The effect of common agrichemicals on the environmental stability of polyethylene films

Abstract

The impact of commonly used agrichemicals (Paraquat, Mancozeb, Chlorpyrifos and Sulfur) on the environmental stability of polyethylene films has been evaluated under accelerated photo-oxidative conditions. Paraquat and Mancozeb when applied to unstabilized clear polyethylene film, followed by exposure to UV radiation, resulted in direct attack of the polymer, evident by faster rates of oxidation and shorter times to embrittlement compared to a polyethylene control. Reapplication of these chemicals during exposure, as often occurs in agricultural practice, resulted in even faster degradation. In contrast, Sulfur and Chlorpyrifos did not have a significant effect on the photodegradation of exposed unstabilized polyethylene film. When the polyethylene film was pigmented (white top layer containing rutile titanium dioxide and carbon black in the bottom layer) and stabilized with the addition of hindered amine stabilizers (HAS), differences in oxidation susceptibility were seen with repeated exposure to Paraquat showing the most dramatic effect. This was evident by an increased carbonyl index, decrease in elongation at break and an increase in tensile stress at yield compared to a control film and other agrichemical treatments. These studies enable degradation from accelerated consumption of stabilizers by the agrichemicals (and their degradation products) to be differentiated from enhanced photochemical initiation of the polyethylene degradation.

Preparation and properties of antibacterial sodium dehydroacetate/modified film

“…It is commonly used in the melt extrusion process, which produces one of the most popular packaging materials. LDPE has a low density and excellent mechanical properties, as well as excellent stress cracking and rigidity, as well as good heat resistance and chemical stability (Kumar et al, 2020;Yeh et al, 2015).…”

Fluorescence quantification of inorganic particle dispersity for anti-aging evaluation of polymer composites

“…The oxidation degrees of these films were calculated according to the equations for carbonyl index (C.I. ): 44 For LDH particles with poorer dispersity (0 min in acetone), the C.I. value after thermal treatment was measured as 0.3107 (Table S3, ESI†).…”

“…The oxidation degrees of these films were calculated according to the equations for carbonyl index (C.I. ): 44 C:I: ¼ absorbance at1716 cm À1 absorbance at 1460 cm À1 :…”

Understanding and predicting environmental effects on degradation of oxo-degradable polyethylene blown films

“…In a recent study, Yeh et al [2015] showed that PE film embrittlment time was retarded by 7 days when sprayed with sulphur containing agrochemical (29 days) compared to no treatment (22 days), under accelerated UV ageing. Our results are therefore in agreement with some of the literature findings, where sulphur compounds had a retarding effect on PE photo-degradation, as they can behave as antioxidants by decomposing hydroperoxide.…”

“…The service lifetime of polymer films is controlled by the chemical reactions leading to chain scission and mediating environmental factors. The rate of PE film degradation depends on several factors such as, but not limited to, the type and concentration of pro-degradant, UV exposure, temperature, rain, humidity conditions, geographical location [Kockott, 1989, Sampers, 2002, Kaczmarek et al, 2005, Basfar and Ali, 2006, Briassoulis, 2007, season [Gijsman and Sampers, 1998, Sampers, 2002, Briassoulis, 2007, pesticides and herbicides [Espi et al, 2007, Yeh et al, 2015, and other external environmental factors [Kockott, 1989, Sampers, 2002. All these factors may interact in synergy or antagonistically [Corti et al, 2010], which increases the difficulty in predicting polymer lifetime.…”