Abstract: To clarify the reason for the red solution of poly(aryl ether ketone), monomers in H₂SO₄, this paper had studied their chemical shifts and florine-ended dipolarity in solvents of CDCl₃, CDCl₃+DMSO-d₆ and H₂SO₄, results showed that, when the monomers in H₂SO₄, their carbonyl carbon relaxation time was shortened and their chemical shifts increased, While the chemical shift of the quarternary carbon attached to carbonyl group was reduced and relaxation time shortened. Based on the above, the polarization mechanism of H₂SO₄ on these monomers is presented for the first time,that is, the sulfo group made electrons in carbonyl group delocalized, which was further proved by ¹³C NMR under variation temperature.

Key words: Monomers of poly(aryl ether ketone)_s, ¹³C NMR, Polarization, Relaxation