Preparation And Properties Of Expanded Vermiculite Composite Flame Retardant Insulation Materials

With the social economic development, the use of energy is increasing greatly, energy crisis has become a major challenge around the world, in order to minimize the energy loss, the demand of thermal insulation materials is also increasing year after year. But in recent years, fire accidents on thermal insulation materials are frequently, of which building exterior thermal insulation materials make up a significant portion, and the loss caused by accidents is the worst. Therefore, the research and development of flame retardant modification about the building exterior thermal insulation materials have become the focus of common concern around the world. Currently building exterior thermal insulation materials commonly use polyurethane board and polystyrene foam board, adding flame retardant is the traditional way of flame retardant modification, but the flame resistance of the thermal insulation materials have not substantial change, which still belongs to flammable material.Expanded vermiculite is the wealth of sources and low price, and is also excellent flame retardant and thermal insulation material. In this work, Aa a main raw material, expanded vermiculite were composited with sodium silicate and phenolic resin to prepare expanded vermiculite/sodium silicate and expanded vermiculite/phenolic flame-retardant and insulation composites respectively; expanded vermiculite/phe nolic flame-re tardant and insulation used foaming technology. The main results and conclusions are described as follows:(1) Expanded vermiculite is prepared by calcining with high temperature. The results show that the best properties of expanded vermiculite were obtained when the temperature was 800 ℃. These vermiculites have the bulk density of 0.1732 kg/m3, porosity of 0.86%, the thermal conductivity of 0.0631 W/(m-K).(2) Sodium silicate was chose as inorganic binder and the preparation of expanded vermiculite/sodium silicate flame-retardant and insulation composites. The results has shown that the suitable mass ratio of expanded vermiculite and sodium silicate was 1:1, the suitable mass ratio of fluorine sodium silicate sodium silicate was 12%, the suitable curing temperature was 160 ℃, the suitable compression ratio was 12%. Products have the apparent density of 297.2 kg/m3, the compression strength of 0.43 MPa, the limit oxygen index of 100%, the thermal conductivity of 0.0718 W/(m-K).(3) Using a low temperature foaming technique, the expanded vermiculite/phenolic flame retardant and insulation composites were prepared from expanded vermiculite and phenolic resin, and addition of several kinds of additives. The properties of composites could be controlled by varying influencing factors such as the amount of the expanded vermiculite, foaming temperature, content of curing agent, content of foaming agent, content of surfactant and curing time. Studies have shown that the optimized conditions for the composite preparation are that the amount of the expanded vermiculite was 60%, foaming temperature was 80 ℃, content of curing agent was 10%, content of foaming agent was 10%, content of surfactant was 5%, and curing time was 2 h. And its apparent density was 190.08 kg/m, The compression strength was 0.32 MPa, the thermal conductivity was 0.0549 W/(m·K), the limit oxygen index was 71.1%, the heat release rate was 15 kW/m2.