Study On Thermal Insulation Properties Of Spacer Fabric Reinforced Composites

Insulation materials have been widely used in the fields of building energy conservation,aerospace,etc.With the improvement of the scientific level,more stringent requirements have been put forward on the insulation materials,which require the materials to have excellent thermal insulation properties and also have fire resistance and high resistance.Strength,light weight,and corrosion resistance have made the research and exploration of thermal insulation materials a hot spot.In this topic,spacer fabric reinforced silica aerogel composite materials were prepared by using spacer fabrics with excellent overall performance as reinforcements and silica aerogels with low thermal conductivity as thermal insulation fillers,and studied its thermal insulation.performance.First,select alkali-free glass fiber plied yarn as raw material,and through rational design of fabric structure,exploring and solving the problems of spacer fabric in the weaving process,double-layer spacer fabric and honeycomb spacer fabric were successfully woven on the multi-beam rapier loom.And triangle spacer fabric,and test and analyze its mechanical properties;then explore the sol-gel process to prepare silica aerogel,and study the factors that affect the density and pore structure of the aerogel;finally,the spacer fabric is combined with aerogel Glue composite,and research and analyze the thermal insulation performance of composite materials.Draw the following conclusions:(1)In the design of spacer fabrics,we should try our best to choose the organization with less warp movement law as the basic structure,which can avoid warp tension fluctuations caused by inconsistent movement law during the weaving process and reduce the difficulty of weaving.(2)The weft tensile strength of the three types of woven spacer fabrics is higher than the warp tensile strength of the three types of woven spacer fabrics,and the honeycomb spacer fabrics are better than the other two types of woven spacer fabrics.After the double-layer spacer fabric is treated at a high temperature of 300?for 12 hours,its strength is about 80%of the untreated strength.After the treatment temperature exceeds 400?,its strength loss is more serious.(3)When using TEOS as the silicon source and ethanol(Et OH)as the solvent to prepare silica aerogel through sol-gel and atmospheric drying processes,the molar ratio of H₂O/TEOS is Between 3 and 4,the sol time is short and the aerogel density is relatively small;when the molar ratio of Et OH/TEOS is about 6,the sol time is short and the aerogel density is small;N,N-dimethylformamide(DMF)/TEOS is the best when the molar ratio is between 0.4 and 0.5;the trimethylchlorosilane(TMCS)modification has a greater impact on the hydrophobicity of the aerogel,and the contact angle of the unmodified aerogel with water is At 59.5°,the contact angle of the aerogel with water after TMCS modification increased to 144°;the TMCS modification treatment made the pore structure of the aerogel more uniform without reducing its thermal stability.(4)The structure of woven spacer fabric is the main factor that affects the heat insulation uniformity of the composite,while the type,density and filling amount of the heat insulation filler material mainly affect the heat insulation performance of the composite.The honeycomb spacer fabric reinforced composite material has the best thermal insulation uniformity.The temperature difference on the surface of the composite material is about25.1?under the heating condition of 300?;the heat transfer at the junction of the spacer fabric is mainly carried out by the heat conduction of the fabric,and the fabric The thermal conductivity is higher than the thermal conductivity of the thermal insulation material,resulting in poor thermal insulation performance at the junction;the density of silica aerogel has an impact on the thermal insulation performance of the composite material,but it is not generally believed that the smaller the density,the thermal insulation The better the performance,but the best density,the aerogel with a density of 0.157 g/cm³shows better thermal insulation performance in this experimental study.