Aromatic polyamides. XIII. effect of the halogen position on the thermal and flammability behavior of halogenated poly (1,3-phenylene-isophthalamide)

Various halogen substituted poly (1,3-phenylene-isophthalamide)s have been prepared. Their glass transition temperature T_g (DSC), thermal decomposition courses (TGA), and flame resistance (oxygen index) are discussed.

The polyamides substituted with halogen in the meta position to NH group showed higher T_g and better thermal stability than those substituted with the same halogen in the ortho position. All halogenated polyamides studied had fairly good flame resistance characteristics: high oxygen indices and high char yields. Halogenated aromatic polyamides with nitrogen ortho to halogen showed the flammability characteristic: limiting oxygen index = 38 + 61 × (weight loss at initial plateau temperature).