Preparation And Performance Of A New Type Of Inorganic Thermal Insulation Materials

The extensive application of organic thermal insulation materials in the building has caused frequent occurrence of fire accidents and threatened the safety of human life.As class A of flame retardant level,inorganic insulation material will be the future development direction for building insulation.There are a series of problems in inorganic insulation materials in China,such as high density,poor heat insulation and poor water resistance.Therefore,the development and research of new inorganic insulation materials is of great practical significance.In this experiment,the preparation and properties of inorganic thermal insulation materials with sodium silicate were studied.1)The properties of sodium silicate foamed materials with different heat treatment temperature and time were studied and the performance of sodium silicate foamed materials was improved.The analysis of thermogravimetric-differential heat and infrared spectrum,exhibits the temperature of the starting foaming of sodium silicate is 121 ^oC.In a addition,the higher the temperature,the higher the curing degree of the sodium silicate.The final experimental treatment time and temperature is 60 min and 450 ^oC.Under this condition,the compressive strength of the sodium silicate foam material is0.267 MPa,the thermal conductivity is 0.0526 w m^-1 K^-1 and the density is 78 kg m^-3,moreover,the compressive strength of the material is small under this condition.Adding fly ash or aluminum silicate fiber to the sodium silicate significantly can increase the compressive strength of the material.When the fly ash content is 6%,the compressive strength is 0.451 MPa,the thermal conductivity is 0.0551 W m^-1 K^-1 and,the density is112 kg m^-3.At the same time,the compressive strength is 0.429 MPa,the thermal conductivity is 0.052 W m^-1 K^-1,and density of 94 kg m^-3 when the content of aluminum silicate fiber was 2%.The modified foaming material of sodium silicate using aluminum silicate fiber is better than that of fly ash.Therefore,the experimental selection is aluminum silicate fiber.2)Basing on the sodium silicate and aluminum silicate fiber,furtherly adding of boric acid can effectively improve the water resistance and reduce the volume water absorption.When the added boric acid is 4%,the compressive strength of the material is0.553 MPa,the thermal conductivity is 0.0556 W m^-1 K^-1,the density is 128 kg m^-3,the softening coefficient is 91.4%,the weightlessness rate is 0.92%,and the volume water absorption is 6.7%.After surface hydrophobic treatment for the material,the volume water absorption is 4.9%,showing that,the combined action of boric acid and hydrophobic agent lead to low volume water absorption.3)Then,using microwave heating method to prepare sodium silicate foam insulation materials,adding of aluminum silicate fiber and silicone improves the compressive strength and the hydrophobic properties,reduces the thermal conductivity.The maximum compressive strength of materials is up to 0.883 MPa.The thermal conductivity is 0.0514 W m^-1 K^-1,and density of 96 kg m^-3,the compressive strength was 0.433 MPa when the content of aluminum silicate fiber was 2%,In addition,the hydrophobic surface angle was 149°,the volume Water absorption is 4.2%,volume water absorption is 12.1%after it is immersed in water for 8 days?192 h?when silicone was 1%,the addition of silicone greatly can reduce the volume water absorption of the material.