Free-radical solution copolymerization of itaconic acid (IA) and acrylonitrile (AN) was carried out in DMSO at 60℃ using azodiisobutyronitrile (AIBN) as initiator.The resulting polymerization solution was spun to form PAN precursors of carbon fibers

which were then characterized by elemental analysis

IR

13C-NMR

DSC and so on.The effect of the itaconic acid content in copolymers on the structure and properties of PAN precursors was investigated.The comonmer content in the copolymer was analyzed quantitatively by IR.The adequate feed ratio of AN/IA was found to be 98/2(W/W).Copolymers having about 2 mol% of comonomer appeared to have higher isotacticity as calculated from methine group signals in the 13C-NMR spectra.Furthermore

in the case of P(AN-co-IA)copolymers

the cyclization may start at a lower temperature and propagate at a slower rate.