Improving physical and mechanical properties of thermal insulation using autoclave molding in inert medium

The structure of the descent vehicle of the manned spacecraft Soyuz TMA uses composite materials based on glass fiber and phenol-formaldehyde binder. The binder contains a large amount of chemically active, including highly flammable, components. Such materials are molded and cured using vacuum and autoclave method under high temperature and pressure of the working medium. When the working medium that is used is air there is a likelihood that reactions involving oxygen may occur, which have a negative effect on physical and mechanical properties of the material and create a threat of runaway oxidizing reactions up to thermal oxidative breakdown of the material. The newly developed technology of molding in an inert medium rules out the material oxidization, breakdown and depressurization of the evacuated rubber covers used in the molding, improves safety and stability of the manufacturing process, the quality and reliability of the products. Particular emphasis was given to creating an environment which provides minimal temperature gradients on the products during heating, thermostatting and cooling, as well as to assuring uniform distribution the binder within the material during molding. The work has resulted in improving the level of physical and mechanical properties of thermal insulation materials, weight, accuracy of the geometric parameters of the products and reduction in mass. The most important factor which enabled the achievement of the above results was the development of a new technology for manufacturing thermal insulation coatings in the inert medium and the highly automated autoclave system, which also provides a technological foundation for manufacturing new advanced products made of composite materials.