Processing stabilisation of PE with a natural antioxidant, curcumin

Tátraaljai, Dóra; Kirschweng, Balázs; Kovács, János; Földes, Enikő; Pukánszky, Béla

doi:10.1016/j.eurpolymj.2013.02.018

Cited by 54 publications

(53 citation statements)

References 34 publications

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“…Both carbon and oxygen centered radicals are present in polyethylene during its processing. The scavenging of the first prevents the formation of long chain branches, and viscosity can even decrease during processing, like in the presence of curcumin, another natural antioxidant [11]. At least a few long chain branches always form if the stabilizer preferably reacts with oxygen centered radicals.…”

Section: Discussionmentioning

confidence: 99%

“…Using some of these materials as stabilizers was more or less successful, while some of the compounds proved to be inefficient or impractical. In a recent study, the antioxidant effect of another natural compound curcumin was investigated in detail [11]. The results revealed that the melt stabilizing efficiency of curcumin is superior to that of the synthetic antioxidant used as comparison and is further enhanced by the addition of a phosphorous containing secondary antioxidant.…”

Section: Introductionmentioning

confidence: 99%

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Efficient melt stabilization of polyethylene with quercetin, a flavonoid type natural antioxidant

Tátraaljai

Földes

Pukánszky

2014

Polymer Degradation and Stability

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The potential use of quercetin, a flavonoid type natural antioxidant, as a stabilizer in polyethylene was explored in this work. Its efficiency was compared to that of Irganox 1010, a hindered phenolic antioxidant used routinely in industrial practice, both in the presence and the absence of a phosphorous secondary stabilizer. The study was carried out with a Phillips type polyethylene and the efficiency of the additive packages was checked by various methods on samples produced by multiple extrusions. Quercetin content changed from 0 to 1000 ppm in 10 steps. The results showed that quercetin is a very efficient antioxidant. It prevents the formation of long chain branches already at a concentration as small as 50 ppm and its dosage at 250 ppm renders the polymer sufficient long term residual stability. The efficiency of quercetin is considerably better than that of Irganox 1010, the hindered phenolic antioxidant used as reference stabilizer. The difference in efficiency might be explained with the dissimilar number of active -OH groups on the two molecules, but the stabilization mechanism of quercetin may be also different from that of I1010. Quercetin interacts with the phosphonite secondary stabilizer used, which improves dispersion and increases efficiency. Besides its advantages, quercetin has also some drawbacks (very high melting temperature, poor solubility in polyethylene and strong yellow color), which must be overcome before the substance can be used in practice.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Efficient melt stabilization of polyethylene with quercetin, a flavonoid type natural antioxidant

Tátraaljai

Földes

Pukánszky

2014

Polymer Degradation and Stability

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“…According to some authors the OH groups on the two phenyl rings participate in the reactions [e.g., 29,33,34], others claim that the β-diketone moiety is responsible for the antioxidant action [35], while other publications [36][37][38] indicate that the strong antioxidant activity of curcumin originates mainly from the phenolic OH groups, but the central methylene group of the heptadione link plays also a role. However, the site of double bond in the β-diketone moiety participating in addition reactions depends also the chemical nature of the reaction partner [39].The effect of curcumin on the processing and high temperature oxidative stability of polyethylene (PE) was studied first in our laboratory [40]. The efficiency of 1000 ppm curcumin was compared to that of the same amount of the commercial phenolic antioxidant Irganox 1010 without and in combination with 2000 ppm phosphonite secondary antioxidant (Sandostab P-EPQ) during multiple extrusions.…”

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confidence: 99%

Efficiency of curcumin, a natural antioxidant, in the processing stabilization of PE: Concentration effects

Kirschweng

Tátraaljai

Földes

et al. 2015

Polymer Degradation and Stability

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The stabilising efficiency of curcumin was studied in polyethylene during processing and under oxygen at high temperature. The effect of the natural antioxidant was investigated at concentrations of 0 to 1000 ppm in combination with a phosphonite secondary antioxidant (Sandostab P-EPQ) of 1000 and 2000 ppm, respectively. The polymer was homogenized with the additives then processed by six consecutive extrusions taking samples after each processing step. The samples were characterized by FT-IR spectroscopy, melt flow index, colour, and OIT measurements. Compared to the effect of pure phosphorous antioxidant, the melt stability of PE is increased already at 5 ppm curcumin content. The melt as well as the high temperature oxidative stability (OIT) of the polymer are controlled by both types of antioxidants. Curcumin hinders the oxidation of polyethylene and the formation of long chain branches during processing, which can be attributed to the fact that curcumin is not only a hydrogen donor but its unsaturated linear moiety can also scavenge alkyl and oxygen centred macroradicals. Curcumin discolours polyethylene already at small concentrations but the colour fades with increasing number of extrusions.Keywords: curcumin, natural antioxidant, polyethylene, stabilisation, phosphonite 3 IntroductionStabilisation of polyolefins with natural antioxidants got into the focus of attention recently because of the unknown effects of the reaction products of synthetic phenolic antioxidants on human health [1]. Health safety has vital importance in many application areas, like food contacting objects (e.g., packaging materials, water pipes), medical applications, toys, etc. The small molecular mass additives used in polyolefins for stabilisation, colouring, or antiblocking are generally polar compounds, therefore their solubility is small and migrate onto the surface of the polymer during application [2]. Their dissolution into contacting substances cannot be avoided but any harmful effect must be prevented.Among the natural antioxidants, first α-tocopherol was studied extensively for the stabilisation of polyolefins [e.g., 3-9]. Intensive research resulted in the application of α-tocopherol for the stabilisation of ultra high molecular mass polyethylene (UHMWPE) used as total joint implant [e.g., 10-15]. Even an ASTM standard specification was implemented for medical grade UHMWPE blended with vitamin E [16]. The study of different natural antioxidants in polymers has been widely extended lately. The goals of the investigations are mainly the improvement of the safety of packaging materials and the development of functional packaging [e.g., 17-25].Curcumin, 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, is the principal curcuminoid of Curcuma longa rhizomes (turmeric). The powdered root is used as a spice, food colorant, and food preservative. The effects and reactions of curcumin have been the subject of investigation in the fields of biology, medicine, pharmacology, and in the food industry yielding a la...

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“…The solubility of the compounds in polyethylene was estimated from changes in the color of the polymer as a function of antioxidant content. In a series of recent studies, Phillips type polyethylene samples containing various amounts of the antioxidants listed in Table 3 and PEPQ secondary stabilizer were produced by multiple extrusions [114][115][116][117]. Their efficiency as processing stabilizer was determined and it was shown to depend on their chemical structure, dispersion and interaction with the secondary antioxidant.…”

Section: Application In Polymersmentioning

confidence: 99%