Study On Shock-Resistant Properties Of Aramid Nonwovens Aerogels With SiO₂

Currently,there are more and more injuries to people caused by explosion accidents and blast waves,so how to reduce the damage caused by shock wave has the practical significance.SiO₂ aerogels is a new type of nanoporous material,and the velocity of mechanical wave in material is low.It can absorb a large amount of energy of shock waves.The paper prepared a kind of material which used Aramid 1313/1414 nonwoven with SiO₂ aerogels having protective effect of shock wave.First based on the rheological properties of sol,the SiO₂ sol can penetrate through the voids of the non-woven fabric.After a period of time,the sol is transformed into a wet gel.By alcohol-water displacement reaction,hydrophobic reaction and drying process,aramid fiber 1313/1414 Non-woven with SiO₂ sol was finished.Second,the structure of the sample was measured.The SiO₂ aerogels are filled in the voids of the Aramid 1313/1414 nonwoven fabric with different sizes.The thickness of the nonwoven fabric is increased and the pore sizes become smaller,while the bulk density is basically unchanged.The thermal insulation and flame retardant effect of the sample was also measured and improved by SiO₂ aerogels.The human body flexibility can be increase because the thermal insulation property is proportional to the thickness of the materials.The thermal resistance of PTFE film does not change significantly,while the limit oxygen index decrease slightly.Third,it is focus on the shock wave resistance of aramid 1313/1414 nonwovens with SiO₂ aerogels.At first,the static compressive property of the samples was measured by universal material machine.It is found that the compressive work and energy absorption capacity of the mixed SiO₂ aerogels and composite PTFE membrane are improved.Then,shock tube was used to measure the shock wave attenuation characteristics of Aramid 1313/1414 nonwovens with SiO₂ aerogels.It is known that the thickness reduce the peak overpressure of the shock wave,and SiO₂ aerogels and PTFE membranes has a significant attenuation effect on the shock wave peak overpressure.Finally,the COMSOL Multiphysics software simulated the attenuation of the shock wave peak overpressure.The results are in good agreement with the shock tube test results,which provide the basis for the study of the shock wave.Forth,the sound insulation properties of aramid fiber 1313/1414 nonwovens with SiO₂ aerogels,which are used as personal protective equipment materials was tested in the paper.The average sound insulation of the sample mixed with SiO₂ aerogels and compounded with PTFE porous membrane increases significantly,and the sound insulation of the sample is the highest at high frequency.