Improvement in the degradation resistance of LDPE for radiochemical processing

Zaharescu, Traian; Pleșa, Ilona; Jipa, S.

doi:10.1016/j.radphyschem.2013.07.009

Cited by 6 publications

(2 citation statements)

References 29 publications

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“…After irradiation, Tcc values show a decrease with radiation dose for all studied biocomposites and high values with increased R concentration are still observed. The presence of rosemary extract in the PLA matrix inhibits the reaction of free radicals with oxygen during radiation processing, because of the improved resistance to degradation [ 58 , 59 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of Gamma Irradiation on the PLA-Based Blends and Biocomposites Containing Rosemary Ethanolic Extract and Chitosan

Vasile¹,

Pamfil²,

Zaharescu

et al. 2022

Polymers

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The irradiation of polymeric materials with ionizing radiation (γ-rays, X-rays, accelerated electrons, ion beams, etc.) may lead to disproportion, hydrogen abstraction, arrangements, degradation, and/or the formation of new bonds. The purpose of this paper is to evaluate the effect of gamma irradiation on some new poly(lactic acid) (PLA)-based blends and biocomposites, which is crucial when they are used for food packaging or medical purposes. The polymeric blends and biocomposites based on PLA and rosemary ethanolic extract (R) and poly(ethylene glycol) (PEG) (20 wt%) plasticized PLA, chitosan (CS) (3–6 wt%) and R (0.5 wt%) biocomposites were subjected to gamma irradiation treatment using three low γ-doses of 10, 20, and 30 kGy. The effect of irradiation was evaluated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), thermogravimetry (TG), chemiluminescence method (CL), migration studies, and antibacterial activity tests. It was found that in comparison with neat PLA, the gamma irradiation in the oxidative conditions of the PLA-based blends and biocomposites, causes modifications in the structure, morphology, and thermal properties of the materials depending on irradiation dose and the presence of natural additives such as rosemary and chitosan. It was established that under a gamma-irradiation treatment with dose of 10–20 kGy, the PLA materials showed minor changes in structure and properties being suitable for application in packaging and in addition after irradiation with such doses their antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium is improved.

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Section: Resultsmentioning

confidence: 99%

Effect of Gamma Irradiation on the PLA-Based Blends and Biocomposites Containing Rosemary Ethanolic Extract and Chitosan

Vasile¹,

Pamfil²,

Zaharescu

et al. 2022

Polymers

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“…The protection mechanisms are totally different. If the active components of rosemary extract, especially the majoritarian constituent of carnosic acid [ 55 ], act as the scavengers of free radicals by the substitution of phenolic-proton-like hindered phenols [ 56 ], hydroxyapatite delays oxidation by the adsorption and superficial blocking of the chain initiator in degradation development [ 2 ]. The evolution of oxidation described by the temporal parameters ( Figure 3 b) highlights the favorable contributions of the used fillers on the last stage of oxidation.…”

Section: Resultsmentioning

confidence: 99%

Structural Insights into LDPE/UHMWPE Blends Processed by γ-Irradiation

Zaharescu¹,

Nicula²,

Râpă

et al. 2023

Polymers

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Ultra-high-molecular-weight polyethylene (UHMWPE) matrices containing low-density polyethylene (LDPE), hydroxyapatite (HAp) as filler, and rosemary extract (RM) as stabilizer were investigated for their qualification for long-term applications. The significant contributions of the blend components were analyzed, and variations in mechanical properties, oxidation strength, thermal behavior, crystallinity, and wettability were discussed. SEM images of microstructural peculiarities completed the introspective survey. The stability improvement due to the presence of both additives was an increase in the total degradation period of 67% in comparison with an unmodified HDPE/UHMWPE blend when the materials were subjected to a 50 kGy γ-dose. There was growth in activation energies from 121 kJ mol−1 to 139 kJ mol−1 when HAp and rosemary extract delayed oxidation. The exposure of samples to the action of γ-rays was found to be a proper procedure for accomplishing accelerated oxidative degradation. The presence of rosemary extract and HAp powder significantly increased the thermal and oxidation resistances. The calculation of material lifetimes at various temperatures provided meaningful information on the wearability and integrity of the inspected composites.

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