Chemiluminescence study on the oxidation of several polyolefins—I. Thermal-induced degradation of additive-free polyolefins

Chemiluminescence Processes in Polymeric Materials

“…This is consistent with the inherent susceptibility to oxidation of the material [42] and the low-density polyethylene must be oxidized at a similar rate when the antioxidants are consumed. In general, a good correlation between the other chemiluminescence parameters I CL-max2 , t max2 , t ½ , and OIT CL170 were found.…”

“…Setnescu et al interpreted the behavior as oxidation of very active sites (double bonds, branches, etc.) of PE and oxidative crystalline-phase conversion [34]. Zlatkevich suggested that overlaid sigmoids reflect two oxidation processes related to two kinds of peroxides with different stability assumed to exist in the oxidized polyolefins [35].…”

A Study on the Aging Degradation of Ethylene-Propylene-Diene Monomer (Epdm) Under Loca Condition

“…It is generally known that when polymeric materials are thermally degraded, particularly at a high temperature and high pressure, polymeric chains begin to respond weakly to oxygen and form free radicals with oxygen (C=O) later. If the reaction products become volatile, their molecular weight decreases and the remaining scission components recombine with carbon (C=C) and stabilize themselves again [23][24][25]. However, current FT-IR analysis found that the spectroscopic intensities of C=O groups generated inside the aged EPDM are not high enough to be detected, even though mechanical property changes and thermal decomposition were discernibly observed during the aging process both before and after the LOCA condition.…”

Comparative effects of cobalt carboxylates on the thermo‐oxidative degradation of LDPE films

“…The absorption band around 1714 cm À1 , which can be assigned to the C¼ ¼O stretching ketonic functionality, grows in intensity and exhibits band broadening, which indicates the presence of more than one oxidation product. Thermo-oxidation leads to the generation of several oxygen containing functionalities, such as aldehydes and/or esters (1733 cm À1 ), carboxylic acid groups (1700 cm À1 ), and g lactones (1780 cm À1 ), [19][20][21][22] which absorb in the same region, leading to the observed band broadening. All films containing cobalt carboxylate showed similar changes in the spectra and the change was more pronounced at higher concentrations of the additive or after longer exposure period.…”