Influence of Tylose MH1000 Content on Gypsum Thermal Conductivity

Abstract

The presented work focuses on the influence of a water-soluble derivative of cellulose, hydroxyethyl methyl cellulose (HEMC), on gypsum thermal properties. The polymer is used as an additive in the weight fraction, up to 1% of pure gypsum. The water-to-gypsum ratio was taken at a level of .74. The study of hemihydrate calcium sulphate hydration of β crystalline form was observed using own-made apparatus measuring the temperature of the system during hydration. The presence of the polymer leads to a retardation of the hydration and setting process of gypsum paste. For the purpose of conductivity measurements, an improved method with a “hot wire” setup was used. A decrease of thermal conductivity and density with added HEMC was observed because of structure modifications of the gypsum product. It was concluded that adding HEMC influences not only the water retention coefficient and the rate of setting of gypsum, it also changes the morphological structure of gypsum-polymer composite, which is reflected in the density and thermal conductivity of the final product.