Acquired biodegradability of polyethylenes containing pro-oxidant additives

Abstract

Biodegrability of high density polyethylene film (HDPE) and low density polyethylene film (LDPE) both containing a balance of antioxidants and pro-oxidants was studied with defined microbial strains particularly with Rhodococcus rhodochrous and Nocardia asteroides in mineral medium. After an abiotic pre-treatment consisting of photooxidation and thermo-oxidation corresponding to about 3 years of outdoor weathering the samples were inoculated, incubated up to 200 days and during the period their metabolic activities were followed by measuring adenosine triphosphate content. Simultaneously the cultures were also monitored by optical microscopy and FTIR spectroscopy. The first initial phase of fast growth caused by the presence of low molecular extractable compounds was followed by a long period of stabilized metabolic activity suggesting that microorganisms continued to gain energy from the substrate but evidently at a much slower rate. Complementary analysis performed at the end of incubation revealed that during the experiment time biodegradation processes probably affected surface layer of materials onl

Thermal Oxidation of Polyolefins by Mild Pro-Oxidant Additives Based on Iron Carboxylates and Lipophilic Amines: Degradability in the Absence of Light and Effect on the Adhesion to Paperboard

“…All spectra of the aged film exhibit the absorption band in the region 1700-1780 cm´1 which is assigned to carbonyl (C=O) groups, as determined by the overlapping bands corresponding to ester (1737 cm´1), ketone (1715 and 1717 cm´1). These bands are evidence for the formation of different oxidized products similar to those found in other studies involving the oxidation of PE [10,[13][14][15]. If comparing the intensity of C=O of the film after thermal ageing and that before ageing, it increases with increasing the ageing time.…”

“…CI is a measurement of the amount of carbonyl compounds formed during the thermal oxidation and is calculated as the ratio of the absorbance (A) of carbonyl peak in the region 1700-1780 cm´1 and the CH 2 scissoring peak at 1464 cm´1 [13][14][15]:…”

“…Many studies have reported that the oxidation of the PE films containing pro-oxidant additive prevalently produces carbonyl (C=O) on its surface [6,[13][14][15][16][17][18][19]. The presence of carbonyl group on PE film surface can lead to an increase in its surface polarity.…”

H<sub>2</sub>O<sub>2</sub> modulates the energetic metabolism of the cloud microbiome

“…This technique is based on an enzymatic reaction involving luciferin and luciferase. The protocol used was adapted from Biothema© commercial kit instructions (Koutny et al, 2006).…”

Mechanical and surface properties of low-density polyethylene film modified by photo-oxidation

“…24,25 This spectral analysis provided evidence for the photo-oxidation of the PE films, and the oxidation of the material was evidenced by the formation of carbonyl groups. 17,[26][27][28][29][30] UV-visible spectral analysis The changes in the UV-visible absorption spectra of pristine and prooxidant-added PE are shown in Figure 7. Each final absorption spectrum is that of the non-irradiated and irradiated PE, BPE10 and BPE20 films.…”