Surface Modification Of Aramid 1313 Fabric Towards Antistatic And Superhydrophobic Enhancement

As one of the high-performance engineering polymer materials,aramid 1313（PMIA）owns characteristics of high modulus,high strength,great temperature resistance,and corrosion resistance,which endow numerous applications in the field of military and aerospace and other harsh environment（for instance outer protective layer of space suit,fire protection suit and so on）.Whereas,with frequent bending and friction in use,the electrical insulation of PMIA fabric may lead to electric charge accumulation and electric sparks,affecting greatly the wear comfort or giving rise to severe safety accidents.Additionally,the accumulated electric charge will lead to excess inorganic particles adherence through electrostatic attraction.As a result,the working duration would be drastically shortened.In view of this,the aim of this work is to fabricate the PMIA fabric with integrated antistatic property and low surface energy by improving conductivity of fabric and preparing the superhydrophobic protective layer,providing guidance for properties enhancement and application widening.The detailed research contents of this paper are as follows:（1）The preparation of the antistatic PMIA/rGO/SiO₂ fabric with low surface energy.In the first step,the surface of the inert PMIA fabric was activated byγ-ray irradiation（Cobalt-60 was selected as the radiation source）.Results showed afterγ-ray irradiation,the number of micro-pits and grooves on the surface of fibers and specific surface area were increased obviously.The content of the oxygen element and oxygen-containing polar functional groups on the surface of fibers were also increased greatly.Secondly,graphene oxide（GO）was decorated to the surface of fabric by ultrasonic-assisted immersion.The decorated GO was subsequently transformed to reduced graphene oxide（rGO）by hydrazine hydrate.After reduction,the rGO can be found not only on the surface of the fibers but also in the gap between the fibers,which can promote greatly the formation of conductive network of fabric.The volume resistivity of the fabric decreased with the increase of concentration of GO solution and the immersing time.To be more specific,the volume resistivity of the fabric was decreased to 0.5Ω·m after treated in GO solution of 6 mg/m L for 30 min and the volume resistivity tended to be a constant regardless of the concentration of GO solution and the immersing time afterward.In the final step,the dense SiO₂ coating was decorated on rGO modified PMIA fabric by impregnating in the suspension of 1H,1H,2H,2H-perfluorooctyltriethoxysilane（PFTS）/hydrophobic fumed silica nanoparticles（SiO₂）,to reduce the surface energy and prevent the adhesion of dust（the water contact angle was as high as 157.2^o）.（2）The preparation of the antistatic PMIA/AgNWs/ATO/SiO₂ fabric with low surface energy.Due to the dark color nature and poor dyeing property of rGO,it is difficult to mark on the PMIA/rGO/SiO₂ fabric for the indication of various application circumstance.To avoid this dilemma,the silver nanowires（AgNWs）and antimony-doped tin oxide（ATO）were used instead in this chapter.Before the modification of PMIA,AgNWs with high aspect ratio were prepared by the polyol method.In addition,to improve the interfacial bonding between AgNWs and PMIA fabric,the waterborne polyurethane（WPU）was added into the AgNWs suspension.Once the AgNWs suspension is ready,the PMIA fabric was dipped repeatedly.Results showed that randomly overlapped AgNWs existed mainly on the surface of fibers and only traces can be found in the gap.With the addition of WPU,the distribution of AgNWs became more uniformly.The volume resistivity of the fabric decreased with the increase of concentration of AgNWs suspension and the immersing time.Interestingly,ATO nanoparticles can serve as the connection points to further improve the conductive network of AgNWs.The minimum volume resistivity of the modified fabric was only 0.62×10^-3Ω·m,which was three orders lower than that of PMIA/rGO/SiO₂ fabric.Lastly,the fabric was further impregnated in the suspension of PFTS/SiO₂ to improve the surface hydrophobicity and realize self-cleaning ability.By improving electrical conductivity and reducing the surface energy,PMIA fabric with antistatic performance and self-cleaning ability was successfully prepared.At the same time,the environmental resistance test proved that the functional layers on PMIA fabric were able to sustain the harsh conditions like acid and alkali corrosion,UV radiation,and friction,expanding greatly the application of PMIA in the area of aerospace and military environment.