Poly oxidative thermal degradation

Yang, L., Heatley, F., Blease, T. G., Thompson, R. I. G. (1996). A study of the mechanism of the oxidative thermal degradation of poly(ethylene oxide) and poly(propylene oxide) using H-1-and C-13-NMR. European Polymer Journal, 32(5), 535-547. 

Gallet and co-workers [27,28] studied the oxidative thermal degradation of poloxamer 407, a poly(ethylene oxide-propylene oxide-ethylene oxide) trihlock copolymer, at 50 °C and 80 °C in air by solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). At 80 °C, it was found that degradation was initiated... 

The complexes [Cu(S2CNEt2]2] and [Cu S2P(OPr )2 2] have been shown to be extremely effective scavengers for peroxy radicals and can be used to inhibit the autoxidation of hydrocarbons.99 Poly(2,6-dimethyl-1,4-phenylene oxide) can be effectively stabilized against thermal degradation by the bistriazene complex (41).100 The stabilizing action is thought to involve quenching of thermally excited states and the decomposition of hydroperoxides by the complex. 

Milled rigid sheets of poly (vinyl chloride) on heating at 185°C. lose weight at a rate which increases with time. By polymer fractionation procedures, it was shown the rate of hydrogen chloride loss increases as the content of tetrahydro-furan-insoluble resin increases. The insoluble resin content accumulates at a rate which depends, in part, on the additive present. This insolubilization reaction is catalyzed by cadmium compounds. The increased dehydrochlorination rate of the insoluble crosslinked resins may result from the susceptibility of the crosslinked structures to oxidation and from the subsequent thermal degradation of the oxidation products. The effects of various common additives on the rates of insolubilization and weight loss are described. 

Virtually all previously published opinions on thermally degraded poly (vinyl chloride) regarded the dehydrochlorination process as being in the first instance, a monomolecular process resulting in conjugated polyene structures, and that all oxidation and cross-linking reactions... 

H. Sato, K. Kondo, S. Tsuge, H. Ohtani, and N. Sato, Mechanisms of thermal degradation of a polyester flame retarded with antimony oxide/brominated polycarbonate studied by temperature programmed analytical pyrolysis. Poly. Degr. Stab., 62, 41-48 (1998). 

HMPEOs are soluble in concentrated mineral acids and exhibit superior resistance to thermal degradation in solution 4). Because these copolymers are of low molecular weight, they are less shear-sensitive than high molecular weight commercial poly(ethylene oxide), which can lose 90-95% of its solution viscosity when subjected to high shears at room temperature for 5 min. By contrast, HMPEOs lose no more than 30% of their viscosity in water or acid solution. These unique properties of HMPEOs make them ideal candidates for applications in petroleum recovery via acid fracturing. 

Biswas and Roy [126] also studied the thermal stability characteristics (Table 16.7) of chemically prepared pyrrole (PY) modified poly-N-vinylcarbazole (NVC) composite P(PY-NVC) and reported the percentage weight losses for PPY, PNVC and P(PY-NVC) during thermal degradation. It was observed that the thermal stability of P(PY-NVC) was intermediate between those of individual components. 50% weight loss was recorded at 400°C in the case of PPY, at 450°C for PNVC and at 425°C for P(PY-NVC) respectively. They inferred that the thermo-oxidative breakdown of aromatic linkages of the polymer matrix occurs in the temperature range of 300-550°C in case of P(PY-NVC)... 

Billow and Miller [187] also reported fairly similar results for poly(phenylene)s prepared from mixtures of terphenyls. Poly(m-phenylene) [188], phenyl-substituted polyphenylene [189] and perfluoropolyphenylene [190] have thermal and oxidative stabilities similar to that of poly(p-phenylene). Polyphenylenes synthesized by Wurtz-Fittig and Ullmann reactions were reported to withstand heating up to 500°-550°C [187,191,192]. Electrically conductive azo derivatives of polyphenylene (cTo= l-40ohm cm ) were stable up to 300°C without any noticeable decomposition, whereas the conductive block co-polymer of poly-phenylene with p-diethynylbenezene could withstand heating for many hours at 400°-450°C [I], Poly(p-phenylene) as well as poly(tetrafluoroethylene) have been reported to withstand a similar temperature without any thermal degradation and may be used safely up to similar... 

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