Preparation Of Polyaniline/graphene /polyurethane Water-based Antistatic Coatings

In recent years,with the progress of society,microelectronic components have been widely used in various fields such as industry,military and daily life.Meanwhile,with the continuous improvement of miniaturization and integration of electronic products,the electrostatic sensitivity of products increases,which makes the market demand of antistatic packaging materials and packaging technology huge in recent years.Therefore,it has important theoretical significance and practical application value to research on an efficient antistatic coating.In this thesis,graphene/polyaniline nanocomposites were prepared by the combination of ultrasonic assisted method and in-situ polymerization method,and then the properties of the composites in the field of water-based antistatic coatings were explored.(1)Polyaniline nanofibers(PANI)were prepared by ultrasonic assisted method and rapid mixing method,respectively.The effects of different polymerization conditions such as doping acid type,concentration and oxidant ratio on the morphology and properties of PANI were investigated.When HCl was used as a dopant,both the ultrasonic assisted method and the rapid mixing method can prepare PANI nanofibers.However,rapid mixing was only suitable for the synthesis of PANI nanofibers at low concentration of aniline monomer,while ultrasonic assisted synthesis of PANI nanofibers at relatively high concentrations of aniline monomers.When PANI was doped with dodecylbenzenesulfonic acid(DBSA),PANI nanofibers with regular morphology could be prepared by rapid mixing method.In addition,when PANI was doped with DBSA,under the condition of n(APS/An)=5:4,c(DBSA)=0.08mol/L,the largest conductivity of PANI was obtained,which was 155S/m.When PANI was doped with HCl,the best conductivity of PANI nanofibers were obtained under the condition of n(APS/An)=1:1,c(HCl)=1mol/L,which was 253.2S/m.(2)Graphene oxide(GO)was prepared of by Hummers method.Next,based on the above optimal experimental conditions of PANI nanofibers,GO/PANI nanocomposites were prepared by the in-situ polymerization method and ultrasonic assisted method.Then,L-Ascorbic acid(L-AA)was used for reducing reduce GO to obtain graphene/PANI nanocomposites.The structure,morphology and conductivity of the nanocomposite was tested and analyzed by FT-IR,XRD,TEM,SEM,and four probes,respectively.The optimum experimental conditions are as follows:the mass ratio of GO/An is 1:4,the reduction temperature(T)is 80?,the mass ratio of GO:L-AA is 1:8,and the reduction time(t)of GO/PANI is 8 h.Under these conditions,the most regular morphology of the nano-composite was obtained,and the composite prepared has the best conductivity of 357.1 S/m at the same time.(3)The water-based polyurethane was used as a film-forming resin and the self-made graphene/PANI nanocomposite was used as conductive filler,a water-based anti-static coating was prepared with functional additives by shearing and mixing.The basic properties of the coating,the wear resistance,adhesion and electrical resistivity of the coating were tested.It is concluded that when the content of conductive filler is5 wt%and the mass ratio of conductive fillers to waterborne polyurethane is 20 wt%,the surface resistivity and the volume resistivity of the waterborne antistatic coating reached a minimum value of 3.6×10~3 K?/cm~2 and 1.2×10~3?·m,respectively,which meets the anti-static requirements of most microelectronic devices..In summary,based on the study of the synthesis mechanism and properties of PANI nanofibers,graphene/PANI nanocomposites were prepared by in-situ polymerization and ultrasonic assisted methods.The PANI nanofibers can be prepared by this way at relatively high concentration of monomer,and this method is also suitable for large-scale preparation of PANI nanocomposites.The nanocomposites prepared in this experiment have both the special morphology and unique doping/dedoping characteristics of micro/nano PANI.The mechanical strength and electrical conductivity of the composite can be improved due to the reinforcing effect of graphene.All these advantages make it have broad application in the field of water-based anti-static coatings.