the propellats important factors of nanomaterials, dispersibility plays a key role in the effect of catalysis of nanomaterials. Because of little diameter and proportion, nanocatalyst becomes the most difficult dispersing composition of many combustion systems.
However, the excellent catalysis of nanocatalyst still attracts many researchers to study [ 4 — 6 ]. As nanocatalysts likely perform much higher catalysis efficiency than microcatalysts, the dispersibility of nanocatalysts is much important than that of microcatalysts.
On the other hand, the dispersibility of nanocatalysts also affected its catalysis crucially [ 7 — 9 ]. Therefore, al dispersibility of nanocatalyst is very important to the heat releasing of propellants. In this paper, kneading time has been ranged from 1 hour to 5 hours to improve the dispersibility of nano-CuO combustion catalyst in composite propellant. Kneading time ranged from 1 to 5 hours to change the dispersibility of nano-CuO catalyst in the propellant.
The pre-dispersing method was applied to improve the dispersibility of nano-CuO before adding it into the propellant.
First, nano-CuO was dispersed in ethanol by ultrasonic. Then AP was mixed with the nano-CuO with the weight ratio of 4: The content of AP is up to 70 percent in the composite propellant. Most catalysts in the composite propellant act on the composition of AP. The nanometer catalysts show excellent catalysis on propellwnts thermal decomposition of AP.
Journal of Nanomaterials
The kneading time of each sample ranged from 1 hour to 5 hours. Three representative areas of each sample were chosen to test its decomposition temperature by DSC. Kneading procedures are always employed to improve the composition dispersity of HTPB propellants as well as nano-CuO catalyst. Because of little diameter and proportion, nanocatalyst becomes the most difficult dispersing composition of HTPB propellants.
Therefore, the dispersity of nanocatalyst becomes one of the key factors of propellant properties, including its heat releasing amount and procedures.
From Table 1as the kneading time increase, the mean values of decomposition temperature of samples decease smoothly from to.
Meanwhile, the RSD values of samples decrease from 4. It means that the increasing of nano-CuO dispersibility in HTPB propellant not only decreases the decomposition temperature, but also decreases the deviation of decomposition temperature.
With the similar tendency of Table 1the mean value of decomposition temperature and RSD value in Table 2 decrease dramatically with the increase of kneading time of HTPB propellant, from to and from 3.
However, when compared with Table 1 at the same kneading time, taking 3 hours for example, all the RSD values and mean values of decomposition temperature in Table 2 are much lower.
Compared with the blank sample, thermal decomposition peaks of the two other samples with nano-CuO are combined together as one peak.
And the thermal decomposition temperatures are much lower than the low decomposition temperature of blank sample. Every combustion heat data of the three areas is a mean value of three testing data. From the combustion data in Tables 3 and 4as the kneading time is increasing, the RSD of combustion heat is decreasing sharply. The mean value of combustion heat in Table 3 is increased steadily with the kneading time increase. However, after 3 hours kneading, the mean value of combustion heat in Table 4 decreases with the kneading increase.
Therefore, when kneading time increases to 5 hours, the combustion heat of propellant in Table 4 decreases to the value of propellant with simple mixed nano-CuO kneading 2 hours. And each explosion heat data of the three areas is a mean value of three testing data. In Table 5the explosion heat of propellant with simple mixed nano-CuO is increased with the increase of kneading time, while the STD and RSD of explosion heat decreased.
Meanwhile, the decrease ratios of STD and RSD of the explosion heat are very smooth when kneading time of propellant less than 3 hours. That is to say, after 3 hours kneading, the dispersibility of nano-CuO catalyst in propellant is improved to a maximum by kneading method.
Other methods should be employed to improve the dispersibility of nanocatalyst in the propellant. The explosion heat value of these data increase with the kneading time before 3 hours, and the value decrease with the kneading time after 3 hours. The value of STD and RSD of explosion heat decreases with the kneading time less than 3 hours then increases smoothly.
The breaking changes the dispersity of nano-CuO in the propellant.
Ammonium perchlorate composite propellant – Wikipedia
ppropellants And it provides new probabilities for reunion of nano-CuO catalyst particles. Far from the situation in Table 6the decomposition temperatures of the propellants, in Table 2are still decreasing with the increase of kneading time after 3 hours.
Therefore, it seems that there is no or little influence on the thermal decomposition temperatures of HTPB propellants in Table 2. Less RSD value is the stand of less change, or less instability, of the explosion heat releasing of the propellant sample. It means that the propellants in Table 6 could be show higher explosion proepllants and more steady explosive procedures than samples in Table 5.
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Ammonium perchlorate composite propellant
Subscribe to Table of Contents Alerts. Table of Contents Alerts. Introduction In recent years, there has been an explosion of interest in the synthesis, structure, properties, and applications of nanomaterials, mainly because of the fact that materials confined in one or more dimension can exhibit interesting pdopellants, such as catalysis. Results and Discussions 3. DSC thermal decomposition curves of AP.
Combustion heat data of propellant with simple mixed nano-CuO.