Relationship between chemical structure and performance of primary antioxidants in PBD

Földes, Enikő; Lohmeijer, Jan

doi:10.1016/s0141-3910(99)00049-x

Cited by 31 publications

(24 citation statements)

References 24 publications

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“…This phenomenon is typical for partially and unhindered phenols. These antioxidants are efficient stabilisers already at small concentrations even when used alone, but their efficiency is often limited by the interaction of their functional groups [50,51].…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…This decreases the solubility of the antioxidant in the polymer. As a consequence, the stabilization of efficiency decreases [24]. Földes [19,24] studied the compatibility of primary AO with PBD by "sorption techniques" and Flory-Huggins free volume theory.…”

Section: The Effect Of Antioxidant Structures On Their Performancementioning

confidence: 99%

“…As a consequence, the stabilization of efficiency decreases [24]. Földes [19,24] studied the compatibility of primary AO with PBD by "sorption techniques" and Flory-Huggins free volume theory. The result showed that Irganox1076 had higher activation energies of diffusion and solubility than Irganox245; the solubility of Irganox245 was only 1.3 w$w -1 % at 50°C, while 71.5 w$w -1 % for Irganox1076.…”

Section: The Effect Of Antioxidant Structures On Their Performancementioning

confidence: 99%

Performance and synergistic effect of phenolic and thio antioxidants in ABS graft copolymers

Guo

Wang

et al. 2010

Front. Chem. Sci. Eng.

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The synergistic effect of phenolic and thio antioxidants on the stabilization of acrylonitrile-butadienestyrene (ABS) graft copolymers has been studied. Three commercial antioxidants Irganox245, Irganox1076 and dilauryl thiodipropionate (DLTP) were selected. Formulations based on hindered phenols and secondary antioxidant DLTP were prepared. Stabilization was monitored in terms of changes in the functional groups (oxidation products), tensile properties and yellowness index. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were also used to assess the stability. The results indicated that the combination of Irganox245 and DLTP showed much better stabilization effect than the individual components due to the strong synergistic effect. Only weak synergism could be observed in the formulation that contained Irganox1076 and DLTP. Irganox1076 and Irgnox1076/DLTP exhibited similar behaviors between antioxidants with the highest and lowest efficiencies.

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“…The division is determined by the types of environmental factors against which the material should be protected [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. One of the most important groups of stabilizers are, undoubtedly, antioxidants.…”

Section: Introductionmentioning

confidence: 99%

Flavonoids as Natural Stabilizers and Color Indicators of Ageing for Polymeric Materials

Masek

2015

Polymers

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Few changes have occurred in the use of various stabilizers over recent years. In the current literature, phosphate derivatives are used as anti-ageing additives in polymers, and the most popular of these are sterically hindering cyclic amines. However, most of these compounds are carcinogenic. Synthetic phenols have been increasingly used as antioxidants in food and in polymers. Ecological standards encourage the elimination of harmful additives in polymeric products that come in contact with food or with the human body. This article presents application of flavonoid (silymarin/flavonoligand) for polymer stabilization and use of natural phytocompounds such as color indicators of polymers ageing time. In this research, I propose two ways of application: traditional, during processing; and the new one, by using impregnation method. Based on the change of deformation energy (ageing coefficient K), FTIR, oxidative induction time (OIT) evaluated by differential scanning calorimetry (OIT), thermogravimetry analysis (TG), spectrophotometric color measurements in terms of CIE-Lab color space values, I confirmed the high antioxidant activity of flavonoids in EPM. They provide coloration of the polymeric materials that changes cyclically as a function of aging time. Additionally, the use of phytocompounds in polymers provides similar stabilizing effect to those of synthetic antioxidants.

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Relationship between chemical structure and performance of primary antioxidants in PBD

Cited by 31 publications

References 24 publications

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

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

Performance and synergistic effect of phenolic and thio antioxidants in ABS graft copolymers

Flavonoids as Natural Stabilizers and Color Indicators of Ageing for Polymeric Materials

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