Preparation Of Flame Retardant Polyacrylonitrile Nanofibers By Electrospinning

Polyacrylonitrile fiberwas favorited by the majority of people due to the excellent properties,such as softness,bulkiness,easy dyeing and so on.Polyacrylonitrile fiber is called "artificial wool",and it occupies an important position in the textile industry.But the polyacrylonitrileis a flammable fiber,the LOI value of the polyacrylonitrile fiber is only about 17%,it is easy to burn,and release the toxic gases in the combustion,this is a threat to people’lives and safty,and pollute the environment.Therefore,it is important to develop the flame retardant polyacrylonitrile fiber,which has the realistic and far-reaching significance.This paper is devided into three parts:The first part is the preparation of chelates.Phytic acid is selected as the chelating agent,it can chelate with metal ions to form a stable complex.The optimal condition of chelation reaction was obtained:the molar ratio of PA and FeCl3·642O is 1:1,the reaction temperature is 50℃,the reaction time is 2hours.Then,the chelate samples are tested by Fourier transform infrared spectroscopy(FT-IR),the characteristic absorption peaks of P-O and Fe-O appeared in the spectrum,it is concluded that PA reacted with FeCl3·6H2O.Thermogravimetric analysis(TGA),it is found that the residual char yield of the chclates at 800℃ is 60.53%in the TGA curve,which showed excellent char formation.The second part is to prepare flame retardant polyacrylonitrile nanofibers by the electrospinning technology.pure PAN,PA-doped PAN and chclate-doped PAN nanofibers are prepared by electrospinning techniques,The SEM is used to observe the morphologies and structure of nanofibers,and the EDX express the chemical composition of nanofibers,it is demonstrated that PA existed in the PA-doped PAN nanofibers and the chelates existed in chelate-doped PAN nanofibers.the XPS is used to analyze the chemical element in the surface of nanofibers,and speculate the composition of nanofibers.FT-IR proved the characteristics functional groups of PA and chelate in the nanofibers,the results of TGA showed that the residual char yield of PA-doped PAN nanofibers at 800℃ is 60.63%,and that of the chelate-doped PAN nanofibers is 50.40%,which increase the char formation of PAN nanofibers,DSC is explored to study the flame retardant mechanism of nanofibers.theLimit Oxygen Index test of PA-doped PAN is 27.3%,that of chelate-doped PAN is 22.8%.The third part is the optimization of electrospinning process.in order to prepare a uniform dispersion solution,the silane coupling agent(KH-560),twelve sodium alkyl benzene sulfonate(LAS),tween 80 are added into the spinning solution,the electrospinning nanofibers have performance test.The SEM is used to observe the morphologies and structure of nanofibers,and FT-IR is proved that the surfactants existed in the nanofibers,the TGA showed that the nanofibers prepared by adding surfactant can improve the char formation.