The polymer impregnated gypsum mineral wool as a new, alternative material for thermal insulation

The paper presents the experiments of formation of needles morphology of gypsum and anhydrite as the result of crystallization from oversaturated solution of sulphuric acid. The materials composed of these needles crystals were impregnated with silicone resins giving the composite of the properties similar to mineral wool. The content of polymers in this composite was about 50%. The produced material was resistance to moisture and even to water, in the case of total immersion of the samples during 24 h. These experiments showed the stability of anhydrite, which proofs the tightness of silicone matrix. The heating of composite up to 500 degrees C did not cause the destruction of samples despite of gypsum dewatering. Also the increase of the sample temperature to 250 degrees C does not provoke the decrease of the good physical properties of specimens in the case of their impregnation with crosslinking resins. The properties important for thermo-insulation applications i.e. the density is in the range 0.25-0.40 g/cm(3) and thermal conductivity coefficient in the range 0.045-0.06 W/m.K are on the good level.