Melt stabilization of PE with natural antioxidants: Comparison of rutin and quercetin

Abstract

The stabilization effect of a flavonoid type natural antioxidant, rutin, was compared to that of quercetin in polyethylene. Additive concentrations changed between 0 and 500 ppm in several steps and also 1000 ppm Sandostab PEPQ phosphorus secondary stabilizer was added to each compound. Stabilization efficiency was determined by changes in vinyl group content, melt flow rate, oxygen induction time, color and the consumption of the secondary antioxidant during multiple extrusions. The results showed that rutin is as efficient melt stabilizer as quercetin used as reference. On the other hand, rutin has a deteriorating effect on the stability of the polymer at small concentrations and partially decomposes during processing. The comparison of bond dissociation enthalpies indicated that the substitution of the hydroxyl group in the C ring of quercetin by saccharide moieties increases their value, but the small increase does not influence the efficiency of the stabilizer. FTIR and DSC measurements indicated the interaction of the natural antioxidant and the phosphonite secondary stabilizer, and the development of interactions was confirmed by molecular modeling. Mainly hydrogen bonds and aromatic,  electron interactions develop between the hydroxyl groups in ring A and the POC group of the phosphonite, as well as between the aromatic rings of PEPQ and the flavonoids, but they do not influence the stabilization efficiency of the antioxidants.

The Protective Effect of Polygonum cuspidatum (PCE) Aqueous Extract in a Dry Eye Model

“…The major active compounds in PCE are caftaric acid, polydatin, rutin, quercitrin, and resveratrol. The five active compounds are present in many natural plant extracts, and previous studies have demonstrated that they have anti-inflammatory and anti-oxidative properties [ 48 , 49 , 50 ]. Therefore, PCE may promote anti-oxidative activity in DED by recovering expression of anti-oxidant proteins such as HO-1, SOD-1, and GPx in hyperosmolar stressed HCECs.…”

Chitosan–Quercetin Bioconjugate as Multi‐Functional Component of Antioxidants and Dual‐Responsive Hydrogel Networks

“…Caffeine was loaded in the hydrogels by soaking procedure with a loading efficiency >85% for both hydrogels and a loading percent, DL(%), of 8.0 and 8.5 for HB and HQ, respectively. The slight difference in the DL values can be related to the ability of Q moieties to interact with drug molecules via aromatic interactions, resulting in higher affinity of caffeine toward HQ.…”

Puerarin, an efficient natural stabilizer for both polyethylene and polypropylene

“…A series of research results suggested that the effects of natural antioxidants in stabilizing of polyolefin come from the interaction of natural antioxidant and secondary antioxidant. [12,15,16,18] Thus, the interaction between puerarin and PEPQ was discussed in this section. For comparison, PE or PP modified with only PEPQ (PE-P 0 -P and PP-P 0 -P samlpes) and PE or PP modified with only puerarin (PE-P 1200 and PP-P 1200 samlpes) were prepared.…”

“…Quite a few of natural compounds derived from plants have been used as stabilizer for foods [3][4]5,6] and polymer. [7][8][9][10][11][12][13][14][15][16][17][18][19] Lignin that comes from cell walls of woods and grasses is a natural macromolecule polyphenol. PE mixed with a mass of lignin exhibited preferable thermooxidative stability and processing stability.…”

“…β-Carotene as the most important representatives of carotenoids [1] could improve the thermo-oxidative stability and processing stability of PE. [11] The application of quercetin, [12][13][14] rutin, [15] silymarin, [16] and curcumin [17,18] as thermo-oxidative and processing stabilizer for PE even at low concentrations has been proved by many investigators. Phytic acid mixed with PE and PP to improve their thermo-oxidative stability.…”