Prepartion Of Composite Thermal Insulation Silicone Foam Material And Study On Its Properties

Due to its excellent high and low temperature resistance,weather resistance,flame resistance,chemical resistance,and heat insulation properties,silicone foam materials are widely used in building materials,daily necessities,medical supplies,the electronics industry,and aerospace,etc.The traditional preparation method of the silicone foam material has low production efficiency,difficult control,poor mechanical properties,complicated process,expensive cost,and environmental pollution.These are all important reasons for the difficulty of industrialization of the silicone foam material.The traditional silicone foam material has a single heat insulation method and only blocks the heat conduction path.The heat transfer method at high temperature is mainly heat radiation,which makes the application of traditional silicone foam material at high temperature greatly restricted.Hollow glass microspheres(HGM)and double-shell TiO2/Hollow glass microspheres(TiO2-HGM),due to their unique closed-cell cavity structure,excellent near-infrared reflectance,and high mechanical strength.These two special hollow fillers can block the three ways of heat transfer(heat conduction,heat convection,and heat radiation),which makes it a research hotspot in the field of heat insulation.In addition to the above properties,the double-shell TiO2-HGM also has excellent near-infrared reflection performance,which makes its application in the field of thermal insulation a hot research topic.Compared with the traditional silicone foam material,the silicone foam material prepared from the silicone resin and HGM has more diversified thermal insulation methods,wider application temperature range,easier control of material parameters,better mechanical properties,and simple preparation process,environmental protection,and low cost.However,there have been few reports on the application of HGM and TiO2-HGM in silicone resins to improve their thermal insulation capabilities.In this paper,silicone/HGM foam material was prepared using liquid silicone resin as the matrix and HGM as the filler.The relationship between the gas volume fraction,the pore size and the material properties was analyzed by characterizing means such as density meter,thermal conductivity meter,TGA,SEM,universal testing machine and Shore hardness tester.The results show that HGM's filling effectively improves the thermal insulation performance of silicone resins.The minimum thermal conductivity of silicone/HGM foam materials can reach 0.06 w/m·k and the thermal stability becomes more excellent.The tensile strength of the silicone/HGM foam material is 1.9 MPa when the air volume fraction is 30%,which is 55%higher than the silicone resin(silicone resin:1.22 MPa).From the microstructure of the cross section of the silicone/HGM foam material,HGM was evenly distributed in the silicone resin,the interface bonding force was good,and no agglomeration occurred.In this paper,the effect of different gas volume fractions and different pore diameters on the properties of silicone/HGM foams is studied for the first time.Compared with traditional silicone foams,silicone/HGM foams have lower thermal conductivity and better mechanical strength.This research also has important guiding significance for the research and application of silicone/HGM foams.On the basis of the above research,this study prepared the TiO2-HGM with heat radiation resistance by hydrothermal method.The effects of reaction time,reaction temperature,the amount of tetrabutyl titanate,and the amount of hydrochloric acid on the morphology of TiO2-HGM were analyzed by SEM.The effects of the amount of tetrabutyl titanate on the performance of TiO2-HGM were studied by means of FTIR,EDS,XRD,UV-VIS-NIR spectrophotometer and thermal conductivity meter.Through a universal testing machine,a muffle furnace and a thermometer,the differences between the properties of silicone/HGM foam materials and silicone/TiO2-HGM foam materials were analyzed.The research results of this paper have high guiding value for the research and application of other polymer/HGM foam materials or polymer/TiO2-HGM foam materials.