Stabilization effect of polypyrrole in ϒ-irradiated low density polyethylene

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Traian Zaharescu ◽  
Silviu Jipa
Keyword(s):  
Antioxidant Activity ◽  
Pyrrole Ring ◽  
Protective Action ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Neat Polymer ◽  
Protection Mechanism ◽  
Stabilization Effect ◽  
Γ Rays ◽  
Oxidative Ageing

AbstractUnder the degradative action of γ-rays, low density polyethylene (LDPE) blended with 5% polypyrrole (PPy) was oxidized extra slow than the neat polymer. FTIR and UV-Viz spectroscopy’s were used for the assessment of the accumulation of oxygen-containing products. The transmittance recorded for LDPE at characteristic bands was higher than similar features obtained for LDPE/PPy samples. The protective action of PPy against oxidative ageing of polymer substrate is due to the movable proton belonging to pyrrole ring. A protection mechanism scheme is proposed for antioxidant activity of polypyrrole

Surface and Adhesive Properties of Low-Density Polyethylene after Radiation Cross-Linking

2014 ◽  
Vol 606 ◽  
pp. 265-268 ◽  
Author(s):  
Martin Bednarik ◽  
David Manas ◽  
Miroslav Manas ◽  
Martin Ovsik ◽  
Jan Navratil ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Performance ◽  
Chemical Properties ◽  
Low Density Polyethylene ◽  
Cross Linking ◽  
Low Density ◽  
X Rays ◽  
Radiation Processing ◽  
Adhesive Properties ◽  
Γ Rays

Radiation cross-linking gives inexpensive commodity plastics and technical plastics the mechanical, thermal, and chemical properties of high-performance plastic. This upgrading of the plastics enables them to be used in conditions which they would not be able to with stand otherwise. The irradiation cross-linking of thermoplastic materials via electron beam or cobalt 60 (gammy rays) is performed separately, after processing. Generally, ionizing radiation includes accelerated electrons, gamma rays and X-rays. Radiation processing with an electron beam offers several distinct advantages when compared with other radiation sources, particularly γ-rays and x-rays. The process is very fast, clean and can be controlled with much precision. There is no permanent radioactivity since the machine can be switched off. In contrast to γ-rays and x-rays, the electron beam can steered relatively easily, thus allowing irradiation of a variety of physical shapes. The energy-rich beta rays trigger chemical reactions in the plastics which results in networking of molecules (comparable to the vulcanization of rubbers which has been in industrial use for so long). The energy from the rays is absorbed by the material and cleavage of chemical bonds takes place. This releases free radicals which in next phase from desired molecular bonds. This article describes the effect of radiation cross-linking on the surface and adhesive properties of low-density polyethylene.

Oxidative Ageing and Structural Characterization of Naturally Weathered Low Density Polyethylene Films

2020 ◽  
Vol 62 (4) ◽  
pp. 416-426
Author(s):  
N. H. Benmiloud ◽  
S. F. Chabira ◽  
A. H. Bhat ◽  
Y. K. Dasan ◽  
M. Sebaa
Keyword(s):  
Structural Characterization ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Polyethylene Films ◽  
Oxidative Ageing

On the durability of low-density polyethylene nanocomposites

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Jitendra K. Pandey ◽  
Raj Pal Singh
Keyword(s):  
Ir Spectroscopy ◽  
Morphological Changes ◽  
Diffusion Path ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Neat Polymer ◽  
The Matrix ◽  
Ft Ir ◽  
The Stability ◽  
Artificial Uv

Abstract Low-density polyethylene (PE) containing nano-particulate clay was prepared after functionalization with maleic anhydride (MA) by reactive grafting in the presence of peroxide followed by blending of maleated PE with neat polymer in different concentrations. Four classes of composites were obtained: (i) exfoliated, (ii) intercalated, (iii) microcomposites, and (iv) intermediate of intercalated and microcomposites, as evidenced by wide-angle X-ray diffraction. All samples were kept for artificial UV irradiation (λ ≥ 290 nm) and for composting to study their photo- and bio-durability. Fourier-transform IR spectroscopy (FT-IR) and scanning electron microscopy were used to monitor the functional group and morphological changes, respectively, whereas biodurability was evaluated by measuring the weight loss. MA functionalization and nature of composites have detrimental effects on the overall durability of composites. Nanocomposites showed higher resistance than microcomposites during initial weathering and composting with a long induction period. The stability of nanocomposites decreases with time and overall durability was worse than of pristine polymer in both environments. It was concluded that the initial protection is due to the filler-generated long diffusion path, which decreases the oxygen diffusion through the matrix. The bio-durability of composites decreased with oxo-degradation. Biodegradation of PE nanocomposites during composting follows the mechanism described by Albertsson et al. as evidenced by FT-IR spectroscopy.

