Sulfonated syndiotactic polystyrene ionomers (SsPS) with 1.8 mol% degree of sulfonation have been studied.WAXD shows that the crystallinity of SsPS ionomers was decreased with increasing diameter size of the counter ions andsPS>SsPS-H>SsPS-K>SsPS-Zn. Moreover

SsPS ionomers only have a α cystal form

while original sPS has two crystalforms: α and β crystal form. TGA shows that the thermal stability of SsPS ionomers is higher than that of the original sPSand SsPS-Zn>SsPS-K>SsPS-H. DSC shows that all the glass transition temperatures(Tg) of SsPS ionomers are higher than that of the neat sPS and SsPS-Zn>SsPS-Na>SsPS-K>SsPS-H.However

the melting temperature (Tm) and crystallization peak temperature (Tp of SsPS ionomers are lower and SsPS-H>SsPS-Zn>SsPS-K>SsPS-Na

while the crystallinity(Xc) of SsPS-Zn is the lowest.Nonisothermal crystallization kinetics shows that the Avrami index of sPS and SsPS-H are both about 4

suggesting the mucleation growth of SsPS-H with lower degree of sulfonation still keeps its three-dimension form.FTIR spectra of SsPS ionomers show a splitting absorption band for asymmetric stretching vibration of sulfonation group.The CH in-plane bending vibration of benzene ring shifted to higher wavenumber and the symmetric streching vibration of sulfonation group changed slightly with different counter ion neutralized SsPS ionomers.