# Effective Performance Modifications for a Composite Rocket Propellant via Coagglomerates of Cyclic Nitramines

## TL;DR

This study explores how adding a new chemical compound to rocket propellant improves its performance and stability.

## Contribution

The novel use of coagglomerates of cyclic nitramines to modify rocket propellant performance is introduced.

## Key findings

- CACs reduce the pressure exponent of the propellant, improving combustion efficiency.
- CACs significantly increase the burning rate at 20 wt% substitution of ammonium perchlorate.
- CACs form a cocrystal mixture with HMX, confirmed by X-ray diffraction and spectroscopy.

## Abstract

The new combustion
modifier cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]­imidazole (BCHMX) was tested on an aluminum HMX/HTPB/AP
propellant. Monitored were the changes in the propellant characteristics,
when the 10, 20, and 30 wt % ammonium perchlorate (AP) were substituted
by pure 1,3,5,7-tetranitro-1,3,5.7-tetrazocane (HMX), mechanical mixture
HMX/BCHMX (PM), and coagglomerate of HMX/BCHMX (CACs), the latter
two in a weight ratio of 8:1. By means of the powder X-ray diffraction
and FTIR and Raman spectroscopies, it was confirmed that CACs are
a mixture of cocrystal β-HMX/BCHMX with excess β-HMX.
The relationships were discovered between the burning rate of the
prepared samples and the heat of combustion (Q
c), ignition temperature, specific rate constant of thermal
decomposition, impact sensitivity, hardness, and specific impulse.
Correspondingly, relationships between Q
c and ignition temperature, as well as the impact and friction sensitivities,
were investigated. It was found that increasing the amount of CACs
in the propellant reduces the pressure exponent, while pure HMX and
PM have the opposite effect. The significantly positive effect of
CACs on the burning rate, especially at 20 wt % substitution of AP
by these microcrystals, is another noteworthy finding.