Structure And Properties Of Polyarylsulphonamide And Fibers

The structure and performances of polyarylsulphonamide and its fiber were studied in order to illustrate the relationship between technology,structure and properties.Firstly,a series of polyarylsulphonamide with various monomer ratios of 4,4'-diaminodiphenylsulfone(p-DDS)and 3,3'-diaminodiphenylsulfone(m-DDS)were synthesized to investigate the relationship between copolymer composition and the properties of polyarylsulphonamide.The copolymer composition was determined from Fourier Transform Infrared Spectroscopy(FTIR)and Nuclear Magnetic Resonance('H-NMR and 13C-NMR).It is found that the copolymer composition of the polyarylsulphonamide varied little with the monomer ratio and similar reactivity of the diaminodiphenylsulfone is shown from the results.From the analysis of the thermal properties of polyarylsulphonamide,high thermal stability of the copolymers was shown both in N2 and air and the decomposition temperature exhibited little dependence on the copolymer composition whiles the glass transition temperatures(Tg)decreased obviously with increasing m-DDS segments,which is helpful to improve the solubility and spinnability of polyarylsulphonamide.Whether polyarylsulphonamide homopolymer or copolymer,crystalline property was shown after high temperature annealing process for a long time.Furthermore,the evolution of the structure and morphology of polyarylsulphonamide fiber during the spinning process were studied with Scanning Electron Microscopy(SEM),synchrotron small angle X-ray scattering(SAXS)and wide angle X-ray diffraction(WAXD)technologies,Dynamic Mechanical Analysis(DMA)and Thermo-gravimetric Analysis(TG).It is shown that crystallinity and crystalline orientation of the polyarylsulphonamide fiber enhanced obviously during the fiber-forming process,especially during hot-stretching and heat-setting procedure,with the increase in crystal plane spacing and crystalline grain sizes,which is helpful for improving the mechanical property of the fibers.The glass transition temperature(Tg)was shown downtrend at first,but after hot-stretching process revealed a obvious increasing phenomenon,which is also due to the increase of the crystallinity and degree of orientation.Finally,the influences of different technological conditions on the structure and morphology of polyarylsulphonamide fiber were investigated by changing the heating temperature,the mode of wetting and drying and different drawing conditions.It was shown that the lamella structure was more consummate with increasing heating temperature,which means the crystallinity and crystalline orientation of the polyarylsulphonamide fiber enhanced,and the fiber microstructure becomes more uniform.The crystalline orientation of the fibers enhanced after vacuum drying,but decreased after wetting.The tensile property is dependent largely on the drawing conditions and the crystal and orientation structure developed with the drawing procedure,which suggests that the mechanical properties can be improved through effective drawing process.