Feasibility of Extending the Composite Propellant Pot Life

Abstract

In composite propellant processing, propellant mixing and casting are the most complex and important operations. A solid propellant mixer must be capable of blending a mixture of solid/liquid ingredients with weight ratios as high as 90% solids and 10% liquids and resultant bulk viscosities ranging up to several kilopoise. Propellant mixing and casting processes are affected significantly by the rheological properties of the uncured propellant. 1 Sometimes too short potlife is a great problem in propellant manufacturing particulary when the solid content is up to 87%. The often used iron compounds generally even in small amounts also catalyze the curing reaction and shorten the pot life. 2 many papers discused the developed methods for improving the composite propellant process by extending its pot life using some affected chemical materials. This work concentrated on a method for improving the manufacturing of the composite propellants dynamically, i.e without adding chemical materials to the propellant formula. This was done by delaying the addition of the curing agent to some hours. During this period a second standared mixing was carrying out. The comparison between the tow kinds of mixing was done to study the effect of the delaying of addition of the curing agent. It was found that viscosity build up test give similar reading for both kinds, which means that the propellant viscocity was not affected by this delaying. It was also found that, the mechanical and performance properties not affected by this step. It confirmed that delaying of the addition of the curing agent in the mixing process can be applied successfully.

A Study of the Influence of Storage Time of Uncured Propellants on the Final Properties of the Composite in Multi‐Batch Processes on an Industrial Scale

“…The confidence intervals of the mean for the angular coefficients of the functions, or properties, analysed are valid within the time interval from two to ten days, this time frame represents the storage times found in the analysed historical data. It is worth mentioning another study present in the literature [35], this study assessed the influence of delayed addition of the curing agent to the mixing. In this regard, a 4-hour time window was used, and it ended up not affecting the mechanical properties of the propellant.…”

Obtenção e caracterização de propelentes sólidos compósitos à base de PBLH, alumínio e perclorato de amônio com binders modificados com dióis de cadeia curta

“…A determinação da massa específica do propelente curado também é relevante em termos de caracterização do material compósito [17]. Durante o processamento também é relevante avaliar e otimizar as propriedades reológicas da pasta, amplamente estudadas através de determinação de viscosidade do propelente durante o carregamento [18][19][20][21].…”