Comparative thermogravimetric studies of poly(ether-ketone/sulfone) imidesand their parent polymers. I. Poly(ether-ketone/sulfone) ethylimide

Thermogravimetry (TG) was employed to study the thermal degradation kinetic s of poly(etherketone/sulfone) ethylimide (PEK-IE and PES-IE). The correspo nding decomposition activation energies and reaction orders were obtained a nd the comparison was made with their parent polymers poly(ether-ketone/sul fone) with Cardo group (PEK-C and PES-C). The results show that the degrada tion activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all th e four polymers. For PEK-IE and PES-IE, the activation energies in the firs t decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage a re larger than that in the second stage, and the two stages can both be tak en as two fast degradation stages. The decomposition mechanism of the two s tages was also speculated.