Thermal stability and degradation of aromatic polyamides. 1. Pyrolysis and hydrolysis pathways, kinetics and mechanisms of N-phenylbenzamide

Thermal Degradation of Meta- and Para-Aramid Fibers in Different Atmospheres

“…In air, the DTA curve of PMIA appears as a exothermal step around 427.0 8C, then a exothermal peak at 648.0 8C, and the DTA curve of PPTA exhibits three exothermal peaks at 548.4 8C, 584.5 8C and 703.7 8C. This behavior has partly been observed by Rodil et al (2001aRodil et al ( , 2001b for PMIA and by Broadbelt et al (1993Broadbelt et al ( , 1994 for PPTA. They proposed different chemical reactions in air and inert gases, but no reasonable explanation of difference between PMIA and PPTA was given.…”

Thermal degradation of poly(p-phenylenebenzobisoxazole) and poly(p-phenylenediamine terephthalamide) fibres

“…The kinetic functions of the two fibres are close; the fibres degrade according to an order law describing a thermal degradation which is controlled by the formation of a gas phase (insulation) inside the polymer and by nucleation and nucleus growth in a heterogeneous medium 11. This is in agreement with the work of Broadbelt et al 25 who showed that the pyrolysis of aromatic polyamides follows a free radical mechanism via several pathways. Moreover, the invariance of the kinetic functions means that oxygen does not play a role in the degradation mode of the fibres, but is an initiator of degradation.…”

“…Under nitrogen, the endothermic phenomenon may be assigned to cleavage reactions. The pyrolysis of PPT has been studied by Broadbelt et al 24, 25 They showed that the degradation of PPT occurs mainly via fission of the CN amide bond. In the case of PBO, the molecule is highly conjugated, which can explain its exceptional thermal stability for an organic material.…”

The thermal degradation behavior of meta- and para- hetero-amide fibers by TGA-FTIR

“…In Table 4 , the clear difference between the pyrolyzate yields from PBIA, PPTA and PMIA can be discerned, which indicates specific effects of the distinctive heterocyclic ring structure in the PBIA backbone. The obtained data of PMIA fiber and PPTA fiber are found to Brought to you by | Western University Authenticated Download Date | 6/7/15 10:57 AM be consistent with the mechanism previously proposed by Bhuiyan and Broadbent [23,24] .…”

“…The conversion of the nitrogen-containing compounds into NH 3 and HCN is usually fast and thus not rate-limiting. A simulation for a propane-air flame doped with methylamine has been used to model a system for fuel nitrogen conversion to NO x [23] . It is found that under oxygen-rich conditions, two-thirds of the fuel nitrogen is oxidized to NO x and the rest converted to N 2 .…”