Preparation Of Expanded Perlite-SiO₂ Aerogel Composite Thermal Insulation Material

Expanded perlite has many advantages such as low thermal conductivity,strong weathering durability,non-combustibility,low price,and the same life cycle of buildings.It is widely used in thermal insulation field.However,compared with organic thermal insulation materials,expanded perlite has relatively high thermal conductivity and low compressive strength.It needs to be closed-cell or composite modified to reduce its thermal conductivity and increase its compressive strength.SiO₂ aerogel is a new type of nanometer-scale thermal insulation material,which is used for some high performance due to its excellent thermal conductivity,large specific surface area,low density and high porosity.In the field of sop Histicated technology,it is limited in the field of building insulation due to its high preparation cost and low compressive strength.It is necessary to optimize the preparation raw materials and preparation processes of SiO₂ aerogel,and at the same time reduce the preparation cost,increase the compressive strength and expand the application range.This study intends to optimize the material from the microscopic level.According to the performance characteristics of the two materials,the two materials are combined into a new material,and the light porous expanded perlite is used as the adsorption carrier,and the vacuum adsorption process is adopted.The aerogel with excellent thermal insulation properties is inhaled into the internal pore structure of the expanded perlite to form a new composite thermal insulation material,which can not only improve the compressive strength of the aerogel,but also reduce the thermal conductivity of the expanded perlite,which is an expanded perlite process.Improvement provides a new research idea.Based on the above objectives,the following research work was carried out:1.Study on the preparation process of SiO₂ aerogel.The hydrophobic SiO₂ aerogel was prepared by sol-gel method.The effect of the amount of anhydrous ethanol and the amount of ultrasonic water on the thermal conductivity of aerogel was systematically studied.The hydrolysis temperature and the p H value of the sol were determined for the aerogel gel.The influence of time,the physical properties and microstructure of SiO₂ aerogel were measured and characterized by instrumentation to determine the best raw material ratio and test conditions.2.Study on the preparation process of expanded perlite aerogel composites.The aerogel was adsorbed into the hollow structure of expanded perlite by vacuum adsorption to form expanded perlite-SiO₂ aerogel composite insulation material.The hydrophobic modification process,expanded perlite particle size and adsorption were studied.The effects of vacancy and vacuum adsorption time on the properties of composite insulation materials were obtained,and the optimal preparation parameters and preparation conditions were obtained.