Differential Thermal Analysis of a Wood-gypsum Composite

Statement of the problem. An increase in the range of production of products and structures based on gypsum binders with the addition of various fillers that improve some of the technological properties of the resulting composites is a promising direction in building materials science. The paper proposes the development of a technology for creating decorative slabs for interior decoration, reinforced with sawdust. Taking into account the increased requirements for thermal protection of buildings (SNiP 23-02-03), the issue of reducing the average density and increasing the thermal resistance of heat-shielding (heat-insulating and wall) for interior decoration is relevant. A decrease in density can be achieved, for example, by porousizing a gypsum product, but this requires carbonates and solutions of acids or salts with the formation of a porous agent in the form of CO2, which is not economically and environmentally friendly enough, so it was decided to introduce pine sawdust into the gypsum composite for decorative boards. In this case, it is necessary to conduct an experiment to identify the effect of adding sawdust on the fire safety of the composite as a whole. Results. In the course of the work, the results of a differential thermal analysis of a gypsum matrix with the addition of sawdust were obtained. It has been established that at an increase above 490 °C, sawdust filler is completely subject to destruction with the formation of coke residue and slight pore formation due to weight loss (judging by the thermogravimetric curve) due to the release of volatile substances, and only CaSO4 inversion occurs near the gypsum part. Conclusions. Thus, when studying the effect of thermal action on the structure and properties of materials by differential scanning calorimetry, it was revealed that exo- and endothermic processes, characteristic of both wood materials and gypsum, are superimposed during kinetic changes. Therefore, a fire hazard does not occur.