Structure And Properties Of Poly(Acrylonitrile)-Based Carbon Fiber Precursor Modified By Attapulgite Nanoparticles

Poly(acrylonitrile)-based carbon fiber(PAN-based CF) has drawn great attention in recent decades due to its excellent performances(i.e.high tenacity,high modulus,high heat resistance,anticorrosion) as well as the application in manufacturing of polymer/CF materials.Carbon fibers can be obtained through carbonization from organic fibers of rayon,PAN and pitch.Recently,with the rapid development of technology,PAN-based CF has gradually dominated the carbon fiber industry and been widely used in every walk of life.The common consensus among researchers home and aboard is that the performance of PAN-based CF is tightly related to the quality of its precursor.The high-quality PAN-based CF precursor must possess some properties like high tenacity,high compactness,uniform structure etc.Attapulgite(AT),whose theoretical half-unit-cell formula is [Mg₅Si₈O₂(OH)₂(OH₂)₄·4H₂O],is a typical of natural fibrous silicate mineral with high aspect ratio(length:500-1000nm diameter 10-50nm).Currently,AT nanoclay has been widely applied to prepare polymer/AT hybrids materials,reducing the cost of polymer materials and enhancing the mechanical properties of polymers.In this work,PAN/AT nanocomposites and fibers were prepared.The work in this paper is summarized as follows:1.The PAN/AT nanocomposites solution were prepared via mechanical stirring in dimethyl sulphoxide(DMSO),investigated by an HAAKE rheometer with plane-cone plate geometry.Low apparent viscosity and fast relaxation indicate that PAN/DMSO solution behave more liquid-like and closer to Newtonian liquid after the addition of certain amount of AT nanorods.2.PAN/AT nanocomposites with different AT loading have been successfully prepared and investigated by FTIR and DMA.It can be concluded that the well dispersed AT may confine the movement of chain segments due to the weak hydrogen bond interaction between AT surface hydroxyl groups and the matrix while overloading AT will aggregate and reduce the effect of percolation structure, therefore increasing the movement of segment.3.PAN/AT nanocomposite have been prepared by wet spinning and investigated by XRD,TGA and SEM,demonstrating that small amount of AT nanorod would enhance the tensile strength(approx.20%) and thermal property. High crystallization degree and smaller crystal size was characterized in XRD characterization.The microstructure of nascent fiber in coagulation bath was observed by SEM and found that the presence of AT may significantly affect the process of coagulation.