Impact of γ-rays on constructional, optical and thermal behavior of alkaline and non alkaline low density polyethylene

2020 ◽  
Vol 175 (7-8) ◽  
pp. 765-777
Author(s):  
M. Madani ◽  
A. S. El-Bayoumi ◽  
S. S. Aly ◽  
A. Abdeldaym ◽  
M. Hammam
Keyword(s):  
Thermal Behavior ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Γ Rays

scholarly journals Influence of Ethylene Plasma Treatment of Agave Fiber on the Cellular Morphology and Compressive Properties of Low-Density Polyethylene/Ethylene Vinyl Acetate Copolymer/Agave Fiber Composite Foams

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
F. Soriano-Corral ◽  
L. A. Calva-Nava ◽  
J. F. Hernández-Gámez ◽  
E. Hernández-Hernández ◽  
P. González-Morones ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plasma Treatment ◽  
Vinyl Acetate ◽  
Fiber Composite ◽  
Ethylene Vinyl Acetate ◽  
Cellular Morphology ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Neat Polymer ◽  
Composite Foams

Agave fibers (AF) were incorporated either pristine (AFp) or surface treated by ethylene plasma (AFm) in low-density polyethylene (LDPE)/ethylene vinyl acetate (EVA) blends at a ratio of 1 : 1 and foamed by chemical means. The role of the AF content (3, 6, 9, 12, and 15 wt.%) and its surface modification on the cellular morphology and mechanical properties of LDPE/EVA/AF foams under compression is investigated herein. Fourier transform-infrared spectroscopy, contact angle, and water suspension of AF suggest that plasma treatment using ethylene successfully modifies the surface nature of AF from hydrophilic to hydrophobic. AF and the surface treatment have an important role on the morphological properties of the foams. Composite foams reinforced with 12 wt.% AFm exhibited the highest mechanical properties improvements. At this fiber content, the composite foams enhanced 30% of the compressive modulus and 23% of the energy absorption under compression with respect to the neat polymer blend foam, as a result to the formation of more uniform cells with smaller size and the enhancement of compatibility and spatial distribution of the AFm in the polymer composite foams due to thin clusters of polyethylene-like polymer deposited on the AF surface.

scholarly journals Effect of Pleurotus tuberregium sclerotium on chemical, antimicrobial and sensory properties of packaged tomato paste

Agrosearch ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 69-80
Author(s):  
F.L. Kolawole ◽  
M.A. Balogun ◽  
O.R. Karim ◽  
A.O. Muhammad ◽  
H.O. Sanni-Olayiwola
Keyword(s):  
Antioxidant Activity ◽  
Storage Period ◽  
Progressive Increase ◽  
Sensory Properties ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Plastic Container ◽  
Tomato Paste ◽  
Fresh Vegetables ◽  
Pleurotus Tuberregium

Tomato (Solanum lycopersicum) is one of the most widely consumed fresh vegetables in the world. Due to its low shelf-life, it is processed into paste with added chemical preservatives. Pleurotus tuberregium (P.t.s) is a good source of bioactive compounds effective against microbial growth, in addition to its load of other nutrients. In this study, the physicochemical, microbial, antioxidant activity and sensory properties of packaged tomato paste supplemented with Pleurotus tuberregium sclerotium flour were investigated using standard methods. The tomato pastes and Pleurotus tuberregium sclerotium flour were mixed in ratios of 100:0, 95:5 and 90:10 after which they were stored in low-density polyethylene and plastic containers at ambient temperature. There was a haphazard decrease in the fungal count of the supplemented samples during storage. A progressive increase in antioxidant activity at different inhibition levels was observed, with the samples packaged in plastic having the highest value at 100mg/ml titration. The DPPH value range obtained for (Day 0), (Day 4) and (Day7) were 4.7 - 49.9%, 50.2 -53.8% and 50.0% - 52.2%, respectively. A slight decrease in vitamins and minerals composition of treated samples as compared to the control was evident after storage period. Moderate addition of 5 to 10% Pleurotus tuberregium sclerotium flour is effective in improving the physicochemical properties, vitamins and minerals content, antioxidant activity, sensory properties and microbial stability of the paste stored in plastic container. Keywords: Tomato paste, Pleurotus tuberregium sclerotium, low density polyethylene, plastic container, chemical composition

scholarly journals Impact of Different Packaging Systems on Selected Antioxidant Properties of Frozen-Stored Broccoli

2019 ◽  
Vol 26 (2) ◽  
pp. 383-396
Author(s):  
Joanna Kapusta-Duch ◽  
Teresa Leszczyńska ◽  
Barbara Borczak ◽  
Adam Florkiewicz ◽  
Anna Ambroszczyk
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Nutritive Value ◽  
Antioxidant Properties ◽  
Quality Parameters ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Total Polyphenols ◽  
High Antioxidant Activity ◽  
Β Carotene

Abstract Broccoli has a very good nutritive value, high antioxidant activity and pro-healthy potential. Freezing is one of best methods for vegetable storage and broccoli belongs to the group of vegetables subjected to this process on an industrial scale. This work investigates the effect of type of container: low density polyethylene (PE-LD) bags and oriented polystyrene (OPS) boxes on selected quality parameters in frozen broccoli. The experimental material was the broccoli cultivar LordF1. The vegetable was subjected to blanching, freezing and 3-month storage. At the every stage of an experiment the material was examined in terms of: vitamin C content; β-carotene; total polyphenols; and antioxidant potential, which was determined basing on the ability to quench the ABTS˙+ free radical. It has been found that vegetables which were kept frozen for 3 months in two types of container had parallel levels of vitamin C, β-carotene; total polyphenols; and similar antioxidative potential.

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