A fundamental study on photo-oxidative degradation of linear low density polyethylene films at embrittlement

Hsu, Yu‐Chieh; Weir, Michael P.; Truss, R. W.; Garvey, Christopher J.; Nicholson, Timothy M.; Halley, P. J.

doi:10.1016/j.polymer.2012.03.044

Cited by 86 publications

(72 citation statements)

References 33 publications

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“…Fig. 5 Evolution of elongation at break (%) of LLDPE-P1-1 (upper layer) and LLDPE-P1-2 (lower layer) films mulching films during cultivation (exposure period 8-11 weeks) and of the two series 'LLDPE-P1 mulch' and 'LLDPE-P1-massive' after being buried in the soil for 7, 8 and 8.5 years a in parallel and b in transverse direction This increase of crystallinity according to Ojeda et al (2009), Kyrikou et al (2011 and Hsu et al (2012) is associated with changes in the crystalline sizes and molecular weight differences that are brought about by chain breaking and secondary recrystallisation during photodegradation. The increase of the crystallinity of LLDPE material containing pro-oxidants during its exposure to UV radiation has also been observed by Roy et al (2008) and Benítez et al (2013).…”

Section: Determination Of the Thermal Properties Through Dsc Measuremmentioning

confidence: 99%

Analysis of long-term degradation behaviour of polyethylene mulching films with pro-oxidants under real cultivation and soil burial conditions

Briassoulis

Babou

Hiskakis

et al. 2014

Environ Sci Pollut Res

133

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Apart from the conventional polyethylene and the bio-based or mainly bio-based biodegradable in soil mulching films, polyethylene mulching films of controlled degradation in soil are already used in agriculture. The use of special pro-oxidants as additives is expected to accelerate the abiotic oxidation and the subsequent chain scission of the polymer under specific UV radiation or thermal degradation conditions, according to the literature. The role of pro-oxidants in the possible biodegradation of polyethylene has been theoretically supported through the use of controlled laboratory conditions. However, results obtained in real soil conditions, but also several laboratory test results, are not supporting these claims and the issue remains disputed. Mulching films made of linear low-density polyethylene (LLDPE) with pro-oxidants, after being used for one cultivation period in an experimental field with watermelon cultivation, were buried in the soil under real field conditions. This work presents the analysis of the degradation of the mulching films during the cultivation period as compared to the corresponding changes after a long soil burial period of 8.5 years. The combined effects of critical factors on the photochemical degradation of the degradable mulching LLDPE films with pro-oxidants under the cultivation conditions and their subsequent further degradation behaviour in the soil are analysed by testing their mechanical properties and through spectroscopic and thermal analysis.

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Section: Determination Of the Thermal Properties Through Dsc Measuremmentioning

confidence: 99%

Analysis of long-term degradation behaviour of polyethylene mulching films with pro-oxidants under real cultivation and soil burial conditions

Briassoulis

Babou

Hiskakis

et al. 2014

Environ Sci Pollut Res

133

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“…During polyolefin photo-oxidation the rates of macromolecular scission and crosslinking changes with the absorbed UV dose [12]. Chain scission mechanism is driven by the free radicals resulting from the decomposition of hydroperoxide in the presence of UV and oxygen [13]. This mechanism takes place in the amorphous phase and in the amorphous-lamellar interface [14], where the diffusion of oxygen in those phases is easier [9].…”

Section: Ultraviolet Effects On Polymersmentioning

confidence: 99%

Effect of UV Ageing on the fatigue life of bulk polyethylene

et al. 2018

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Abstract. Polymers operating in various weathering conditions must be assessed for lifetime performance. Particularly, ultraviolet (UV) radiations alters the chemical structure and therefore affect the mechanical and fatigue properties. The UV irradiation alters the polymer chemical structure, which results into a degradation of the mechanical and fatigue behavior of the polymer. The polymer properties degradation due to UV irradiation is the result of a competitive process of chain scission versus post-crosslinking. Although few studied investigated the effect of UV irradiation on the mechanical behaviour of thermoplastics, fewer examined the UV irradiation effect on the fatigue life of polymers. This study focuses on investigating the effect of UV irradiation on the fatigue properties of bulk semi-crystalline polymer; the low density Polyethylene (LDPE). Tensile specimens were exposed to different dose values of UV irradiation then subjected to fatigue loading. The fatigue tests were achieved under constant stress amplitude at a frequency of 1Hz. The results show an important decrease of the fatigue limit with increasing absorbed UV irradiation dose.

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“…Changes in elongation-at-break and tensile stress at yield were monitored since both of these factors are indicative of structural changes in polyethylene due to photodegradation [34]. Reapplication of Paraquat to white-on-black film showed the most dramatic reduction in elongation compared to the virgin material ( Figure 10) and, to a much lesser extent, a reduction in elongation was also noted for Mancozeb-and…”

Section: Filmsmentioning

confidence: 99%

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

Yeh

Nikolić

Gomes

et al. 2015

Polymer Degradation and Stability

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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.

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A fundamental study on photo-oxidative degradation of linear low density polyethylene films at embrittlement

Cited by 86 publications

References 33 publications

Analysis of long-term degradation behaviour of polyethylene mulching films with pro-oxidants under real cultivation and soil burial conditions

Analysis of long-term degradation behaviour of polyethylene mulching films with pro-oxidants under real cultivation and soil burial conditions

Effect of UV Ageing on the fatigue life of bulk polyethylene

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

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