Analysis Of Thermal Isolation Properties Of Weft-Knitted Spacer Fabrics Integrated With Silica Aerogel

The interest in multifunctional textile materials has been increased due to the health care and safety of living beings.Moreover due to the increase in excessive temperatures（unfavorable conditions）,there is a need for insulating the clothing for the protection of the wearer.Therefore this work investigated the thermal isolation properties of untreated and treated three-layered weft-knitted spacer fabrics with different thicknesses（2mm,3mm and 4mm）by using silica aerogels（SAs）.Three samples of spacer fabrics（300GSM,350GSM,540GSM）were coated with nanoporous silica aerogel at a 26^oC temperature and then kept for aging,exchanging the solvent,surface modificationThis study associates an environmentally friendly method（sol-gel method）for preparing silica aerogels which were used for coating on weft-knitted spacer fabrics.The silica sol-gel process was carried out in two stages i.e.firstly acid-catalyzed TEOS hydrolysis and finally base-catalyzed gelation.Silica aerogels were prepared by Tetraethyl Orthosilicate（TEOS）and other substances through sol-gel method.The eventual silica concentration of the sol solution was11.11-wt%.The characteristics of spacer fabric samples i.e.thermal resistance,thermal conductivity,yarn arrangement angle,density,porosity,air permeability and add-on%of silica were investigated.SEM（Scanning Electron Microscopy）test and FTIR-ATR（Fourier Transform Infrared Spectroscopy-Attenuated Total Reflection）test were used to explore the surface morphology and surface changes initiated by the silica coating.Moreover,tensile test,compression test and bending test were performed to characterize the mechanical properties.The experimental results indicated that the treated weft-knitted spacer fabrics having a 3mm thickness（with 350GSM）have a higher thermal resistance of 0.09131 m²KW^-1,higher porosity（90.33%）ratio,higher air permeability,higher arrangement angle,and lower density.The statistical analysis also verified the significant performance（p=0.000）of treated fabric samples at the 0.05 level.It means sample 2 type has higher porosity ratio as compared to other samples.The highest porosity ratio possessed the highest thermal resistance.Moreover,it was noticed that the add-on%of silica on the three samples were 49%,62%,and 55%respectively.That means the higher the add-on%of silica the higher the thermal resistance of samples（sample 2）.They have light weight and large yarn arrangement angles thus are compatible with industrial textiles.The weft-knitted spacer fabrics are suitable for industrial textiles because weft knitted spacer fabric has good thermal isolation properties,better comfortable properties,softer and warmer based on experimental results.Spacer fabric has several qualities that make them model for a variety of uses including insulation,strength,and stability.Spacer fabrics are recyclable,which makes them much more environmentally friendly Moreover,Silica aerogels based coated fabric is unquestionably the best choice as insulation materials for some specific application s such as space suits,down jackets and cold protective materials.We also intensely believe that our work will inspire the researchers for the more thermal isolation applications.