Synthesis and characterization of composite materials using calcium sulfate for fire protection
The increase of prevention and the introduction of more and more restrictive standards are challenges for the development of new materials resistant to high temperatures. The aim of the study is to develop a fire panel with both good properties of thermal insulator (low thermal conductivity, fumes tightness) and mechanical properties sufficient to maintain a structure integrity in case of fire.That kind of material is composed of an inorganic matrix mainly composed of calcium sulfate dihydrate and of additives used as thermal and mechanical reinforcements. The first part of the study is focused on the matrix, especially on the determination of a particle size distribution for which the mechanical properties are optimized. Then, the matrix is chemically characterized. A study by isothermal calorimetry of the hydration reaction of the calcium sulfate hemihydrate (plaster) is conducted to understand the mechanism of hydration and to control setting times. For this, the influence of the grain size, of the quantity of water, of the chemical composition of plaster, of additives on the kinetics of hydration of the plaster is studied. The second part of this work resumes the different steps of the selection of additives. After that, the relation between the microstructure and thermo - mechanicals properties (thermal conductivity, Young modulus, Shore C hardness) of the system is studied.This study has permitted to establish a panel formulation having very good thermal and mechanical properties to ensure building integrity in case of fire. The formulation has been patented in December 2010 (No BIP207506FR00) and it is currently marketed as panels by Extha.